One speaker louder than the other !

Hi Folks,

I recently got a new pair of Living Voice Auditorium II to go with my existing Simaudio Moon CD and cheap old Rotel Amp (2005 I got it).

Running in new speakers I was up first this morning so just thought I'd warm up the electronics while the wife slept in....

At very low volume I noticed that the right hand speaker was still more prominent and next to nothing out of left...at normal listening volumes you can't spot this.

Panic, is it my new speaker ??? So I switched the cables round at Amp end and it was thankfully now the left speaker more prominent !!! So Phew not speakers....so what does that leave, amp or cd player.....the cd player costs 5 times as much as the amp, so I was really hoping it was not the cd player.......then I had an idea....I'll swap in my DVD player to eliminate the cd player......and another Phew.....same issue, so that means it has to be the Amp.......OR does it ? Could this be a cable issue....

Heck as I type this I just realised I could swap over the cables to find out of it's cables...I still have old set....

If it is amp, has anyone else come across this? Should even a budget Amp still be balanced...I'd have thought so ! Rotel was £500.......however I am looking to replace this relatively soon !

 

It is the volume control causing it and you are now noticing it because your speakers are much more efficient / sensitive.

Normal stereo volume controls are curved strips of impregnated plastic film that a metal contact or follower is swept around when you turn the knob. The impregnation is a semi resistive layer of carbon or metal film that provides an increasing level of attenuation as the control is turned. The manufacture / matching of the beginning of these tracks (as they are called) is the hardest part, and to assemble them accurately to start at exactly the same time is very difficult. So potentiometer manufacturers specify their products very carefully. You can buy dual pots at 10% 5% or 1% tracking error tolerance. The less tracking error the more expensive. But all of them only say this tolerance is valid after the first 5% of the travel of the pot. So the problem only exists as you describe.

How to solve it - well you could replace the pot, but it may be better it may be not, and the problem could channel reverse, or use less sensitive loudspeakers, or put up with it!

 

Thanks Richard, good technical explanation. I am not worried about it as I'd eliminated the speakers and CD player....and at a sensible volume it is not at all noticeable. For me the speaker and CD player spend was significant, so I'm probably just being over sensitive......got it blasting away now and sounds great......am really enjoying the LV speakers....just the amp to change and I'll have a system I'll be happy with for years to come !

 

Does you Rotel not have a balance control volume pot, many of them do. Grab the back of the volume knob, and twist the front. Should be obvious if no balance control exists n the front of the amp.

 

I would also not rule out room acoustics. In my old home I had glass covering the stairwell, and the opposite wall was brick. This had volume differences between channels aswell as tonal imbalances.

If you are getting signal through both speakers at louder volumes, it is unlikely to be cables, which in my experience will just either connect and transmit signal - or not. They don't do half-asssed at low volumes through one channel..

 

This is a vid I took on day 2.....speakers drivers have loosened of a little more since then....forgive the camera work, was using my Canon DSLR !