Axiom Home Page Forums General Discussion Home Theater HT Installation

Which inputs were you using on your Sherwood? It was probably expecting a maximum line level that the Denon pre-out was surpassing.

I doubt this type of distortion is very dangerous to speakers, apart of course from the sudden need to destroy them after long exposure to bad sound!

I was using the CD input. Is there a better option?

CD input sounds good to me. Finding a good balance is what matters (I actually had to do that yesterday between the new headphone amp's volume control and the volume control in the receiver).

I'm not the expert (hopefully Alan will chime in) but I would say anything in the chain that causes clipped, squared-off waves would be dangerous to a tweeter if played at enough volume...

From what I've learned going from the pre out on the Denon to the cd input of the Sherwood would be a mismatch in terms of how the units are designed because then you run the risk of overdriving the input to the Sherwood, which has a preamplifier input (CD) which is designed to accept what used to be called "a line level signal," which would come from a different output on the Denon, usually labeled audio out.

A CD input is designed to accept the output of typical CD player, which generates a lower and more restricted range of signal that that potentially generated by a pre out output from a receiver.

You can't adjust the volume level with your universal remote control then of course; I ran into this with my Rotel integrated preamp/amp, I used the audio out from the 663 and adjusted the volume on the Rotel. The 663 manual states that the pre out outputs generate the same level signal as the speaker outputs, so you have situations where the output would be way too high for a preamplifier input to receive.

Obviously there may always be a range in which the levels would be workable (without distortion), sounds like you may have found that range.

I think we're going to have to create a new forum for the Mrs. to post about the woes of brownouts in the SK household 'cause the audiophile of the house has been rocking out to his Axioms again.

Yeah, Jason; the pre-outs are intended to feed directly into an amplifier section(a few receivers have inputs that feed their amplifier section directly, bypassing their pre-amp section)rather than another pre-amp. The CD input leads to the pre-amp of the Sherwood, so you have two stages of pre-amplification in tandem. Since the Denon pre-amp has a gain of four or more times for the voltage coming out of the player, the Sherwood has to pre-amplify that higher level, which can result in distortion if it has to output perhaps four times the contemplated voltage. The solution, as you found, is to turn down the Denon level control to reduce the player voltage which it pre-amplifies. You apparently came close to what's sometimes termed the "unity gain" setting. For example, if the gain is four times but you turn down the level control far enough so that only 1/4th of the player voltage is let through, the net result is that the output voltage is the same(unity)as the input voltage from the player, despite the four times gain. A little bit of distortion is added in the process, but it's very low and the Sherwood CD input then receives the sort of CD player voltage which it can amplify without audible distortion.

Sat, you may have misread the 663 manual on that point. The pre-outs have the same signals(e.g.,the same musical content)as the corresponding speaker outputs, but the levels are greatly different. As mentioned in the previous reply, the amplifier section which feeds the voltage to the speaker outputs adds a voltage gain on the order of 30 times the voltage which the pre-amp feeds to the pre-outs.

Thanks John,

Yes I realized this afternoon after posting that I must have read the manual wrong, it made no sense when I thought about it because that would have to mean that the pre out was equal to the post internal power amplifier output to the speakers.

I appreciate both of your explanations and am still trying to grasp the fundamentals, I may regurgitate my understanding again at some point to make sure I get the implications for my setup.

Well you caught me there but actually I'm jonesing because she has me on a pretty short leash. I can't wait till Friday (or tomorrow?) when I'll be home working alone and she's not also working at home so I can check out the volume that this puppy is capable of.

Tonight the fam was watching a TV show and the 663 was set at -2db and it sounded good but just wasn't that loud--fits quite well with what JohnK says about it all being relative. I want to experiment but I don't want to blow anything up, despite that you have all reassured me that the M80s are pretty much invincible, I just couldn't take that right now you know?!

Can't wait til tomorrow!

Self deleted post. I was in the wrong thread.