36W for Bass?

[deadgame]

Has anyone modified this circuit for playing Bass? I have someone asking and figured since I successfully built an 18, maybe a 36 would be a cool next project.
Thanks
Don

[zevoz]

You'll need a lot more clean headroom or it will just fart.

[deadgame]

Yea I dont have any experience with the 36 watt but it was my understanding that it had a lot more headroom than an 18. So I figured with some guidance I might be able to clean it up even more to eliminate the "fartyness" and with the right speakers get some good garage jaming bass action.
thanks
Don

[deadgame]

Ok, so nobody liked that question; must have been stupid... I have a more specific quesition. Is there a good SS recto circuit I can plug into this instead of using the GZ34? Any drawings or something most people would use for the 36 watter? I think I am seriously going to try doing this.
thanks
Don

[Ballz]

Don...just "some guidance" won´t help, I´m afraid. If you want to have decent bass sound thru a 36W it´s more a matter of actually redesigning the preamp a bit to suit bass, stiffening up the power supply and redesigning the power amp section (maybe for other output tubes like 6L6 or EL34). You decide if it´s worth the trouble. With 4 x EL84....I doubt the tonal result will be all that great. But then, that´s me..and Vox made a "bass" version of the AC30 that sounds pretty good up to a certain level.

In any case - good luck with it.

Cheers /Rick

[bigsbybender]

Bass is Best with 6550's or KT-88's 6L6 is ok but a little dirty even. I used 2x EL34 and liked it but it got a little wierd and wild in the midrange at any usable volume. EL84 or 6V6 aren't too usable either.
36w isn't enough for bass except sitting in a bedroom

my 2 yen

J.

[deadgame]

Thats cool, I am open to suggestions... I am just hesitant to run to another site looking for schems and layouts because I know the 18 site is trustworthy resource. If there are better projects out there people please suggest.

P.S. I am still interested in the 36Watter for reasons other than bass so if you can guide me to an applicable ss-recto circuit I would still appreciate.
thanks
Don

[Kingfish]

I put together a very credible bass amp using the JTM 45 schematics as a starting point. After all, the JTM 45 traces its lineage to a bass amp and all of the parts are readily available. I used KT66's for the power tubes and changed values around based on the Ampeg B15. Pushing a 15 inch speaker, it sounds great and keeps up well with a guitar player using an 18 watt. YMMV

[SpentMusic]

I have to agree with Ballz.

You will need to make almost a new amp if your end result is planned to be only for bass. The EL84 just does not have a good solid bottom end. Even the Jtm 45 layout, which came from a bass amp ( one of the worst bass amps ever made, LOL) just does not have the head room. The 36 watt is twice the size but really does not have anymore head room then the 18 watt. Just louder.

Suggestion is to make the 36 watt amp and use the V, T channel for experiementation for a bass circuit. You have everything there and just add in an extra filter cap (watch out for working the rectifier to much) for that channel (will increase head room a bit) and change the slope resister and cap size to change the tone range. A few easy things to do and if you go it stinks, just change it back to a normal 36 watt channel!!!

You will learn a lot just doing it.

Jeff Swanson
DST Engineering
www.dst-engineering.com
www.swansoncabinets.com

[deadgame]

Thanks I have been looking for a JTM45 layout and schematic and have found a few Traynor schematics and photos that might be good for this project. What is the best resouce on JTM45 type amps?

[Tof]

you might need a hi fi OT for that

[SpentMusic]

Hi deadgame,

There is a great forum on Yahoo dedicated to the Jtm 45 amp. You can get to it here. http://launch.groups.yahoo.com/group/JTM45/

Lots of schematics and people that know that amp inside and out.

Jeff Swanson
DST Engineering
www.dst-engineering.com
www.swansoncabinets.com