Aleph30 (and other Class-A amps) Hi-Lo Power Switch?

[relder]

My homebuilt A30 is a little much for it's heat sinks. I intentionally gave it higher than spec'd rails so it gets hot. If there's the slightest bit of breeze it's OK, but where mine lives there isn't much of a breeze, so I modified the power supply to switch in sets of inductors to give it a LC power supply instead of the usual C power supply. In addition to the additional filtering it lowers the rail voltage, thereby lowering power. I don't know if a stock A30 chassis has enough space to add 4 inductors. I made the mistake of getting inductors that run too close to their rated current so I get a little mechanical hum when I have them in circuit, but I can switch them off at will.

Rob

[gmphadte]

with just half voltage in + rail , CCS for input LTP will go mad

I don't know whether ur amp will work but I have seen a Telefunken stereo that works on 8x1.5 volts cells but when on mains, power amp supply is 50 volts DC. No change of components done here.
12volts to 50volts is quite a large ratio.

Gajanan Phadte

[Daveis]

Can the same power lowering effect be achieved by removing 2 output transistors (Q6/Q9)? How is this different than lowering the current source current by altering R19 and R14?

Also, can the input DC blocking cap(C11) be simply bypassed if you know for certain your source has no DC offset?

What R19 and R14 values would give roughly half the power of the normal A30? I guess that would mean 100watts roughly instead of 200 watts idle.

Thanks Nelson.