Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: SILVERGUN on April 10, 2013, 06:52:57 pm
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After seeing this breadboard on one of DL's posts, I am convinced that I must fulfill my destiny....I'm really excited about this project and want to get started right away
I built an amp 6 months ago and I am still tweaking it, moving the tone stack around, trying different MVs, getting ready to put an active effects loop in it,,,,and I've rewired the tube socets multiple times, moved the ground buss out onto the side of the chassis, added a tube, will add another.....................etc., etc.,etc. .......anyone else??
And this is just my FIRST experiment......
So before I waste anymore time trying to re-squeeze all of these add-ons into a chassis,,,I have decided to commit to the future and build a lite version of what you see here....
Please give me any suggestions you might have and post any pics you have of your own experimental stations
So far I'm thinking of a multi-tapped main xfmr,,,,universal P-P OT,,,,univ. single ended OT,,,separate little Radio Shack 12.6VAC filament xfmrs....
I would love to hear thoughts from you guys, and build something that could be inspirational to others
DL,,,thanks so much for posting this and inspiring me to think bigger :thumbsup:
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My suggestion is if you build a circuit with this and want to test it out by playing your guitar be sure to use a long enough cable that you can stand far enough away from it that if you break a string it can't reach and touch high voltage and shock you.
Also have a handy kill switch/ yank the cord out of the wall/ power strip with switch/ etc.
Something you can get to instantly to kill the power(from the above mentioned safe distance away)if something does go wrong.
Also, be sure to check/discharge caps before swapping parts. I know you know that but stay sharp. Make it a habbit, if that board catches you sleeping it'll give you a shock.
I wouldn't hold the guitar(touching the grounded strings) with your left hand and turn the pots with your right. One slip and...
Not trying to scare ya but I always think about WCS.
I got a couple of those strips for that purpose but never got around to actually doing it. Ideally I'd like to use something with a flip top lid. Flip open the lid, change parts, flip the lid closed, then play in total safety. I had an old house fuse box I was going to set up like that.
Once again you've inspired me. Think I'll build one too to test that pedal/tube amp hybrid.
Good luck & be safe
Jeff
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put a hinged lid on if you're a pussy :l2:
seriously. put a lid on it :angry:
all kidding aside, you could make a frame from 80/20 or ??....screw down a big sheet of FR4 to the frame, bolt all the screw terminals thru the FR4 to frame cross members, and make a lucite or plexi or perspex or someclearshitgluestogether to make a safety lid....
and sell them! All this crap is available from McMasterbator-Carr
http://www.mcmaster.com/#t-slotted-framing/=m9mvp4 (http://www.mcmaster.com/#t-slotted-framing/=m9mvp4)
good stuff
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put a hinged lid on if you're a pussy :l2:
Yeah!
F@*& saftey, right!
I'm gonna go cut the F@*&in' seatbelts outta my car right now!
Right after I rip the 3rd prong off all my amps cords. Who needs that $h#% anyway?!? Pussies, right!
They only put that 3rd prong to trick you into buying more copper than you need and to sell you those stupid 3 to 2 adapters!
Pussies! :bravo1:
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SG, I set up mine so that I can hookup the PT and OT that I'm actually going to use. My thought was there's enough difference in iron, even from the same maker that I wanted to "build" the amp, and then swap all components over. My board isn't really done yet, I have just been adding stuff on as I needed to. In fact, I need to clean up the power supply area before I start the next project. I won't post a pic, but trust me, it's nothing like DL's. :laugh:
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Think I'll build one too to test that pedal/tube amp hybrid.
That's what I'm talking about :thumbsup:
Separate paths for preamp, effects loop(s?), effects, power amp,,,,maybe even plug-able like an old telephone line switchboard
SG, I set up mine so that I can hookup the PT and OT that I'm actually going to use.
Nice John,,,good idea.....even as an option :think1:......so have some universals mounted and then be able to plug in the real stuff when you're ready.....nice touch
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:rolleyes:
I feel like a four year old who just found the erector set he's gonna be getting for Christmas....
and sell them! All this crap is available from McMasterbator-Carr
http://www.mcmaster.com/#t-slotted-framing/=m9mvp4 (http://www.mcmaster.com/#t-slotted-framing/=m9mvp4)
good stuff
Thanks K,,,,yeah, I imagine if we can make it simple enough guys will want to buy/build them
I'll try to keep a BOM, and make some kind of "build notes",,,but it's all pretty obvious
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:rolleyes:
I feel like a four year old who just found the erector set he's gonna be getting for Christmas....
and sell them! All this crap is available from McMasterbator-Carr
http://www.mcmaster.com/#t-slotted-framing/=m9mvp4 (http://www.mcmaster.com/#t-slotted-framing/=m9mvp4)
good stuff
Thanks K,,,,yeah, I imagine if we can make it simple enough guys will want to buy/build them
I'll try to keep a BOM, and make some kind of "build notes",,,but it's all pretty obvious
I'm w/ you on DL's breadboard. I remember when they were creating it (prob couple yrs ago...search old posts here)....and I started a Solidworks model on how I would have done it.....using separate HT PT w/ regulated variable HT (VVR?), variable screen supply, and 6.3V heater trannie. I've done designs w/ Al extrusion for laser systems, and this stuff is exactly that....big boy pants erector set.
I like the idea of a hinged lid, tho...even if it's wood.
I'm all into this slackerspace/maker movement lately, so I've been looking for a slacker project like this......
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Found these old threads:
http://www.el34world.com/Forum/index.php?topic=11131.0 (http://www.el34world.com/Forum/index.php?topic=11131.0)
http://www.el34world.com/Forum/index.php?topic=9036.0 (http://www.el34world.com/Forum/index.php?topic=9036.0)
Love the LCD meters on this one:
http://jazzbo8.wordpress.com/2012/03/27/tube-amp-breadboard/ (http://jazzbo8.wordpress.com/2012/03/27/tube-amp-breadboard/)
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Glad you like my LCD meter display - it has 4 voltmeters and 2 ampmeters - all housed in a cardboard box - how's that for hi-tech :icon_biggrin:
The novel to octal adapters are not ideal, sometimes the leads (made out of 20 gauge solid copper wire) would dislodge themselves. So I am going to try PCB sockets with long leads to see if they work better. The breadboard is very useful, but it does take up a lot space, so I made mine with handles, and the whole thing could be moved out of the way when you need the extra space. Looking forward to see what you come up with...
