Thorens TD-160MKII Channel Imbalance

Hello.

I have a Thorens TD-160MKII turntable that has a problem with channel balance. The left channel is around 1dB louder than the right. Below is my current set up and a list of things I’ve checked.

Currently I have an Ortofon Super OM cartridge and an OM20 stylus. They’re mounted to a TP63 arm-wand (the upgrade to the fiddly TP62) on the stock TP16 tonearm. I’ve kept modifications to a minimum only changing the bottom plate to one with leveling legs, certain parts of the suspension (new foam, leveling washers), replaced a broken arm-lift cable and upgraded the RCA cables to ones from Blue Jean. I wired the cables the exact same way as the originals, grounding through the left channel as opposed to an independent ground. Also, a new platter mat. The table has been professionally serviced and meticulously taken care of. I rebalanced the suspension in the last year.

I use an Oscilloscope application on my computer with the Analogue Productions test record.

-I have aligned the cartridge using both the Thorens gauge as well as the Feickert Protractor using Baerwald geometry. Same result.

-Azimuth is spot on.

-VTF is set to the recommended 1.5g. Increase and decreasing has no effect. All measurements are done on a digital scale, not by eye.

-VTA is currently set at the factory height with the needle aligning with the Thorens gauge. I had a 1.5 mm shim under the cartridge before and the result was the same.

-Anti-skate seems to make no difference either. Setting it to 1.5g, dialing it all the way up or down has no effect. I know the AS is working to some extent because when the arm is floating, increasing the AS increases the speed it pulls outward toward the arm rest fairly significantly.

-Turntable leads both measure around .990 ohms. I think one is like .992 and the other .987.

-Tried going through my SX-1050’s preamp and a standalone Cambridge Audio one and get the same result.

-Reversed the leads, reversed the cartridge wire. The problem reverses in both scenarios.

-I thought maybe the OM20 had a crooked needle. Tried the OM10 stylus. No change.

-Turntable is leveled from the platter. As it has a suspended subchassis leveling from the plinth isn’t as accurate.

The only thing that helps is if I skew the Azimuth way off I can get the levels on the Oscilloscope to match.

I had a modified arm with an Ortofon Blue before and got the same issue. Frustrated, I changed everything back as close to factory as possible, which is where I am now. I switched from the Blue to the Super OM because the latter is higher compliance and better matched to the arm, or so I thought. Also, it was the closest in spec to the original VMS (or something) cartridge it shipped with.

What am I missing? Is the AS way too strong even when dialed all the way down. Does the arm need to be rewired? Please help.

Thanks in advance.

-Doug