2. amps-preamps
  3. 159332-148430

Speaker hiss from power amp

I have a Mark Levinson 532H amp that is connected to a Levinson 390S CD processor only (no preamp).  Recently, I switched from single-ended to balanced interconnects (Cardas Neutral Reference) because it's a pretty long run (~12 feet) between the components.  The 532H has switches on the back for selecting balanced or unbalanced interconnects.  The switches had always been set for the RCA single ended inputs, so I just noticed that when the switches are set to balanced, there is a very slight hiss coming from my tweeters.  When unbalanced are selected, the hiss is substantially reduced, nearly but not quite silent.  Both speakers have an equal amount of hiss.  In balanced mode, the hiss is only audible when my ear is 3 or 4 inches from the tweeters so it doesn't in any way detract from my overall musical experience.  I should note that the hiss is evident whether or not anything is actually connected to the amp (other than the speakers, obviously), and there's no difference with gain when I have the 390s connected.  Also, the addition of a power conditioner has made no difference at all.  Two other things: there is a very slight hum coming from the amp (again, only audible if I'm very close to the amp) and the A/C power from my outlets seems pretty inadequate (probably less than 5 amps according to the Parasound).  Appreciate any ideas on why the hiss increases when the switches are set to balanced inputs and how it could possibly be eliminated.  
rwatson

Showing 4 responses by rwatson

rwatson OP
6 posts
 
Interesting since I thought the point of using balanced interconnects was to reduce noise.  I guess corollary questions, then, are: 1. Should I go back to single ended and potentially what could I be losing by doing so and, 2. Is the fact that I can hear ANY hiss possibly indicative of a faulty amp?  The second question is what’s really weighing most heavily since, as I said, the hiss isn’t audible at all from where I listen and, otherwise, everything sounds great to me.  Also, I was thinking of upgrading speakers (General suggestions on synergistic brands (my local shop sells Focal)?  Currently, I’m using older B&W Matrix 3 Series 2s that I purchased in the 1980s) and would hate for the noise floor to then become audible!
rwatson OP
6 posts
 
@georgehifi, if I'm following you, the hiss can't be explained by the DAC since it's present whether the 390s is connected or not.  Thanks!
rwatson OP
6 posts
 
All good stuff—thank you, everyone!  I guess it’s pretty apparent that I’m new to some of this, so appreciate your patience.  That said, to millercarbon’s remark, I actually was a professional jazz musician in my past life (albeit a horn player so not involved in the electronics side of things except for moving other musicians’ heavy gear).  I’m 56 now so I don’t need to impress anyone—I just appreciate well-made and designed stuff, whether it’s furniture or appliances.  Anyhow, it doesn’t sound like there’s anything I need to be concerned about in terms of equipment health, so that’s the main thing.  Millercarbon, I’m definitely all ears if you have suggestions on single-ended interconnects.  And speakers, for that matter! 
rwatson OP
6 posts
 
Thanks, @mrdecibel, I really appreciate it!  To clarify, I have a Parasound Max 5500 (actually, borrowed from a video set up in another room) that indicates (what I assume is) amps from the wall.  Again, forgive my lack of knowledge regarding electronics, but I've often heard of dedicated 15A circuits, etc., for audio systems.  Bottom line is that I don't have anything like that.  Perhaps it's a non-issue, or perhaps I need to have an electrician come in.  It sounds like you're saying the latter might be advisable?

Regarding speakers, I am really just looking for some initial manufacturer suggestions since synergy is another thing that is often discussed on this forum and I'm sure there are speakers which are particularly well suited to the Levinson gear.  It might be best to start another thread so we don't drift too far off topic.  But, for what it's worth, I really only listen to vocal and instrumental jazz and classical music.  I'm sure there are many modern speakers that are far more accurate and better sounding than what I've been using.  Piano, small instrumental and vocal ensemble music sound quite nice to me on the B&Ws and I can definitely tell which recordings are not particularly well mixed.  One area where I'm sure there's a lot of room for improvement, however, is in detail and dynamic range with big band and large orchestral recordings. 

Stay safe (and sane) as well!
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