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Increasing Carver amp sensitivity?

PianotunerNJ

Well-Known Member
Ok, so I have 2 Carver amps, a PM175 and a PM600, both have balanced XLR inputs and TS 1/4” inputs and are sensitive from 1.5 volts. I was hoping to run my main speakers in my 5.1 system with one of these amps (both plenty powerful and sound excellent). Seems like no problem since I’m using a Denon X3500H which has preamp outputs for 7.2 channels.

So, here’s the issue. The Denon pre outs run at a nominal 1.2 volts and generally don’t send enough juice to get the Carver amps to engage. I also have other sources, specifically my SMSL M500 which has enough voltage to bring the Carvers to life so I’ve narrowed my problem down to this discrepancy.

It seems there is no way to make the Denon throw a higher voltage through the pre outs, so I’m left with trying to find a way to decrease the required voltage for the Carvers or place some active buffer between the two which is not an idea I love.

One other thing. So, I’m using both inputs at once, the balanced from the M500 and the unbalanced from the receiver. If I turn on the M500, the additional line voltage seems to be enough to activate the Carver and allow me to run the receiver through it. But, 2 things, one is that I don’t like the mandatory running of the DAC just to trigger on the amp, and the other is that this conglomeration of connections creates a very slight buzz. Barely noticeable but I’m running this amp to improve SQ so bringing in a new buzz kinda sucks.

I feel like if the amp could be made to come to life with 1 volt vs. 1.5 I’d be solid and quiet only running one input at a time. Ideas?

Just to be clear, the amps both work exactly the same way, respond the same way to the configuration. And it doesn’t change if you use power switch or the trigger line from the receiver. That does successfully turn the amp on, but it doesn’t change the functionality. Seems low voltage line input prevents the amp from actually working, but it is powered up and works as soon as you hit it with a hotter signal.
 
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Seems I was mistaken about something. I can’t have XLR cables plugged in or they shut off the 1/4” plugs. Somehow when you fire up a balanced signal, the amp pulls from both. So, in the short term it’s working fine from the receiver now, and I can plug in the XLR cables when I want to listen in stereo pure Freon my DAC. No biggie, but I assumed that a line with no signal would be OK just plugged in there, apparently I was wrong. There must be a switch in there.

The output voltage from the receiver is adequate and the amp is responding as it should.
 
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