Picked up a set of outputs, the power tranny and even the filter cap from a single sale
on eBay. Apparently, the guy disassembled some small console or phono player.
The outputs turned out to be by Woodward-Schumacher, but I have no idea who made the
power tranny. All are date coded 1963.

The original tube was the 6AQ5, so I decided just to stay with that since that told me the trannys
could likely handle the 45-50mA, but probably not more than 300V anyway.
I also wanted to try one of these pentodes which has specs like a 6V6 (one of my favorite tubes).
Frankly, I didn't know what to expcect.

Been playing around with plate feedback lately, and liking what I heard,
so I started with that as the premise. That lead to a high gain input tube, and fitting the overall
small tube influence, I looked at the 7-pin 6AV6.

The 6AV6 is not often seen, probably because there is only one triode per bottle.
Yet, this is an interesting tube, with designed-in consideration for low noise since
it was intended to be used as a detector amplifier. I wanted some gain to toss away
into the feedback mechanism, and with nice plate curves, the deal was sealed.

After testing the free filter cap, I decided to use it. Nice strong values.
I even used the low voltage section as part of the cathode bypass, although I added
some better stuff of my own including film.

Here is the schematic.
In the final setup, I didn't get quite as much B+ as I wanted, but everything
considered, and how it sounded, I left it alone.
The amp uses PIO coupling caps, and the output cathode are Panasonic low ESR bypassed
with the original 70uf and further bypassed with a 20uf film.

I've always wanted to build an "amp in a box" kinda thing.
So I started out designing a small box-like chassis, but then ran across
this home-made box at a yard sale, an decided everything could fit.

Update 8/14/09:
Circuit and assembly is finished and the amp sounds great.
Virtually dead quiet on heaphones.
Plenty of power for my little speakers (about 3.5W/ch.).
I forgot to take a pic of the actual assembled amp circuit, but I've added a few
more pics. Box is ready, but I haven't mounted it yet.

Update 8/15/09:
All completed! The old box is a little rough, but all in all it presents well.
Overall size (closed) is about 7" x 7" x 10.5".
Since I wanted to NOT use regular speaker connectors to help make things fit,
and not have them sticking out the back, I made a special set of color coded speaker
wires using some 16 ga. oxy-free copper wire to use with this amp.

Rectifier is 6CA4/EZ81.

Earlier pics: