yamaha B-4 amplifier

[muddasirwaheedmalik]

Hi.
I have access to a pair of yamaha B-4 amplifier.
It has a button in front to opera te into class A for 30W, else its AB into 100W.
I am planning to use the pair on my tri-amped speakers with 30 watts going to tweeter and 30 to mid on each side. the bass bins would fed by yamaha B-5 250W per channel amplifier.

I did not have access to the amplifier listening in silent settings so cannot judge whether class A button really makes any difference in sonic output. What i have gathered on net that the buttton reduces the rail voltages and increases the bias.thats what i know aboout it.

Any ideas? any one having experience with yamaha B-4 or B-5 amplifiers??

[jitter]

Originally Posted by muddasirwaheedmalik

Hi.
I did not have access to the amplifier listening in silent settings so cannot judge whether class A button really makes any difference in sonic output. What i have gathered on net that the buttton reduces the rail voltages and increases the bias.thats what i know aboout it.

Any ideas? any one having experience with yamaha B-4 or B-5 amplifiers??

No experience with B-4 or B-5, but with Marantz PM-80SE. This has the same feature of selectable class A or class AB (must only be changed with power switched off!).
At normal living room listening levels, I could hear no difference between the two classes hence used it in class AB for longer life (not that the STK3102 (VAS) had a long life) and lower power bill.