Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: JJones on October 19, 2015, 09:51:35 pm
-
Hey all, still reading, but haven't been very active here.
I ran across a Silverface Bassman 10 at an auction and snagged it for a pretty good price. Based on the info I can gather, I think it's 1973 vintage. Other than the "Made in China" tubes (yes, that's all they say and they're pretty ugly) the amp looks completly stock and in good shape. The speakers are in good shape (square magnets at 32ohm each) with the only flaw being a couple of tears in the grill cloth. It fires up fine, seems pretty quiet, but sounds a little thinner than I expected (or remember from a freinds amp).
I'm going to put new power tubes in, but was looking for opinions on the PS caps. They're cardboard Mallory's, but no visible signs of problems.
Thoughts? Up date these while I have it on the bench or give it some time?
Thanks for all the great reads!
Jim
-
I have seen SF caps be "bad", I have seen them be "OK". They will not be "great". But they could last for a long time. If I was going to play the amp out, in a band, and gig with it and be dependent on it, I would do the caps. If it was an amp just for home use, then it matters little whether they blow now or blow in 3 years. They generally do not destroy stuff when they go unusable, they just blow fuses. Be sure the fuse is the right size (Always a good idea to check this on a used amp, yes?) so that it protects what it is supposed to protect. If the amp is reasonably quiet and not "hummy" you could let the caps go.
Taking a Fender amp in and out of the cabinet is not an an enormous bother, that wouldn't be my deciding factor.
-
> sounds a little thinner
Cathode caps.
Tack a 10u-33u across each (there are three). If a "25u"cap has decayed to 1-2uFd, a dozen+ extra uFd will bring back an octave+ of bass. When you find the punked-out cap(s), replace it (them). (Nearest standard value; here Fender was going for "all bass", the exact value is not critical.)
And if it is no-change, tack-solder is easily un-done so it is still dead-stock original (for what that's worth).
-
Thank you folks for the input. I did full maintenance on the old beast and it sounded so good, I thought a new grill was in order. I did upgrade the one cathode cap.
Great Fender clean, but volume is a bit much to get break up. I'm thinking of playing with the NFB, but right now, I'm just enjoying it too much. I did about 70% of the blackface upgrades and I love the way it sounds.
Thanks for being contributors on such a great site!
-
Nice grill cloth work!!