Jaz
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PT w/ regulated variable HT (VVR?), variable screen supply, and 6.3V heater trannie.
yes and no; power amps have too much variance in PT requirements and filter size and arrangement also, rectifier type and loading + you you're stuck with fixed rectification & if it's switchable, then it's still probably not what you'd put in the final plan - breadboard as close as to possible what you're planning to build.
load up the PT you'd like to use & that you think will work, then use the variac to dial in B+. if things aren't matching what you expected on paper, then swap PT for the "right one". like most others here, i use sim tools to design the PS and have hit the mark more often than not with them.
having an auxiliary 5V & 6.3V PT for just filaments is a good idea, that way filament V is constant even though you may not be running at mains voltage on the PT primary. the sum of it all, again, prototype the PS your going to use for at least the power amp. save whistles and bells super_duper_ultra_regulated_um_t_clutch PSU for preamp/low power amp or learning experiments. for VVR, i'd suggest a PCB setup like we did in zilla2. BTW, we call our breadboards ProtoZilla.(TM) ;)
just my 2cents...
--pete
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I like a mix of this
(http://www.tubelab.com/images/TL3/6AV5_amp.jpg)
(http://www.sotxampco.com/Images/Zilla-BzDz.jpg)
K
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Always thought this one looked really cool:
http://ampgarage.com/forum/viewtopic.php?t=17780 (http://ampgarage.com/forum/viewtopic.php?t=17780)
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Always thought this one looked really cool:
http://ampgarage.com/forum/viewtopic.php?t=17780 (http://ampgarage.com/forum/viewtopic.php?t=17780)
That's kinda what I had in mind.
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http://ampgarage.com/forum/viewtopic.php?t=17780
Nice but a bit too sophisticated to me
K
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put a hinged lid on if you're a pussy :l2:
Burn...nice one :laugh:
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Working on a layout,,gathering parts
Still open to suggestions.....
I've got an pp OT laying around that will get me started,,,and then I'm considering using Merlin's Universal OT permanently on the board
http://www.valvewizard.co.uk/OT.html (http://www.valvewizard.co.uk/OT.html)
Then maybe a small single ended Hammond?:
http://www.hammondmfg.com/125SE.htm (http://www.hammondmfg.com/125SE.htm)
Not sure about the PT right now, cause i'll probably just run separate heater xfmr(s)
Any suggestions would be appreciated :icon_biggrin:
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If you build, say a 15w tweed deluxe and use a 100w OT it's gonna sound different than using a 15w Fender type, which is probable overrated (really less than a 15w OT) anyway. Bass will be stronger/cleaner for one.
Same thing with an overrated PT HT B+ wind. Use a PT with 500mA B+ for an amp that only draws 150mA it's going to sound different (sag/compression and bass responce) than with a PT with only 150mA B+ wind.
And if both are overrated even more difference.
So you build a circuit on the breadboard with the overrated PT/OT and spend time tweaking it till it's just right to your liking. Than you decide to build it as a finished amp but now you use a different PT/OT because you don't need those overrated/over sized/over priced PT/OT for the amps circuit and....... :think1: What happened? It's not the same amp, sounds way different. :BangHead:
To me one of the nicest things about DL and RichardD's breadboard is the ease of swapping different PT's and OT's in and out of the test build.
Brad :icon_biggrin:
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A couple of amps that come to mind are the DeArmond R15T/Martin 112T which is, as far as the circuit is concerned almost dead on a 5E3 tweed deluxe, except for the OT. DeArmond/Martin OT is way bigger. Their a rare amp but guys who have heard/played through them rave about them over a 5E3.
BF Princeton/reverb is another. Some guys love the OT in that amp and don't like swapping in a BF Deluxe OT which is a bigger OT. That's why they play through the BF Princeton instead of the BF Deluxe.
A 3rd would be an Alamo amp that is said to be the amp that Billy G used for most of the Tres Hombres album. It's supposed to be a 5E3 with a weak PT/power supply and small underrated OT. Lots of sag.
Brad :icon_biggrin:
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put a hinged lid on if you're a pussy :l2:
:l2: My two favorites:
http://youtu.be/XZHgfYxqCSY (http://youtu.be/XZHgfYxqCSY)
and from the self proclaimed expert (at least he finds humor in it):
http://youtu.be/1lozkT1zrIU (http://youtu.be/1lozkT1zrIU)
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http://ampgarage.com/forum/viewtopic.php?t=17780
Nice but a bit too sophisticated to me
K
no pics?
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To me one of the nicest things about DL and RichardD's breadboard is the ease of swapping different PT's and OT's in and out of the test build.
Point taken...thanks for taking the time.....
You're so right.......being new to this means I've never seen the effects of sag,,,cause the first PT I bought was huge
And I have a feeling the next one will be too :icon_biggrin:
I've never understood the idea of putting a PT in anything that is right on the edge of the current requirements :dontknow:
But, the one thing I've been looking to experimenting with is OT's,,,,so I will be making accomodations for swap-ability.....thanks for all of those examples, of mis-matching in both directions
Got some parts ordered today and I'm ALL IN :thumbsup:.....like the 600V rating on this one
http://www.newark.com/macromatic-controls/70169-d/din-rail-relay-socket/dp/04M6767?in_merch=Popular (http://www.newark.com/macromatic-controls/70169-d/din-rail-relay-socket/dp/04M6767?in_merch=Popular) Relay Accessories
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@ Pete This attached is the picture of the previous link
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@ SILVERGUN
About the PT I think it will be nice to have one (big) in a separated metal box as a laboratory PS
as to be used for general purpose of the breadboard
for specific project to be defined, a free space in the breadboard as to put there the specific PT of the current project
Franco
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About the PT I think it will be nice to have one in a separated metal box as a laboratory PS
as to be used for general purpose of the breadboard
for specific project to be defined, a free space in the breadboard as to put there the specific PT of the current project
Exactly K.....I agree
I'm thinking about a big main PT that I can dial down with a variac, with a nice LCD display (any suggestions?)
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Using a Variac on the primary of a big transformer or better 2 transformers with 120v primary / 240v secondary (reuse for spare isolation transformers ?)
having the primary in parallel and having a switch as to parallel or put in series the secondary (with a CT intake)
will give you the ability to have a very large voltage excursion
a little transformer with 60v secondary with a big rehostat for Bias supply
and
a completely separated couple of filament transformers as to have 6.3v + 6.3v that you can arrange as a 12.6v CT transformer
about the voltage reading there are many disposable little instruments similar to this
http://www.tychoice.com/product/15178454323/DL85-2041+bi-color+dual+display+LED+AC+voltage+meter+ammeter+digital+voltage+meter (http://www.tychoice.com/product/15178454323/DL85-2041+bi-color+dual+display+LED+AC+voltage+meter+ammeter+digital+voltage+meter)
those on the link (that I've) isn't the best solution as it starts from 80v and is AC, but you can find also unit for DC
a bunch of fuses on the primary and secondary (not in the bias circuit) of course is a must
if you can find it, with a comfortable value, also a resettable fuse salvaged from an old apparatus may be useful
K
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Perhaps it has already been suggested, but I recommend that you get an old lab power supply instead of using a variac on an over-sized transformer, it might be even cheaper than the variac-transformer combo if you can find a deal somewhere. The old lab supplies usually have 0-500V (regulated), a negative bias supply and a filament supply housed in a sturdy case, many have volt and amp meters built in, so that will save you the trouble of wiring everything up, and it should be safer to operate as well.
