Hi Paul
I was also under the mistaken befief that the Cayin A88T is self/auto-biasing. This is NOT so. I have got this information directly from the manufacturer (Spark Audio). They have, infact, sent me the biasing instructions. I will be happy to email this to you. Can you confirm your email address?
The amp has to be biased from the inside. The bottom cover has to be removed. There is a cathode resistor for each tube. The voltage has to be measured across each resistor and the biasing pots (again internal), have to be set.
I checked the bias (actually the technician did) about 3 months from getting the amp. It turned out that one of the tubes was not biasing properly. I replaced it and the amp sounds much better now. The bias holds properly since then.
I don't know why the Chinese manufacturers mislead customers on the issue of biasing. Probably they are scared of liabilities in the unlikely event of a mishap.
I was also under the mistaken befief that the Cayin A88T is self/auto-biasing. This is NOT so. I have got this information directly from the manufacturer (Spark Audio). They have, infact, sent me the biasing instructions. I will be happy to email this to you. Can you confirm your email address?
The amp has to be biased from the inside. The bottom cover has to be removed. There is a cathode resistor for each tube. The voltage has to be measured across each resistor and the biasing pots (again internal), have to be set.
I checked the bias (actually the technician did) about 3 months from getting the amp. It turned out that one of the tubes was not biasing properly. I replaced it and the amp sounds much better now. The bias holds properly since then.
I don't know why the Chinese manufacturers mislead customers on the issue of biasing. Probably they are scared of liabilities in the unlikely event of a mishap.