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Stereo channel balance/image

I just recently setup a rega p3 turntable with a cambridge 540p phono preamp on my system. I noticed that there is somewhat of a channel imbalance. The left speaker is just slightly weaker than the right speaker. I tested every possible thing , moving the speakers, swapping the wires, changing interconnects and i've come to the conclusion that it is not the amp. There's something definetely wrong with the turntable or the phono preamp it only seems to happen when I play vinyl. Strange thing is when I played Bob Dylan's "love and theft" lp, the stereo image seemed just right same thing for the "bringing it all back home" 180g lp... I also noticed that the right woofer is working and "thrumping" more than the left when the music is louder. Does any know why this is hapening? Any suggestions?
128x128decapg
8 responses Add your response
jaybo
4,478 posts
 
needle/cartridge alignment is the first place to look.
ghosthouse's avatar
ghosthouse
4,306 posts
 
I have to say channel imbalance is something that makes me crazy. You should be able to isolate imbalance to either TT or phono pre-amp - I think. Can you switch TT leads into phono pre-amp first? If it doesn't change anything try switching phono pre-amp to amp leads next. Have you checked the cartridge/stylus alignment? That would certainly explain the "vinyl only" symptoms...on the other hand if Dylan sounds balanced maybe your system is OK??? Can you listen to the recordings that seemed "imbalanced" on another system? I'll be curious what you find out if you do track down the cause.
docsavage
109 posts
 
This sounds like improper cartridge alignment. Alignment, VTA, azimuth, VTF
and anti skate are fully covered in the archives. These adjustments are critical to balanced playback.
decapg's avatar
decapg OP
11 posts
 
Ghosthouse: i'm not sure what you mean when you say "switch TT leads into phono pre-amp first or switching phono pre-amp leads next"? Do you mean connecting the turntable's rca's into the output of the phono preamp instead of the phono input? Thanks in advance.
eldartford
4,262 posts
 
Are you playing a mono LP when you notice the "imbalance"? A stereo LP will obviously have a difference between channels. For example, a soloist is located where the mix engineer put him/her, and that is not always dead center. You must use a mono recording to check channel balance.
ghosthouse's avatar
ghosthouse
4,306 posts
 
Decapg - Please DON'T plug TT outputs into preamp OUT! What I was suggesting was a pretty obvious diagnostic that probably already occurred to you...
I assumed you had an outboard phono preamp. What I was suggesting is just reverse the left and right turntable output cables...plug left TT out into the right channel phono preamp INPUT. Plug right TT out into left preamp INPUT. If the lower volume imbalance DOESN'T move to the right channel this would implicate the preamp (or something else downstream). If it does move, it means the problem is with the TT. If you have an outboard preamp, you can try the same exercise. Reversing preamp L & R channel outputs going into amp inputs. Hope this clarifies
decapg's avatar
decapg OP
11 posts
 
Thats what I thought well i've come to the conclusion that its either my amp or my cd player, I now notice it on cd's aswell. Tried everything the only thing left to do is to test the speaker wires. This is driving me nuts. Is imbalance usually common in gear?
newbee
4,767 posts
 
IME most imbalance issues, apart from weak tubes and TT set up, are due to system set up, including seating position, which is caused by unbalanced reflections, such as having the left speaker further or closer to a wall than the right speaker, or having the listening chair in a place where the reflections from one side are heard as louder due to furnishings etc.

To check out pre-amp and amp you really need a mono source. On many occasions when I have heard an imbalance I just put on a mono source and find I have a dead center image and the problem was a poor recording. On a couple of occasions I shifted my chair a couple of inches.

If none of this works, visit your friendly ENT and have him check/clean/test your ears. :-)
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