A-77 Output level calibration question

[MilanMilosevic]

I have 2-track calibration tape from BASF and now I have to calibrate the reference output level but on 4-track A-77. Obviously, I cannot use output level sections on test tape because of track mismatch.
My question is: could I use full-track sections on calibration tape for setting output levels? On calibration tape, there are two full-track sections for bias (1 kHz and 10 kHz, both -10dB). Would it be wrong to use these full track sections and set output level to -10dB below reference level (which is +6dB, therefore -4dB VU)?
Thank you in advance for kind assistance.

[HaraldZindel]

AW: A-77 Output level calibration question

Stravo Milan

The full Track Section with 1 Khz 0db works just fine for calibrating. But what kind of Flux-Level do you have on your calibration-Tape ? For Revox - as far I know - it should be 257 nWbm. ( with Studer I use 320 nWbm, or 514 nWbm )

It should read then ( on a external Instrument !!! ) approx. 0.755 Volts ( 0 VU ). If you are done, you can calibrate then the VU's itself. Even the -20db Section with 10 Khz works fine. But as far I know there is no frequency aligment for Revox A 77 / A 700.

By the way: all calibrating Tapes wich I use are always full Track recorded.

Best regards
Harry

[pvandersande]

Re: A-77 Output level calibration question

At 19cm/38 cm you can use the 320nWb/m for 0Vu specially with professional back coated tapes from BASF or Quantegy.
Professional nominal output these days is 2.45 Volt RMS = +10dB/u that should translate to a peak flux on tape of 1020nWb/m
If you have a 320nWb/m test tape your output level should be 0Vu at .775 Volt RMS for this spec.
if you have a 257nWb/m test tape your output level should be -2Vu at .61 Volt RMS for this spec.
If you have a 185nWb/m test tape your output level should be -4Vu at .485V Volt for this spec.
0Vu at .775Volt should be -18dB for tranfer to digital media

Both the A77 and A700 have HF compensation adjustment for the replay head.
regards,
Peter