Jaz
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The most part of the (used) laboratory PS for tubes I've seen till now were expensive and with low current abilities
but you never know, a chance to find one right for the use could happen
K
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A regulated B+ PSU up to it's current handling abilities will have no or very little sag.
being new to this means I've never seen the effects of sag,,,cause the first PT I bought was huge
And I have a feeling the next one will be too :icon_biggrin:
I've never understood the idea of putting a PT in anything that is right on the edge of the current requirements :dontknow:
The old amps were never built to be turned up past 4 or 5. So they could under size the PT and OT with out problems. So they cost less, were smaller, easer to fit on the chassis, radiated less of a magnetic field, so a little less noise/coupling, weighed less for the player to carry around and cost less for the company to ship to music stores. It worked all the way around for everyone involved.
But when guys started to turn up their amps past 5 and the amp started to sing they liked it. When the amp calls for more current than the PSU can give the B+ voltage drops until the note or chord starts to die off. Then it goes back up to where it normally is. This has the sonic effect of an automatic volume control or built in compression. Lower the B+ volume goes down, raise the B+ and volume goes up. I've read that if your a fast player you can actually out run an amp that has enough sag. I don't play anything faster than a singer would sing most times so I haven't experience this.
Some like under sized and some like over sized PT/OT, it's up to you to decide what you like or need to get your tone. But the point remains that they will change the sound and feel of an amp.
Brad :icon_biggrin:
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Different strokes for different folks... I view the breadboard as a platform for testing out ideas but do not use it to finalize the design, since as you said different transformers will have effect on the tone, that's why I eliminate sag from the equation during the breadboard phase - if it does not sound right without sag, I am not sure it will improve all that much with sag... In any case you will need to tweak the PS once you finalize the design anyway... But you may prefer to do things differently.
As for being expensive and low current, I am not sure what current you are require but most of the old lab supplies designed for vacuum tube circuits are fairly robust and should be able to handle most amp designs (perhaps not the really high power big bass amps), and the cost I think is relatively reasonable if you factor in your time, cost of material, etc. For example, there are quite a few Heathkit available >> http://www.ebay.com/sch/i.html?_trksid=p2050601.m570.l2632.R2.TR3.TRC2&_nkw=heathkit+power+supply&_sacat=92074&_from=R40 (http://www.ebay.com/sch/i.html?_trksid=p2050601.m570.l2632.R2.TR3.TRC2&_nkw=heathkit+power+supply&_sacat=92074&_from=R40)
There are other brands as well, KEPCO, EICO, VoltLab, etc. and of course HP, Fluke, Lambda, GenRad (these are more expensive)...
Jaz
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Different strokes for different folks... I view the breadboard as a platform for testing out ideas but do not use it to finalize the design, since as you said different transformers will have effect on the tone, that's why I eliminate sag from the equation during the breadboard phase - if it does not sound right without sag, I am not sure it will improve all that much with sag... In any case you will need to tweak the PS once you finalize the design anyway... But you may prefer to do things differently.
Jazbo8 I say this with respect and not to be argumentative but after all the trouble and expense of building a breadboard why not finalize as much as possible of the amp with it?
Yes you can use it to test out ideas and get them up and running but you can also do more than that with it.
We build tube guitar amps to color the sound and the PT and PSU along with the OT are a large part of this. So how can you take that out of the equation?
If you tweak the amps circuit with a rock solid PSU and large OT it will handle the bass/mid/treble and distortion way differently than with a lesser sized (current rated / uF value / less H choke, if it has 1) PSU and smaller sized OT.
They are part of the circuit.
Brad :icon_biggrin:
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http://www.ebay.com/itm/9-pin-breadboard-prototype-tube-socket-for-DIY-experimenting-/161002768017?pt=Vintage_Electronics_R2&hash=item257c834691 (http://www.ebay.com/itm/9-pin-breadboard-prototype-tube-socket-for-DIY-experimenting-/161002768017?pt=Vintage_Electronics_R2&hash=item257c834691)
http://www.ebay.com/itm/DIN-Rail-Mounting-PCB-Support-for-35mm-32mm-or-15mm-DIN-rail-/300876375259?pt=LH_DefaultDomain_0&hash=item460da124db (http://www.ebay.com/itm/DIN-Rail-Mounting-PCB-Support-for-35mm-32mm-or-15mm-DIN-rail-/300876375259?pt=LH_DefaultDomain_0&hash=item460da124db)
http://www.ebay.com/itm/NEW-DIN-RAIL-12-LONG-STEEL-CHROMATED-PHOENIX-CONTACT-0801733-NS35-7-5-/221130534662?pt=LH_DefaultDomain_0&hash=item337c682f06 (http://www.ebay.com/itm/NEW-DIN-RAIL-12-LONG-STEEL-CHROMATED-PHOENIX-CONTACT-0801733-NS35-7-5-/221130534662?pt=LH_DefaultDomain_0&hash=item337c682f06)
some suggestions...
--pete
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Thanks again EVERYONE!
Lots of good reading and great links there DL....
I am listening :icon_biggrin:
How important do you think it is to have the preamp tube sokets moveable and/or DIN mounted?
I'm considering putting a row of them on some board material (like Doug sells) with terminal strips attached right to the board :dontknow:
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Thanks again EVERYONE!
Lots of good reading and great links there DL....
I am listening :icon_biggrin:
How important do you think it is to have the preamp tube sokets moveable and/or DIN mounted?
I'm considering putting a row of them on some board material (like Doug sells) with terminal strips attached right to the board :dontknow:
whatever will work for your application and is the easiest for you to fabricate. no DIN rail to worry about would definately make things simpler to assemble.
--pete
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Got some parts ordered today and I'm ALL IN :thumbsup:.....like the 600V rating on this one
http://www.newark.com/macromatic-controls/70169-d/din-rail-relay-socket/dp/04M6767?in_merch=Popular (http://www.newark.com/macromatic-controls/70169-d/din-rail-relay-socket/dp/04M6767?in_merch=Popular) Relay Accessories
SG, do you have a link to the 9 pin version of this socket? I'm not planning the breadboard thing but these will be perfect for my next solid state to tube conversion:
ETA: Hold the phone. I may use these: http://torresengineering.stores.yahoo.net/sumo9pintuso.html (http://torresengineering.stores.yahoo.net/sumo9pintuso.html)
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:director: :blob8:
This is a very serious topic!
Jeff's satire on safety reminded me of a safety hazard for those of you who are new to old oscilloscopes, two channel, crt type.
