Rotel RSX-1056 questions

[csloo]

Hi all,
If i use external power amp for center & rear speaker on Rotel RSX-1056, will the main channels be 100w per channel? Since (allmost) all the current from the transformal will be supplied to these channels, will there be a problem driving 4 ohm speakers? I am getting a pair od mmg's soon.

Or, would it be advisible to use my Marantz MA500 or RB1050 to drive the mmg's?

Thanks in advance.

[gianni]

As long as you don't try to get very high volume levels in a big room, 4 Ohms are no problem. I have been running 4 Ohm M&K speakers for 2 1/2 years with my RSX-1055 with no problems with very nice performance.

[Andrew Pratt]

If you've got MA500's use them on the fronts not the centre or surrounds.

[weijst]

...If i use external power amp for center & rear speaker on Rotel RSX-1056, will the main channels be 100w per channel? Since (allmost) all the current from the transformal will be supplied to these channels...

I asked a guy at tech support a simular question. My question was if the power output / channel would increase on my RMB-1075 when I use only 2 channels (2ch stereo / bypass mode). The answer was that the power output may increase a little to say 130 watts / channel (instead of 120 watts / channel when all channels are driven). Not something to get exited about...

However, in your situation (where the amps of the main channels are able to output 100 watts / channel in 2ch mode), I think your assumption is valid... Looking at the amplification section in your RSX-1056 the same 'main-amps' are used in 2ch as in and multichannel mode... So why would they not be able to output 100 watts / channel when the rest of the channels are not used (as is the case in 2ch mode)?

However this theory also implies that when all but the main channels are using very little power in multichannel mode (surround effects rarely demand a lot of power (this also depends on the speakers, I know)), the main channels should also be able to draw up to 100 watts / channel...

This means Rotel's specification of 75 watts / channel is extremely safe and only applies when all channels are fully used (for instance in 5ch stereo).

Hmm, interesting... Could someone with more knowhow please jump in here?

[lvhung]

You should use some easy to drive speakers like JMlab Chorus 716
and dont buy seperate power that is too cpmlicated

[srb]

The power output of an amplifier is determined by the power supply AND the current rating of the output devices, whether they be transistors or tubes.

Even if you were to triple the size of the power supply of the RSX-1056, the power output will still be limited to the maximum current rating of the output transistors on each channel.

I think the tech's response to weijst is closer to reality, but some amplifiers may be able to generate more power in 2-channel vs 5-channel operation than others, depending on circuit design and output device selection.