It's raining here.......

[SILVERGUN]

After seeing Sluckey's recent work on the AC15, I felt the need to post something to show him how his work inspires others.

It's pouring rain here, and I couldn't care less......and that's what made me think of the AC15 thread.

I'm sooooo far off the reservation on this one that I'm just going to give you a glimpse into the future,,,,and then wait to make sure it works before I post the rest. 
I promised myself that I was never gonna try to squeeze 100 lbs. of crap in a 20 lb. box,,,and yet, here I am.

Yes, that's the PT in the base of a 2x12 cabinet  .... I am tempting the amp gods...
Cross your fingers for me.

[Ritchie200]

Supply on one side - tubes and tonestack on the other?  I take it the controls are on the top where the cutout is?  That seems like a lot of signal wire routing?  Lots of grunt, tiny living space! Cool!  I like the Al angle for the supply and on/off switch - been there!

Jim

[Ritchie200]

Where is the corncob gonna go!?!?  You can always use it as a carry handle!

Jim

[SILVERGUN]

Supply on one side - tubes and tonestack on the other?  I take it the controls are on the top where the cutout is?  That seems like a lot of signal wire routing?  Lots of grunt, tiny living space! Cool!  I like the Al angle for the supply and on/off switch - been there!

Yeah, just separated the power supply from the chassis.....the tubes, board and controls will all go in chassis like usual....controls in cutout

Where is the corncob gonna go!?!?

I put it where you suggested and I haven't been able to sit all week. 

 

[SILVERGUN]

Do I have to worry about grounding my choke to the chassis?

[sluckey]

Do I have to worry about grounding my choke to the chassis?

no

[HotBluePlates]

Will the speaker fit?

[SILVERGUN]

Will the speaker fit?

Yeah, it's tight but clears by about a half inch.....front mount

Good lookin' out! 

[SILVERGUN]

I found these small, cheap 1kv- 35 amp power entry plugs that I'll use to get the B+ and bias voltage into the chassis safely:

http://www.newark.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=15003&langId=-1&urlRequestType=Base&partNumber=25R4664&storeId=10194

http://www.newark.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=15003&langId=-1&urlRequestType=Base&partNumber=25R4668&storeId=10194

For the record....
I'm gonna do male by female for one connection and female by male for the other connection so that they won't be able to get plugged in the wrong way...
In other words, have a female connector on the chassis to attach B+ to and then a male conector on the chassis to attach the bias V in

[llama]

Now Thats Mad Science with a bit of Voodoo thrown in for flare!
 

[SILVERGUN]

Now Thats Mad Science with a bit of Voodoo thrown in for flare!

OK,,,,maybe not all that, but it's good to see you lurking here llama   


For all of you amp porn aficionados out there, this thread will be the equivalent of the slow striptease...
Partially because I am slow,, but mostly because I usually do a horrible job of documenting what I do,,,and I'm trying to change that.

So, sorry for the lame pics, but I assume it's better than no pics.
I added the rivets on the corners because one of the spot welds popped on me....I don't like using this thinner .04 aluminum, but it was the only thickness I saw available in this 17" x 4" x 3" chassis.

[sluckey]

The first three amps I built this millennium used that same chassis. One of them broke and I pop riveted to fix it. They are OK if you don't put any iron on them. You can literally twist them like a pretzel with just your hands!

Oh, and it's very tight working inside. You really gotta plan ahead and layer your stuff as you build. Doug's 3.125" wide boards do not work well. I ripped my boards to 2.5" to give room for input jacks. If that chassis had only been 5" wide it would have been soooo much easier to work with.

Here's a link to a couple pics of my 3x4x17 Hammond projects...

     http://home.comcast.net/~seluckey/amps/5e3/sisters_rear.jpg

     http://home.comcast.net/~seluckey/amps/18w/18w_03.jpg

Not trying to dis your project at all. But I wanted to share my thoughts about that chassis.

[SILVERGUN]

The first three amps I built this millennium used that same chassis. One of them broke and I pop riveted to fix it. They are OK if you don't put any iron on them. You can literally twist them like a pretzel with just your hands!

Yeah, I noticed that,,,and that's how I popped the one spot weld,,,just by twisting it a little to straighten it..
And, that's why I decided to separate the power supply,,,cause it's a pretty big PT, and there was NO WAY that chassis would hold it up for a second.

Oh, and it's very tight working inside. You really gotta plan ahead and layer your stuff as you build. Doug's 3.125" wide boards do not work well. I ripped my boards to 2.5" to give room for input jacks. If that chassis had only been 5" wide it would have been soooo much easier to work with.

Yup, I'm with ya...I've spent about 10 hours sitting around drawing layouts,,,and now you've got me re-thinking it again, 'cause I was gonna use a 3 1/8" wide board.....
I like pre-assembling, so I'll do whatever I can outside of the chassis first.......It's gonna be tight, but at least I eliminated a bunch of power supply wiring.
Wish me luck!

[kagliostro]

To build the amp with a splitted chassis isn't a bad idea

Sluckey and HotBluePlates buided amps in that way, not exactly as you want to do, but similar


http://home.comcast.net/~seluckey/amps/vox/vox.htm

http://el34world.com/Forum/index.php?topic=14263.0

---

it's a pretty big PT, and there was NO WAY that chassis would hold it up for a second

a simpler solution would be to use a 2 mm thick aluminium sheet to reinforce the top of the chassis

you could put the reinforcement sheet on the external or internal side of the top of the chassis

Ciao

Franco

[SILVERGUN]

I think its a great idea to separate the power supply from the chassis.

Thanks Dr.....let's hope we are right!

a simpler solution would be to use a 2 mm thick aluminium sheet to reinforce the top of the chassis
you could put the reinforcement sheet on the external or internal side of the top of the chassis

Thanks K....that is a good idea, and I will probably have to do that for the OT
 

[lego4040]

That is a fantastic idea, that sucks about your chassis problem

[SILVERGUN]

That is a fantastic idea, that sucks about your chassis problem

Thanks lego,,not really a chassis problem as much as just a chassis heads up for other guys who might be considering using one of these Hammonds.

Sluckey did the right thing by pointing it out, so that others will learn from our misfortune.

I'm kinda glad it made me think outside the box,,,and I just hope that this plan flies....I'm finding that the hardest thing I do is start something that I've never seen done, and then try to plan on the fly. That's why I made the comment on the AC15 thread that I would've stuck to sluckey's original design, because it's always a lot harder to re-invent the wheel.

I was hoping to be further along right now because now I have to watch the Flyers in the playoffs....
Since you're in Manhatten, I'm going to imagine that you are the enemy 

But if you're not a hockey fan, then we're still cool 

[kagliostro]

BTW HotBluePlates used with satisfaction an XLR connector to pass B+ from one chassis to the other


K

[Willabe]

I was hoping to be further along right now because now I have to watch the Flyers in the playoffs....
Since you're in Manhatten, I'm going to imagine that you are the enemy 

But if you're not a hockey fan, then we're still cool 

Mehhhh!!!!!!!!      1st off you might have to go through the Black Hawks!   

2nd and much more importantly, don't wanna hear about a winter sport after this last winter,           

                              It's baseball season!       

                              162 game regular season!


               
                                                    GO CUBS!!!!!!!!!!!!!!!!!


              "Red Hots, get your Red Hots here, Peanuts, get your Peanuts here!"

                        Brad     

[SILVERGUN]

Baseball - Schmaseball.....(meh!!! is right)
NOTHING even comes close to playoff hockey....get off my thread you lousy "Sweet Home Chicago"ian 
Last time I saw the Blackhawks in the finals, they stole my cup on a weak goal in OT   

 

[SILVERGUN]

BTW HotBluePlates used with satisfaction an XLR connector to pass B+ from one chassis to the other

Thanks AGAIN K, I might have to use that trick for the filaments.....?


I know how much you guys like pictures, so here are a couple more from last night...
Notice the "ash-tray" standby switch  , to be able to keep the power supply all together in that corner...
I didn't like it at first, but it has grown on me, and I'll just say it adds 'character'.
And I mounted the choke right next to it keep it all tight.
I also had to screw in some wood blocks on the inside of the cabinet to fill the space where the chassis wasn't wide enough

[Willabe]

Baseball - Schmaseball.....(meh!!! is right)
NOTHING even comes close to playoff hockey....get off my thread you lousy "Sweet Home Chicago"ian 

 

"Play Ball!"                          "Beer here, get your cold beer here!"


