C52 hiss

[eedork]

Hey guys -

Earlier this year I traded my MA6600 + D100 in towards a new C52. I love it and am very happy with the upgrade. My plan is to eventually get a new amp as well (having a hard time deciding on tube vs. SS), but for now I am using an old MC7100 which is doing just fine.

I do have one concern however. This morning I noticed that there is a little hiss coming from the tweeters if I put my ear within a few inches of them. The hiss is definitely coming from the C52; if I turn the C52 off and leave the MC7100 on, the hiss disappears. I'm using balanced cables to connect the two components. I also removed everything from the C52 to confirm that the hiss was not coming from a source component.

Has anyone else noticed anything like this? I don't recall the MA6600 having any hiss at all.

Thanks!
-Matt

[BlueSky]

I normally don't listen to my system with my ear a couple of inches away from the transducer. If you can't hear that hiss from your listening position I'd say you are good to go! I didn't mean to be critical but I'd suggest letting reality be a guideline here. To wit, I can hear hum coming from my subwoofer if I have my ear within a couple of inches of the cabinet but, from the listening position, it's quiet. Enjoy your fantastic system!

[kzhtoo]

Seriously that is the advice?

[kzhtoo]

Hi Matt,
My Ayre KXR pre doesn't make a hiss, dead quiet but my Anthem MXR receiver that I used as a pre/pro for movie does. I tried everything I could think of but it's still there. I'm waiting for the day I replace it with something that doesn't make a hiss.

[eedork]

Thank you guys. The C52 sounds wonderful, I just want to make sure that it is not defective in any way. I will contact my dealer and ask about it.

The hiss is definitely not audible from the listening position. But it is when I am maybe a foot away from the speakers and it is worse when the equalizer is enabled. I noticed it while repositioning speakers, and do not remember my old MA6600 doing this. I'm surprised by the hiss because the C52 is supposedly quieter than the MA6600 with an SNR of 100dB vs 92dB.

-Matt

[MBlue72]

Matt:

It is ironic I came across this thread today. Two days ago my C52 came back to me from McIntosh (via my dealer). They had it for 2-1/2 months. I have exactly the same issue. McIntosh sent it back with a note: "Could not duplicate malfunction. Meets spec."

My amp, like yours, is an older unit -- an MC7300. My speakers are Klipschorns, so very efficient (said to be ~105 db).

Here are specific observations I passed on to McIntosh for my situation:
• Slight static/hiss … with no signal … very, very slight.
• Becomes more pronounced when equalizer invoked.
• The static/hiss … does not get louder when volume knob increased.
• Occurs on all inputs equally.
• In fact, when I pulled all input plugs … the noise remained.
• The noise remains regardless of whether C52 is plugged into my voltage regulator or directly into the wall outlet.

My dealer let me use a C50 as a loaner during the protracted testing by McIntosh. Somehow I didn't think to listen for the same issue while using the C50 until I heard back from the dealer that McIntosh could not find anything wrong with my C52. Then I listened for this "hiss" using the C50 (with equalizer invoked) -- it was there.

So it seems the issue somehow must be related to the MC7300 ... or the interconnect cables ... I guess.

Hope this helps,

Dave

[Mamrak1]

I own the C52 and it makes no hissing noise through the speakers and is dead quiet. I do have the equalizer engaged however mostly the settings are close to flat. PS... I run balanced cables between the C52 and the Mac MC152.

[eedork]

Thank you for the feedback guys.

Dave - the symptoms you described are exactly what I am experiencing.

I will try a different set of balanced interconnects at some point to rule that out. I suppose the hiss could also be power related. I have the C52 connected to an APC G5 which I doubt is the cause of this issue .. however, I will try going to straight into the wall socket to rule out a problem with the APC.

-Matt

[MBlue72]

A few more bits of information on my situation:

1)... even when I set the equalizer completely flat, the more pronounced hiss/static is present as soon as the equalizer is turned on
2)... my voltage regulator is an APC LE1200 Line-R 1200VA
3)... the cable from my C52 and my MC7300 amp is unbalanced (6-foot I think)

It has been hectic for me lately but when I get a chance I'll check with my McIntosh dealer to borrow one or two sets of cables for further testing. The dealer is really very good and I'll bet they will do this for me. They were very embarrassed that McIntosh took so long ... only to give the unit a clean bill of health. I'll report back when I have more information.

Dave

[eedork]

No worries Dave. I just pulled the rack out and did some testing. I tried the following:

1. A different set of balanced cables
2. A set of unbalanced cables
3. Repeating 1 and 2 with the APC G5 unplugged and the C52 + MC7100 plugged directly into the wall

In all cases the hiss is still present, and worse when the equalizer is engaged. It does not vary as I change the volume.

Maybe this is just normal. I do have a C35 in another room that I will experiment with tomorrow. I don't recall it having any hiss, but I wasn't exactly listening for it.

-Matt