Vibration from Volume Control

[jcPanny]

I am using a couple of channels on my Emotiva LPA-1 amp to power some house speakers in 4 different rooms. I started with an extra pair of bookshelf speakers in the garage and a Russound impedance matching volume control. The problem is that the VC vibrates and makes an audible buzz sound when there is any low fequency content playing (CD w/ bass vs. Radio). I tried a less expensive Pheonix Gold VC and there is a slight buzz, but it is barely audible, unlike the Russound.

Let me know if I should return or replace the Russound VC or if another component like the amp or receiver line output could be at fault.

 

[mtrycrafts]

I am using a couple of channels on my Emotiva LPA-1 amp to power some house speakers in 4 different rooms. I started with an extra pair of bookshelf speakers in the garage and a Russound impedance matching volume control. The problem is that the VC vibrates and makes an audible buzz sound when there is any low fequency content playing (CD w/ bass vs. Radio). I tried a less expensive Pheonix Gold VC and there is a slight buzz, but it is barely audible, unlike the Russound.

Let me know if I should return or replace the Russound VC or if another component like the amp or receiver line output could be at fault.

I doubt it is the line out fault. Either an issue with that one controller, or if all of them you have from Russound do it, a production line issue, or design.
Obviously Phoenix Gold has reduced the vibration so that alone would eliminate the line out cause.

Have you taken one apart? Is there any coils in there that vibrate at higher current at the low end? Or, is it the case that vibrates or a combination that is amplified by the case and wall-plate? Have you called the maker?

 

[Jason Coleman]

I've actually had the same issue with a couple of my rotary volume controls...house brand Russound knock-offs. Too much power made them vibrate or "thump" when low-end material was cranked through. I just pulled them out and the dealer replaced them. Maybe defective parts, don't know too much about the inner workings of a VC switch, or maybe a bad jumper or whatever. Not a problem, so hopefully swapping it out does the trick.

J.

 

[jcPanny]

VC Issue

Thanks for the feedback. I will probably swap out or return the Russound VC.

When I emailed the manufacture they suggested that the amp was causing the problem due to excessive distortion. I did notice that the tape line out level is pretty hot, I only need 3 or 4 clicks on the VC to play the speakers in the garage pretty loud. Maybe the attenuator is trying to disipate too much power. This should be a non issue when I have 4 pairs of speakers and 4 VCs each receiving 30-50 Watts instead of 1 VC receiving up to 100 Watts.

 

[mtrycrafts]

Thanks for the feedback. I will probably swap out or return the Russound VC.

When I emailed the manufacture they suggested that the amp was causing the problem due to excessive distortion. I did notice that the tape line out level is pretty hot, I only need 3 or 4 clicks on the VC to play the speakers in the garage pretty loud. Maybe the attenuator is trying to disipate too much power. This should be a non issue when I have 4 pairs of speakers and 4 VCs each receiving 30-50 Watts instead of 1 VC receiving up to 100 Watts.

I seriously doubt distortion would cause this. After all, that is just another signal for the VC. Now that you mention power, are these speaker level type VC and what is their power ratings? I bet it is the low frequency mag fields that are causing the vibration in the part and the unit was not designed right, no isolation from the rest of the parts. Similar to a power transformer that develops a a 60Hz buzz that becomes audible.

 

[Jason Coleman]

I actually melted an outdoor VC that I had temporarily hooked up to our Anthem MCA (225wpc). It literally melted the jumpers on the VC and smoked the whole board. Fortunately it didn't result in a house fire, but it sure did stink to high heaven. After speaking to Russound, they suggested that I run a tad bit less current into the VC...

J.