Pre Amp break-in balance issue

I just got a Luxman C700U pre amp to go with a Sanders Magtech amp and the left channel is weaker than the right. If I set the balance at 9 O'clock I get a balanced soundstage but in the middle it's tilted right. The amp is pre owned while the pre is new. Can this be a break in issue that will correct itself? I checked and rechecked the connections repeatedly. Thanks for any input, Joe.


I don't think break-in will correct it. If you're pretty sure the speakers and cables are working fine, my suggestion is to connect the preamp's right output to the power amp's left input, and the preamp's left output to the power amp's right input. If the left channel is still weaker than the right channel, the problem is with the power amplifier. If the right channel is weaker, the problem is with the preamp.

If you are a ROON user, then the following thread may help as a stop gap solution.

Audiogon Discussion Forum

I own a Sanders Magtech amp and I use it with a Magnepan LRS+ speakers. What a combo and I am so lucky I changed my mind about selling the amp. I needed to use the Schitt Yggi+ LIM DAC to get the total satisfaction I have now with this gear.

I bought my amp used from Roger Sanders and he was incredibly helpful with my questions and demo requests. I would contact him first since your amp was used.


I am assuming that with your previous preamp the balance was good?

I am not familiar with that preamp, but I take it that it is SS and NOT tube?  Because a weak tube in a certain socket could cause that..  What I do to verify that the signal is the same at both speakers is I put in a Cd with a test tone designed for that and then I set my multimeter to AC volts and probe + and - on one speaker and then do the same on the other and compare readings.  If I've got a real well matched pair of tubes in the balanced input sockets of my preamp, the readings are almost identical to each other. 

This is not a break in issue, but sounds like a bad volume control.

To be sure, swap cables to amp and see if channel problem moves also.

poor description + unhandled shipping by carrier and/or seller probably equates to poor condition preamp. 

My plinius sa100 xlr right channel is weaker after I over drive my Martin Logan request many yrs ago.Thinking maybe the fuse inside are the issue. Replaced the fuse still the same. But on rca no problem.I am not sure what’s the problem.

please clarify, you say the amp is pre-owned, i.e. it was/is your existing amp, worked properly, OR, you also just bought it used?

preamp is new, warranty?

cables/speaker wires: still using yours? worked properly previously? solid connections?

as mentioned, you can figure some stuff out by swapping l to r, at preamp, at amp, speaker wires from amp.

leave preamp balance control in the middle, what moves l or r, when, what changed,

my memory sucks I draw diagrams and write stuff down, things get confusing, you end up repeating things .....

Thanks for the replies, after a sleepless night racking my brain I decided to try something. I have 2 Synergistic Research UEF devices that plug into unused rca connections that I used to great effect in my 509X and had plugged them into the pre outs on my new preamp. Today I removed them and plugged them into 2 inputs instead and VOILA great balance. I have no idea why they would have altered my balance into the pre outs but not inputs but I'm learning in my old age that I don't have to have all the answers. I started with these devices installed into my SR ethernet switch and have enjoyed the soundstage improvements with my modest Shiit Yiggy/Aurender N100H. Then adding 1 and then another into my 509X things just got better and better. They are certainly worth a 30 day money back trial. So far the C700U/Sanders combo sounds great with my ML ESL11As and the pre is not broken in yet. Another shout out to Albert Sportis at PAV in Chicago who has given my great advice and deals for years, a real gentleman. I have been enjoying the 509X and didn't think I would ever move on from it but having heard that the Sanders was made for ESLs finally took the plunge. So far so good. Thanks again for the thoughtful replies. Joe. rca

Yes there is a break in on SS devices, but it’s for both channels equally.  If one channel is softer than the other, something is wrong. Send it back and get another one.

All the best.



‘Happy ending. I’m old enough to appreciate a problem going away without following it.

 but I'm learning in my old age that I don't have to have all the answers

I hear you.  I can just accept good news (in my old age) instead of questioning it.  Mostly, anyway.  Good to read that it worked out for you!

Is it possible that the room acoustics and positioning of your speakers account for the balance issues? I've found that using spades on my spkr cables improved the overall balance compared to bananas which can loosen up. I've gotten to the point that a preamp without a balance control isn't worth owning.

Great outcome joeyfed55 I usually find weird issues like this to be operator error somehow. I know that’s been the case with my dumba$$ more than a few times. 🤣