Good evening,
A while ago I bought a VS100 (head) with an electronic problem. The volume was very very low, and every channel sounded distorted. Also, there was a dead resistor, R20, that every time i changed, it would burn.
The output transistors had already been changed, wrongly: the two pairs of BDV65 and BDV64 were changed to four TIP142.

I changed two of them to TIP147 (T11 and T12), and discovered that T10 was shorted, changing it too.
T8 was dead, so I replaced it and R20 stopped burning. T7 is fine.
Every 5W resistor was dead (R 19,21,24,25) and when i replaced them, the volume problem was fixed!
The valve was changed too.

Now I just have the distortion problem: clean channel is distorted (not too much). Also, when I play more than one string, it looses all sound definition (the sound become "muffed"), whatever the channel.

Today I replaced T4 and T6 (someone told me they were a common problem in this amp) and every output transistor. The problem is still here.
Any idea?

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