Questions on amps

[swechsler]

I personally wouldn't try that. Usually receivers have pre-amp sections designed to drive the input of the power amp section. That configuration would mean you're driving two amps in parallel; a task no pre-amp in a receiver is intended to do. There are pre-amps with more than one output. My Adcom GFT-500 has two outputs. That would be the better solution.

Pretty much any preamp should be able to drive two power amps (either internal or external to the receiver) simultaneously. Most preamps with dual outputs simply have them wired in parallel, which would be the same electrically as using an external Y cable.

 

[spark1]

Pretty much any preamp should be able to drive two power amps (either internal or external to the receiver) simultaneously. Most preamps with dual outputs simply have them wired in parallel, which would be the same electrically as using an external Y cable.

Yes!

If not, then the use of preamp out connections for powered subwoofers would be a mistake as well.

 

[whoaru99]

There is some point to receiver pre out driving parallel loads vs. a preamp pre out driving parallel loads.

Most of my preamps have pre out impedance less than 50 ohms. With those it's no problem to drive several amps in parallel.

However, what does the typical receiver pre out have in that regard? I'd expect they are probably not that low of output impedance but since receivers are not my forte I don't know what might be typical.

As well, it depends on the amp input impedance. Some are sufficiently high that a couple in parallel is generally of little concern, for others it is a factor.

 

[Guest159]

Pretty much any preamp should be able to drive two power amps (either internal or external to the receiver) simultaneously. Most preamps with dual outputs simply have them wired in parallel, which would be the same electrically as using an external Y cable.

No... It's entirely possible and easy to mismatch pre-amps to power amps, much less two power amps. Pre-amps with output impedances over 1000 ohm are hardly unheard of, as are power amps with 15 or 20 k-ohm inputs. You'd really take a pre-amp with a 1000 ohm output and try to drive 2 amps with a 20kR input? Yeah, I guess it would work at an absolute bare minimum, but that's less than ideal. You WILL hear that. My amp has a 100k ohm input and the difference between a pre-amp with a 900 ohm output and a 150 ohm output is immediately obvious.