Studer A810 audio path upgrades

[atavacron]

At the risk of being told to UTSF and read a schematic (which I will do), I'm wondering if anyone's played with the repro and record cards of their A810. I've got an ATR-102 and the feel of the audio coming off these heads is of significant difference to make me wonder if I need to be replacing any capacitors or chips. The deck is aligned beautifully and heads are good, transport is A-OK. It's an '85. My issue is with an overall flattened thickness - actually useful in a colored rock mixing contest, but not so good for reference listening. I'm running Quantegy 456 at +6.