-/+16v Power Supply & 48v Phantom.

Hello all,

I'm checking for racking 8 strips of those puppies:



Those are MIDAS PR04A input modules.  They need -/+16v and phantom.  I'm investigating power supply solutions.  So far, two interesting options:

- JLM Audio's Power Supply
- SSLtech's KPS-1 (Kev's)

First, 16v seems a bit of a bummer, it's not standard voltage...  The closest regulators I've found were either 15v or 18v.  I'm pretty sure the strips would work at either 15v or 18v, still I'm not 100% sure.  Is it better to go under voltage or overshoot?

JLM's solution got trimpots for adjusting the output voltage, that's great.  I could probably adjust it to 16v sharp.

Now, powering 8 strips might be a little different that two.  I'm pretty sure that those power supplies were designed for powering 2 mic-pres, not 8.  So, I'm a bit lost, it's my first time racking console strips.  It's a learning process.  Thanks in advance for any info!

[quote author="Marc Girard"]- SSLtech's KPS-1 (Kev's)[/quote]
Well, I've been called Ken, Keoth, Keef, but never 'Kev' before...

..I'm flattered!

-Get a couple of 1N4001 diodes and stick them in the 'common' leg of each 15V regulator. That should give you 16.1V or so...

However, my cheap-n-cheerful design does get warm, and the more voltage it drops (per unit current), the hotter it gets. You may need to try an 18V supply, with 3 1N4002 diodes in series with each output, and an electrolytic cap-to-ground at the output, just for good measure, That should also give you about 16.2V.

Keith

[quote author="SSLtech"]Well, I've been called Ken, Keoth, Keef, but never 'Kev' before...
..I'm flattered!
[/quote]



when Kev is MIA
... Keef will take all Kev related stuff
you will be in excellent hands

it's all good

KEV!

KEV!!!

:green:

:guinness:

Thanks Keith, eh, I mean Kev! :wink: :green: :thumb:

I don't know this from any experience, but I'd suspect you can run those at 18v too.

In which case, something adjustable like the JLM power supply would be perfect.

I recently powered up a pair of NeoTek Series IE with the JLM 3-rail supply, and I am very happy with it. I would also suspect that you can run those strips at 18 volts as well.

Cheers,
Zach

That's exactly what I ordered: JLM AC/DC 3 rails PSU... Joe seems like a very nice guy too. I can't wait to have it and start building!

It doesn't get much easier than the AC/DC 3-rail supply. Thanks Joe!!!

Cheers,
Zach

did you ever get these going? i have a channel that a cobbled into a box...eq looks versatile but sound is too noisy. it has 741 type ics. i was wondering if it is worth changing ics and puting in proper box or should i just pirate the sowters

You can simply use adjustable regulators like the LM317/337 for the +/-16v rails and you can even use one for the Phantom power.....

I also have a schematics for an adjustable PSU supplying 2 Voltages +/-12v up to 28v and Phantom power....

If you want to take a Look at it let me know and I"ll send it to you....


Cheers

Yes, I got them going fine actualy!  Everything works perfect, once again, JLM Audio solutions are very nice, easy to build, not too expensive and you can fine tune the voltage of the power-supply for your -, your + and 48v, it's very easy to setup.

Now, I gotta work some more on that front panel!  I'm learning the ways of FPD.  So far, so good, here's what I got,

Shot of the panel...



Shot of the mock-up...



I still gotta figure out a way of putting everything cleanly in my Par-Metal box, but I'm coming along fine.

More on this later...

[quote author="Marc Girard"]

First, 16v seems a bit of a bummer, it's not standard voltage... The closest regulators I've found were either 15v or 18v. I'm pretty sure the strips would work at either 15v or 18v, still I'm not 100% sure. Is it better to go under voltage or overshoot?

[/quote]

Hi,
i'm in the same situation; need +-16V psu, for Amek2500 preamps. I'm not sure if they would survive +-18V. So, should i do what Keith said, add a few diodes and cap on the outputs, or use +-18V?
I'm looking at this schematic:
http://www.beatbazar.com/guests/ssltech/kps-1/index.htm

Miha

Hey let's call him Special "K"

I used the 48v section for a phantom supply feeding 46v a.c. to it
but seem to be getting 58v out [ from K's psu schematic ]

I'll triple check my [ breadboard ptp wiring ]
can someone tell me which resister to replace with a trimmer
[ assuming my wiring is correct ]

tia regards Greg

Well if i were you, i would use a LM317/LM337 based PSU and trim the voltages to the desired value. Actually i don't use any fixed regulators anymore. Those adjustable are just much more convenient.

