My brother (he's the leader, I'm following) and I were attempting to adjust the Vbias on our respective Adcom amps; his is the 555II and mine is the 535II. I read that the Vbias in a complementary feedback bipolar amp should be 8 mV for optimum sonics (from book by G. Randy Sloan).
My amp had 12.8 mV on one channel and 11.3 mV on the other. I got the Vbias set to 8 mV on each channel with no load and with the heatsinks at a warm temp (I left the amp powered on without speakers or interconnects for approx. 1/2 hour). The amp produces more SPLs, is less harsh (lower THD in upper frequencies?) and seems to have more bass (all subjective conclusions, no data to back it up).
Is this the correct proceedure (i.e. is the 8 mV measurement a 'quiescient' measure)? Or does the amp have to be as 'hot' as it would be under normal usage? Is 8 mV the correct figure I should be shooting for?
Thanx.
My amp had 12.8 mV on one channel and 11.3 mV on the other. I got the Vbias set to 8 mV on each channel with no load and with the heatsinks at a warm temp (I left the amp powered on without speakers or interconnects for approx. 1/2 hour). The amp produces more SPLs, is less harsh (lower THD in upper frequencies?) and seems to have more bass (all subjective conclusions, no data to back it up).
Is this the correct proceedure (i.e. is the 8 mV measurement a 'quiescient' measure)? Or does the amp have to be as 'hot' as it would be under normal usage? Is 8 mV the correct figure I should be shooting for?
Thanx.
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