Lets build a breadboard!

[SILVERGUN]

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  

[jeff]

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

[Katie 77]

put a hinged lid on if you're a pussy
seriously. put a lid on it

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
good stuff

[jeff]

put a hinged lid on if you're a pussy

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!
 

[John]

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. 

[SILVERGUN]

Think I'll build one too to test that pedal/tube amp hybrid.

That's what I'm talking about  

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  ......so have some universals mounted and then be able to plug in the real stuff when you're ready.....nice touch

[SILVERGUN]

 

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
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

[Katie 77]

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
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......

[SILVERGUN]

Found these old threads:
http://www.el34world.com/Forum/index.php?topic=11131.0

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/

[jazbo8]

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 
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

[DummyLoad]

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

[kagliostro]

I like a mix of this





K

[gar13]

Always thought this one looked really cool:

http://ampgarage.com/forum/viewtopic.php?t=17780

[Katie 77]

Always thought this one looked really cool:

http://ampgarage.com/forum/viewtopic.php?t=17780

That's kinda what I had in mind.

[kagliostro]

http://ampgarage.com/forum/viewtopic.php?t=17780

Nice but a bit too sophisticated to me

K

[Ghetto_Soundwave]

put a hinged lid on if you're a pussy

Burn...nice one 

[SILVERGUN]

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
Then maybe a small single ended Hammond?:
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 

[Willabe]

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.......            What happened? It's not the same amp, sounds way different.    

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    

[Willabe]

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          

[jojokeo]

put a hinged lid on if you're a pussy

  My two favorites:

http://youtu.be/XZHgfYxqCSY

and from the self proclaimed expert (at least he finds humor in it):

http://youtu.be/1lozkT1zrIU

[DummyLoad]

http://ampgarage.com/forum/viewtopic.php?t=17780

Nice but a bit too sophisticated to me

K

no pics?

[SILVERGUN]

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  

I've never understood the idea of putting a PT in anything that is right on the edge of the current requirements  

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  .....like the 600V rating on this one
http://www.newark.com/macromatic-controls/70169-d/din-rail-relay-socket/dp/04M6767?in_merch=Popular Relay Accessories

[kagliostro]

@ Pete This attached is the picture of the previous link

---

@ 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

[SILVERGUN]

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?)

[kagliostro]

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

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

[jazbo8]

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

[kagliostro]

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

[Willabe]

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  

I've never understood the idea of putting a PT in anything that is right on the edge of the current requirements  

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      

[jazbo8]

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

There are other brands as well, KEPCO, EICO, VoltLab, etc. and of course HP, Fluke, Lambda, GenRad (these are more expensive)...

Jaz

[Willabe]

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      

  

[DummyLoad]

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/NEW-DIN-RAIL-12-LONG-STEEL-CHROMATED-PHOENIX-CONTACT-0801733-NS35-7-5-/221130534662?pt=LH_DefaultDomain_0&hash=item337c682f06

some suggestions... 

--pete

[SILVERGUN]

Thanks again EVERYONE!
Lots of good reading and great links there DL....

I am listening 

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 

[DummyLoad]

Thanks again EVERYONE!
Lots of good reading and great links there DL....

I am listening 

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 

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

[alerich]

Got some parts ordered today and I'm ALL IN  .....like the 600V rating on this one
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

[rob_h]

 
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

[SILVERGUN]

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

[kagliostro]

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

Franco

[jazbo8]

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      

  

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   

Jaz

[moonbird]

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

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* . 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!!!

[SILVERGUN]

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  

FUN  

[SILVERGUN]

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 

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 

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  )....but this thing isn't about looks 
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!

[jojokeo]

Great idea SG but why 12v heaters am I missing something? And why aren't those things soldered and wired up yet??? 

[kagliostro]

Here's a couple progress pics in case anyone's curious...

Oh, we are ! We are waiting  you showing your next step

--

Nice realization  

---

Just don't forget that exist also some interesting 7 pin tubes 

K

[kagliostro]

That 8 pin board is nice but a bread-board requires screw connections, and 25$ may be is too much

K

[SILVERGUN]

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"  

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

I'm thinking that this "test power supply" will not be mounted on the breadboard

[jojokeo]

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.

[SILVERGUN]

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

[sluckey]

12ax7 @12.6Vac draws .3 amps X 8 total tubes = 2.4 amps)

12AX7 @ 12.6v only draws .15 amps.

[SILVERGUN]

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  ,,,I'm sure you've answered this question 10,000 times befroe 

[kagliostro]

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