Silverface Fender Twin identification

steamabacus

A friend has a silverface Fender Twin and is after a user guide & schematic but is struggling to identify the model. It's this one ...



It has a pull pot on the master volume which doesn't seem to do much although he also says the pot needs replacing.

Any ideas?

Dodge

it's either a 100 watt or 135 watt 70's Twin.  The pull pot on the master engaged a crap sounding gain boost of sorts - best left well alone.  Hoepfully, it'll be the 100 watt one as the 135 watt ultralinear Twins are pretty sterile and cold sounding.

100 watt: http://ampwares.com/schematics/100W_Mast_Vol_SF_Twin_Rev.pdf

135 watt: http://ampwares.com/schematics/twin_reverb_sf_135.pdf

steamabacus

Cheers, @Dodge    ;

Dodge

No worries - I may have a scan of the manual somewhere too, I'll have a look later.

ICBM

100W or 135W, it will say on the back next to the speaker jacks.

If it's the 135W you can make it a lot better by setting the voltage selector to 260V - preferably by hardwiring it inside, if it hasn't been done already - this reduces all the internal voltages, makes it less hard on valves, slightly quieter (although still around 100W) and slightly warmer sounding.

If you want to more extensively mod it, it's worth removing the whole pull-boost circuit and re-configuring the master volume as a post-phase-inverter type with the pull-switch to engage it. This is a pretty simple mod and makes the control much more useful, although you do have to be careful not to accidentally disengage it if you're running the channel volume up high and the master low .

jpfamps

Flash logo would suggest 1974 at the latest.

MV came in in 1972, so I would guess its a 1972-74 model.

This would be 100 W.

steamabacus

Thanks chaps.