I have a Studer A807 with an odd EQ issue. I have a deck capable of 3.75ips, 7.5ips, 15ips. It's one of 13 I maintain. During preventive maintenance I noticed the EQ was dipping in the mid-range on both channels. I immediately thought it was a head problem since we use these daily to archive media and heads eventually wear out. However after trying several other head blocks I determined it was with the player's electronics and not head. Everything else looks good, tensions, head wrap, azimuth, but I'm seeing a 4db-6db drop in the frequencies between 2KHz and 8Khz. The remaining 8KHz-20KHz is down also, but only around 3db-4db with the high-end adjustment at max. This is true at 3.75ips and 15ips. The 7.5ips reading look good (+/- 1db 32,5hz to 20KHz).
I've tried going into the soft switches, particularly #13 which specifies the EQ curve which is used (NAB/CCIR) and tried all settings, but the response only got worse. I've tried re-seating cables and cards, but still the same. This issue is with both channels so the cause has to be common to both. Before scratching a bald spot into my head I decided to ask for help. Any ideas?
I've tried going into the soft switches, particularly #13 which specifies the EQ curve which is used (NAB/CCIR) and tried all settings, but the response only got worse. I've tried re-seating cables and cards, but still the same. This issue is with both channels so the cause has to be common to both. Before scratching a bald spot into my head I decided to ask for help. Any ideas?