JVC TD-V661 Internal Bias Calibration Part 1

Today I recalibrate the internal bias of my JVC TD-V661. I originally asked my tech to calibrate it for the last generation XLII when I had it serviced. That was a mistake! I found out that generation XLII required a lot of positive bias, so if I leave it centered, it’s fine for this tape, but every other tape requires negative bias. Some tapes required so much more negative bias, I couldn’t even bias them at all on this JVC!

So according to the service manual (found https://www.hifiengine.com/manual_lib..., I just need to keep external record and bias knobs centered, then start biasing a normal tape (it didn’t specify which brand and model), and adjust the pots labeled VRU11 and VRU21 (record level and record bias adjust respectively) until it says it’s calibrated on the VU meters. It’s that simple!

But as with anything seemingly simple, there’s actually more to it. I’ll show you in the next video what I mean. For now, I hope this helps those who own the JVC TD-V661 and TD-V662 cassette decks. Both models are the same, just different external color (black vs titanium).

Watch part 2 here:
   • JVC TD-V661 Internal Bias Calibration...