Phant.P. resistor on Studer 089 = 15k - why?

[RFSiesta]

Short question:

Our studer 089 has no phantom power switches on inputs, I need 48V switchable for beeing able to drive ribbon mikes, so I decided to implement this.

While examining the layout, I found the Phantom power series resistors in this desk to be 15k instead of 6.8   
??? Never heard of that... Has anyone else?

Thanks!

 

[PRR]

Old?

The earliest Phantom mikes only drew 1mA, 2mA was considered ample, and I don't think anybody really thought about it.

Later mike designers got greedy, which led to 3.4K and 10mA. However an awful lot of Phantom mikes still use only 2mA. If yours has been working no-problem, that's why.

 

[zamproject]

Hi

Is that a MKI or MKII ?
I don't know for MKI, but if it's MKII it's a mod.

Best
Zam

 

[RFSiesta]

Yes, I assume it works with 90% of mics, most don't even have problems when voltage drops even under 40V, but since it's a rental room, I would prefer to meet today's specs. We will examine if the PSU is capable of driving the whole 15 channels at 2*6.8k.

Is that a MKI or MKII ?
I don't know for MKI, but if it's MKII it's a mod.

It's the MK II. It might well be a mod, as those desks where in use at the Austrian broadcasting (ORF) and some of the fader modules have a "ORF version" lable on them.

 

[zamproject]

Yes, I assume it works with 90% of mics, most don't even have problems when voltage drops even under 40V, but since it's a rental room, I would prefer to meet today's specs. We will examine if the PSU is capable of driving the whole 15 channels at 2*6.8k.

Is that a MKI or MKII ?
I don't know for MKI, but if it's MKII it's a mod.

It's the MK II. It might well be a mod, as those desks where in use at the Austrian broadcasting (ORF) and some of the fader modules have a "ORF version" lable on them.

15 channel ??? is that a 089 or a 189 ???
The P48 supply can deliver 100mA (.026 version PSU) so do your math
if it's a 189 you should have two PSU
Best
Zam

 

[RFSiesta]

15 channel ??? is that a 089 or a 189 ???
The P48 supply can deliver 100mA (.026 version PSU) so do your math
if it's a 189 you should have two PSU

Not 15 discrete channels, 9 mono 3 stereos. It's a 089 Mk II from 1976.
100mA explains the 15k
Maybe I could declare 2 channels to "high power" ones, in case anyone experiences troubles.
Or build me another additional 48V supply.
Best
Richard