Custom console - what power supply?
« on: December 22, 2016, 07:46:27 PM »
I have a custom-built console which will have 16 xformer balanced DOA-based mic pres (TBD: either either EZ1290's or some type of JH990 design) + 1 stereo aux out,  4 main outs and 4 monitor outs. VU meters for all ins and outs. No LED's or lights whatsoever. VU lights will be powered with separate 12v supply. I will be using an external phantom supply.

I've found a +/-24vdc power supply with +24v/1.8a and - 24v/1.8a rails. Would this be adequate for such a console? Thanks!


Pip

Re: Custom console - what power supply?
« Reply #1 on: December 22, 2016, 08:07:32 PM »
I like Accopian! They are not the cheapest by any means but they are reliable!

acopian.com
Pip
New York City
http://geosonixlab.com

Re: Custom console - what power supply?
« Reply #2 on: December 22, 2016, 08:43:35 PM »
I like Accopian! They are not the cheapest by any means but they are reliable!

acopian.com

Yeah I'll probably end up going with acopian. I guess I'm more concerned about the amperage/current rating. I'm guessing the components/DOA's themselves will draw around 2-3 amps (around 120ma max each) and I should reserve another 1 or 2 amps for "headroom".

Pip

Re: Custom console - what power supply?
« Reply #3 on: December 22, 2016, 09:50:31 PM »
Yeah I'll probably end up going with acopian. I guess I'm more concerned about the amperage/current rating. I'm guessing the components/DOA's themselves will draw around 2-3 amps (around 120ma max each) and I should reserve another 1 or 2 amps for "headroom".

JH990=25MA  so that means you can power approx. 70 of them give or take with a 1.8A supply!
Pip
New York City
http://geosonixlab.com

Re: Custom console - what power supply?
« Reply #4 on: December 22, 2016, 10:57:44 PM »
JH990=25MA  so that means you can power approx. 70 of them give or take with a 1.8A supply!

The data sheet says 25ma with no load but 260ma max peak output current. I'm guessing average current during normal operation would be around half of max/peak.

PRR

Re: Custom console - what power supply?
« Reply #5 on: December 23, 2016, 06:50:24 PM »
> 260ma max peak output current.

Yeah, my car can do 117 MPH, but I've never had it over 75.

The usual minimum load on a 990 is 150 Ohms which on +/-24V supply is "only" 147mA peak.

I doubt you drive many 150r loads. Nominal 600r is far more likely. 38mA peak.

Peak is not Power Supply current! For a totem-pole, peak happens at-most half the time on each supply.

If you would possibly do Max Square Wave Output, figure the load on the supply as 4X the audio load. 1,600 ohms.

We usually assume Sine Wave. Figure 6X the audio load, 2,400 Ohms. (Factor is really 6.28.)

All happy audio signals are smaller than Full Power Sine.

Total 48V across 2,400 Ohms is 20mA per opamp. Add the idle current, 2-10mA? This suggests 30mA each. Do you have >60 990s?

Pip

Re: Custom console - what power supply?
« Reply #6 on: December 23, 2016, 07:15:14 PM »
JH990=25MA  so that means you can power approx. 70 of them give or take with a 1.8A supply!

Yes you are correct I looked at the DS to quickly. But that is maximum I agree with the other post no need to go for broke! Now that I am thinking more clearly will you be using other opamps for output and eq etc...?

So that means with your 1.8A supply you can do like 16.


« Last Edit: December 23, 2016, 07:18:21 PM by Pip »
Pip
New York City
http://geosonixlab.com

Re: Custom console - what power supply?
« Reply #7 on: December 24, 2016, 12:46:39 AM »
You can also look at the PowerOne supplies, I've used those for almost everything.  I can usually find them used for cheap, really cheap.

You can rig 2x 24v  5 amp single rail supplies in a 3u case and have power for the rest of your life :)

Re: Custom console - what power supply?
« Reply #8 on: December 24, 2016, 02:56:01 AM »
Yes you are correct I looked at the DS to quickly. But that is maximum I agree with the other post no need to go for broke! Now that I am thinking more clearly will you be using other opamps for output and eq etc...?

So that means with your 1.8A supply you can do like 16.

No EQ's on this console. I'm picky about EQ....using outboard 500 series and tube Pultec clones....will probably build a few CAPI's as well.

So just 16 line or mic ins,  about 10 outputs and 4 aux returns. So if I need 30 op amps @ say 50mA Max each, that's 1.5A max....300mA of "headroom" sounds about right.

Re: Custom console - what power supply?
« Reply #9 on: December 30, 2016, 02:17:19 AM »
Console showed up yesterday. Inasmuch as I can tell, the 19 x 741's are driving the insert ins and outs. It also contains 6 x 2n3053 and a couple LM381N's.

