Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: six el six on December 13, 2011, 10:41:34 pm
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Anyone have any experience with the components on the board of this era Fender?
I've heard these blue coupling caps aren't too popular. Anyone know why?
I'm attaching a pic of the board.
Is that exploded or oozing capacitor goo I see? I'm asking because I can't find the cap that seems to have caused it.
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I don't see any "exploded cap goo." If you're talking about the bubbled-up thick stuff on the board, that era Fender always had a heavy coating of wax on the fiberboards. Perhaps it was to keep them from absorbing moisture and becoming partially conductive.
I may be wrong, but it looks to me like someone has done quite a bit of modification to this amp. Not so much with parts values swaps, but all the small electrolytics were replaced some time back, and there are extra pots that I've never seen on a Twin Reverb. There's also a jack of a type I've never seen in a Fender before, next to the speaker jack (the way it overhangs a socket makes me nervous).
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I don't see any signs of anything having ever been done to it though I certainly could be wrong as I've never seen inside one of these beasts.
This is a 135 watt late seventies early eighties jobber.
Looks exactly like the schemo. Schemo attached.
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the pots on the back are the hum balance and output tubes matching. nothing special about them.
that type of jack was also used for the speaker output in the Super Twin Reverb. the jack next to it is a line out and probably a secondary speaker out. i think even the electrolytics are are stock, they look the same as in the Super Twin Reverb.
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I've heard these blue coupling caps aren't too popular. Anyone know why?
I've heard (& experienced) just the opposite....those are pretty good caps, especially when compared to the dull brown "dog turd" caps found in some of the early 70's models. I'd keep them (if they are not leaking & the amp sounds good, that is....)
$0.02
G
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I've heard (& experienced) just the opposite....those are pretty good caps, especially when compared to the dull brown "dog turd" caps found in some of the early 70's models.
You're thinking of the other blue Fender caps.
There were blue caps in 60's Fender's with a solid plastic outer shell and a paper label; the label said "molded" on it.
Later, in some late 60's to early 70's amps were the brown dipped caps that you're talking about. Even further later on, there were blue dipped caps with white lettering printed on them. They had nothing in common with the blue molded caps that everyone seems to be nuts over.
For what it's worth, people have only said anything nice about those blue molded caps since ~2000 and after. Before that, the "only caps that mattered" were Astrons. I'm 90% sure that's because they were in the tweed amps becoming very expensive at that time, and the "mojo" was attributed to the caps (among other things).
At the same time, "orange drops" were supposed to be the greatest thing since Astrons, although there are two different series of orange drops from Sprague, and many more by other companies. And the OD's that everyone used sound nothing like Astrons. Anyway, people used to pull the molded blue caps out of their blackface amps to through OD's in there.
I'd thank Gerald Weber for making everyone think Mallory M150's are the next great cap, as he announced they sound like old Astrons (and thereby justify their use in his tweed amps that meticulously copy every other detail of a tweed Fender).
Now of course, we also have audio-phool caps muddying the waters, and limited capacity manufacturers like Sozo proclaiming they have the best thing out there.
It also surprises me that I can't recall anyone talking about mustard caps in british amps until within the last 5-10 years.
[Background: The first "amp forum" I ever got on was via dial-up in the early 90's. Mark Baier was one of the forum members before he started Victoria Amp Co, and was seeking the ultimate combination of parts and tubes to make a tweed Bandmaster at home. That was the brass ring because so few were sold, they were very hard to come by and very expensive.]
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There's also a jack of a type I've never seen in a Fender before, next to the speaker jack (the way it overhangs a socket makes me nervous).
Fender did use that Jack, but I've only seen it in Super Twins.
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That could explain it. I've only seen a Super Twin in person once, and had zero desire to open it up.