Balance control?

L/R channel balance is definitely something that can drive me crazy. I’ve obsessed over it before. There are many sources of L/R imbalance in a 2ch audio system:

• acoustics / room
• cartridge - even high end MC cartridges are often spec’d at most to <= 0.5dB, sometimes as high as 1.0 or 1.5 dB!
• cartridge & arm setup
• mismatched tubes (usually this has to be a fairly large mismatch to notice, > 15% at least)
• speakers (really any transducer)
• speaker & listener positioning
• bad cable or contact connections (in particular, bad headshell contacts or leads have caused this for me in the past)

A test LP with a "center image" track (like the HiFiNews one) can be useful to help isolate imbalances. A "mono" switch on your pre/phono or a mono adapter cable (patch in as needed) can also be useful for diagnosis.

I have 2 high end preamps I alternate use of here: one without balance control (VAC Master), one with (ARC Reference 6). The Ref 6’s balance is implemented in such a way that engaging it does NOT degrade sonic performance. However some would argue the digital IC chip it uses for volume control compromises baseline performance, balance correction engaged or not. I enjoy both preamps. The Ref 6’s balance control is really nice but I try to not depend on it (because it’s not there with the VAC).

Clean all you cable connections, and sometimes I will swap channels L/R on certain slots (which takes experimentation), or tubes, in an effort to cancel out imbalances. For example, if you have a room asymmetry that makes R seem dominant, and you have a cartridge that is also R dominant (even after careful setup), swap the phono cabling so the cartridge’s R side reinforces the L instead of exacerbating the R imbalance. You would have to be willing to swap L/R image for this (which strangely doesn’t bug me). Some kinds of offset swaps you can do without mirroring channels.

My older preamp, Rogue Hera, has a high quality stepped attenuator for the main volume control (very transparent) and a cheap Alps Blue potentiometer (I can always hear the effect of these next to a higher quality control) for the balance control. When you engaged balance, the Alps got spliced into the circuit. That definitely affected SQ, and I couldn’t abide that. So any penalties of using the balance control will depend on implementation.

@mulveling 

yeah the channel imbalance is a challenge for sure! I did swap the L/R cartridge leads for a bit but went back because I couldn’t live with the flipped image. It did help though.

I really appreciate your replies here. Super insightful and very helpful. I was going to start a new discussion thread but maybe I’ll just ask you here - you once mentioned I could look at a Benz Micro wood cart as an upgrade to the Hana SL (which I really like) I’m running now. Which Benz wood should I consider? I feel like there  are a handful of Benz Wood carts out there. 
 

Thanks! 

@paulgardner

Hi Paul,

Here’s a rundown of my thoughts on the wood Benzes I’ve owned:

• Benz Wood 2M, SM (caramel colored Bruyere wood with swirly grain) - These are now discontinued. They have a lively, pleasing and fun sound with a little warmth in the mids. Not as refined, smooth, or detailed as the other Benzes on this list.
• Zebrawood L (new 2020 model to replace old "Wood" series) - Really nice cartridge for the price. Easy to work with in most system configurations. Great sonic balance, not too warm, not too bright. Definitely better than prior Wood series. This cart is probably the easiest Benz recommendation!
• Ebony L (replaces old "Reference" series) - A real chameleon. In some system configs this cart ends up a little leaner than I’d like in mids and bass, with top end a little too sharp. BUT is pairs brilliantly with gear that has gives very powerful bass response combined with a slightly relaxed (or at least flat) top end, like the Quadratic MC-1 SUT, the ARC Reference preamp & phono, or Apollo Dark monoblocks (in various combinations). When paired just right, the Ebony L exceeds the Zebrawood L. When the Ebony is really ON it competes even with my Koetsu Blue Lace. But the Zebrawood doesn’t require as careful system matching.
• LPS - This cartridge is hard to work with in two ways. One, its huge mass (16g) requires a lot of counterweight on your arm. I used a Graham Phantom with extra counterweight. Two, it doesn’t sound its best with a SUT, which is my preferred device for MC gain. You will want an active JFET MC stage that has high gain AND very low noise. I put this cart away a while ago and haven’t tried it with my ARC Ref 3SE yet, which should be its optimal partner. Before that, I got best results from the cheap little Hagerman Trumpet MC stage, and it sounded very good this way - but was miffed I couldn’t get super results with my VAC phono stage .

@mulveling wow thanks for the breakdowns. Super helpful! Sounds like the Zebrawood L is a good place to start. Like I said I really like the Hana SL but I think it’s time for a change and I hoping to smooth a bit of the top end harshness of the B&W 805s I sometime experience with some recordings. Much appreciated! 

@paulgardner

You’re welcome! And yes, I agree the Zebrawood L is a solid choice. A really good embodiment and implementation of the "Benz" sound. Also I think it’s a very handsome cartridge!
All my Benzes so far have had excellent L/R channel balance.