simple guitar push pull amp

[dan _s]

Hello all

i have a small Peavy guitar amp+speaker cabinet. i'd like to build a tube amp to replace the transistorized unit in the cabinet. i have a push pull output transformer which i could use for that

what i'm looking for is the schematics for a guitar amplifier to which i can incorporate the speaker and transformer. it may use a pair of 6550 or EL34. preferably with an option for overdrive / distortion modulation

the the transformer has primary impedance 4500ohm, secondary 8ohm. the cabinet has one driver, resistance 3ohm.

i got a referal to this webpage http://www.drtube.com/guitamp.htm it contains hundreds of circuits but there's no way to browse this list by amp specs. i'd also like recommendations for proven designs


thanks
dan

[leadbelly]

First of all, please identify the original thread when you cross post the same question to a different forum.

Also, I am not sure all of your requirements can be met. You have a 4.5K:8 OPT, a 3 ohm speaker, and want to use a pair of 6550's or EL34's.

If you use that transformer with a 3 ohm (let's call it 4 ohm nominal) driver, the primary impedance will be 2.25K. That's too low for 6550's or EL34's, especially if you expect to drive the output stage hard for a dirty sound.

So, what do you want to compromise? If you must use that transformer, you should either pick a different tube to use, or maybe use a quartet of lower power tubes (e.g. EL84's or 6V6's). Or do you insist on your tube choice and want to buy a different transformer?

[dan _s]

i didn't i would make a difference, my first post on this matter in this BB system was here

what i have in hand is the OP transformer (a pair in fact) and the driver in the cabinet. i don't care which tube to use as long as it's electrically suitable and easy to find and buy
i also bare in mind the possibility that the what i have may not fit together

[leadbelly]

Well, frankly, because there are so many choices out there, I'll have to move into subjective & personal opinions.

You want a proven design. To me that says clone a classic amp and stay away from the AX84 ilk (I know I may be spammed for this). For that OPT, you can build a Vox AC30 clone with a quad of EL84's or a Fender variation with a quad of 6V6's. If you are thinking practice amp those are too much power so use a quad of 6K6's.

[dan _s]

Thanks!

[ray_moth]

Leadbelllly's advice makes good sense.

Leadbelly": I know I may be spammed for this

I hate to disappoint: SPAM!

[Merlinb]

Originally posted by leadbelly
stay away from the AX84 ilk

Why? Surely a guitar-amp dedicated website is exactly the place to hang around, if you're into that sort of thing...

[mashaffer]

I got a lot of very good help from the AX84 guys on my build. I ended up using their preamp schematics to develop mine. I used a 6V6 18Watt style output though.

[leadbelly]

Originally posted by Merlinb
Why? Surely a guitar-amp dedicated website is exactly the place to hang around, if you're into that sort of thing...

I guess the spamming is starting I was referring to designs of that ilk. He wanted a proven design so I told him to clone a classic amp rather than build a DIY design that few people have built.