Junk Pile Delight

[odourboy]

I was looking at my junk pile a few weeks back and realized that there was most of what I needed to cobble together an amp along the lines of a 6V6 D'Lite. So late last week, I started to assemble this 'frankenstien', recycling as much as I could.

The core of this project is an old Hammond Organ A0-35 reverb amp chassis and transformers (and some sockets). That chassis is very 'compact' so I bolted on a couple of 1/8" aluminum front and rear panels that I liberated from another defunct project to gain some extra real estate for controls (A solution to a problem that I thought was worth sharing.) I had to make some custom boards, but most everthing else (including a good portion of the components) are recycled.

Everything is pretty tight (for instance, no room for 6PS caps, so I settled for MPPs for the most part) so there's a good chance I'm going to run into some issues... time will tell. Although there's still quite a bit to do, here's a funky slide show of a few build pics I took today:

http://s197.photobucket.com/albums/aa16 ... 74766a.pbw

Cheers, Brian

[Johnhenry]

Very nice lookin build, i can tell you put some Thought in to it, it show's !
My kind of amp, I love to take the ugliest mess and revive it into somethin that sound's good, plus sometime's your saving an old amp's life that might have got pitched in the trash,
+ to you Brian.
Johnhenry

[nickt]

Hey that looks pretty cool - especially for a junk pile! ...ahhh ... but I see the pots are yet to be connected...

Nice job odourboy!

[Bob-I]

As many folks can attest, I love junk pile amps, the junkier the better.

Looks really great. I like the layout with the way you mounted to board. I may use that in the old movie projector amp I pulled out of a trash can a few years ago.

[phalanges]

Very resourceful.
You make it look easy.
I also dig how you've mounted the board.

[heisthl]

Outstanding - I've got a junk pile you wouldn't believe - will you make me some amps?

[odourboy]

Thanks guys!!

Nick - pots will be wired in today. Should go smoothly - most of the wiring is to the top edge of the board.

heisthl - LOL! You are the master and I am but the lowly grasshopper.

[BobW]

Odourboy, Where I can locate the transformer info or schematic? I've got an old Hammond tone Cab w/ chassis, and every transformer on the chassis is unmarked and sprayed with a silver overcoat. no markings on the inside either. It seems to have two OTs, both have RCA 6L6GCs. any help is appreciated.

[heisthl]

Odourboy, Where I can locate the transformer info or schematic? I've got an old Hammond tone Cab w/ chassis, and every transformer on the chassis is unmarked and sprayed with a silver overcoat. no markings on the inside either. It seems to have two OTs, both have RCA 6L6GCs. any help is appreciated.

Nice find for doing stereo FX return to output. Most of those old Hammond Organ amps were rated at 25 watts. How big is the power xformer? Is the P/S typical half wave, full wave, doubler or rectifier tube? If the tubes are good and you can find the right buyer, they're probably worth the cost of the new parts to make an amp. Without a schematic you can still reverse engineer the P/S with new parts and gut every thing else (Keep track of the OT leads) and treat it like a new build, even relocating it to a new chassis if desired.

[odourboy]

Odourboy, Where I can locate the transformer info or schematic? I've got an old Hammond tone Cab w/ chassis, and every transformer on the chassis is unmarked and sprayed with a silver overcoat. no markings on the inside either. It seems to have two OTs, both have RCA 6L6GCs. any help is appreciated.

Yep - mine is like that too - but using the Hammond part number for the amp chassis (stencilled on the outside), I was able to locate a schematic... here:

http://www.captain-foldback.com/Hammond ... matics.htm

No specs on the transformers, but the OT on mine was orignally an EL84, so I am confident the impedence would be suitable for 6V6 as well. And Hammond was notorious for over-engineering their amps. Hope you can find what you need there.

[skyboltone]

I think I got about 6 or 8 hammonds in the shop. I'm just floored by the front and back extensions to the AO-35 chassis. Why didn't I think of that?

Anyway, the AO-35 PT and the AO-29 OT make an outstanding two hole liverpool.

On the AO-39 and 43? I think, you get an 8k OT that mounts above the chassis rather than sticking through. I think it helps a bit with hum. The AO-29 is a 10.5K OT. The AO-35 is 8.8K.

Dan

[BobW]

No specs on the transformers, but the OT on mine was orignally an EL84, so I am confident the impedence would be suitable for 6V6 as well. And Hammond was notorious for over-engineering their amps. Hope you can find what you need there.

Thanks! seems I have the JR-20 chassis. w/ a typical 5U4 rectifier and bass compensation switch.

http://www.captain-foldback.com/Hammond ... code_C.gif


And heisthl is right, it's probably a 25W output based on the 6V6s called out on the schematic. That's still OK, I can use the 6L6s in my 100W (still watin for parts though)

[odourboy]

Well - a couple of days later and the we have liftoff! I wired in the pots and temporarily hooked up switches for OD and PAB (I'll be installing relay boards from Ampdoc but I don't have them yet).

Anyway, I fired it up, tweaked the voltages a bit, fixed the OT primaries (why does it seem I ALWAYS get these backwards ), fixed another small blunder due to a layout error... and got tone!

I have not but any means put it through it's paces, but out of the gate, It sounds pretty decent. Still to do... relay boards, combo cabinet, foot switch, front and rear face plates. Here's some progress pictures:

http://i197.photobucket.com/albums/aa16 ... CN1777.jpg

http://i197.photobucket.com/albums/aa16 ... CN1774.jpg

http://i197.photobucket.com/albums/aa16 ... CN1776.jpg

http://i197.photobucket.com/albums/aa16 ... CN1775.jpg

Thanks for looking!

[nickt]

In the last photo I think I see a dry joint on pin 3 of V1...



... nah just kiddin'


Still looking pretty cool odourboy!