I'm looking at taking it even further by following exact calibration steps from the service manual. Previously I have only done Wow/Flutter, and speed adjust using a scope program on my computer and a test tape which was made by a professional. The service manual mentions a Vacuum Tube Volt-Ohm Meter which is used for the majority of the tests. It seems that there are only vintage units of these still available 2nd hand. My question is, what alternatives do I have? Is there something more modern that I can use or purchase fairly cheaply?
Also a Big Thanks to Joe for the advice on the OP Amp, us Amateurs need all the help we can get! I hope in time that I can get up to Pro level with these decks when it comes to service manual calibrations.
Dropped the OP2134PA into Line input stage, it worked and sounds great. Recorded Natalie Merchant's 'Tigerlily' MFSL CD, excellent result. I will also upgrade the other two decks with this mod including muse caps.