THE GROUND CLIPS ARE CONNECTED INTERNALLY TO EACH OTHER AND TO THE CHASSIS OF THE SCOPE AND TO THE GROUND PIN ON THE POWER PLUG!
Think about it! If your ground clip is attached to ground on your circuit, no problem. If you clip it to a 300vdc wire on a circuit, with power on, you will see a bright light as your ground clip is vaporized in your hand, OR if you are lucky, a fast blow fuse will open. If you use an adaptor to isolate the ground pin, your scope chassis will float to whatever voltage the ground clip is attached to. Clip onto a 300v wire and your scope chassis is also 300v to ground. You can measure it with a volt meter if you have to prove it to yourself. Also if you use both probes, they both MUST be attached to the same point, electrically, because if you are floating your scope, to measure the difference across a hot resistor, compared to a grounded component, you will be shorting the two points the ground clips are attached to. I use a techtronics digital scope with isolated probes to 1kv so I don't have to worry abput ground clip shorting. But occasionally, when I have to use an old scope, I have to think and double check my connections before turning on the circuit power, and I've been using one since 1977. I've been shocked by the scope chassis at 277vac and 500vdc to ground. It's not funny!
Please be careful and aware of the dangers of oscilloscopes and NEVER attach a ground clip on a live circuit! Have Safe Fun!
Sincerely,
rob_h
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SG, do you have a link to the 9 pin version of this socket? I'm not planning the breadboard thing but these will be perfect for my next solid state to tube conversion:
Haven't seen these in 9-pin, but I have seen guys make adapters using an 8-pin base
Anyone else see a good 9-pin socket to use?
Check this link from DL:
http://www.ebay.com/itm/9-pin-breadboard-prototype-tube-socket-for-DIY-experimenting-/161002768017?pt=Vintage_Electronics_R2&hash=item257c834691 (http://www.ebay.com/itm/9-pin-breadboard-prototype-tube-socket-for-DIY-experimenting-/161002768017?pt=Vintage_Electronics_R2&hash=item257c834691)
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For 9 pin tubes or you draw with eagle a PCB, or buy those that millet sell
or you go DIY as here
http://www.tubelab.com/images/TL3/6AV5_amp.jpg (http://www.tubelab.com/images/TL3/6AV5_amp.jpg)
Franco
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Different strokes for different folks... I view the breadboard as a platform for testing out ideas but do not use it to finalize the design, since as you said different transformers will have effect on the tone, that's why I eliminate sag from the equation during the breadboard phase - if it does not sound right without sag, I am not sure it will improve all that much with sag... In any case you will need to tweak the PS once you finalize the design anyway... But you may prefer to do things differently.
Jazbo8 I say this with respect and not to be argumentative but after all the trouble and expense of building a breadboard why not finalize as much as possible of the amp with it?
Yes you can use it to test out ideas and get them up and running but you can also do more than that with it.
We build tube guitar amps to color the sound and the PT and PSU along with the OT are a large part of this. So how can you take that out of the equation?
If you tweak the amps circuit with a rock solid PSU and large OT it will handle the bass/mid/treble and distortion way differently than with a lesser sized (current rated / uF value / less H choke, if it has 1) PSU and smaller sized OT.
They are part of the circuit.
Brad :icon_biggrin:
No worries, it's good to have different take on things. I think if I already know which PT, OPT and the speaker that I want to use before hand, e.g., building from a proven design, then I agree - put them all on the breadboard, make some minor tweaks for personal taste then you are pretty much ready to build. But in the case where I am testing out new ideas, or iffy designs, i.e., without firm specifications for the PT and the OPT, then I would rely on the lab supplies and generic OPTs for experimentation. Since the PT and OPT are usually the most costly items in the amp, I try to hold off on ordering them until I am pretty sure that the design does not "suck" on the bench with the hope the sound would improve even more with the proper PS and OPT installed... Well at least that's the plan, I still botch it up sometimes :BangHead: :laugh:
Jaz
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I have a couple of these type boards - seem to me to be very high quality. There are several different layouts.
http://www.ebay.com/itm/VERO-BLANK-PROTOTYPING-PCB-B-BOARD-FOR-TUBE-AMPLIFIER-/380250965640?pt=US_Amplifier_Parts_Components&hash=item5888b94688 (http://www.ebay.com/itm/VERO-BLANK-PROTOTYPING-PCB-B-BOARD-FOR-TUBE-AMPLIFIER-/380250965640?pt=US_Amplifier_Parts_Components&hash=item5888b94688)
Please note there are no traces on the boards - just many plated through holes. The socket holes are designed for (cheap) PCB sockets and the holes are plenty big enough to stuff a 18 ga wire along with the socket lead. I was thinking to "cut" out each socket with a fiber saw and then attach edge screw type connectors to get multiple socket assemblies per board (sorry Pete). Most of the layouts feature two or three different socket type (i,e 7-pin, noval and octal) on top of each other so they are very flexible!!
One question I have for the group -- whadda ya think of running the signal connectors "above" board and the heaters below into some kinda bus. Might keep things quieter. DL -- in your experience would it be worth the fuss?
I special ordered some plastic poly peg board (ala tubelab). It is indestructible (even for me). It is around - check the web. However those big metal lag bolts tubelab was using to secure the "modules" kinda scared me given shaky hands so I bought some nylon bolts instead.
I was also able to find a restored Heathkit bench supply specifically for tube designs with a 0-400V HT plus 6.3V and 5V awhile back on the BAY. I will try to remember to pull the number off it this weekend. I am in the process of moving so *where ever* I am, the thing I want is *at the udder place* :l2:. However - my new digs have a great grandpa cave so I will be trying bring up my (backward) version of the skunkworks directly. More than worth all the hassle I reckon.
This thread is perfectly timed SILVERGUN!! Youda man dude!!!
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One question I have for the group -- whadda ya think of running the signal connectors "above" board and the heaters below into some kinda bus. Might keep things quieter.
Thanks moon,
Yeah, that's very similar to what i've settled on....I'm gonna roll my own and just put 4 preamp tube sockets on one board (regular board making material), with a filament in (on the left side) and out (on the right), and just string 'em across the bottom of the board with a 2 position screw terminal strip on each side of the board for connection flexibility......I'll have screw terminal strips along the front and back edge of that same board, and just run wires from pins 1,2,3 + 6,7,8 up through holes in the board to the barrier strips......
I'm also planning to make a dedicated reverb interface board, and a dedicated D'lator board, plus PI board with PPIMV option
I will also be using those octal relay sockets on a short DIN rail because I like the flexibility there..........and they look cool :wink:
FUN :happy1:
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Here's a couple progress pics in case anyone's curious...
I built a preamp board as a "modular" board that will be able to be moved around
Still really excited about the future with this thing on my bench :icon_biggrin:
The 24 terminal barrier strip will provide a tie off point for pins 1,2,3 + 6,7,8 of each preamp tube (6 pins X 4 tubes = 24 = perfect)
The two 8-pin strips will provide B+ tie ins,,,etc.
