NAD 1967 BF Bassman AB165 rough player

Silverface

Doctor of Teleocity
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Joined
Mar 2, 2003
Posts
10,151
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Regarding the AB165 1967: The previous owner had been using it in it current configuration. I know that the caps need to be replaced.
Again, just friendly advice - the former owner using it "in the current configuration" is totally irrelevant - and un less he is a close friend you don't actually know he was using it st all- or how much.

While amps that have been sitting for years, and the buyer is the first one to turn it on in a long time, are the most likely to be grenades ue to crystallization of the electrolytic paste in filter caps - ANY amp with caps over 15-20 years old can blow with ZERO warning - in fact, many seem to sound incredily good right before there's no sound and sdmoke comi g out of the open jacks!

I've had at least a couple dozen newly purchased amps brought to me for repair by surprised buyers who simply turned them on, or used them for a couple minutes - and the seller said they'd been using the amp, provided pictures of everything(even old filter caps - or buyers didn't know to ask how old they were.)

Most are a little surprised at the $150-200 estimate for a cap job and general service - which, BTW, techs make little to NO money on - but the ones who get a $500 estimate for a cap job, power transformer replacement, cleanup of electrolytic paste and smoke residue and general service are shocked and often ask for a letter blam ing the seller so they can get the work paid for or get a refund.

Nope. The seller is not at fault, and buyers who try to find a tech who will blame the seller are out of luck around here. It's the buyer's fault for being careless.

I've bought quite a few vintage amps myself. Filter & bias caps and grounded ACC cords are the first things I look for, and I never power them up until those items are handled - as they can damage the amp.

And FWIW less knowledgable buyers ignore those items and replace old tubes right away, because they are...old.

Which is plain silly. Power tubes *might* have drifted off-bias match by more than 5ma - but not usually. Generally ALL the 50-60 year old GE, RCA, Sylvania and other original tubes are fine. 2 of my 3 blond Fenders have all original tubes, and the third (a Bandmaster) has 2 replacements in the preamp.

WHY players think they need to re-tube every amp yearly or every 2-3 years are apparently reading info posted by reps from tube companies....

Enjoy the amp - but please, for its health...and your wallet. don't turn it on again until AFTER the filter and bias caps are replaced and other parts tested and replaced as required.
 

ETMusic777

Tele-Meister
Joined
Apr 29, 2022
Posts
107
Age
42
Location
California
Thanks, Ive learned to do the work on my own amps, spending hundreds of hours here, on Rob Robinnette site, youtube videos and coursera courses to expand my prior knowledge of electronics and apply it to amps. So far, I have recapped/restored several vintage blackface amps and am going to tackle the 1967 Bassman next week.


I dont know how amp techs make money on these things. Parts are inexpensive for the most part, but time costs money.
 




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