In my KT150 Push Pull amplifier project I used the ABS-Q autobias module from Audioamp.eu.
“The module dynamically controls automatic bias settings to maintain a strict symmetry of currents through both tube branches in the output stage, and to completely avoid flow of DC current through the output transformer, all with minimum requirements on the anode current in the tubes. The DC saturates the output transformer which results in increased distortion of low-frequency sounds. Bias control is realized by maintaining a constant bias on output tube grids, independently on the level of the driving signal.”
For some reason after more than a year one channel no longer worked.
I contacted Pavel from Audioamp.eu and he immediately sent a new ABS-Q board, free of charge. Problem solved.
That’s what I call service!
Regards, Gerrit
“The module dynamically controls automatic bias settings to maintain a strict symmetry of currents through both tube branches in the output stage, and to completely avoid flow of DC current through the output transformer, all with minimum requirements on the anode current in the tubes. The DC saturates the output transformer which results in increased distortion of low-frequency sounds. Bias control is realized by maintaining a constant bias on output tube grids, independently on the level of the driving signal.”
For some reason after more than a year one channel no longer worked.
I contacted Pavel from Audioamp.eu and he immediately sent a new ABS-Q board, free of charge. Problem solved.
That’s what I call service!
Regards, Gerrit
