Firefly PP power amp

[LiLFX]

I'm wanting to borrow the poweramp from the Firefly. Does this look ok? I'm not too versed in tube circuits, and this seems very straightforward, but even the most simple things can be complicated.

http://imgur.com/J7sYrTH

[gtudoran]

Yap, that should be it. It's a self-split configuration. As for the first run i would take C2 out of there and bypass R3 with 100uF / 16V (or anything over)
And i would go with R2 = 500k and a bright cap for the volume pot 100p over pins 2 and 3 of the pot.

Regards,
DeX

[MetalGuy]

From what I remember about this type of self split circuit R3 should NOT be bypassed.

[gtudoran]

That is true, my mistake ... a reminiscence from the true PP amp

Regards,
DeX

ps: but there are PP self-Split configurations that are using bypassed resistor http://www.tdpri.com/forum/attachments/shock-brothers-diy-amps/241849d1404408880-self-split-6ak6-sv83-el84-self-split-guitar-amp-jpg

Little different topology

[PRR]

The VOL pot looks backward. As-drawn, it shorts-out the driver/preamp when all the way down.

Since zero is not a normal playing setting, and many preamps can be shorted with no lasting harm, it *may* be this way. But it's also a common mis-drawing, so check your source.

I'd say C2 can stay or go. Is NOT essential. Makes very little difference. If this cheapo half-balanced amp makes nasty highs, C2 may tame them some. If very nasty you might want a bigger C2. OTOH if your speaker has no highs, you may not notice any need for C2. But it will play without C2, well enough for you to decide where you want to take the tone.

[GFR]

Besides loading the pre it also adds series resistance before the power amp at lower volumes (removing some brightness at low volume to compensate hearing curve?).