                     Brad     

[sluckey]

Just a little something to think about... Will you be able to get to those chassis mounting screws once the chassis is full of stuff?

[SILVERGUN]

Just a little something to think about... Will you be able to get to those chassis mounting screws once the chassis is full of stuff?

THANKS again for having a look sir,,,
I'm hoping they will be ok.
I drilled them a little too quickly, in my haste to get the chassis ready for filament wiring......I like to have all the holes there before I start wiring so I don't get any stray aluminum shavings.

If this was my second one of these, this would be A LOT easier 

[Ed_Chambley]

I read, but I cannot tell what you are building.  You have a PT, but have not mentioned what it is.  I see 2 power tube holes, so I know it will not be 400 watts.  With only 2 tubes, this is NOT up to your usual mindset  Are you getting old or something?  For all I know you could be planning 2, 6v6.


I mean I thought 190 watts was low wattage for you.  Where are you planing the other 6 KT150's.


Seriously, it is pretty cool and I do see a few additional preamp tubes and I assume, knowing you, they are not for Tremolo.  What sort of high gain monster you planning.  I have never seen a high gain split chassis design.  Are you sort of making it up as you go along or did I miss your schematic and layout?


Spill the beans baby, inquiring minds want to know.

[SILVERGUN]

Seriously, it is pretty cool and I do see a few additional preamp tubes and I assume, knowing you, they are not for Tremolo.  What sort of high gain monster you planning.  I have never seen a high gain split chassis design.  Are you sort of making it up as you go along or did I miss your schematic and layout?

Spill the beans baby, inquiring minds want to know.

This is that one I mentioned that I'm building for someone else......the schematic only exists in my head and scribbled onto empty pizza boxes.....and the whole project is sponsored by Red Bull 
It's coming right off of the breadboard.

- 2 channel... 5E3'ish clean with just input vol., tone, clean vol.
                    Ultra High Gain channel with 4 gain stages into cathode fol. driven tone stack
- Tubenit'ish fx loop with parallel mod
- 2 - EL34s for 50'ish watts into 2 Celestions.....  G12 Century Vintage (for lighter weight on the PT side)  and G12K-100
- PT, OT and choke are JCM800'ish
- Nothing fancy!

This player needs a big punch in a small package that will probably take some road abuse, and have to fit in a trunk (hence the shrunken design).....the clean channel will only get used if they accidently fall on the pedal. 
I voiced it for lots of tight bass and added a NFB "contour" type control.

I spent approx. 7000 hrs. in the last 2 months, thinking, obsessing, tweaking, playing.....repeat

The very last move was something I picked up by reading a post from HBP, about 2 weeks ago...
I had a little too much sloppy bass and was trying a bunch of stuff, and he had told someone to knock down the value of the coupling caps from the PI to the Output tubes (pretty obvious right?)
Well, that was the magic touch...
In my attempt to have a strong bass presence I had used .1uf,,,BUT found a much tighter sound, feel, response in a lower value of .05, and it shaved just enough to make the speakers happier, without losing the impression of "crushing" bass.

I'll never forget walking out of my shop that night with a big smile, thinking....that's it....I GOT IT! 

Thank you HBP, and everyone else who takes the time to repeat themselves, over and over....sometimes we just need to read it more than once 

[Ritchie200]

Baseball - Schmaseball.....(meh!!! is right)
NOTHING even comes close to playoff hockey....get off my thread you lousy "Sweet Home Chicago"ian 
Last time I saw the Blackhawks in the finals, they stole my cup on a weak goal in OT   

 

SG, Don't worry, the Blues will be spanking the babies and sending them packing in the first round - as a matter of fact, the puck just dropped.  We have several of our stud Blues players that have been cheap shot injured (HELLO! League office?!?! HELLO! Anybody home?!?!  what a crock...), but don't make this dog mad....

