ethervalve
Well-known member
Hi folks,
I've been working on refurbishing a pair of Studer 169 consoles to link together and replace my old Tascam.
Everything has been going fairly well so far (replaced all the electrolytic caps, many of the tantalum caps, went through the console alignment procedure), but I just have a couple questions for those of you who are familiar with the board:
1) The previous owners modified the console to have meter lights. They used some sort of two transistor regulator scheme with trimpots to get the voltage (fed from the +15/-15). They used #373 bulbs (rated at 14v/0.08A) with the voltage trimmed to about 8v.
Was this sort of modification common? I was having some stability issues where the console would shut down when levels got really high (one of the transistors in the DC to DC convertor would get very hot). I unhooked the bulbs and I haven't been able to reproduce the shutdown issue since, but do you think that the bulbs could have been the cause of the problem? (there were six of them in each console's meter bridge).
2) The manual called for -10dBu @ the channel insert (channel fader @ -10) to give -10dBu at the bus insert (master fader @ -10) +/-1dB. I'm getting between -8 and -8.5dBu pretty consistently across channels. Is this worth worrying about?
3) two of the channels have very weak bass and a thin sound on the mic input (the line in on these channels is working perfectly). I attempted to the demagnetization procedure in the manual to no avail (i even tried a han-d-mag and bulk tape eraser after that failed). The phase switch gives an enormously loud pop on both of these channels. Any ideas on what to check next? Could the transformers be broken?
4) Limiter calibration. After replacing the diodes (thanks for posting that tip roginator) and zener diodes, the limiter calibration went pretty well but I ran out adjustment for the final step; so when feeding the bus a 20dBu signal, instead getting an output of +10.4dBu, I was stuck at +9dBu max. This is pretty consistent across all four busses. Should I try replacing the trimpots?
5) Limiter distortion calibration. There were two step in the limiter calibration that I just ignored. I was supposed to measure distortion and "adjust for minimum deflection". Is there any software anyone could recommend for realtime distortion measurements? Or should I just leave this alone? I don't *hear* any distortion at reasonable limiting levels--could it be relatively unimportant like the distortion adjustment in the 1176?
6) PPM reference. This is more of a general use question for folks who are used to working with PPMs--the previous owners set the resistors on the 'console interconnection bus' for a +10dBu line level. I would be a bit of a hassle to change this. I've aligned the PPMs so that 0 = +10dBu and -6 or so = +4dBu (0 vu on all my tape machines). I've never used a PPM before and I was just wondering if the way I have it set up makes sense for analogue recording, does it jibe with a typical setup?
Thanks in advance for any help.
I've been working on refurbishing a pair of Studer 169 consoles to link together and replace my old Tascam.
Everything has been going fairly well so far (replaced all the electrolytic caps, many of the tantalum caps, went through the console alignment procedure), but I just have a couple questions for those of you who are familiar with the board:
1) The previous owners modified the console to have meter lights. They used some sort of two transistor regulator scheme with trimpots to get the voltage (fed from the +15/-15). They used #373 bulbs (rated at 14v/0.08A) with the voltage trimmed to about 8v.
Was this sort of modification common? I was having some stability issues where the console would shut down when levels got really high (one of the transistors in the DC to DC convertor would get very hot). I unhooked the bulbs and I haven't been able to reproduce the shutdown issue since, but do you think that the bulbs could have been the cause of the problem? (there were six of them in each console's meter bridge).
2) The manual called for -10dBu @ the channel insert (channel fader @ -10) to give -10dBu at the bus insert (master fader @ -10) +/-1dB. I'm getting between -8 and -8.5dBu pretty consistently across channels. Is this worth worrying about?
3) two of the channels have very weak bass and a thin sound on the mic input (the line in on these channels is working perfectly). I attempted to the demagnetization procedure in the manual to no avail (i even tried a han-d-mag and bulk tape eraser after that failed). The phase switch gives an enormously loud pop on both of these channels. Any ideas on what to check next? Could the transformers be broken?
4) Limiter calibration. After replacing the diodes (thanks for posting that tip roginator) and zener diodes, the limiter calibration went pretty well but I ran out adjustment for the final step; so when feeding the bus a 20dBu signal, instead getting an output of +10.4dBu, I was stuck at +9dBu max. This is pretty consistent across all four busses. Should I try replacing the trimpots?
5) Limiter distortion calibration. There were two step in the limiter calibration that I just ignored. I was supposed to measure distortion and "adjust for minimum deflection". Is there any software anyone could recommend for realtime distortion measurements? Or should I just leave this alone? I don't *hear* any distortion at reasonable limiting levels--could it be relatively unimportant like the distortion adjustment in the 1176?
6) PPM reference. This is more of a general use question for folks who are used to working with PPMs--the previous owners set the resistors on the 'console interconnection bus' for a +10dBu line level. I would be a bit of a hassle to change this. I've aligned the PPMs so that 0 = +10dBu and -6 or so = +4dBu (0 vu on all my tape machines). I've never used a PPM before and I was just wondering if the way I have it set up makes sense for analogue recording, does it jibe with a typical setup?
Thanks in advance for any help.