I should clarify that this is a response to rotation

Flo

[quote author="okgb"]Hey let's call him Special "K"

I used the 48v section for a phantom supply feeding 46v a.c. to it
but seem to be getting 58v out [ from K's psu schematic ]

I'll triple check my [ breadboard ptp wiring ]
can someone tell me which resister to replace with a trimmer
[ assuming my wiring is correct ]

tia regards Greg[/quote]
Resistor to substitute with a trimmer would be R1 (8k2), but more likely you might have D1 (1N4003) soldered in reverse, your regulator is broken, or you have no load connected.

Yeah no load that's true didn't want to feed the 58 v to any mic
i jamed the board in tight so it's hard to get to it " in circuit " but thanks for the idea's

Great topic. I was actually wondering myself about adding a regulated ps to a pair of BA-31b's I am racking up. I have a stack of SSLTech (Kyle's) ps boards left over from an SSL 9K build and was wondering if it was worth altering one of them to fit my needs? Admittedly, my power supply design experience is nil, so I wasn't sure if just swapping out a regulator would do it. I also haven't seen a regulator with a stock 30V output so I'm guessing I would need to drill the board to insert a resistor for an adjustable regulator.

My first idea is to use two boards and only stuff the 48v side. The first board would stay stock for phantom. On the second board I would change R2 to a 5k56. I figure that would get me 30.2 volts. I'd love to be able to get both voltages from one board, so if anyone can think of a way, I'd be thrilled.

My only thought is to take the +18 side of the board, replace the LM7818 with an LM317 turned the other way. I would make C1 220uf 100v. I would then bend up the middle pin and put the R1, R2, D1 circuit across the other two pins and ground in shrinkwrap or something. My question with this setup is do I need to move C6 so that it is after C1 like it is on the +48 leg (C11 comes after C5), or does it matter?

Schematic :
http://www.beatbazar.com/guests/ssltech/kps-1/index.htm

Sorry to hijack, and thanks again SSLTech (Kramer)!

[quote author="mushy"]Great topic. I was actually wondering myself about adding a regulated ps to a pair of BA-31b's I am racking up. I have a stack of SSLTech (Kyle's) ps boards left over from an SSL 9K build and was wondering if it was worth altering one of them to fit my needs? Admittedly, my power supply design experience is nil, so I wasn't sure if just swapping out a regulator would do it. I also haven't seen a regulator with a stock 30V output so I'm guessing I would need to drill the board to insert a resistor for an adjustable regulator.[/quote]
A 7824 regulator with a 6V zener between 0V and reg.com and a 2k4 resistor between reg.out and reg.com for a current draw of 10 mA (same as 7818 / 12V zener / 1k8 resistor) should get you there. Your transformer secondary would be min. 24-0-24 and C1 will require a /50V or /63V rating.

[quote author="mushy"]My first idea is to use two boards and only stuff the 48v side. The first board would stay stock for phantom. On the second board I would change R2 to a 5k56. I figure that would get me 30.2 volts. I'd love to be able to get both voltages from one board, so if anyone can think of a way, I'd be thrilled.[/quote]
Voltage would be as calculated, but the voltage multiplier as designed will most probably not supply enough current for your BA's.

[quote author="mushy"]My only thought is to take the +18 side of the board, replace the LM7818 with an LM317 turned the other way. I would make C1 220uf 100v. I would then bend up the middle pin and put the R1, R2, D1 circuit across the other two pins and ground in shrinkwrap or something. My question with this setup is do I need to move C6 so that it is after C1 like it is on the +48 leg (C11 comes after C5), or does it matter?[/quote]
LM78xx (in/com/out) and LM317 (adj/out/in) have a different pinout, so you'll have to bend it a little more than quoted. No need to up the rating of C1 to 100V. 1000uF/50V or /63V may still fit the pcb as the -18V part is unstuffed. Placement of C6 is fine as is (C1 and C6 are in parallel).
(Whats so wrong with a little piece of perfboard :green: )