Speaking of spanking...wanna talk about the last Cards/Cubs series?   (Sorry Brad, I couldn't hep meself! )

SG, build looking good!  Will this have the Herzog?  Are you gonna give us a recording of this one when you are done?  +1 on the XLR connector.  Ritchie used isolation trannies for his Majors when he toured.  His tech ditched the power cords and set up connection for power via XLR connectors on amp and trannies (see pic below).  Those things can handle some power.  The plugs you are using look good too.

Jim

[lego4040]

Yeah I'm a Ranger fan, I'm up in Buffalo now with nephew watching the game. Flyers have always been a tough team, Blackhawks tied right now too, those aluminum chassis can be soldered but the aluminum rods are expensive. The ride from manhattan to buffalo was nice but ling

[SILVERGUN]

SG, build looking good!  Will this have the Herzog?  Are you gonna give us a recording of this one when you are done?  +1 on the XLR connector.  Ritchie used isolation trannies for his Majors when he toured.  His tech ditched the power cords and set up connection for power via XLR connectors on amp and trannies (see pic below).  Those things can handle some power.  The plugs you are using look good too.

Thanks man...no Herzog on this one....I gotta get this one done so I can get back to that...
I never would've guessed about the XLR's, but now I'm thinking about them.
And yeah, I'll get a clip of me hacking up some metal riffs when it's time.   

Yeah I'm a Ranger fan

Alright, I'll look the other way, this time 
Tough night for us tonight.....good game, bad score.


Back to the amp on Fri...and the good news is, I've had a layout epiphany 

More good news...preliminary voltage tests were 100% on the money..I can move on!

[lego4040]

Of coarse I missed third period to eat and hang with inlaws and missed it. Glad voltages went well, I got to remember to call about my transformer order tomorrow. Having a goaltender that hasn't  been playing is tough.
This is my first scratch amp but looking coward to build a next scratch amp

[Willabe]

Speaking of spanking...wanna talk about the last Cards/Cubs series?   (Sorry Brad, I couldn't hep meself! )

Yeah, gonna be a long summer, but still better then that last loooooong winter!                


                       Hot Dog, get your Hot dog here! Beer here, get your cold beer here, Play Ball!



                  Brad        

[SILVERGUN]

Here's a progress update so you guys don't think I gave up....
Sluckey was dead right about this chassis size being difficult to work in....ehhh
Ed's probably got me on the clock, so I figured I better show some progress before I get demoted back to a Level 1 

I also took a couple minutes and cropped out the crap---painless,,,and I was able to get 4 pics in one post with room to spare
Back on it on Mon. night and I'm getting that,,, getting close feeling 

[TIMBO]

GO SG GO GO SG GO  GO SG GO.......................... SG SG SG SG SG

[lego4040]

I dig it man, where'd you score the turret board? It's a nice color, what are you using for your passives?

[Ed_Chambley]

Here's a progress update so you guys don't think I gave up....
Sluckey was dead right about this chassis size being difficult to work in....ehhh
Ed's probably got me on the clock, so I figured I better show some progress before I get demoted back to a Level 1 

I also took a couple minutes and cropped out the crap---painless,,,and I was able to get 4 pics in one post with room to spare
Back on it on Mon. night and I'm getting that,,, getting close feeling 

Nice!  No clock here.  Good work takes time.  I have some projects I have been working on for much longer, but not to say they are good work.  Seriously, great concept.  Gain to go!

[SILVERGUN]

You got it TIMBO! 

I dig it man, where'd you score the turret board? It's a nice color, what are you using for your passives?

Thanks lego, I bought a sheet of this Garolite G10/FR4 and a sheet of the G-11 (green)
I had a bad experience with some prepunched black boards being conductive, so I looked into it a little deeper and found this...I like the black for a "metal" type amp 
http://www.mcmaster.com/#garolite/=rp2os2
I use a wet tile saw to rip it down and a steel chop saw to cut to length.

Passives ,,,metal film 1/2 watt resistors and a combination of Orange drop and Mallory 150 caps....nothing fancy
In some spots I like to split the value of capacitance and use a combination of each cap type for "better" tone..
You just missed this thread by a couple months: (still just an unproven theory)
http://el34world.com/Forum/index.php?topic=16281.msg159408#msg159408

[SILVERGUN]

Nice!  No clock here.  Good work takes time.  I have some projects I have been working on for much longer, but not to say they are good work.  Seriously, great concept.  Gain to go!

