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Old 1st April 2022, 04:39 PM
lilolee's Avatar
lilolee lilolee is offline
Join Date: Dec 2005
Location: Maidenhead, Berks
Posts: 94
Default Golden Tube SI-50 mkII amp

Thought I'd post this here as you guys don't mind getting your hands dirty.

This a working amp, remote switches inputs and controls volume. However I am selling as spare and repairs and think it would somebody who is looking for a project. Full details under photos.

Not sure what it is worth. I have original box.

Is 300 silly?

Many years ago a tube failed and instead of blowing the fuse it blew the bias circuit. John Caswell got it working. However this needs to be biased by hand either by ear for minimum hum or with a meter. There is still something wrong with the circuit of the blown valve (V2) as, when the other valves are bias to the recommended 450mv, V2 has minimum hum at about 120mv. Bias is performed between the fuse and earth and adjusted using small screws, as can be seen in attached photo.

Also attched is the circuit for SI50 mkI which is similar but not exactly the same.
Attached Images
File Type: jpg Golden_5.jpg (84.6 KB, 19 views)
File Type: gif SI50Mk1_Schematic.gif (49.7 KB, 37 views)
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