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Old 10th June 2006, 10:55 PM   #1
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Exclamation antique fender bassman 50 retubed HELP

a friend of mine had put a fender bassman to repair on local guy. but he didnt check the amp properly. he retubed it and changed all the power supply caps fixed the bias section and bla bla bla but now it has LOTS of gain. it distorts BADLY i0m tring to get the gain better but that new ( sovtek ) tubes are hungry for gain.

i have about 140 / 150V feeding the preamp tubes and the cathode resistor is now 2K2 ohm. it has less gains but stil has to much.

sould i uze a kind of voltage divider on each gain stage of this amp ? or what kan a go better ? are the preamp tubes 'cold' with 150V ? anr with 2k2ohm on the cathode ?

The schematics are at

http://www.schematicheaven.com/fende..._bassman50.pdf

on the last gains stage before the phase spliter i get the cleanest sound that i ever heard.

so the gain problem is before that.

please help

i home i'm clear enough.

tankx in advance ^^
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Old 26th May 2008, 11:06 PM   #2
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Red face bassman 50 head, 1973

obviously missing a resistor to ground or a wrong value's been fitted, could be a faulty capacitor or bad valve. you can't really go wrong these are such simple circuits.. you can e mail a close up of the amp i'll have a look, or send it to me with the valves and case removed and i'll fix it. (you pay carriage both ways though..)
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