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Is it a Waste to Connect an Outboard Amplifier to My Receiver?

Al Griffin  |  Feb 6, 2014

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Q I’d like to know if it would be a waste to use a power amplifier connected to the preamp outputs of an AV receiver with the same rated power. The AV receiver I have in mind is the Denon AVR-3313CI.—Morris Barber / via e-mail

A It depends on the power amp you plan to connect to the receiver. Power amp specs rarely tell a complete story; just because one amp is rated to deliver 125 watts per channel (WPC) doesn’t mean its performance will equal that of another amp rated to deliver the same output. You have to look at what’s behind the specs. The Denon you cite, for example, has a rated power output of 125 watts into 8 ohms, 20 hertz to 20 kilohertz bandwidth, at 0.08 percent THD (total harmonic distortion). And while Denon’s measurement accounts for the full audio range—a more rigorous test than just measuring at 1 kHz—the AVR-3313CI’s spec sheet indicates that it’s for two-channel output.

For Sound &Vision’s AV receiver and amplifier tests, five- and seven-channel continuous-power measurements into an 8-ohm load are also performed. And though we didn’t test the AVR-313CI, we did review a step-down model from the same line, the AVR-2313CI. In that example, the receiver exceeded its 105-watt (8 ohms) power rating for two channels driven continuously but came in below that on five- and seven-channel tests, an outcome that’s likely to be similar for the AVR-3313CI. That said, reduced power on all-channels-driven tests is fairly common for AV receivers—something that ultimately isn’t a huge deal since movie soundtracks rarely demand full power on more than a momentary basis, especially in the surround channels.

To wrap up, using an external power amplifier with the same rated power as the Denon AVR-3313CI wouldn’t necessarily be a waste—as long as its measured perfomance bests that of the receiver’s own built-in amps. (And also if your speakers and room require that much power, which is a different kettle of fish entirely.)

COMMENTS
javanp's picture
Submitted by javanp on February 6, 2014 - 9:02am

Even if the amp section of the 2nd receiver isn't as impressive as the main receiver, you could still use that 2nd receiver to power SOME of the channels, thereby splitting the workload between the two receivers. That method would allow for more headroom and maximum power output in each channel.

LordoftheRings's picture
Submitted by LordoftheRings on February 6, 2014 - 2:01pm

If you purchased a receiver like the Denon AVR-3313CI that means you don't truly need more powerful external power amplifiers to start with. ...Unless your room is very large and that you like listening @ very loud volume levels.

But then, you would have purchase separates in the first place. ...Right? : -)

pcweber111's picture
Submitted by pcweber111 on June 23, 2014 - 8:30am

Not necessarily. I have a smallish room but went with an outboard amp because dynamics are better. It's not always about pure power.

prerich45's picture
Submitted by prerich45 on June 25, 2018 - 5:27am

Many have opted to buy a receiver instead of separates for several practical reasons:
1. Receivers generally cost lest than prepros and a receiver with preouts can be used as such
2. A receiver gives you a fall back, just in case your amp needs servicing
3. With the exception of XLR (balanced ins or outs) most receivers can offer more features than a competing prepro.

I used separates for a long time, I think up until Bluray and the entire TrueHD and DTS-HD Master thing happened. At one time, I actually used my PC as my prepro. With the the lossless and now the immersive audio tracks , I did my home work and found that a receiver with preouts would give me the best bang for my buck. I still look at separates, but even now, I'd more than likely chose a Lexicon RV-6 over a MC-10 ...due to ability to serve as a prepro - while possessing many of the features that the MC10 has .... same thing for Denon x4400h vs a Marantz AV-7704 (although the Marantz has better op-amps)...maybe a Marantz sr6012 may be a better comparison vs the Marantz av-7704. So it's not all cut and dry ;) :)

pw's picture
Submitted by pw on February 9, 2014 - 1:32pm

Not a pro just a advanced dabbler. These back outlets are useless. Esp. for a power amp. Power amps plugged into the wall outlets only and/or perhaps a pro style or better power conditioners like a Furman. Have you seen the newer outlets from Oyaide?

pw's picture
Submitted by pw on February 13, 2014 - 3:23pm

Sorry I misread. But use the extra amp to bi amp your main and center speakers if possible.

Mittchell's picture
Submitted by Mittchell on February 9, 2014 - 4:13pm

They are talking about the pre-amplifier output connection jacks (usually RCA style jacks ; sometimes balanced XLR style jacks) .... not the A/C power outlet socket.

vulcan1017's picture
Submitted by vulcan1017 on February 13, 2014 - 10:45am

I have a Yamaha RX receiver that has preamp outs. My Magnepan 3.3 speakers are too power hungry for the puny receiver ... So I have two Aragon 4004 power amps driving the two speakers. The rest of the channels are handled by the Yamaha. I balanced the setup and it sounds out of this world. Much if the credit goes to the Aragon+Magnepan3 combo.

pw's picture
Submitted by pw on February 13, 2014 - 3:26pm

Sounds like your amp/loudspeaker over match a junkie Yamaha mid fi component. Get a better preamp I suppose.

prerich45's picture
Submitted by prerich45 on June 25, 2018 - 5:31am

Excellent!

jerichor's picture
Submitted by jerichor on April 18, 2014 - 1:02am

I'm in the same dilemma. I was using a BK AV5000 with my Onkyo 809 to power a 7.2 set up (Polk TSI 500, 200, 100 and 2 BIC Acoustech PL200 subs) until a technician told me that I did not need the power amp. My room is 15 x 20. I used to play it with the amp in the garage and really liked it. But I have to tone it down inside the house. I'd appreciate anyone's opinion. Thanks.

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