OB-8 envelope calibration
2002-06-07 by swwood2001
Well, my OB-8 is now singing again, with many thanks to Dean Batute in Toronto for the repair, and David Wiseman in the UK for the chips we couldn't find here. I remember again why I bought this sucker 17 years ago... One issue has arisen that has seemed to stump us, however. Software revision A7 (made through Engineering Change Order 427, later cancelled by ECO #433, also referring to 422) refers to envelope calibration software that for some bizarre reason, does not seem to be on my machine, which shows as version B3. When performing the envelope calibration, the DAC calibration goes fine, then when the 'rate' knob is lifted to go into envelope Offset mode, the machine seems to think it's back into DAC calibration mode. Hmm... End result? My two voice card's EGs will not match up. If the attacks are perfect, the releases are way off, and vice versa. The best that my tech could do was to trim the offsets (via newly installed pots)to be as minimal as possible across the range. However, the difference is very noticable, especially on longer releases or lower sustain levels. and decay is whacky. Does anyone have any suggestions that we could pursue? Love this thing too much to just shrug my shoulders and sigh. Thanks....Steve