1960 Fender Bassman /// Restoration Project
JC Maillet (c) 2005
posted 2/15/05
I friend of mine who techs on the island contacted me to ask if I was interested in tackling an old Fender that hadn't worked in a long time and seemed beyond his skills to repair (which I highly respect). The amp was a gift to the owner by a guitarist who had passed away - a very precious item in many ways !
I went through the amp and changed all the electrolytics, and put in a variable bias circuit - a must with this kind of tone potential ... someone had disconnected the presence circuit and had removed an Atom signal cap ... by putting in a three-prong cord and disabling the (now) un-necessary ground switch I took the 0.1uF/400 Atom cap from there and luckily used it as an identical replacement in the Presence control circuit ... except for new grid and screen blockers on the power tubes the rest of the signal path remained stock - which I was quite happy about ... no burnt or cracked resistors anywhere ...
I did find two nasty cold solders in the circuit : one at the speaker jack and the other hiding on the underside of the component board near the front jacks ... it can be quite tricky to lift the board without damaging any wiring - best way is to unscrew the pots and jacks and lift from that side rather than unsolder tube socket wiring. Interestingly, even though the amp is a 5F6-A the output stage is actually as in the 6G6 version, with a 6k8 resistor int he PI circuit and a scratch-less Presence circuit (with a 25k pot) ...
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Groove Tube glass all around (repackaged EH tubes) ... supreme, "unimaginable
tone - simply baffling, what a beauty ! (... yep, the best ...)
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I would like to thank Jim for sending these gorgeous pics ... what a treat is was to revive this fine piece of craftsmanship and ultimately get to final test it for a few days ... :)~
viva Analog /// jc -> lynx.net