The power section appears to be unregulated....there's a 24V relay. tha has a bunch of wires running to the master section.

I don't know enough about this stuff to figure out the type of power rail(s) this console will need. If ya'll can take a look at the pictures and give me your thoughts, I'd greatly appreciate it! I've tried to label the pictures to identify components when possible. Thanks fellas!!!

PCB's and components: https://drive.google.com/drive/folders/0BxiPOzSDUqGKWmlvY0diaDlmZjA
General pics, transformers, power supply (missing transformer): https://drive.google.com/drive/folders/0BxiPOzSDUqGKSGk1V3haS0ROX1k


sahib

Re: Custom console - what power supply?
« Reply #10 on: December 30, 2016, 01:01:06 PM »
Check my floorbox power supplies.

https://groupdiy.com/index.php?topic=52462.0

FB1  output is rated at 1.9A but the transformer is actually 150VA.  Take away around 12VA for the phantom. That leaves you just under 70VA per rail. I bet it will do you fine.

But if you would like to have a bit more I also have a 216VA version of the transformer. The case also accepts a second dual output regulator. This can power your lights and other things.

The main dual rail regulators are LM 338 and the board is designed to provide 5A.  There is a provision for an external heatsink for high current output.

The power supply has its own mains switch, integrated with the IEC but I have recently designed an optional relay card for remotely turning the outputs on/off.

The picture of a five output version with the remote relay board is attached. +48V board is placed under the relay board.

We can customise to any version you need.

Assembly manual
http://www.robotica.co.uk/tac/FB_PSU_ASSEMBLY_MANUAL.pdf
« Last Edit: December 30, 2016, 01:30:36 PM by sahib »

Re: Custom console - what power supply?
« Reply #11 on: December 30, 2016, 01:43:49 PM »
Check my floorbox power supplies.

https://groupdiy.com/index.php?topic=52462.0

FB1  output is rated at 1.9A but the transformer is actually 150VA.  Take away around 12VA for the phantom. That leaves you just under 70VA per rail. I bet it will do you fine.

But if you would like to have a bit more I also have a 216VA version of the transformer. The case also accepts a second dual output regulator. This can power your lights and other things.

The main dual rail regulators are LM 338 and the board is designed to provide 5A.  There is a provision for an external heatsink for high current output.

The power supply has its own mains switch, integrated with the IEC but I have recently designed an optional relay card for remotely turning the outputs on/off.

The picture of a five output version with the remote relay board is attached. +48V board is placed under the relay board.

We can customise to any version you need.

Assembly manual
http://www.robotica.co.uk/tac/FB_PSU_ASSEMBLY_MANUAL.pdf

Sahib, you've got some great products there! But I still need to figure out the actual voltage that this board needs. Are you thinking it's +/- 16?

sahib

Re: Custom console - what power supply?
« Reply #12 on: December 30, 2016, 06:41:23 PM »
I thought the assembly manual would clarify it but I'll explain further.

I realise that you need + - 24V.

The transformer has 4 sets of identical  0 - 17.5V - 25.5V secondaries for the main rails and one 0 - 48V secondary for + 48V.

For 16V you use 17.5V tap and for 24V you use 25.5V tap.

On 216VA transformer 24VA is allocated to +48V (500mA) which is normally way more than what you need but it is there nevertheless.

That leaves us 192VA.

We pair the secondaries by connecting two in parallel.  That gives us 96VA per rail. That gives us  4A @ 25.5V per rail.  1/3 of that will be used as charging current. So you are looking into clean 2.5A @ 24V per rail after regulation. 

This is obviously more than what you need and it seems 150VA transformer hence FB1 will do your job. You do not have to use external +48V.

For the VUs you can connect the bulbs in series if you use 12V bulbs. But if you insist on powering them individually you can then fit a second single rail board into the case and set the output to 12V, though you will be wasting quite a bit of energy. The other option would be to use the redundant 8V tap (between 17.5V and 25.5V taps). That will give you roughly unregulated 11VDC.
« Last Edit: December 31, 2016, 04:52:53 AM by sahib »

Re: Custom console - what power supply?
« Reply #13 on: December 31, 2016, 02:29:59 PM »
I thought the assembly manual would clarify it but I'll explain further.

I realise that you need + - 24V.

The transformer has 4 sets of identical  0 - 17.5V - 25.5V secondaries for the main rails and one 0 - 48V secondary for + 48V.

For 16V you use 17.5V tap and for 24V you use 25.5V tap.

On 216VA transformer 24VA is allocated to +48V (500mA) which is normally way more than what you need but it is there nevertheless.

That leaves us 192VA.

We pair the secondaries by connecting two in parallel.  That gives us 96VA per rail. That gives us  4A @ 25.5V per rail.  1/3 of that will be used as charging current. So you are looking into clean 2.5A @ 24V per rail after regulation. 

