Friday, December 17, 2010

Bell 2122 Classic 6V6 Tube Amp

Bell 2122 Working Again!

When I was in 4th grade I listened to this amp playing classical hi-fi from a FM Tuner in Chatham NJ.  Years later I took it to college with me as a freshman.  The next year I upgraded to real stereo. The Bell worked until a few years ago when the power supply had the dreaded 'Hummmmm....' of a bad filter capacitor.  A quick Internet search led me to a post by someone else who had one and I acquired a nice copy of a 1948 Sams Photofax for the unit.  This year an internet search led me to Ampmonster, an Austin TX guitar amp company that had a good write up on restoration of the Bell.  With this site and the photofax I made a list of parts needed to redo the amp but when I opened it  up yesterday I tested the caps and found many of them to test close to value the electrolytics were bad though.  I took a 220uf and clip leaded it in parallel with the HV filter and the hum went away and the 2watt resistor connecting the two filter sections opened with some sparks and a small amount of escaping smoke.  An old replacement resistor was found and seemed to run cool so I wired the cap in for a more permanent temporary fix which will allow me to play with the amp a bit if desired.  Some DeOXit sprayed into the controls seemed to help and the tubes were tested and one bad 6SC7 (dual triode similar to the 12AX7 in a metal octal package) tube was replaced.

New Filter Cap in place

Sticker inside bottom plate

Rear panel

Pair of 6V6's 

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