[sdiy] sort of OT: Ward Airline phono input test: success!

[anthony]

So I cleaned up that neat looking Ward Airline radio's chassis, changed some 
caps and plugged my guitar through a hotrodded Peavey Hotfoot into the phono 
input of the radio. It's weird, it actually sounds like the AGC is working 
even when you're running it through the phono input - I got LOTS of 
disortion but not extra volume from the Hotfoot. It does sort of make sense 
though since the only preamp stage between the 6V6GT and the phono input was 
a 6AV6 hi-mu triode/dual diode - all sharing a common cathode. I'm pretty 
sure the diodes are for the AGC since there's a 6AL5 that I'm pretty sure is 
being used as the detector here (since this is an AM/FM radio). Hooking the 
amp straight through sounded nice and clean, but not much break-up since 
there was only 1 triode gain stage.

I was inspired to make this an amp only by an amp I saw on the Dirty Amps 
website, where he shows a radio he turned into a practice amp from a small 
radio. I think I can continue to use this amp as while tearing out the radio 
guts around it to make room for more gain stages. There are 2 9-pin sockets 
so I can use some 12AX7A's or 12AU7A's. Too bad most of the sockets are 
little 7-pin jobbies, oh well. I have some 6J6's that I could parallel up 
and I have some more 6AV6's too. I guess for a smallish table-top amp I 
don't really need to go for that much extra gain, but like I said before: 
I'm pretty sure I can fit a short to medium-sized reverb spring in here and 
I'd like to use a cathode follower before the power amp. I'm pretty sure I 
can adapt a lot of the AX84.com circuits in here to great effect.

I'll keep you all posted.

This will be my second radio become guitar amp, but this one is sort of a 
ready-made. The first used parts from 3 different All American 5 radios 
(well one was a Zenith 7-tube FM-only oddball) on a chassis that was 100% 
gutted (except for the sockets).

Also is there any advantage to be gained from switching - after years of 
use - which end of the filament that's used for the cathode on a 
direct-heated rectifier or is one of them always designated as the one to 
use?


cheer,
aa