Power supply for using PG MS at home.

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phonixx
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Power supply for using PG MS at home.

Post by phonixx »

Hi, i`m planning to use some old PG MS amps for my home theather and looking for power supply. Found one claiming to put out 2x80A. It can adjust output voltage 12vdc-30vdc but it can also adjust output current for manual charging of lead-acid batteries. Can this be used for amps? Can i just set the current to max and let the amps take the current it needs or will it burn the amp with 80A? is this supply just useless for amps?

Thanks

https://www.rcpro.no/detaljer/HW4820CL2 ... -12-30v-dc
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Eric D
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Re: Power supply for using PG MS at home.

Post by Eric D »

I use some of these...

https://www.audioauthority.com/product_details/978-100

And am very happy with them. They are reasonable on eBay.

The internal fan is somewhat loud, so I put it on a switch to bypass it. For constant use, I would suggest a slower and quieter fan. The stock fan is sized assuming the power supply is shoved in a display cabinet at a store. If it had more airspace around it, a slower fan would be fine. It has thermal and over current protection anyway.
Got "schooled" by member shawn k on May 10th, 2011...
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trickyricky
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Re: Power supply for using PG MS at home.

Post by trickyricky »

Eric, aren't those power supplies LOUD and a bit inefficient compare to newer power supplies like APS power supplies? I say because I use have a 2/77 and that sucker was loud (hum) and not to mention was about 50lbs. I now use APS90's which are quiet (the only noise is the fan which kicks in once the power supply gets warm...usually when its >30% of it's current capability and they also only weigh about 8lbs and are much smaller than the AA's.
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Eric D
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Re: Power supply for using PG MS at home.

Post by Eric D »

Mine don't have any hum. They are switching supplies, not transformer based, so they likely switch at a frequency higher than I can hear. I have run them for hours with the fans off, so I don't have any issues with the fan noise which would clearly be an issue if you sit right next to them (as I do).

I don't know how efficient they are, as I never measured it. I know they produce little to no heat, so I would think they are pretty efficient.

The other bonus for me is they are light. I had a transformer based 60A supply I needed help to move around, and these I can lift with only one hand.
Got "schooled" by member shawn k on May 10th, 2011...
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Hands down the forum's most ignorant member...
Don't even know what Ohm's law is...
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phonixx
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Re: Power supply for using PG MS at home.

Post by phonixx »

Thanks for your reply guys, i will have a look at Ebay and see what i can find.

The Power supply i linked to i my first post is a little suspect i think, its called Hop Wo and the 2x80A its when operating in 25V. At 30V its push out 67A but at 12v i couldn`t find out, it just says 2000w?
Suspect that its like the Pioneer GM120 in the 80`s, 2x60w but it was crushed by an M25 :-)

Bjornar
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Re: Power supply for using PG MS at home.

Post by trickyricky »

The power supply in the link you provided seems to have dual outputs (don't know if they are controlled together but isolated or parallel), it's a total of 160a at 12v but if it is indeed dual isolated outputs then you will have 80a on each side hence the 2x80a on the description of the product.

I am not familiar with this specific model, but even if you have two 80a power supplies that is more than plenty for a couple large amplifiers.
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phonixx
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Re: Power supply for using PG MS at home.

Post by phonixx »

Hi again,
It showed up that the Audioauthority was discounted so i ended up with a guy selling modified server Psu`s. The spec was 13.5V/100A.
He could also connect 2 of them together either into 27V/100A or 13.5V/200A.

He said they were professional modified to operate in parallell. Not sure what that mean but i guess 2 power supply's working in parallell requires an exact matc in voltage to avoid one with highest voltage send current into the input on the one with lowest voltage?

So i bought one 13.5V/200A

He sendt me a load test where the output was 187.7A at 13.21V. They went into overload at 212A. Input-2601,5W, Output-2479,5w. efficiency 95,3%

I`m planning to run a total of four MS275.
1 to each front speaker. Kef q700 Biamped, 1 for center Kef Q600c and 1 for back speakers small Infinity.
All the MS275 will run in 4 ohm and just play above 60Hz so i guess the current draw isn`t to bad.
For subwoofers i will use a Mps2500 1 ohm mono, i guess it can use 100A+ occasionally?

I think 200A is enough but time will show :-)
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Jacampb2
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Re: Power supply for using PG MS at home.

Post by Jacampb2 »

Those supplies routinely sell for about $20 each. I have several that I use around the shop. In order to run them in parallel it does not require any special voltage matching, but one supply has to be isolated from ground. The bad way to do this (and what you should check when you receive them) is for the seller to just clip the earth lead inside the supply. The right way to do it is to isolate the the DC side of the supply from the case while leaving the primary side earthed. There are a lot of websites that show the correct modifications.

