03-09-2014, 05:36 PM
Well, couple of things...
1. I replace the Bumble-bees (which I think were leaky, you are right Mondial) with 0.047uF 400V I had in stock, conveniently in qty of 2, the film type.
2. The voltages indeed became exactly as the chart says.
3. Now while before the oscillation became distorted some, it would continue oscillating. Now the oscilation lasts about 2-3 minutes, after that the saturation occurs on one side, and then the amplitude start decreasing very rapidly and within 10-15 seconds after that the oscillation is gone.
As before the saturating side swaps with the output tubes.
I suspect the higher plate voltage simply makes the tube fail faster, this is why.
You think one of them tubes is bad? I never checked for gas......
BTW even without load the output tubes run quite hot.
PS. Checked for gas, both are OK.
The tubes are 6AV5, not 6AU5 (both could be installed)
One tests 7500, another about 8200 uMho.
1. I replace the Bumble-bees (which I think were leaky, you are right Mondial) with 0.047uF 400V I had in stock, conveniently in qty of 2, the film type.
2. The voltages indeed became exactly as the chart says.
3. Now while before the oscillation became distorted some, it would continue oscillating. Now the oscilation lasts about 2-3 minutes, after that the saturation occurs on one side, and then the amplitude start decreasing very rapidly and within 10-15 seconds after that the oscillation is gone.
As before the saturating side swaps with the output tubes.
I suspect the higher plate voltage simply makes the tube fail faster, this is why.
You think one of them tubes is bad? I never checked for gas......
BTW even without load the output tubes run quite hot.
PS. Checked for gas, both are OK.
The tubes are 6AV5, not 6AU5 (both could be installed)
One tests 7500, another about 8200 uMho.
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