Thanks Boss,
I kinda forgot how time consuming this stuff is.....breadboarding is CHEATING

Concept is the key word here......we'll see 

[Willabe]

Nice!!!!!


             Brad     

[TubeGeek]

Nice!  No clock here.  Good work takes time.  I have some projects I have been working on for much longer, but not to say they are good work.  Seriously, great concept.  Gain to go!

Thanks Boss,
I kinda forgot how time consuming this stuff is.....breadboarding is CHEATING

Concept is the key word here......we'll see 

 


Speaking of breadboard….I have been thinking of finally building one of those and I really liked how yours came out so I'll be "borrowing" the design.

[SILVERGUN]

Speaking of breadboard….I have been thinking of finally building one of those and I really liked how yours came out so I'll be "borrowing" the design.

Do it!
Best thing I ever did for myself....
It doesn't have to be the greatest breadboard ever,,,it just has to be.
The creative freedom it has given me is priceless, and I enjoy it so  much that I had to make another 
I was able to build this amp in 2 nights (coulda been one), tweak it for a month, and THEN start drilling holes....

My variable voltage supply is my favorite part because I built it separately from the 1st board, with a variac + xfmr than can supply 0-480VAC that also has a front panel outlet that can deliver 0-120VAC, so when I'm not using the breadboard, I can still use the variac.

[lego4040]

I actually read that article and had that topic going over at BYOC. some people say it's not worth it and I've read from amp builders it's a great way to do the couplings. It's not much more work at all, my thing is figuring out which ones would be the coupling caps. I'm no amp tech, I'd remember it if some one said it's this cap off of this pin but I couldn't just look at a circuit and know. Could you school me quickly?

[SILVERGUN]

I actually read that article and had that topic going over at BYOC. some people say it's not worth it and I've read from amp builders it's a great way to do the couplings. It's not much more work at all, my thing is figuring out which ones would be the coupling caps. I'm no amp tech, I'd remember it if some one said it's this cap off of this pin but I couldn't just look at a circuit and know. Could you school me quickly?

I'm not really qualified to give technical explanations, but here's my own simple explanation that I use so I can sleep at night...
Coupling caps are used between gain stages to block DC from entering the grid of the next stage.....and at the same time, they are used to shave frequency at a desired point.
The higher the value of capacitance, the lower the frequencies that make it through to the next stage....

[lego4040]

Your input cap would be a coupling caps as well then wouldn't it

[SILVERGUN]

Your input cap would be a coupling caps as well then wouldn't it

Input cap?...

[lego4040]

Shoulda been more descriptive. One article I was looking at about coupling caps. The schematic he had as an example had a cap right after the input jack before the preamp tube and he had it labeled as coupling cap. If you were building say a pedal, you always have the input"tone cap" right after the jack on your build.  From looking at schematics of some amps I have laying around none if them had that. It's input jack/resistor then preamp.

[TIMBO]

Hey lego, the marshall jubilee has that cap at the input. It keeps DC off your guitar pots, not sure about it being a tone cap.

[Tone Junkie]

Some of the real high gain amps will have whats he,s calling an input cap. I don't know the proper name, could be just that. There is an example in Merlins book a .1 cap to ground at the input on the first tube. Right after the 68k or what ever you use on the first input stage. It cuts high frequencies to curb fret squeel . When you slide your hands down the strings. Ive used it a couple times  it also allows me to use smaller caps across the anode resister. Because I have cut some highs at the front end.
Bill
I will find an example and post it later. 

[Tone Junkie]

Hey lego, the marshall jubilee has that cap at the input. It keeps DC off your guitar pots, not sure about it being a tone cap.

The one Im talking about would be right after the 68k to ground right at the tube. On that schematic I will look.
Bill
PS SG I really like the small footprint you have on this one with a high gain channel to.

[lego4040]

Ah ok, but it is used for blocking DC. Thank you, learning a lot here but there is so much

[Willabe]

Ah ok, but it is used for blocking DC.

No.

A blocking cap is in series and acts like a gate that blocks the dcv but lets the ac signal through.

The cap their describing here is bleeding hi-freq. to ground, so it's not 'blocking' anything, nor is it coupling anything.


                  Brad