Sony TC-K770ES calibration and record/play test (with some Koto!)

Decided to try a Sony TC-K770ES from the early nineties this winter. Overall it's a very nice machine with direct drive, dual capstan, manual tape calibration and lovely peak meters. Here I'm recording a Maxell UDI CD (quite nice type 1 tape, but flimsy and cheap shell) pushing the levels unnecessarily high. Somehow I find that very amusing. Disclaimer: This is a very unscientific test made just for fun. The source material is of debatable quality, the sound card not very good for the purpose (it cannot handle the output levels from the line out, thus the output has been routed through a cheap Sony MiniDisc to bring the levels down but reducing the quality) and, naturally.. The result will be better with a Metal, sadly they don't grow on trees these days (and probably never did). :) Story mode: The deck was in quite good shape when I got it, but I decided it was worth somewhat of an overhaul with: New supply and take up pinch rollers (FixYourAudio) New capstan and mode belt (Hi-Fi RetroParts) Replacement of an SMD capacitor on the DD motor board Cleaning and lubrication of the transport (TCM-200D6) and the heads (no lubrication) Playback level adjustment (245 mV RMS @ CX20188 Dolby IC pin 21 and 22) Minor REC-level, BIAS and calibration adjustment Playback speed check (WFGUI, 3000-ish Hz, below 0.05% W&F DIN) Azimuth check (audioTester 3.0) Frequency response check (audioTester 3.0, almost flat 20 Hz to 20 kHz, Sony Metal XR) Playback level, speed and azimuth was verified with the U04103-70C combined test tape (A.N.T. Audio). Alignment of the supply roller was made using a hobo style mirror cassette. Thanks to the people at Tapeheads.net and "Cassette magnetic tapes and tape decks" on Facebook for providing a nice source of information and a place to discuss this very weird hobby of ours. :)