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Oppo 105 and Power Amplifier Input Sensitivity

Novice here and needing some advice! Yesterday, I picked up an Oppo 105 to use as my pre/pro for a dedicated 2-channel listening setup. Until I get a set of XLRs, I am using the unbalanced RCAs. I was reading that the output on the oppo is 2.1V unbalanced and 4.2V balanced. I am running the Oppo straight to my Krell S-275 which has an input sensitivity selectable, 2.4 V or 4.8 V - stereo. Using the analog volume control, could I experience clipping that could blow tweeters or my amp? I have read about the 15x rule of thumb on input impedance, but what about the input sensitivity? The Krell is powering B&W Nautilus 804S's. I just want to be sure I don't have to worry about watching the volume when I'm tying one on! ;) Again, sorry for the noob questions. I'm usually a safety third type of guy, but not when it comes to my precious equipment, Ha! 
bconman
atmasphere's avatar
atmasphere
11,806 posts
 
Yes. You could run a Passive Volume Control too. If you go that route, keep your cables short! IME they tend to rob some of the bass impact if less than full volume; that's why I prefer other means. 
unsound
7,329 posts
 
Wouldn’t wouldn’t using the 4.8 Volt input throw away a lot of costly power potential?
bconman OP
5 posts
 
That's part of what I'm trying to figure out as well...would I be better off with a pre-amp with a lower output sensitivity? Also, the Oppo recommends 47K Ohms on the input impedance. My Krell only has 20K Ohms... what am I losing in this combination? 
atmasphere's avatar
atmasphere
11,806 posts
 
You're going to need a preamp that can drive that impedance since the Oppo will be bass shy and more likely to make distortion into that load.


So then the input sensitivity of the amp will be less important.


Sounds like you want to run balanced; have you sorted out a budget and do you know if you want tube or solid state?
bconman OP
5 posts
 
Well, shoot. I thought I was being sly and budget conscious to use the Oppo as a pre/pro for the Sabre DAC... If I get a true preamp, that renders the oppo DAC useless right?  Thank you, btw, for helping me understand how this works!
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