Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: 8wattjack on February 09, 2016, 04:27:39 pm

Title: What amp to build from spare parts?
Post by: 8wattjack on February 09, 2016, 04:27:39 pm

1

Title: Re: What amp to build from spare parts?
Post by: sluckey on February 09, 2016, 05:00:48 pm

Welcome!

You're in the right place. Which organ? Which amp? Several of us have converted Hammond amps into nice guitar amps. I've done AO-39, AO-43, AO-44, and AO-63. And I believe a member has a current project that uses iron from a Hammond PR-40. It's usually a good idea to keep transformer sets together and build a power amp that uses the same tubes. Locate a schematic for your Hammond and keep it handy. It could be that the power amp of your dreams is already built on that chassis and you just need to add a guitar friendly preamp.

Here's a Hammond conversion I did this past December.

     http://sluckeyamps.com/hammond_2/hammond2.htm (http://sluckeyamps.com/hammond_2/hammond2.htm)
 

Title: Re: What amp to build from spare parts?
Post by: Paul1453 on February 09, 2016, 05:53:36 pm

Yes, Welcome.

That PT should have excess capacity if you just do a PP 6L6 or 6V6 circuit.

You would need to know mA of current available for each supply to maximize what it could run.   :dontknow:

If your 800vct has enough current available you might be able to power 4 6L6GCs for around 100W of output power.
That would need a proper OT, obviously.   :icon_biggrin:

There are lots of very knowledgeable people here that help keep us straight.  Not me.
I'm also trying to learn how to maximize the old tube gear components I accumulate.
PTs and OTs are the most expensive parts,
so not burning them up needlessly trying out something you probably shouldn't have just makes sense.  :icon_biggrin:

Title: Re: What amp to build from spare parts?
Post by: Paul1453 on February 09, 2016, 06:47:56 pm

Here is a Hammond organ chassis I bought off Ebay.

It also had 3 amplifier circuits, but no Power Supply.

I decided to make 3 separate amps from these 3 OTs.
2 PP EL84 and 1 PP 6L6 amp.

I too have thought about having multiple amps on 1 chassis,
but more knowledgeable people here have clued me in to the problems that poses.   :BangHead:

I've decided I need to KISS (Keep It Simple Stupid),
until I am much more knowledgeable than I am now.   :icon_biggrin:

Title: Re: What amp to build from spare parts?
Post by: Paul1453 on February 09, 2016, 07:31:21 pm

You might want to read through this thread 1st:
Maybe it will keep you from starting off on the wrong foot like I did.  :sad2:

http://el34world.com/Forum/index.php?topic=19406.msg200705#msg200705 (http://el34world.com/Forum/index.php?topic=19406.msg200705#msg200705)

I am still fairly confident that amps like we have envisioned are possible to make.
But there are no schematics/layouts/known good configurations to simply follow.

I'm not convinced a multiple monster amp is worth more than 3 separate amps.
Who would buy this monster from you at a high enough price to justify your efforts?
It would be much easier to find buyers for 3 more conventional amps at profitable prices, IMO.
My idea was for an amp just for me and to never be sold.
Maybe someday, when I have learned many more untold things, I can pursue this dream again.   :l2: