Help identify power supply

[jdurango]

I'm looking for a bipolar (+/-) 24vdc, around 7A power supply for a mixing console. I'm seeing many on flea Bay that have + outputs and -  outputs along with ground. I'm assuming this means they are bipolar, but then again, we all know what can happen when you ASSume.

Anyhow, how can I make sure I'm getting both rails? Often data sheets are not available or they also are ambiguous (just saying 24VDC, not mentioning specifically - 24v)

Thanks fellas!

 

[CJ]

you can ask the seller questions, if not , i would not buy it,

+ - and gnd would usually indicate bi-polar, link to the item in question so we do not have to use ESP. 

 

[abbey road d enfer]

I'm looking for a bipolar (+/-) 24vdc, around 7A power supply for a mixing console. I'm seeing many on flea Bay that have + outputs and -  outputs along with ground. I'm assuming this means they are bipolar, but then again, we all know what can happen when you ASSume.

Anyhow, how can I make sure I'm getting both rails? Often data sheets are not available or they also are ambiguous (just saying 24VDC, not mentioning specifically - 24v)

Thanks fellas!

Are you looking for a linear PSU or smps?
A bipolar PSU is technically two separate 24V supplies with the positive sied of one connected the the negative side of the other, the junction being refeerd to as "ground" or "0V".
I would buy two smps, like this one
http://uk.rs-online.com/web/p/embedded-switch-mode-power-supplies-smps/7127247/
Some may argue that smps are noisy compared to linear, but any half-decent mixer should work flawlessly with a modern smps. And there's always the possibility to filter passively the rails with additional inductors and capacitors.
Often, linear PSU's designed to power mixers have  a built-in start-up system that ensures both rails settle simultaneously. You won't have that with an smps. However, this is supposed to reduce the start-up transients, but not very successful at it.

 

[jdurango]

you can ask the seller questions, if not , i would not buy it,

+ - and gnd would usually indicate bi-polar, link to the item in question so we do not have to use ESP. 

Thanks CJ. Here's a couple links. It's a 16ch console I'll be adding EZ1290 and JH 990 based preamps to. 7A is probably overkill, but I figure better to be on the high side.

http://m.ebay.com/itm/OMRON-S82G-Power-Supply-S82G-1524-24-VDC-Output-/232152292982?hash=item360d5ade76%3Ag%3AQuUAAOSw4GVYNQKB&_trkparms=pageci%253A6c9868aa-c813-11e6-99c4-005056974d32%257Cparentrq%253A254ee02e1590a605a4cddd6bffd31181%257Ciid%253A14

http://m.ebay.com/itm/OMRON-24VDC-4-5A-POWER-SUPPLY-S82J-10024D-/291964418307?hash=item43fa6f7903%3Ag%3A9TIAAOSwo4pYRt6D&_trkparms=pageci%253A51338c88-c815-11e6-a54f-74dbd180f337%257Cparentrq%253A255b48191590a605b71c76f9ffdd2c89%257Ciid%253A1

There is a cheaper one of these but wires are blocking terminal labels: http://m.ebay.com/itm/LAMBDA-LCS-C-24-REGULATED-POWER-SUPPLY-/360396052456

 

[gridcurrent]

the "ground" terminal on power supplies including units from Lambda and Acopian; refer to chassis. 
a dual/bipolar power supply will have a terminal labeled "com",  "common" or 0V.
the Lambda LCS-C-24 is a single output supply.

 

[jdurango]

Are you looking for a linear PSU or smps?
A bipolar PSU is technically two separate 24V supplies with the positive sied of one connected the the negative side of the other, the junction being refeerd to as "ground" or "0V".
I would buy two smps, like this one
http://uk.rs-online.com/web/p/embedded-switch-mode-power-supplies-smps/7127247/
Some may argue that smps are noisy compared to linear, but any half-decent mixer should work flawlessly with a modern smps. And there's always the possibility to filter passively the rails with additional inductors and capacitors.
Often, linear PSU's designed to power mixers have  a built-in start-up system that ensures both rails settle simultaneously. You won't have that with an smps. However, this is supposed to reduce the start-up transients, but not very successful at it.

Found this one. It's definitely bipolar 24vdc and appears to be linear (transformer sticking out the side). Not sure about the current rating though. I'm guessing for 16 xformer balanced preamps + master section I should have at least 2 or 3 amps. Watcha think?

http://m.ebay.com/itm/GA-GENERAL-ATOMIC-24V-DC-POWER-SUPPLY-ASSEMBLY-PART-02810600-001-/161997511069?hash=item25b7cdd99d%3Ag%3ADp0AAOSwu1VW2jt9&_trkparms=pageci%253A7de8c6dc-c81e-11e6-b9f6-74dbd1807b4b%257Cparentrq%253A259768971590a6062573eb56ffd2d92e%257Ciid%253A1

 

[abbey road d enfer]

"The buyer will need to replace the fuses and holders." That is not a good sign.

 

[mjrippe]

Search ebay for "power one HE24-7.2".  These are 24v 7.2A linear power supplies.  Prices start around $12 USD!!!  Buy two for bipolar.  Hell, buy six and you will have spares for life.

 

[jdurango]

Search ebay for "power one HE24-7.2".  These are 24v 7.2A linear power supplies.  Prices start around $12 USD!!!  Buy two for bipolar.  Hell, buy six and you will have spares for life.

Yeah I was thinking about picking up two Acopians, I know they're good. I'll check out these Power Ones too. Is it as simple as running one in polarity  (ie + to +, -  to -) and another out of polarity (+ to -, - to +) to get +24 and - 24?

 

[mjrippe]

Yes, as Abbey said earlier tie the negative of one to the positive of the other and use that connection as common.  Pic attached...

 

[jdurango]

Yes, as Abbey said earlier tie the negative of one to the positive of the other and use that connection as common.  Pic attached...

Aha, so you're basically creating a 120AC>48VDC transformer with a center tap? Thanks very much for the help!

 

[metalb00b00]

Are you looking for a linear PSU or smps?
A bipolar PSU is technically two separate 24V supplies with the positive sied of one connected the the negative side of the other, the junction being refeerd to as "ground" or "0V".
I would buy two smps, like this one
http://uk.rs-online.com/web/p/embedded-switch-mode-power-supplies-smps/7127247/
Some may argue that smps are noisy compared to linear, but any half-decent mixer should work flawlessly with a modern smps. And there's always the possibility to filter passively the rails with additional inductors and capacitors.
Often, linear PSU's designed to power mixers have  a built-in start-up system that ensures both rails settle simultaneously. You won't have that with an smps. However, this is supposed to reduce the start-up transients, but not very successful at it.

I'm so happy to know that I'm not the only one who prefers a switch mode power supply over a linear one.

For some projects here which require a +/-15V supply, I use MeanWell PD-2515 (each rail is 0.8A, more than enough juice), and if I need phantom power, I just add a small board with a step up DC converter like LM2585, supplied by the +15V. Additional LC filter for each rail is probably an overkill, but better be safe than sorry, right?

 

[mjrippe]

Aha, so you're basically creating a 120AC>48VDC transformer with a center tap? Thanks very much for the help!

No.  A transformer is AC on both sides.  The power supply converts AC to DC.