combine this preamp with that power amp

[embotone]

I am still pondering an interesting circuit for an acoustic guitar amp.  Would there be any issues combining the preamp form RicharD's Janitor amp  http://www.el34world.com/Forum/index.php?action=dlattach;topic=11329.0;attach=22892;image   with a power amp like this  http://www.r-type.org/static/5-20b.jpg.  How could I incorporate reverb into this amp?

[DummyLoad]

why not build the whole ckt?

--DL

[embotone]

don't really need that kind of power and would prefer to keep the amp lighter than  what I  think that one would end up weighing

[DummyLoad]

don't know if i would build an acoustic amp with cathode bias EL34 - IMO, not enough headroom, yes, you could join the two - tweak the PI to drive the EL34s or leave it alone, or just steal AB763 LTPI or something similar. 


--DL

[PRR]

> RicharD's Janitor amp

Power stage has gain near 9.

> a power amp like this

Power stage has gain of 57.

Big difference.

> don't really need that kind of power

Probably not a huge difference. 35W vs 50W?

Change Richard's plan to 6K OT, convert bias to the 470 ohm cathode resistors; power will come down the few watts. Vacuum rectifier will drop a bit more. For "Clean", I'd change his PI tube to 6SL7 so the NFB is more solid.

[RicharD]

The Janitor never made it off the protoboard.  Honestly it wasn't all that loud, but it was 100% clean sound.  A little deceptive to the ears.  Heavy?  Uh yeah!  The choke alone is massive.  I like PRR suggestion about the PI given my recent NFB experiments.  I think I'd keep it fixed bias which is not the norm for me (I like cathode bias).  I am flattered people are still looking at this circuit.  It was a very cool experiment which I may revisit some day.

[embotone]

Well, I would like to incorporate the ideas in this amp, but I am really trying to avoid building a heavy beast(by request of friend who asked me to build him something). If I could reduce this down to 35- 40 watts or so,  I could use lighter transformers and choke.  My buddy doesn't really need anything too loud, he probably will be using it in his living room 99% of the time.  Heck, he could probably just use a Mr Microphone, that's about how discriminating his ear for tone is.  I just wanted to build something that I found interesting. By the way, what specifically is a Zilla supply.  I realize it is a regulated power supply for the heaters.

[RicharD]

>what specifically is a Zilla supply

Me being too lazy to redraw the 12VDC regulated supply that lives on my protoboard, named Zilla.  Here's a picture of the protoboard and a schematic that has the 12VDC supply shown.