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Old 20th Feb 2018, 7:27 pm   #24
crackle
Rest in Peace
 
Join Date: Mar 2011
Location: Basildon, Essex, UK.
Posts: 4,100
Default Re: KB 381 5 valve AC/DC superhet

The only real problem is the volume, it is still very quiet, I have radios with weak output valves but they still produce enough volume to require them to be turned down substantially.
When you say the voltage readings for V1. g1 and g2 are very unlikely to be correct, do you mean errors in taking the readings or a fault in the chassis.

I feel the problem is in the OP stage, there are 2 tests I will try.
1. injecting an audio signal in via isolating capacitors.
2. test the output valve and the double diode triode on my Sussex valve tester.
At least that will give an indication as to how bad the valves are.
As the chassis for the KB 405 is out of the cabinet at the moment, I may "borrow" the speaker and transformer from that to test.

Mike
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