Input stage for multi-zone amp.

[wsmckenz]

So I got my 4 quad power amps from sure electronics. I've been running them on the bench with a 24V/3.5A SMPS and I'm very pleased with the results. I haven't had any of the problems reported by others with the boards. So now I want to run 3 of them together as a multi-room distribution system. Problem is that the amplifiers want less than a volt a 50Kohms and I want to use the line out from my linn majik, which is somewhere are 6-8v @300ohms.

I'm guessing I can do this passively, but I dont really know exactly how. I want to divide that signal between 6 channels and make sure I dont over-drive them amps.

What sort of circuitry would be appropriate here?

Thanks,
Bill

 

[bwaslo]

To each amp input, run a series resistor of about 10k ohms (any wattage) from the preamp(?) output. Also put a 1k (or so) resistor from each amp input (same point as the 10k goes to) to ground.

Did you need volume control too? (Don't know what a linn majik is). If so, instead for each amp run one 100k resistor from the majik output to the top of a 10k volume control. Ground the bottom of the control and use the wiper to drive the amplifier. There are other ways to do it with fewer separate resistors but resistors are cheap.

 

[wsmckenz]

Perfect. Thanks so much. I was using up pads of paper trying to get the perfect attenuator circuit. The Majik is an integrated amplifier, and I'm just pulling the line out from it, so I do have a volume control, but I think I'll just go ahead and put a small dual pot on each amplifier channel.

An externally hosted image should be here but it was not working when we last tested it.

I'm going to have the input rca jacks in the upper right at the back, the pots resistors would all go on the individual bits of prototype boards, then run to the amplifier boards. Do I need to use shielded cable for all of this?

Thanks again,

Bill