In case you want to look for more and the seller removed the labels, they are almost certainly these supplies: HP DPS-1200FB.

Good luck,
Jason
M: M100, M44 for a custom amp project
Zx: Zx500, Zx450, Black Zx350
ZxTi: 4 Zx600Ti's, 1 Zx400Ti
Ti: 5 800.1's & 900.7 for a custom amp project. 1 1200.1, 1 1000.2
Tantrum: 2 1200.1's, 1 600.4, 1 500.2
XS: XS6600
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Eric D
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Re: Power supply for using PG MS at home.

Post by Eric D »

I am guessing if you are going to run 4 MS275s high pass, you could get away with a single 50A supply. I ran a MS1000TA off a 30A supply to a pair of home speakers and played it at ear bleeding levels with no issues.

The only reason I mention this is maybe the fans in those HP supplies are somewhat loud. If you want this for home theater, I am guessing you want the supply as close to silent as you can get.

On my amp repair test bench I routinely use a 15A fuse while testing amplifiers. I have only blown this fuse once while playing music, and that was when I added a subwoofer to a large stereo MTX amp.

Generally speaking, high pass music signals don't draw a lot of current.
Got "schooled" by member shawn k on May 10th, 2011...
No longer really "in tune" with the audio industry, and probably have not been for some time.
Hands down the forum's most ignorant member...
Don't even know what Ohm's law is...
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phonixx
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Re: Power supply for using PG MS at home.

Post by phonixx »

Thanks for the info guys, i will check how the parallell connection is done. The seller told that the fan is very noisy at high load like 80-90% but hi claimed it was very quiet at low and middel load because it was Temperature and load-dependent. I guess i must hear myself but if its very noisy at any load i must try to modify with a bigger quiter fan or just find me another Power supply :-)

I have a Diamond GZV4000 40A used for President CB but it has a fan to and i am not sure how noisy it is at high load.
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Jacampb2
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Re: Power supply for using PG MS at home.

Post by Jacampb2 »

The HP supplies I have are whisper quiet. I have never run them anywhere near the rated capacity, so I can't attest on how they do at high load, but with one powering a PG tantrum 1200.1 at a reasonable output, I can hear the PG 1.5" fan and not the supplies...

I think it will probably do the trick for you, but report back and let us know how it works out.

Later,
Jason
M: M100, M44 for a custom amp project
Zx: Zx500, Zx450, Black Zx350
ZxTi: 4 Zx600Ti's, 1 Zx400Ti
Ti: 5 800.1's & 900.7 for a custom amp project. 1 1200.1, 1 1000.2
Tantrum: 2 1200.1's, 1 600.4, 1 500.2
XS: XS6600
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phonixx
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Re: Power supply for using PG MS at home.

Post by phonixx »

A little test setup. I will pick up the third ms275 at the post office tomorrow and then all 3 of them is going for recap. The Mps2500 has done the recap.
Havent bought the fifth amp yet but will do soon. Not sure if its gonna be a 2125 og 275. Have a recapped 2125 by hand.

My setup by now is a Denon AVR-X4000 used as a prosessor/preamp/power amp. I have 2 active subs. 1 Cerwin vega 12" and one JBL 12"
My plan is to replace the active suns with 2 12" PG of some kind connected to either a Mps2500 or maybe a MS2125. Depends on whether the subs get a total of 2 ohm or 1 ohm.

Then the Denon will do the job as a prosessor + preamp and crossover and to tune levels to each speaker. The power amps will only be Phoenix Gold Ms.
Not sure how this will sound or if the sound will be better or worse compared to what I have today when Denon does all the work but i think and hope it will work out great.

Mavbe this is crazy but i love to have those beauties with the green light on in my livingroom :-)
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phonixx
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Re: Power supply for using PG MS at home.

Post by phonixx »

Now i have the Psu connected to 2 MS275 bridged 4ohm, one on each frontspeaker in a 5.1 setup. It runs very well and i can hardly hear the fans between songs, like Jacampb2 said its whisper quiet. This is a recommended solution with a lot of amperes for the money. My plan is a total of 5 Ms/Mps amps, 2 more Ms275, one bridged for center and one 4 ohm stereo for back surround speakers and one Mps2500 for subwoofers.
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phonixx
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Re: Power supply for using PG MS at home.

Post by phonixx »

Jacampb2 you are absolute right, these are 2 HP DPS-1200FB in parallell. These can be adjusted to 12.5V ish but they are capable of compansate up to 1.5V.
So these are modified with a resistor fooling the psu to compensate +1.5V so that the output is 13.6V ish.
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