Blackfacing and Silverface Twin

[wingobingo]

1971 (maybe 1972) Silverface Twin Reverb - 100W, master volume - not push pull pot. What is involved with "Blackfacing" this amp? Can it be done and still retain the master volume pot and circuit? Any ideas/thoughts would be great here.
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American Strat HSS, Gibson L6S 1973, Strat 1980, Alessandro Doberman, 1979 Marshall 2104 (Mk II), 1971 Fender Twin,

[selloutrr]

a quick search engine (yahoo, google) "blackfacing fender"

will give you days worth of reading and a wealth of information.

[Firestorm]

The presence of the pre-PI master volume in that amp will change its character a little, compared to a non-master BF Twin. You could try a different style master volume, or put the existing master on a switched pot so you can switch it out of the circuit.

There's a 220K resistor in series with ground connected to the reverb recovery output and the input to reverb mix amp. Change that to a 250K pot and you'll have a master that doesn't add any new load to the circuit. It only works on the Reverb Channel, though.

[Roe]

remove that master and install a larmar. personally I like BF but prefer the SF PI as well as the 680ohm reverb driver cathode

[buddyrama]

What is a larmar? Thanks.

[Tonegeek]

At one point, I BF'd my -72 Twin and it was not worth the effort, really. It made the amp slightly brighter. I also converted the balance pot to a bias adjust like the earlier amps so that was very useful. The Master IMHO is terrible on those amps so if you want to keep it, you might consider converting it to a post PI master (ala Ken Fisher), or some other type other than the Fender implementation.

Recently I converted my Twin to a NON HRM Dumble style and its the best amp decision I ever made but if I was to do it again, I would have a third channel. there are enough tubes in that amp to have 3 channels, 1 stock Fender, and the 2 Dumble ones (clean and OD) AND a buffered FX loop OR 1 tube Reverb. Someone on the Dumble forum has done that so there is help there if needed. Twins are great platforms for mods and since they don't sell for much, you might as well make it into something you can really enjoy.

[Gibsonman63]

Blackfacing is very subjective. If you have some specific goals in mind in terms of how you want your amp to sound compared to how it sounds now, these guys will be all over it, but either way you'll learn a lot by tinkering.

[Roe]

larmar is a mv:http://metroamp.com/wiki/index.php/Lar/Mar_PPI-MV

also, I prefer the SF 220uf caps to the BF 70uf caps

[jaysg]

Some of the silverfacing was done to simplify lead-dress. If you undo all that, then you have to be careful where you route the wiring. Luckily, the BF versions show you how. I don't know which ones are the most susceptible, but anywhere you see a wire coil is probably a problem area.

[Gibsonman63]

Some of the silverfacing was done to simplify lead-dress. If you undo all that, then you have to be careful where you route the wiring. Luckily, the BF versions show you how. I don't know which ones are the most susceptible, but anywhere you see a wire coil is probably a problem area.

When they changed from the cloth covered wire to the PVC insulated wire, it did not behave and stay put very well. Add 40 years and that wiring is pretty much where it wants to stay forever. I rewired my '72 Super Reverb with cloth wire and it was extremely labor intensive, tantamount to a new build, but I am very happy with the results.