I liked the Millet designed boards, but couldn't bring myself to spend $18 per piece......now that I have built this,,,I like it better :thumbsup:
So far, about $30 for this board,,,but I already had most of the stuff here
I'm thinking if anyone wanted to build one of these we could come up with a template for Hoffman's CNC board cutter...
I had to make some compromises to make this board work....(8-pin strips aren't centered....and 24-pin strip is flush with one edge, but one hole off the other edge :sad:)....but this thing isn't about looks :wink:
Used some 3/4" standoffs, and will be using wood for the main board surface......I'm really trying to not over-engineer this....I need it built so I can get back to the buisness of chasing sound....this will make that a lot easier!
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Great idea SG but why 12v heaters am I missing something? And why aren't those things soldered and wired up yet??? :wink:
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Here's a couple progress pics in case anyone's curious...
Oh, we are ! We are waiting you showing your next step :icon_biggrin:
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Nice realization :thumbsup:
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Just don't forget that exist also some interesting 7 pin tubes :angel
K
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That 8 pin board is nice but a bread-board requires screw connections, and 25$ may be is too much
K
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Great idea SG but why 12v heaters am I missing something?
Thanks jojo,,,, I've got some of these Radio Shack 12.6V CT 3A xfmrs and I just figured it would be OK to use them for this...also seemed a little simpler/cleaner to wire on the bottom of the boards
And I figured I could use one for the effects power supply and regulate it down to 9V
Does it make a difference in the "performance" of the amp?.....I just figured "heaters are heaters" :dontknow:
I'm planning on having a seperate main xfmr (or 2) where I can control the input with a variac and dial my B+, and I figured it would be best to keep the filaments constant
I like K's suggestion of two 240VAC isolation xfmrs in parallel........or I'll just tap 480 off of the wall here (gotta check with PRR on that one)
EDIT- crossed out really bad idea :icon_biggrin:
I'm thinking that this "test power supply" will not be mounted on the breadboard
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You'd want to keep the heaters seperate using the variac idea so that's good planning but I'm also thinking the pi and pa will still (also) need 6.3v heaters too. So now you'd need two heater trannies. Also what about if you ever wanted to use octals? It's your project so go for it but w/ one high capacity 6.3v tranny you could use it for everything and only need one.
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Thanks again jojo,
Yeah I was actually thinking of keeping everything separate....
Separate PI board, separate reverb board, separate D'lator style board, all off of the one 12V xfmr,,,,where I can patch them in and out for different applications
Those 8(?) total 12ax7s would get me to 2.4 amps on that xfmr (right?----my math ----12ax7 @12.6Vac draws .3 amps X 8 total tubes = 2.4 amps)
Then a separate xfmr for just the power tubes...
I can still pull 6.3 off of these by using one leg and the center tap...
I do appreciate the questions,,,just in case I'm missing something......I'm still new at this :icon_biggrin:
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12ax7 @12.6Vac draws .3 amps X 8 total tubes = 2.4 amps)
12AX7 @ 12.6v only draws .15 amps.
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12AX7 @ 12.6v only draws .15 amps.
Thanks Sluckey,
So that's--- both triodes in series at 12.6v = .15 amp draw per tube
Sorry :embarrassed:,,,I'm sure you've answered this question 10,000 times befroe :icon_biggrin:
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Usually we don't see preamp tubes with filament in series (each other)
such architecture is considered prone to humm
we can see more easily final tubes with filament in series
those are less prone to problems as the level of the signal present at their input is higher
so, if possible for the model of tube, wiring a preamp tube for 12.6v is better because of the lower current flowing in the circuit
but teorically is to avoid to connect two preamp tubes as to have a 12.6v filament circuit
May be you only were referring to arrange the pin of a tube (like 12ax7) for 12.6v heater and this is safe
So excuse me if I eventually misunderstand your intention
K
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May be you only were referring to arrange the pin of a tube (like 12ax7) for 12.6v heater and this is safe
K, I'm not sure I understand.... take a look back at my wiring in reply #41, and tell me if it'll be OK like that (not prone to hum)
Thanks for looking :thumbsup:
UPDATE:
I just got my hands on a control xfmr for FREE, out of a scrap welding machine!!
It's got 115v primary and dual 230v sec. that I can wire in series for 460VAC @ 1 amp....perfect for a bench PS :grin:
Thanks for that idea :thumbsup:
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Your arrangement is 12.6v for each tube and each tube is paralleled to the other
that is perfect if you don't plan to use 6.3v for heaters
I would plan also a board like those in #41 devoted to 6.3v tubes
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It's got 115v primary and dual 230v sec. that I can wire in series for 460VAC @ 1 amp
WOW that is an Homungus PT :icon_biggrin: 460v AC 1A - you can think at ~600mA-650mA DC available current
May be not the best as to test SAG performance in a Champ, but you can breadboard also 200W-300W and more big amps :icon_biggrin:
if you find it on the cheap also a 12v transformer can be used instead of the devoted 12.6v transformer in tubes like 12ax7 tollerance for filament voltage is in the order of + or - 10% till 20%
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I haven't something like your salvaged control xfmr but I'm lucky, a friend give me a 220v / 6.3v x 6 windings with 2mm winding wire (I assume there is enough current as to breadboard also very big amps there :smiley:)
Ciao
Franco
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Hi all -
Here is an example of that Heathkit bench power supply I have that I intend to use on my breadboard. My bad before -- It only has 0-400V @.1 A, 6.3V @ 4 A and 12.6V @ 2 A. No 5 V.
http://www.ebay.com/itm/Heathkit-SP-17A-Variable-Dual-High-Voltage-Tube-Power-Supply-HV-0-400v-DC-/321102388700?pt=Vintage_Electronics_R2&hash=item4ac3319ddc (http://www.ebay.com/itm/Heathkit-SP-17A-Variable-Dual-High-Voltage-Tube-Power-Supply-HV-0-400v-DC-/321102388700?pt=Vintage_Electronics_R2&hash=item4ac3319ddc)
However 5V @ 1.5 A is available from one of these:
http://www.ebay.com/itm/Vintage-Old-Collectible-Heathkit-IP2718-Tri-Power-Supply-/280828466846?pt=Vintage_Electronics_R2&hash=item4162ae569e (http://www.ebay.com/itm/Vintage-Old-Collectible-Heathkit-IP2718-Tri-Power-Supply-/280828466846?pt=Vintage_Electronics_R2&hash=item4162ae569e)
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I need a breadboard. I'd love to see a parts list for anybody that's made one.
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So far, mine is a piece of plywood with a bunch of barrier strips from Radio Shack. I'm going for the rustic look.
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:laugh:
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So far, mine is a piece of plywood with a bunch of barrier strips from Radio Shack. I'm going for the rustic look.
