Trying to find a 28 VDC Bipolar Power Supply

Archived from groups: rec.audio.pro (More info?)

Use 2 power one 24 volt supplies. Tweak up the voltage adjust to about
28 volts. Reverse the one feeding the negative supply.

Jim Williams
Audio Upgrades

Archived from groups: rec.audio.pro (More info?)

"John Noll" <jn145_deletethisfirst_@verizon.net> wrote in message
news:4304A077.6020003@verizon.net...
> jwilliams3@audioupgrades.com wrote:
>> Use 2 power one 24 volt supplies. Tweak up the voltage adjust to about
>> 28 volts. Reverse the one feeding the negative supply.
>>
>> Jim Williams
>> Audio Upgrades
>>
>
> Thanks Jim,
> I thought of trying something like that. I have a Lambda 28 VDC supply and
> could get another.
>
> My concern is that there is a common ground connection on the modules.
> Connections are Common, +28 and -28. If the second PS is reversed with
> the - connected to the -28, the + connection would connect to the common
> ground? Wouldn't that create a problem having +28 VDC connected to the
> common ground?
>
> --
> --


yes.. that's the problem with doing it this way. You can order a dual
supply from Power One.


> John Noll
>

Archived from groups: rec.audio.pro (More info?)

"nap" wrote ...
> "John Noll" wrote ...
>> jwilliams3 wrote:
>>> Use 2 power one 24 volt supplies. Tweak up the voltage
>>> adjust to about 28 volts. Reverse the one feeding the negative
>>> supply.
>>
>> I thought of trying something like that. I have a Lambda 28
>> VDC supply and could get another.
>>
>> My concern is that there is a common ground connection on
>> the modules. Connections are Common, +28 and -28. If the
>> second PS is reversed with the - connected to the -28, the +
>> connection would connect to the common ground? Wouldn't
>> that create a problem having +28 VDC connected to the
>> common ground?
>
> yes.. that's the problem with doing it this way. You can
> order a dual supply from Power One.

Except that most of those generic power supply modules
have floating outputs where NEITHER the positive nor
the negative are tied to ground. They are designed so that
you can use them with either side grounded. It is trivial
to check/confirm floating output with a $5 ohmmeter.

Archived from groups: rec.audio.pro (More info?)

John Noll <jn145_deletethisfirst_@verizon.net> wrote:
>I'm have a hard time trying to find a +/- 28VDC power
>supply to power up some Quad Eight modules. I've tried
>Mauser, DigiKey, eBay, etc with no luck.
>
>Any suggestions? Thanks.

So get two +28V ones.

Or get some +24V ones and crank them up a little bit... most will go
a little bit higher and +26V is probably close enough for the job.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Archived from groups: rec.audio.pro (More info?)

"John Noll" wrote ...
> I'm have a hard time trying to find a +/- 28VDC power
> supply to power up some Quad Eight modules. I've tried
> Mauser, DigiKey, eBay, etc with no luck.

You really need to know how much current those modules draw.
Or else just buy a big honkin' solution and "brute-force" it.

Here are a some suitable 24v supplies with floating outputs.
Two of them would make the bipolar supply you need....

Twinfly P1-60-24 24VDC @ 2.5A (switching) $30
http://www.mpja.com/productview.asp?product=15064+PS

Twinfly P1-100-24 24VDC @ 4.5A (switching) $36
http://www.mpja.com/productview.asp?product=12418+PS

Condor HN24-3.6-A 24VDC @ 3.6A (linear) $50
http://www.mpja.com/productview.asp?product=15667+PS

Condor F24-12-A 24VDC @ 12A or 28V @ 10A (linear) $100
http://www.mpja.com/productview.asp?product=15698+PS
This one is advertised as adjustable to 28V, but some of the
others may be also. OTOH, we don't know how critical it is
to run those particular modules at +/- 28V vs the more commonly
available +/- 24V

Note that this is a big honkin' and heavy unit and requires
some air flow when running anywhere near the maximumm
ratings (and remember you need two of them) But seems
unlikely that the modules will want even half the rated 10A
at 28V.

Archived from groups: rec.audio.pro (More info?)

this might work for
you....http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=58288&item=7539001607

Archived from groups: rec.audio.pro (More info?)

danger wrote:
> On Thu, 18 Aug 2005 13:44:39 GMT, John Noll
> <jn145_deletethisfirst_@verizon.net> wrote:
>
>
>>I'm have a hard time trying to find a +/- 28VDC power
>>supply to power up some Quad Eight modules. I've tried
>>Mauser, DigiKey, eBay, etc with no luck.
>>
>>Any suggestions? Thanks.
>>--
>
>
> Google accopian

It's Acopian with one c. That, Power One and Lambda
were the first places I looked. Off-the-shelf bi-polar
28 VDC supplies don't seem to exist. Nonetheless as I
mentioned in an earlier post, I used a pair of Lambda 28
singles with floating grounds as instructed by several
posters here. It's working fine now. I still come here
to learn a few things and often succeed with the help of
some of the those around here who are smarter than me.

After two days I sorted out the confusing pinouts and
the CL-22's are now ready to squeeze.

--
--
John Noll
Retromedia Sound Studios
Red Bank, NJ

jn145_deletethisfirst_@verizon.net

http://www.retromedia.net