Guild RC20 Reverb Converter

This one is on Ebay now. Not many around ... didn't sell? Didn't last? See Guilds O Grot or Hans Moust about dates of manufacture. In pretty good condition; it imports a dry signal from another amp, fed through a volume control, and into the preamp. With the reverb switched off, it's a sweet little 6BM8 single-ended 10 watt amp. Auction includes Guild foot-switch with fluted ... or routed ... upper edges.




Except for using diode rectifiers, pretty much a dupe of the Gibson GA1RT; single 12AX7 for preamp and driver, triode half of the 6BM8 as the tremolo oscillator, and the 6BM8 pentode as the output tube. This model still has a death cap - red X - and two of the original power supply caps are getting ready to go south with blisters showing / magenta arrows:




The '371' EIA code on the alnico belongs to Best ... that's it ... Best; 10" ... almost anything newer would be a major uptick:



Thanks to an LTG member who found it taped to the back of his Guild 98RT, the schematic is available here in pdf form




For anyone with a 'dry' amp who wants to say good-bye to reverb via dig-pedals, this or Littlesongs' Ampeg EJ12A are the way to go. This one with a new cord, fresh caps, and a new speaker ... $150 or so ... would be a fine way to get both reverb and a stereo (dual mono) effect.

Sold $355 with 13 bids.

I'd like to build one of these but I have no idea of what reverb tank it uses. Anybody??

Standard Fender reverb tank. 8 ohm imput because you will most likely be alligator-clipped to an 8 ohm speaker on the signal source amp.

From some quick pokin' around the 'net I found it could be an Ampeg-style 4F tank. The high input impedance (1475 ohm) wouldn't interfere with the amp's output as much as a Fender-style's 8 ohm input. No idea what the output impedance would be.

I can't offer an opinion as I only have internet on the BBerry and I can't open pdfs yet. Pretty sure the Gibson GA1-rt has an 8 ohm input tank.