Yeah,,,this is a project that will be different everytime someone else builds one.....it is what you need it to be..
I've found that the fancier I try to make it the more time it sucks out of my life....imagine that :icon_biggrin:
I'll post pics this week of my almost completed piece of plywood ...........it's just some boards I wired up with tube sockets (as pictured previously),,,,a couple of transformers,,,,some barrier strips,,,,a little DIN rail,,,,some octal relay sockets....etc, etc,
I think DL said something like,,,,,build one and then you'll realize what you need it to be :l2:
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Here's a pic of my completed preamp board with the wiring labeled, to give you something to think about...this is one way to do it :wink:
I thought that it was a good idea to have 2 separate connections for the plates of the preamp tubes so that I can bring the B+ in from the top, and then run the signal from the duplicate connection on the opposite side of the board (as pictured).....in my layout,,,that makes sense
I also built a reverb board, based off of sluckey's beautiful schematic of the AB763 reverb design......it'll get the job done for now, and has a mini switch for on/off,,,plus the phono jacks and xfmr built right onto the board (pictured last)
The phase inverter board is a simple 2 tube board that is just a smaller version of the preamp board, and will be able to use the second tube as an effects send/return, or post phase inverter driver (not pictured).....for now
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Nice execution and interesting plan !
Your reverb board give me an idea also for a tremolo board
Thanks for sharing
K
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SG -
Going with 12volt for the heaters really simplifies the heater wiring. Bravo! :thumbsup: I think I am convinced. I have a couple of Radio shack 12v transformers that will fill that bill nicely. Using the pre-drilled turret board is also a great idea. Makes it quick. But those barrier strips are pricey dude!!! You know somebody who carries them home at night? :laugh:
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OK, here we are today at about 90% complete.....
I can't believe it's been this long since I started this thread,,,and I'm over budget (of course),,,but I'm pretty happy with what it is
Maybe not the most versatile breadboard,,,,but a great platform to build a couple of amps on and see where it leads me
My favorite part is that the main blank board in the bottom left of the pic can be substituted for an actual,,soldered up preamp board for testing :thumbsup:......kind of an accidental discovery, that came to me as I was laying everything out for spacing,,,,,,,,priceless :icon_biggrin:
I put the second pic in so you could see the "layering effect" that I used to bring the components in the back up into reach and create a flow for the eventual wiring,,,,,by putting a second layer of plywood under the power tubes and "cap farm",,,,,and then a raised aluminum "grounding deck" that also provides spots for the PT and OT to sit.
Still have to permanently mount some stuff,,,,but I'm getting close, and it's about time!
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Cool :thumbsup: :thumbsup:
Franco
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Man SG, very nice!
It looks great and it looks like you've put a lot of good thought in to it too.
But if as you start to use it and get new ideas from hands on experience with it, don't feel bad if you see some things you'd like to change. Hind sight is always 20/20.
Really does look great and well thought out.
Brad :icon_biggrin:
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What is the switch on the verb board for?
Brad :think1:
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Thanks guys!! :thumbsup:
But if as you start to use it and get new ideas from hands on experience with it, don't feel bad if you see some things you'd like to change. Hind sight is always 20/20.
Yeah, that's kinda why it's taken so long.....it was a compromise between what I could imagine and what I actually need to get up and running.........and with limited experience in general,,I probably had limited vision,,,,,for now, It'll do :wink:
The most difficult part was just settling and just starting to drill holes.....once I got rolling, it finished itself
The whole time I was thinking in the back of my mind that I wanted "you guys" to think it was good.....so I did spend too much time just staring at it :huh:
The switch on the reverb is in place of the footswitch.....just on/off
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The switch on the reverb is in place of the footswitch.....just on/off
And there you have it, I can't even figure that out.
Brad :laugh:
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:l3:
Don't be too hard on yourself......I had to stare at it for a day before I could drill the hole :grin:
I still have to take it off the standoffs at least 3 more times to triple-double check the wiring, before I plug it in.... :BangHead:
I think that's why my amps usually work the first time,,,,,,because I spend a month verifying what I have spent a month verifying......It's an illness
That's it....now I just jinxed myself :rolleyes:
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what are you going to do about tube shields? grounding the shields? some circuits will likely be fairly noisy without them...
--DL
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what are you going to do about tube shields? grounding the shields? some circuits will likely be fairly noisy without them...
--DL
Originally I thouight I was gonna use socket savers on the preamp tubes, so I didn't install the shield-type sockets (now I realize how high off of the board the tubes would be if I used them)....
I'm gonna "wing it" for now and see how much noise there actually is....
Part of the modular design is that I'll be able to change boards out,,,and if the noise is a big issue,,,I'll have to wire up a new board :sad2:
I'm OK with adjustments as I go.....like you kinda said.....I'm not gonna know what it needs to be until I build it and find out :wink:
Chaulk it all up to a general lack of experience......and also to the fact that I just went and built it and didn't ask for any advice along the way :rolleyes:
Thanks for looking out, and coming back to pose an excellent question......I noticed it after I had already wired up the first 2 boards
So make a note kids: If you're gonna build one,,,make accomodations for socket shields :icon_biggrin:
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Thinking a little more about it...
Do you think there would be any value in having some smaller pieces of pipe?(or equiv.) cut to size to slip over the tubes as temp shields to see what kind of difference it makes with noise? ...(not grounded?)
Or just a loose tube shield?
Is it a 50/50 purpose for the shield to also hold the tube in the socket (in amps)?....or is it more llike 90% for shielding 10% hold down?
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Ciao SILVERGUN
I really don't understand where is the problem
The shielded sockets I've are near identical to normal sockets
(and your's looks to be the same)
see this one
(http://www.parts-express.com/images/products/standard/055-500_s.jpg)
(http://t3.gstatic.com/images?q=tbn:ANd9GcT9YxAKnRp123BLeIOozrAuq6kL83hsFqCoCZ5H6ErFAGpoRtB2)
the metal base of the shielded sockets can substitute the metal part of a standard socket (talking about the base, not the shield itself)
so if I unscrew the normal socket and substitute the upper metal part with those of a shielded socket
all will fit on without problem
an additional wire can be add to the screws as to have a ground connection for the shields
K
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I really don't understand where is the problem
I was under-thinking that one.....again,,,lack of experience
1) I didn't realize that the tube shields get grounded :embarrassed:
2) I have one of the shielded sockets here and the shield base is crimped onto the socket...I thought they were all like that :embarrassed:
As I was building my breadboard I thought to myself at one point "Do you really know what you're doing enough to deserve this?"
My answer was "No,,,but it's going to be a great tool to learn with" :icon_biggrin:
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Their grounded automatically when bolted to the chassis.
