Frequency/Channel imbalance. Help

I'm using a Benz-Micro H3 Ebony on a VPI Scout w/JMW 9 Sig arm. Since purchasing this TT I've mounted 2 carts to it and have noticed a frequency/channel imbalance on both carts so much that the center imaging bends to the left channel. Almost if a bandpass of upper freq are louder. It is mostly apparent in the upper range where the throatiness of vocals reside and I don't know what could be the problem. I can't decide if the left channel sounds a bit too harsh giving the impression it's louder assuming the right channel sounds correct or the right channel is missing the upper presence and sounds to soft. I heard it with the previous cart I used a Clearaudio Virtuoso and am now hearing it with the Benz, with new and used vinyl. I'm at my wits end with this because I love the lushness of vinyl and use it as my primary playback source and I'm not interested in upgrading my digital front end right now. I've meticulously checked the leveling of the table, cartridge loading, VTA, VTF, overhang, etc. I thought it may be the anti-skate but over a period of listening since it's broken in I've adjusted it slightly till I've minimised the sibilance distortion in either channel. I've gone through the whole system swapping channels to see if the cables or one of the preamp devices have a problem and I haven't heard a change. The only thing left is to reverse the pin config from the cart to TT outputs to see if it moves from one channel to the other but I wanted to use that as a last resort. This is actually my second time posting this question in the hopes someone has had a similar occurance they've rectified.

Side question: The dealer that sold me the cart also set it up and put the added weight between the cart and tonearm. I've noticed significant low freq excursions. Sounds like the arm resonance is too low. Should I remove the weight to reduce that?
Have you checked the cartridge's azimuth to be certain it's perpendicular? The mirror method works well for this.

My L/R balance is always slightly "off". I compensate either by adjusting the left or right gain controls on my phono preamp, or the balance control on my integrated amp. No biggie.

The only thing left is to reverse the pin config from the cart to TT outputs to see if it moves from one channel to the other but I wanted to use that as a last resort.
Rather than doing this, you can simply criss-cross the L&R turntable interconnects at either the TT outputs or at the phono preamp inputs. Same difference, and considerably less hassle.
this would appear to be a problem in the phono pre
Honestly if you have swapped left to right channel at the turn table and it does not follow the cable swap meaning it stays still as the problem in one channel.. Then your Phono amp on down might be having something going on... Only other thing is that its possible it is not your equipment or setup..

Its far simpler, room acoustics... something on that side is causing this increased volume or excess of something, and making things sound like they are more targeted to sweep to the left..Or other people I have seen have rooms setup completely with one speaker far further from a sidewall than the other, the room must be mirrored to be extremely accurate.. Also Doorways, or any other obstruction sometimes between the speakers excites this problem as well in my experience, and for some reason the little microphone otherwise known as a cartridge definitely can also feedback this issue more..

I had this exact same issue and it was really apparent when running my turntable, however it could be slightly detected with digital as well having the sound stage skewed off center to one side.. I changed rooms since, put in good room acoustics, and now have zero issue with this, everything is dead center at all times, even if you sit off to one side of the room or the other, you can tell the image is stable to the center still. Some are not willing to address room treatments, so good luck and hopefully it is something else.
Excellent points by Undertow.

The channel imbalance in my system is largely caused by the room due to drapes on the left wall and none on the right.
I have same issue and because of varies changes in equipment I am convinced it is my room, as it is dual use and our living room I have to live with it and dream of a dedicated audio room in my future.
Tvad, I took your advice. I don't have a mirror to check azimuth but I used a record I own that has no grooves on one side as my mirror. I did notice my cart was leaning to the side just slightly. Aside from using 2 volt-ohm meters to tweak the channel seperation based on crosstalk(as per the Michael Fremer video). The stereo seperation has opened up immensely. Although now I notice depending what record I play it leanes a bit to one or the other side and the center image isn't always dead center not nearly as severe. Un/fortunately I have no balance control on my pre.

Thanks all for your responses. They're greatly appreciated and I will have to give them further thought

06-20-07: N803nut I notice depending what record I play it leanes a bit to one or the other side and the center image isn't always dead center not nearly as severe.
That's odd. Once a cartridge is aligned and tightened down, the azimuth should not change. Are you sure the azimuth angle isn't appearing to change in relation to a record that has a convex or concave shape to the vinyl?
I don't know what's happening here. Maybe there are slight convex/concave issues with the record surfaces. Maybe on some of the used records one channel is more worn. Maybe some sort of weird electrical phenomena is happening to cause this. I have my TT about 4 feet from the cartridge so I wouldn't think that magnetic flux interaction would be the factor. I still plan on getting the Cardas record and checking azimuth by figuring channel seperation to get it very close considering it's a 180g record and I think it will change just slightly playing 150g LP's with the unipivot arm. But I can say the stereo image seems more sweet and the instrumentation seperation in the mix is much better since I made the visual azimuth adjustment.
"I have my TT about 4 feet from the cartridge"

There's your problem! ;-)
Hardy Har Har, Piedpiper:)
Azimuth adjustment per se has very little effect on the output per channel (i.e., balance). This fact is mentioned in two erudite treatises on azimuth to be found in the Vinyl Asylum archives, authored by Victor Khomenko and B Kearns, respectively. To check this out, I made measurements across a wide range of azimuth settings using my Wheaton Triplanar with Koetsu Urushi, a sensitized Signet cartridge analyzer, and a Shure test record. The max difference in channel balance effected by the most extreme changes in azimuth was about 1 db. Azimuth affects channel separation (i.e., the amount of L channel signal leaking into the R channel and vice-versa) but not the difference in output signal between channels (much). This comes up all the time on this and the other forum. Look elsewhere for your the solution to your problem.
Thank you Lewin. I will do that.
Hi N803nut

I have the EXACT same problem as you do, and i strongly think that your problem is due to your listening room, as other had said. My room is also a living/listening room and it doesnt have the ideal shape for speaker placement. I also tried everything you mentioned but there's only one thing that helps the most: Speaker placement. Try to find a spot that is most balance in your room to set up your speakers there: Meaning a spot that speakers "see" the most balance in furniture placement/density, walls or any surface that can create early reflection, It's kinda weird that the digital playback doesnt suffer this as much as vinyl. Maybe that's because of the frequency responses of digital and vinyl are different. I have some female vocal LPs that have dead-centered image and some have the center image shifted a little to the left (but the same music on CD doesnt do that) because of this problem. It was a nightmare for me but the good thing is that i figure it out now and stop blaming the equipment that i starve myself to get 'em :).

Best wishes to you on this problem ...and please let us know if you can resolve it.