Ok, I got a very informative reply from GML. However, I did get the obvious answer "buy the mastering version" the only problem with that is that it costs twice as much
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Here's the reply from Jeff Warren:
"Hello,
Thanks for contacting me. And, congratulations on your recent purchase, although I'm sorry to hear the unit is not operating exactly how you want it to.
We strongly encourage mastering clients and others requiring high precision to consider the Model 9500 rather than the Model 8200. The 9500 employs switches and discrete resistors for all controls and thus provides not only L/R matching but also consistency across the entire production history of the unit and vanishingly low distortion performance. Because the 8200 employs potentiometers, the front panel markings can only ever be approximate.
L/R matching depends on various components, each with its own tolerance (5 or 10% in capacitors, 1% resistors). The controls themselves have the widest tolerance (10%); however, this only specifies end-to-end (total resistance) tolerance: anything is possible between the full-ccw and full-cw positions, especially for a non-linear taper. Also, keep in mind when looking at L/R matching that all three controls (level, frequency and bandwidth/shape) matter -- including, naturally, their tolerances.
While the only solid guarantee for L/R matching is to use switches with discrete resistors, GML production attempts to provide L/R matching so far as is practical by selecting controls in matched pairs to be inserted in the same position of each channel. The effectiveness of this measure, however, is limited by the reality of non-idealized potentiometers.
Noting this, conducting a post-manufacture hand-matching procedure to establish marginally improved L/R matching is certainly possible -- but is likely to be judged cost-prohibitive.
Best regards,
Jeff
=====
Jeffrey Warren
GML, LLC.
Nashville, TN USA
www.massenburg."
Although I really appreciate Jeff's informative email, I guess it sums it all up. Not the reply I was hoping to get form the creators of the "Parametric Equalizer offers astonishing precision and sonic accuracy when sculpting the response of any source." a it says in the manual. Interesting, as I said, my Mass Pass and IBIS are not that off...
I think I may pass...