Brad :icon_biggrin:
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2) I have one of the shielded sockets here and the shield base is crimped onto the socket...I thought they were all like that
is it the SAME size as the sockets you used? what size hole is required by the sockets currently in place?
look carefully, they come apart. use a small jewelers strait-slot screwdriver to open up the locking tabs. looking at the pics you posted, it does seem like you used the 7/8"(22mm) sockets.
buy some of doug's two-piece ceramic model and use just the shield mounting ring, from the pics you posted, it looks like they'll drop right onto your sockets. attach a ground lug underneath each socket mount-point then wire daisy-chain from socket to socket. the last socket gets a wire to a terminal and that's the system ground for that preamp section.
on a footnote; if you replace just the socket mounting ring with the shield base mounting ring, all you're fancy-schmancy filament wiring will be saved... :wink:
--pete
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OK.....tradgedy averted....
I can keep my facncy-schmancy wiring in tact AND use shields with my current setup....
You guys are the best :icon_biggrin:
One minute I feel like a genius and the next right back to idiot.....this new "hobby" is tough on my self-esteem
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i've had some time to hack out some new sockets for my breadboard. two types, and a third in the works...
first solution is a double deck. the sockets mount as they would in a chassis and wring is made under the board to the single-row PCB type barrier strips. this makes the deck height of the barrier strips fairly high, so i designed a pair of accompanying component boards; one has a 1.75" center - center and the second has a 2.5" center - center.
complex to build but solid and heavy. wiring from socket to board is less trivial and less flexible since it is soldered at both ends. this design also assumes use of DIN rail to mount both the socket boards and the component boards.
second solution is a bit cleaner, has a lower deck height, more flexible and easier to wire the sockets to the barrier strips, however, the socket mounting is a but unorthodox and potentially more fragile. i used .190" thick material to improve the axial strength of the standoff attach points to the board. lastly this design requires use of double-row barrier strips and probably the path i will take since it allows me to use the existing breadboards component rows.
DIN rail mounts i used are available from Winford Engineering - i used the DINM15-rc part; URL link below.
http://www.winfordeng.com/products/dinm12-15.php (http://www.winfordeng.com/products/dinm12-15.php)
URL link to photos below.
http://s2.photobucket.com/user/pmitchel/library/Breadboard%20Stuff?sort=3&page=1 (http://s2.photobucket.com/user/pmitchel/library/Breadboard%20Stuff?sort=3&page=1)
PM me if you'd like a copy of the mechanical drawings & fab. templates in VSD, PDF, or DXF format.
--pete
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i've had some time to hack out some new sockets for my breadboard. two types, and a third in the works...
Nice stuff there DL,,,thanks for sharing :thumbsup:
I finally got aroung to starting a project on mine,,and it is an absolute joy to use....
I really enjoyed not having to sit around and draw a layout,,,,but just jump in start screwing down parts as I was following along on the schematic
I have one problem area,,,which is of course, the PI board that I took for granted....it's too crammed for space, especially because it will be an area of focus on this new project
I plan on rewiring a new board and leaving more space between sockets, so we can have the PI tube and PPICF components all right there
Other than that, this is the coolest tool I have ever owned,,hands down.......thanks again for the inspiration :thumbsup:
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Boy that looks like fun! Though I know you've gone thru some trials and tribulations constructing it, it almost looks like more fun than building an actual amplifier! I like the Fender logo. I would, I suppose, be concerned about finalizing a design without knowing for sure that "bad layout" noise might or might not go away with proper construction techniques on a real chassis, but I imagine if that was a real concern, you could build the preamp part and lash it into the breadboarded remainder of the circuit.
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it almost looks like more fun than building an actual amplifier!
Yeah,,, I was questioning the worth as I was building it,,,,but now that it's done I realize that I have built the potential for 100 amps and not just one amp......especially because I like to build "special" amps, and I'm a chronic tweaker
I like the Fender logo. I would, I suppose, be concerned about finalizing a design without knowing for sure that "bad layout" noise might or might not go away with proper construction techniques on a real chassis, but I imagine if that was a real concern, you could build the preamp part and lash it into the breadboarded remainder of the circuit.
The Fender logo is for this build....it's gonna be a AB763 with an attempt at a PPI CF driver circuit.....so once we get that in order, I hope to just use Doug's layout and board for the final product...
And if you look at the black board in the bottom left corner,,,,I'll be able to replace that with an actual wired up preamp board to test
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Ok my turn. :icon_biggrin:
I need to build 1 of these now. I have gathered some parts since this thread started but I have a question.
Where did you get your dual row terminal strips?
I found some at home depot but their rated at 300vac/30A. Same thing for what I found at Mouser.
I'm thinking that I can treat these as we treat a Carling switch? Where they're only rated at 240vac/6A we use them at a much higher vac (<500vdc) with a much lower current (<0.5A).
Brad :think1:
Edit; Added < (less than sign), Brad
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Ok my turn. :icon_biggrin:
I need to build 1 of these now.
YES!!....yes you do. :thumbsup:
The ones I saw at home depot were too large because they wont tighten down on one single resistor lead....the holes are too big.
I got some of mine at Radio Shack but most of them from Newark.
The brand is Molex and I think the smallest ones they make turned out to be my favorite.
You'll want to get down to 22AWG
The spacing of the holes also matched the pre-punched boards, so it was a winner.
I think it was these:
http://www.newark.com/molex/39100-0912/terminal-block-eurostyle-12pos/dp/46M3769 (http://www.newark.com/molex/39100-0912/terminal-block-eurostyle-12pos/dp/46M3769)
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I have a few different circuits I want to play with before I commit to an eyelet/turret board, drilling a chassis and having face plates made.
The ones I saw at home depot were too large because they wont tighten down on one single resistor lead....the holes are too big.
I got some of mine at Radio Shack but most of them from Newark.
The brand is Molex and I think the smallest ones they make turned out to be my favorite.
You'll want to get down to 22AWG
The 1's I got at HD are Tyco Electronics and say on the package; 10 to 22 AWG. I just tried a piece of solid 22AWG and it grabs real strong. (You scared me for a second! laugh:)
Are you sure you really like those Euro style 1's? I'm not too sure I'll get used to them by looking at them. Maybe I'm wrong?
The link you posted says 300vac/20A.
Brad :icon_biggrin:
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The 1's I got at HD are Tyco Electronics and say on the package; 10 to 22 AWG. I just tried a piece of solid 22AWG and it grabs real strong. (You scared me for a second! laugh:)
Oh yeah, I was referring to the euro style ones....those tyco ones are good and grab great, they are just a little bit more annoying than the euro style, because you have to wrap the leads around the screw or they will push out when you tighten the screw.
Are you sure you really like those Euro style 1's? I'm not too sure I'll get used to them by looking at them. Maybe I'm wrong?
Yes, and that's why....it's just way more convenient to push the lead in the hole and tighten the screw (on the euros) without worrying about the screw head twisting the lead as you tighten it (on the tycos).
