Monday, 7 November 2011

An ageing Fender amp

A very old Fender Tremolux guitar amp recently entered the workshop.  A brief investigation revealed that it was a 1962 6G9-B, a blonde, brown face.

About 30 years ago, the owner had bought a good working Tremolux combo and this "non-runner" came with it as a spares donor.  It had been in his loft ever since and now it's time for a total electronics rebuild.

A little bit scruffy.

Pity we're not going to re-do the tolex as well as the internals.

The chassis is looking a bit tired.

The filter caps are in various stages of decay and the cover is missing.

A few valves missing, but we're going to replace them all anyway.
This is where most of the work is going to happen.

And a view from the other side.

Check-out the hand wiring.

The mains transformer turned out to be defective, so we'll have to find a replacement.

This is looking a bit better now.

Some new filter capacitors fitted, those carbon resistors are still  good and can stay.

The original amp was 110v ac input, a bit of new labelling applied  at the  rear end.

The new mains transformer courtesy of Mike at Danbury Electronics.  The size is perfect, it drops straight in. 

A close-up of some new pots.

This is the replacement for the peculiar 350k/70k tapped pots used in the treble positions.  I can supply these if anyone needs them.

When fired up, it turned out that the output tubes were running a bit hot.   This is a little mod   for adjustable bias,  now we can trim it a bit more accurately.  Apart from this little bias issue, the amp worked first time.

Topside after completion.  Those tube shields cleaned up nicely.

A cleaned up front panel with a matching set of the original design knobs.
The finished amp.

IEC fitted at the rear, instead of the grubby old Powercon that was on there.

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