Originally Posted by ss9001
personally, I think you are, as we say, barking up the wrong tree.
1st, the input sensitivity of the rotel 1080 is (copied from their web site specs):
Input Impedance/Sensitivity: 1.5V, 32 kOhms)
in other words, in order for the amp to reach FULL power output, it should have 1.5 volts input.
2nd, some forum member several years ago got this info straight from a tech person at Pioneer for the SC-09, similar Ice amp design) and no reason to think Pioneer changed it just for your model:
For preamp out : output impedance is 490ohm.
output level for -20dBFs input , 0dB VR position => 150mV
-20dBFs input , +12dB VR Position(MAX) => 600mV0dBFs input, 0dB VR position => 1.5VThis output level is determined by THX. (THX model is the same.)
in other words, to reach 1.5v, the volume should be at 0.0
and notice that if the receiver is THX certified, it must meet this spec'd output
if you calibrated the 35 with the rotel connected as your front 2 ch amplifier, it will have AUTOMATICALLY compensated for any differences in output by adjusting the channel levels for your fronts in order to achieve reference levels all around.
unless you have a defective SC-35 & its preamp opamps are weak & it needs repaired, your info is incorrect about being "weak".
I hate to say this, if you are thinking the Rotel amp is supposed to make it sound dramatically different used in place of the Ice amps, then I think you are going to be disappointed. I also use a hi powered class a/b amp, with much more power on tap than your Rotel (600 wpc @ 4 ohms)
and it really does not sound dramatically different. With MCACC off, the Ice amps sounded a very slight touch clearer on the highs, but the class a/b amp sounded a slight touch better on bass. I use it because I have very inefficient planar speakers and the ext amp provides better transient attacks (percussion, piano, etc) because of the extra power headroom and current.
If you are expecting a big difference in sound, using the Rotel over your Ice amps, then you will be wrong
. 1st, any freq response differences will be compensated by MCACC EQ IF you calibrated with the Rotel in use. 2nd, if you have stronger or weaker bass, don't use a sub or set fronts as Large, then re-run MCACC. If you do use a sub, then bass freq's lower than the Xover point are being handled by the sub, not the Rotel.
Instead of chasing rabbits, your choice should be, do u like the "sound" of the SC-35, meaning how MCACC equalizes your speakers? if answer is no, then get a different receiver using Audyseey or Yamaha's YPAO. Connecting your BD player directly to the amp using a DAC with volume control or a 2 ch preamp tells me that you prefer NOT using MCACC for the fronts. In that case, have you tried Front Aligned MCACC calibration?? which leaves fronts un-EQ'd but EQ's all the rest to "match" the non-EQ'd fronts? Or Pure Direct mode? Or manually tweaked certain freq bands to taste? Pure Direct & also turn MCACC completely OFF in the menu, is the ONLY way to compare any potential sound differences between sources & amps. If you have done this, then have did you rerun MCACC after you added the Rotel?
Or you can look at adding a 2 channel preamp with a home theater bypass. Some are unity gain, meaning no change in signal level input to output but still going thru the preamp, and some are true bypasses, with a relay/switch bypassing the preamp circuitry all together and you can still send receiver outs to amp with the preamp turned off. Parasound, most tube preamp companies like Audio Research, Cary, Conrad Johnson, Rogue Audio, etc even companies like Emotiva, have preamps with HT bypass modes implemented in some fashion.
But to think the SC-35 preamp output is somehow weak and that's why your Rotel is not performing the way YOU THINK it should is wrong-thinking. Unless it needs repaired of course. It's rated preamp output is consistent with comparable Denon, Onkyo and Yamaha receivers - if you don't believe me, check these specs on comparable models:
Denon 5308 - THX certified - analog section rated output 1.2 V & digital section rated output 2 V @ 0 dB
It's analog preamp output looks to be consistent with your SC-35 - comparing the 2 plugged into your Rotel, I doubt you would not notice any significant difference in volume levels between the 2, especially since the Rotel at that input levels would be able to crank out its full 200 wpc @ 8ohms in either case IF the soundtrack demanded that much transient power to reproduce it.
I think your disappointment lies elsewhere....