# Adding power amp for front 2-channels in 5.1 system



## Wiggle (Sep 21, 2013)

I currently am using a Pioneer Elite VSX-23TXH to power a 5.1 speaker system. The speakers are all DIY and the entire front soundstage has an approximate impedance of 4-ohms (which the receiver is not recommended to drive). I have a Dayton APA150 amplifier I would like to use to to power only the front Left/Right speaker for stereo use and to remove load from the receiver in 5.1 mode.

The APA150 has a somewhat lower power rating (75 WPC at 4-ohms stereo, .01% THD) than the integrated amp (110 WPC at 8-ohms, .09% THD) but is confirmed as 4-ohm stable and it's power rating was taken at a lower THD so I have confidence it will be plenty for my use. On the off chance that it is not the best arrangement for the stereo pair I can also bridge it and use it as a dedicated center channel amp which would take a substantial load off for home theater use.

I am assuming that all that is required is to connect the RCA pre-outs on the AVR to the inputs of the APA150. My question though is regarding levels and calibration:

Will any receiver calibration in regards to EQ, distance correction etc... still be applied through the pre-outs in the same fashion as the current speaker outputs?

What is the best way to manage the volume? Should I leave the channel correction for the front L/R at 0 dB and see if I can the gain on the APA150 high enough to match the integrated amp output? Or is it generally preferable to the AVR pre-amp a bit hotter and reduce volume on the power amp?


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## AudiocRaver (Jun 6, 2012)

Distance and EQ should all stay the same. I would run the AVR level at 0 and trim the power amp controls to give the same SPL you had before. That keeps all speakers balanced.

Then if you are confident you have some headroom to burn, you could change he AVR's level trims easily to give a small volume boostg.


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## Wiggle (Sep 21, 2013)

Thanks 

I got it all hooked up and found that running the power amp full bore and the channel levels at +3 dB was a perfect blend to the system. I'll do a calibration later but I'm confident it's quite close to the old blend now just testing by ear.

Listening tests in stereo are positive so far. First thing I noticed was imaging. I thought I may have left PL2 mode on because the center image was more stable and almost sounded like the centre channel had to be helping out. The depth of the soundstage seems to have increased as well. Hard to say without a proper test but just the first things that jumped out to me.


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## AudiocRaver (Jun 6, 2012)

Great! Let us know what else you discover!


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