Topic: Separate amp for rear speakers

[allan1836]

Good day! I am currently using a Yamaha rxv995, 5.1 a/v rcvr with 5.1 outputs and I was thinking of adding a small intg. amp to power my rear surrounds. Will it help increase the power of my yammy going to the front and center speakers? Will the change, if there is, be noticeable?
My other option, though more expensive, is to get a prologic rcvr with 3ch logic feature for the rear, to simulate a 6.1 matrix. Again, will there be noticeable improvement to justify the added cost?

Kindly share your experience on this set ups, I'm very glad to hear your feedbacks.

Thanks.             

[av_phile1]

You can use a prologic receiver for the rear L and and R,  and using the prologic mode, a third rear center channel can be simulated.  This is essentially the same as a 6.1 processing where the rear center is just simulated.  But you would be controlling two volume knobs at any time.

Using a separate integrated for the rear theoretically will relieve your receiver from having to drive 5 channels.  But I doubt if the sonic difference will be telling enough except at high volumes when the receiver needs more current reserves.  Again, you'd be controlling two volume knobs.

If your receiver has pre-outs, you could benefit from having a separate stereo power amp to drive the fronts and let the receiver power the rest.

[allan1836]

av_phile1, thanks for the insight. Isn't it that a/v rcvrs with pre-outs automatically gets their signal from the pre-amp section of the receiver too. Meaning, even if you use a separate intg. amp or power amp, at that, the master volume control is still with the primary a/v rcvr, in my case, my rxv995. In the case of an intg. amp or a prologic receiver, to be used for rear duties, their volume control will be set only one time to approximate the sensitivity of the main a/v rcvr, then adjustment to your volume needs will only be done at the main a/v reciever. In a way the main a/v receiver will act as a "powered" pre-amp/processor.

I was thinking also of using a power amp for my fronts but I'm afraid to use a different amp because it might have a diff. tonality with my reciever which will still handle the center and rear. At least, a diff. amp for the rear is not so critical as the center.

Your thoughts sir ....         

[av_phile1]

It is not adviseable to use the pre-outs of your AVR to drive the line level input of an integrated amplifier. There'd be impedance mismatch and could overdrive your integrated to distortion at loud levels from your AVR.   I was thinking more of using the analog RCA rear channel output of your DVD player to feed the integrated's stereo line input.  So I said you'd be using two volume controls. 

Now if your integrated amp has a jumper at the back connecting the pre-out to a main-in, disconnect the jumper and use the main in to connect to your AVR rear channel pre-out.  That's the right connection - AVR's pre-out to the integrated's main-in.  The AVR's pre-outs are expecting a power amp input, not an integrated amp's line in.

In very few situations, a power amp may have a different sonic timbre than a receiver. Like using a tube vs an SS receiver of the same power.  OR using an amp with known coloration against one that is more neutral.    But I am confident that in general, most well-made amplifers and receivers within the same power range have reasonably flat frequency responses and respectable THD and IMs to exhibit distinguishable tonal differences at normal listrening levels than between different speakers.  So among well-designed commercial gears, tonal differences between SS amps in the same power range can be perceptibly negligible on random HT and musical sources at comfortable levels.  You would have to be looking at pink noise tests, single tone sweeps and tone bursts on an oscilliscope or graphic spectral display to spot any difference. And the amps would have to be operated at or near their rated power to really hear any  difference.  It is only when the amp starts to strain itself that its true sonic character becomes apparent. 

Having said that, I could be missing on some exceptions.  Try to set it up and check if you can hear any difference.  Try a DVD material with known movement of a car or airplane from front to back or left to right and see if you can hear objectionable difference in timbre as the car or airplane moves between channels.  I am assuming your 5 speakers have no timbral dissimilarities.

[hattori_hanzo]

I used to do that configuration, I was using a separate integrated amp (konzert 502a) to power my rears and I only set the konzert's volume control fixed on my desired volume, then the rest is controlled by my RXV995, but I make it appoint that my rears are within audible range to my fronts so that it will have a tonal balance and steering from front to back with proper timbre matching using a test DVD with freq sweep...

just me though... 

[hattori_hanzo]

after you connect the separate amp for the rear using the pre-outs of your 995 set both amps volume control using a DVD tester for tonal balance, similar to YPAO caliberation... after getting your desired results, the 995 will be the master volume and you can leave the current setting of your rear amp.

example of the caliberation test:






 

[wolvenfang]

ok yan audio test nyo sir hanzo i believe nabibili yan sa carriedo station lrt?

[allan1836]

av_phile1, thanks for a thorough explanation of amp compatibility. I will be "re-evaluate" my set up first again and will probably go with power amps.

hattori_hanzo, did you experience any impedance mismatch or overdrive on your konzert amp when feeded by the yamaha rear output signal?