This is obviously more than what you need and it seems 150VA transformer hence FB1 will do your job. You do not have to use external +48V.

For the VUs you can connect the bulbs in series if you use 12V bulbs. But if you insist on powering them individually you can then fit a second single rail board into the case and set the output to 12V, though you will be wasting quite a bit of energy. The other option would be to use the redundant 8V tap (between 17.5V and 25.5V taps). That will give you roughly unregulated 11VDC.

Hey Sahib,

That all makes sense. I'll need 24v if I add Neve or JH990 based preamps, but the way the mixer is configured right now,  I'm not sure what kind of supply it needs. Your power supply sounds like a good option since it has multiple taps.

Here's some pics of the electronics....it uses 150 or 600 to 600 transformers for much &  line inputs. Any idea what kind of power voltage it needs as is? Thanks!

https://drive.google.com/folderview?id=0BxiPOzSDUqGKWmlvY0diaDlmZjA

PRR

Re: Custom console - what power supply?
« Reply #14 on: December 31, 2016, 04:35:59 PM »
The '741 and all likely replacements will be eating +/-15V more or less (+/-18V ab max). Less than 10mA or 0.010A each, but I am not going to go through all those pictures trying to count what you have. I really doubt >0.5A, 1A would be ample, but if a high-quality 1.9A presents itself that would be excellent.

Find the +/-15V power lines. Confirm by cap polarity markings. Try to isolate just one channel board. Feed +/-15V through 100r resistors and see if you get > +/-12V at the board. 0.6V or zero suggests backward. Zero both ways suggests dead-short rail caps.

That will probably get "most" of it working, no Phantom.

sahib

Re: Custom console - what power supply?
« Reply #15 on: December 31, 2016, 09:06:33 PM »
The black and red wire pair seems like the rails. Now, I am not sure if these represent +  - rails and there is a separate 0V connection but from the picture annotated as "mic? line?" it looks to me as the board is powered by a single rail supply which common sense would dictate as black being the 0V and red +V.  Best way will be to reverse engineer that board and draw the schematic which should be very easy to do. Power connector will also give a good clue.

As for the voltage rating PRR has a good estimation. If it is powered by a single rail I would not imagine it being greater than 30V. 24V would probably be nominal. Only way to find out is to remove one of the input modules and power it in isolation and test. If something goes wrong then at least you do not damage the rest of the mixer.



Re: Custom console - what power supply?
« Reply #16 on: January 11, 2017, 01:00:54 AM »
Okay, just put together a schematic of these cards. It's my first schematic, so it's not very pretty, but I've checked everything and it should be accurate.

The "switch" referred to in the labels (ie. green, white, red, blk (small gauge), red (small gauge) and shield) is the switch that selects between transformer taps for 150:600 and 600:600 and a third. The switch is labelled MIC, -15dB and LINE. I'm guessing 150:600 for MIC, 150:600 with a pad for -15dB and 600:600 for LINE.

Anyway, here's the schematic. Let me know watcha think. Thanks!

https://drive.google.com/file/d/0BxiPOzSDUqGKLUp4ejlxWUNfUlU/view?usp=sharing

Re: Custom console - what power supply?
« Reply #17 on: January 11, 2017, 01:54:58 AM »
Are you are the same guy with the Harrison?

I'm noticing that most of the caps are rated 25v, and there's one big one in the power supply area rated 20v. My guess is it's going to be 15-18v and not 24.

Can you draw a schematic or expand on the area that was the power supply portion? What are all those big caps connected too?
« Last Edit: January 11, 2017, 02:08:08 AM by Johnblue »

Re: Custom console - what power supply?
« Reply #18 on: January 11, 2017, 02:18:59 AM »
Are you are the same guy with the Harrison?

I'm noticing that most of the caps are rated 25v, and there's one big one in the power supply area rated 20v. My guess is it's going to be 15-18v and not 24.

Can you draw a schematic or expand on the area that was the power supply portion? What are all those big caps connected too?

I used to have a Harrison console, sold it about a year ago.

Just traced the red hvy gauge wire back to a punch block which then traces off to leads on two different 24v regulators. One is labeled 7824 the other LM340T-24  (same thing? Different part #?). The black hvy gauge wire is definitely ground, goes to a heavy ground strap then to the punch block then out to one lead on each large PSU cap. Looks like I'm just missing the transformer itself.
« Last Edit: January 11, 2017, 02:31:15 AM by jdurango »

Re: Custom console - what power supply?
« Reply #19 on: January 11, 2017, 02:43:52 AM »
The 7824 goes to the channel card PCB's, the LM340T-24 goes off to the card with all the op amps for the insert i/o, auxes, etc. (LM3053 and LM741's).
« Last Edit: January 11, 2017, 03:53:56 PM by jdurango »