mikedoubleu
Member
- Joined
- Oct 13, 2013
- Messages
- 5
Hi there,
Wondering if anyone could lend me some brains for a quick problem.
Been trying to get a pair of channel strips from a studer 961 to work in a rack I made. So far, I've managed to activate the mute light but not much more...
The psu I'm trying to use is a also Studer. It's a 1.915.100 which gives me + and - 15vdc, 48vdc and 30vdc unregulated, which seems like it ought to do the job and more if necessary . I used an LM337 to get the 30v down to -6v for the logic supply and my multimeter is telling me that's what I'm getting, but perhaps it's not clean enough? Or is the regulator circuit reacting differently under load? I'm guessing there's enough current for only two strips, half an amp for logic....
Maybe (...likely) I am overlooking something in that department?
Anyway, it seems to me that I might have a problem in the logic domain because signal doesn't seem to be passing the FET switching gain selector section (R44 and downstream). I haven't done a whole lot of probing beyond signal tracing yet, but I feel this part of the circuit is truly not in my league. I don't quite understand the role of the logic chips.
Perhaps it's all just a grounding problem? I've got OV Audio, OV Logic, OV reference, 0V External and "chassis" to think about on the strip side. I connected the OV A to the common 0V for the + and - 15V on the psu, OV logic to the other side of the regulated -6V, OV reference to 0V External and "chassis" on the strip, as well as the rack unit chassis.
Schematics for strip:
1 http://s7.postimg.org/5tqmprl23/961_mic_pre_1_Page_1.jpg
2 http://s4.postimg.org/705izr6ql/961_mic_pre_2_Page_1.jpg
3 http://s27.postimg.org/zai6lv8gz/961_mic_pre_3_Page_1.jpg
PSU
http://s28.postimg.org/t2rtb3ta5/psu_Page_1.jpg
Any help would be great. I'm learning lots, but I certainly feel like I could benefit from a push in the right direction at the moment.
Wondering if anyone could lend me some brains for a quick problem.
Been trying to get a pair of channel strips from a studer 961 to work in a rack I made. So far, I've managed to activate the mute light but not much more...
The psu I'm trying to use is a also Studer. It's a 1.915.100 which gives me + and - 15vdc, 48vdc and 30vdc unregulated, which seems like it ought to do the job and more if necessary . I used an LM337 to get the 30v down to -6v for the logic supply and my multimeter is telling me that's what I'm getting, but perhaps it's not clean enough? Or is the regulator circuit reacting differently under load? I'm guessing there's enough current for only two strips, half an amp for logic....
Maybe (...likely) I am overlooking something in that department?
Anyway, it seems to me that I might have a problem in the logic domain because signal doesn't seem to be passing the FET switching gain selector section (R44 and downstream). I haven't done a whole lot of probing beyond signal tracing yet, but I feel this part of the circuit is truly not in my league. I don't quite understand the role of the logic chips.
Perhaps it's all just a grounding problem? I've got OV Audio, OV Logic, OV reference, 0V External and "chassis" to think about on the strip side. I connected the OV A to the common 0V for the + and - 15V on the psu, OV logic to the other side of the regulated -6V, OV reference to 0V External and "chassis" on the strip, as well as the rack unit chassis.
Schematics for strip:
1 http://s7.postimg.org/5tqmprl23/961_mic_pre_1_Page_1.jpg
2 http://s4.postimg.org/705izr6ql/961_mic_pre_2_Page_1.jpg
3 http://s27.postimg.org/zai6lv8gz/961_mic_pre_3_Page_1.jpg
PSU
http://s28.postimg.org/t2rtb3ta5/psu_Page_1.jpg
Any help would be great. I'm learning lots, but I certainly feel like I could benefit from a push in the right direction at the moment.
