Calrec DL2934 racking questions

Hi all,

I need to rack a Calrec DL2934 compressor module for a client, have figured out the pin out for it.
The only thing that bugs me is the power supply situation: it needs +16V,0,V-16 Volts and a 0V +8V for the bulbs or LEDS.
Pinout for supply:

15 - 16 Volt
16 + 16 Volt
17  Common rail, so I presume this is 0 Volt
18  0 Volt
19 + 8 Volt

My questions is if I am using a  JLM AC/DC, with the +48 ramped modified to +8 Volts can I use the common 0 volts on the PSU to be used for  both voltages on the Calrec or will this not work?

Thanks in advance!

Kind regards,

Willem.

I would get two MeanWell IRM-05-24 and one IRM-02-9. They are little PCB mount AC/DC switchers that are ~$7 USD on Mouser. Then I would make a PCB for them with chokes and regulators to make +16 ad -16 from the 24V modules and a simple capacitance multiplier to drop the 9V module to +8V from the LEDs. If done correctly, it will be much superior to a linear supply. The chokes take out the high frequency noise and the regulators do the rest. The only thing to watch out for is if you don't load the modules they can generate low frequency noise. But I doubt that would be a problem in this case because they are small enough that I think they will be loaded properly (and the regulators would get the noise anyway). If the +-16 supply actually needs more power you could use IRM-10-24 instead.

Thanks for the Meanwell info but I have a JLM PSU prepared for this job, just curious about the double 0 volts thing, and if I do link them what the consequences will be.

Willem.

In the "World of Calrec":
CR = Centre Rail = Audio Ground
0L = 0V Logic

In a console these grounds are connected together in ONE place only. This is the ground reference point.

I am not familiar with that particular dynamics module, but as you have the pinout figured, you will no doubt be able to run a bench test to check the current requirement of the +8L rail. If you can get your JLM PSU's +48V output reduced to around 8V or so, and it provides an adequate current, it should do OK.
If the 48V plan does not work, down-regulate the JLM's +16V output and use that. You are only dealing with a single module so the un-equal load on the + & - rails will not be an issue.

So then it sounds like you want to run separate wires for CR and 0L back to the power supply ground at the filter caps.

But I don't think you can use the 48V for 8V. There could be 20 LEDs on at any one moment which at 10-20mA each is ~300mA. So if you draw 300mA across 40V, that's 12 watts! No. That 48V is for phantom which is low current. It's not even going to be close to 300mA.

UPDATE: Actually is it "AC/DC Ver. 4"? I was just looking at that schem and it looks like it's just using voltage doubler. So depending on the transformer being used, you could hack that to make a lower voltage. What transformer are you using?

Thanks all for the advise, the board is the AC/DC version 3, I did the mod as in the picture from  JLM.
Removed the doubler bridge and  adjusted it to 8 Volts.
Transformer is a Talema  2 x 18 Volts, 50 VA, that should be sufficient enough.

Kind regards,

Willem.

justanalogue said:

Transformer is a Talema  2 x 18 Volts, 50 VA, that should be sufficient enough.

Click to expand...

Yes. It's about 10x more than you need actually. Just think about how much more efficient, lighter, smaller, cheaper and  higher performing it would have been if you had used SMPS.

squarewave said:

Yes. It's about 10x more than you need actually. Just think about how much more efficient, lighter, smaller, cheaper and  higher performing it would have been if you had used SMPS.

Click to expand...

I'll keep that in my mind for sure in the future, SMPS are really good nowadays!
Thanks for your input, highly appreciated.

Kind regards,

Willem.

Hi Willem.

I am also in the process of racking up 3 x Calrec pcb’s a PY2929 Mic amp & router, QF2925 Stereo EQ for witch I have a little info but I could do with any info you may have regarding the DL2934 I have sorted out the power supplies but could do with info regarding the in/out pins this would save me hours of poking around guessing Ha! If you would like the info I have on the other pcbs, mail me and I can mail back to u I have only photos of the original schematics but they show everything you need pin outs etc.

My Best Regards
John