Fender Super Twin.

[DrNomis_44]

Just doing some minor servicing-work on my Fender Super Twin amp at the moment, one of the input sockets seems to go a bit intermittent every now and then, also one of the octal sockets for one of the six 6L6 power tubes seems to have some contacts that need re-tensioning.


So, here's what I'm going to do:


1 Replace both of the stock input sockets with a couple of new ones.

2 Replace all the Carbon Comp input resistors ( 2 X 33k and 1X 1M) with some new 1W Metal Film resistors, mostly cause I've got them, secondly, Carbon Comp resistors are notorious for generating lots of hiss-noise, secondly they go high in value over time.

3 Re-tension all the contacts in all the octal-sockets of all six 6L6 power tubes.

4 Spray all the control pots and bright switch with some Electrical Clean and Lube.


Hopefully after all that it should be all good.

Update:

After studying the schematic for my Super Twin amp, it appears that when you plug into input one, the signal goes through one 33k grid resistor, if you plug into input two the same thing happens, the signal still goes through one 33k grid resistor, what I believe should happen is this.


Plug into input 1, the signal should pass through one 33k grid resistor.

Plug into input 2, the signal should then pass through the two 33k grid resistors connected in parallel with each other.

Or am I mis-understanding it?, I don't really understand why Fender would design the input wiring so that no matter which input you plug into, the result is always the same, why have two inputs then?

My understanding is that the two inputs are supposed to give two different levels of gain, or, to attenuate the signal level coming from a pickup with a hot output, such as a humbucking pickup.