The link you posted says 300vac/20A.
Yeah....I wouldn't worry too much about that V rating in this application.....most of those connections will never see even 1/2 of an amp.
Current is more of a concern than actual voltage.
On the "son of a breadboard" I switched over to mostly euros and it is much more convenient to use that board....yes, they will wear out sooner, but I'll just plan on replacing them at some point.
WAAAYYYYY easier to work with the euros.
http://el34world.com/Forum/index.php?topic=16551.msg163203#msg163203 (http://el34world.com/Forum/index.php?topic=16551.msg163203#msg163203)
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because you have to wrap the leads around the screw or they will push out when you tighten the screw.
Well it's only a temporary connection we need. Just need to be tight enough to stay in place and not get loose and arc. It's not a permanent connection like in a fuse panel or a welding machine.
DL did bring up a 'washer' that I think stopped that from happening?
Yes, and that's why....it's just way more convenient to push the lead in the hole and tighten the screw (on the euros) without worrying about the screw head twisting the lead as you tighten it (on the tycos).
On the "son of a breadboard" I switched over to mostly euros and it is much more convenient to use that board....yes, they will wear out sooner, but I'll just plan on replacing them at some point. WAAAYYYYY easier to work with the euros.
Ok, I'll try buying a few, it makes sense what your saying.
Yeah....I wouldn't worry too much about that V rating in this application.....most of those connections will never see even 1/2 of an amp.Current is more of a concern than actual voltage.
Like what I said about the Carling switches Fender used for decades. They traded higher voltage for lower current through the switch.
Brad :icon_biggrin:
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I'm thinking of taking a little bit different approach with this bread board.
For instance, I want to try a few different reverb circuits. Then if I like 1 or more of them, I want to build a separate board that I can just swap in a different verb circuit in a build. Like your verb board.
I also want to do the same thing with different vibrato circuits and to see if they can be chained in series with each other.
And I have some different iron sets for a SE Champ build that I want to test.
I'm thinking, maybe some of these circuits can be modular so everything (all the circuit parts) don't have to be bread boarded every time?
Brad :think1:
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I started with this one
:dontknow:
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:laugh:
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which one was stolen from the other ? :icon_biggrin:
(http://www.ladyada.net/images/parts/breadboard-half.jpg)
(http://www.thegreenhead.com/imgs/bamboo-bread-board-with-crumb-catcher-4.jpg)
:l2:
K
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Forget the board, I want the bread!!!!!
Brad :laugh:
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Well I sat down this morning and measured up my parts to make a list of nuts, bolts, washers and standoffs to put this together, then went shopping.
I was able to get everything except the 1" nylon #8 standoffs, will order them online.
Next I'll start placing parts on the board to get a feel for how big it will be. I have a nice piece of 48"x24"x1/2" AA pine plywood. Not sure yet if I'll paint it or just put a coat of boiled linseed oil on it after it's all drilled. Just to keep it from drying out and warping/cracking. I'm leaning towards linseed oil. I really like it for sealing wood, it's very easy to apply and I have a ~gallon of it here. :think1:
Brad :icon_biggrin:
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After thinking about this a little more, I just ordered the Molex Euro style terminal strips from Newark.
I found that they stock the same 12 terminal strip but rated at 600v@20 for $2.93, when you buy 10. $0.12 (each) more for double the voltage rating. Nice. :icon_biggrin: (Molex, part #39100-0812)
Yesterday I cut my plywood to 24"x24" and gave it a good coat of Linseed oil. I left a fan blowing across it overnight to help it dry.
I also cut and drilled my 9 pin (x6) fiberglass board, came out nice. As soon as I use it to transfer the standoff bolt holes to the plywood I'll start to wire up the socket pins.
I found a Hammond toroid dual primary/secondary; 15VA/120/240v, 50/60Hz, 6.3v @ 2.38A (parallel/total) or 12.6v @ 1.19A (series), that I bought some years ago from AES on close out.
So I'll wire it up as 12.6 and it will power 7, 12 _ _ 7 tubes nicely; 0.150A x 7 = 1.05. :icon_biggrin: I'll power any big tubes and rectifier tube from the main PT.
SG, how are your 9 pin tubes spaced? I went with 2 1/4" on center.
Brad :icon_biggrin:
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what are you going to do about tube shields? grounding the shields? some circuits will likely be fairly noisy without them...
--DL
I am questioning the need for this. I am aware the shields are grounded by virtue of the chassis if metal. I have a HIFI stereo build inside an antique silverware box. All of the sockets are countersunk to be level and installed with metal rings. None are grounded, not even the 2A3 tubes since the top of the box is burled walnut. I just have 2 star groundings. No shields or cover of any kind.
Now I plan on doing it, but how can this cause noise? Does the ground shielding keep stray currents from being picked up by a tube?
Also, I was reading an old Popular Science from 1958 where and article mentioned wrapping solder around a tube to stop microphonics. It works!
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SG, nice work there.
I was wondering if you had a solution for using pentode preamp? I know it is moduar and you can add another preamp board as you want, I was just wondering if you have already made accommodations for testing them in a preamp?
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SG, how are your 9 pin tubes spaced? I went with 2 1/4" on center.
Mine are on about 2 1/8" centers
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SG, nice work there.
I was wondering if you had a solution for using pentode preamp? I know it is moduar and you can add another preamp board as you want, I was just wondering if you have already made accommodations for testing them in a preamp?
On the big board (this thread) I made a separate little one socket board...it's adorable
On the "son of a breadboard" I wired the 2 sockets on the far right of the long board for pentode use.
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Mine are on about 2 1/8" centers
Ok, I was asking because of the spacing on the Euro strips.
Brad :icon_biggrin:
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I got my Euro strips today. :icon_biggrin:
I'm thinking I'll space them in 3 rows on 2 1/4" center's. What did you space them at SG?
Brad :think1:
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I got my Euro strips today. :icon_biggrin:
I'm thinking I'll space them in 3 rows on 2 1/4" center's. What did you space them at SG?
Brad :think1:
\
On the "son of a BB" I just lined em up along the edges and spced em like they were gonna be just one long strip...and I like that A LOT!
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No, I mean the space in between the strip rows, center to center.
Brad :icon_biggrin:
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No, I mean the space in between the strip rows, center to center.
Brad :icon_biggrin:
Oh...duh
Well,, I didn't measure, but that black Garolite is 3 1/8" wide and I just lined em up with the edge and then tried to space the boards a similar distance.
I'm not much of a pre-planner.....I just did it. :rolleyes:
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Ok, that's close to what I was thinking, because of the R/C leads.
I got my 4 rubber feet on and a piece of pre drilled angle iron across the front.
I think I'll start a new thread with pics when I get a few more parts bolted down.
Thanks, Brad :icon_biggrin: