Stereomour II buzzing sound when powered off [resolved]

[lskiii]

Hi -

Really loving my Stereomour II but I had 2 questions that I'm hoping to get some help with.

1. Recently, I've been hearing a buzzing sound from my speakers when the power is shut off to my amp.  It does not go away if I disconnect it from any inputs and it also doesn't go away if I remove the power cord do I fee.  The buzz does go away when I power on the amp.  My uneducated guess is that this might be a bad capacitor?  My speakers are fairly efficient (Klipsch Heresy IIs).  Any suggestions for how I isolate or resolve this?

2. I've done every available upgrade to my amp except for the morequiet attenuator.  I can't tell for sure, but it appears to me that the upgrade would remove the balance control.  Is this in fact correct?  I do use the balance control as my sitting area isn't perfectly symmetrical.  Just wanted to confirm my understanding.

Thank you! 

[Paul Birkeland]

Yes, the MourQuiet attenuator removes the balance control.

If you had an original pair of Paramours that you had said you have used every day for the last 20 years, then maybe we would explore a capacitor issue.  (You don't have a bad capacitor)

Do you have a powered subwoofer hooked up to the Stereomour?  Can you describe your system in more detail?

[lskiii]

So, you have solved the mystery!   I recently added an SVS SB-1000 to my setup.  And, now that I think about, it was shortly afterwards that I noticed the buzz, but I just didn't add 2+2.  I just unplugged the sub and voila, no buzz.  I'm embarrassed that my troubleshooting skills didn't lead me there!

To your question on my whole system the source is a Bluenode into Denafrips NOS DAC (which was a big upgrade IMHO from my previous DAC) into Stereomour II to Klipsch Heresy IIs and I have the SVS SB1000 sub essentially piggybacked stereo off of the banana plugs to my speakers.   I was loving my Stereomour with the only small caveat was I wishing for deeper bass / more "slam".  I had tried running the system at 4 Ohms rather than 8.  This helped, but I still wasn't where I wanted to be and it seemed like my speakers just weren't capable of what I wanted so I added the SVS and did some room EQ (room wizard, etc) and now everything is wonderful  (and I've put the amp back to 8 Ohms).  I'm even thinking about getting a 2nd sub.

Now, the obvious question that I have to ask - Is there anything that you know of that I can do to mitigate the buzz that is clearly being caused by the Sub?  The only thing that I can think of is trying to do a trigger/power supply so that power is turned on and off to the sub when I activate my streamer (but wiring that will be hard to implement cleanly).  Perhaps some sort of power conditioner?  Any suggestions are welcome!

Thank you again!!

PS - Bummer about the attenuator.  I really do need a way to tweak the balance.  If you have any suggestion for how I accomplish both the upgrade and a way to do balance, I'd love to know.

[Paul Birkeland]

A balance control and the stepped attenuator is a possibility on the new BeePre, but not so much on the Stereomour II.

Does your subwoofer have a 2 or 3 wire power cord?

[Paul Joppa]

... and are the subs running on the same power circuit as the rest of the system?

[Gerry E.]

PS - Bummer about the attenuator.  I really do need a way to tweak the balance.  If you have any suggestion for how I accomplish both the upgrade and a way to do balance, I'd love to know.

Hi:

I use a Harrison Labs 3dB in-line attenuator on one channel (preamp input) to compensate for a channel imbalance.  It works perfectly and if it does anything negative to the sound, I can’t hear it.

They are sold by Parts Express but I ordered directly from HL who were willing to sell me two different values -3 and -6dB.  That gave me 3 different values to try but -3dB was perfect.  I wonder if they would make custom values (Ex. -1dB, -2dB)?

Gerry

[lskiii]

Regarding the sub, it's a 2 prong (no ground) plug.  I have it plugged into a different outlet from the rest of the system.  I'm 90% sure that they are on the same circuit.  Would any of that make a difference re: the buzzing?

Also - to the other comment re: the balance, that's a great idea re: an inline attenuator.  Seems like a simple and inexpensive way to allow for me to get the morequiet upgrade... hmm!

Thanks again!

[Doc B.]

I once spent a day tracking down a faint buzzing hum in the midranges of a set of mastering monitors. It was a multi-amped system and the mids each had their own monoblocks powering them. The studio had several sets of outlets along the front wall, and the electrician said he had put them all on the same circuit. After killing the buzz by putting everything into the same outlet we determined that the guy had split the 220 feed into two 110s and alternated the out of phase circuits down the wall.

[Paul Joppa]

As an experiment, get a power strip and some extension cord(s) as necessary to power the whole system from a single socket. That will eliminate one kind of ground loop at least, and might make a difference.

[lskiii]

The support that you all provide on this forum is awesome!  Thank you for the help in troubleshooting what turns out to have been an issue w/ my sub ;-). To close the loop, in case this helps someone in the future, I took your advice and tried connecting the sub to the same outlet that the stereomour is connected to.  This didn't change anything.  Then I used a long extension cord and connected the sub to a completely different circuit - again no difference in the buzzing (which goes away when the amp is on).  Finally, it dawned on me that when I bought the sub, I didn't use the powercord that it came with.  I had an identical looking power cord that had a 90 degree angle to the connections and I liked that it would lay flatter on the floor as I have the sub about a foot away from the wall.  So, I fished out the original power cord, swapped it with the one I was using and to my amazement the buzz went away (almost completely - I can still hear it if I have my ear up against my speaker, but from 2 feet away I hear nothing).  I don't know much about power cords, but at least the buzz is gone.  My guess is perhaps the 90 degree cord had poor shielding or something like that? Also, it's odd to me that when the amp powers up that the buzz goes away.  I'm guessing it has something to do with the sub's standby mode...

Regardless, thank you again.  This forum is terrific.

Thanks!