Class A of a Conrad Johnson EVO2000

[RobertS61]

Hi,

I recently acquired a Conrad Johnson Evolution 2000 hybrid stereo amplifier.
I have a schematic and parts list which I will attach.

It has four 5751 dual triodes in the pre-driversection and 20 MOSFET devices in the output-section which are driven by 4 Mosfet drivers.

To measure the quiescent current or bias of the outputstage I connected a MM in amp mode across one of the fuseholders (with the fuse removed )of the railfuses (F4 & F5 as depicted for the right channel) after the amp was warmed up and measured 0.63 Amps. The amp draws when idling approx 1.7 Amps continuously from a 220 Volts main. There's no provision for manually correction DC only two 20 turn trimmers R37 and R38 for the bias.

Is my assumption correct that this amp can (only) deliver:
(0.6 x 0.6) times 8 = 2.88 Watts Class A peak and 1.44 Watts RMS to a 8 Ohm load?

 

[Zen Mod]

if 0A63 is Iq for one channel , then possible current envelope of class A is double that ,approx.

so , with 1A26 and 8R load , that would be 2Iq^2 x Rl = 12W7

if 0A63 is for both channels , then 0A63 x 8=3W175

 

[RobertS61]

if 0A63 is Iq for one channel , then possible current envelope of class A is double that ,approx.

so , with 1A26 and 8R load , that would be 2Iq^2 x Rl = 12W7

if 0A63 is for both channels , then 0A63 x 8=3W175

Thanks for your swift response (as usual) Aleksandar.
Unit has two railfuses per channel(positive - and negative rail).
I measured the currentflow when idling over one of these fuseholders and got the .6A reading with the amp drawing 1,7 Amps from a 220V line.