Hi, I've been looking for a SMPS to power audio power amps. Coldamp.com make some SMPS that look pretty good, except they are rather expensive and output voltages are too high. Ideally, I'm looking for +/- 24v with about 5A for stereo should be enough to play with (240W output). I know of the skynet 8080. Price is right but it would take 4 of them to get +/- 24 and that would be too big.
Is there anything else out there I've missed? +/- outputs is the main thing that most SMPS lack. I would just design my own SMPS at this point, but I can't
lol
Is there anything else out there I've missed? +/- outputs is the main thing that most SMPS lack. I would just design my own SMPS at this point, but I can't
lol
Here is the one I was referring to.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=31614&perpage=10&highlight=&pagenumber=1
http://www.diyaudio.com/forums/showthread.php?s=&threadid=31614&perpage=10&highlight=&pagenumber=1
well, yes you can forget it unless your purpose is specialized like weight restrictions, etc.
This one seems to work quite well: dual + 48 VDC isolated output for +/- 48 VDC rails. The extra torrid hum bucking inductors and the extra 1500 uF 100 volt electrolytics keep the output very quiet indeed ... total weight about 15 pounds ... ("flat pac" topology useful in 1 Up rack mounted chassis from: http://www.vicr.com/products/configurable/flat_pac/ )
This one seems to work quite well: dual + 48 VDC isolated output for +/- 48 VDC rails. The extra torrid hum bucking inductors and the extra 1500 uF 100 volt electrolytics keep the output very quiet indeed ... total weight about 15 pounds ... ("flat pac" topology useful in 1 Up rack mounted chassis from: http://www.vicr.com/products/configurable/flat_pac/ )
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" .. What hope have you got when you don't have the resources to design the supply nor how to start modifying it. ..."
? Resources: costs each manufactured supply module ~ US$180.00 delivered (X 2) ... (DIY SMPS's from ground up would have cost much more, considering design time, mfger time, assembly time, parts ...). These supplies are "hospital grade" intended for industrial applications like running motors & ultra sound scanners, etc. Note also lab equipment grade EMF filter on line cord and circuit breaker / power switch (usually a no - no for golden ear gear), but no EMF allowed in or out of the box. I am using my own "secret sauce" on the supply outputs = those counter wound humbucking torrids knock almost all of the residual switching supply noise off of the power rails. The interconnecting power & speaker wiring is fine strand #12 AWG silver, teflon coated, likewise input signal wires are of shielded stranded silver / teflon wire from the gold plated RCA connections to the gold plated amp module connections ... which rmay or may not do much, but the customers love it. (The interconnects and amp modules are more co$tly than the power supplies.)
" .. And what if it needs debugging after assembly? .."
? So far all switching supplies have passed muster = no worry mate, no failures, no excessive heat, no bad news ...
This dual channel amp is for a special project to be sold when (or if) it passes all the tests. These are 500 watt into 4 ohm MOSFET amp modules, downgraded in output to about half that for thermal reasons, mostly = to be run 24/7/365, hopefully without any hangups, ever. Another model will use open frame + 60 VDC X 2 SMPS modules for +/- 60 VDC rails and closer to 350 watts per channel ... but weigh a little less = 14 to 15 pounds (!)
" .. And then will it sound OK? ..."
So far they sound just great = healthy, plenty of guts, tight bass, clear highs. The ultimate customers are professional musicians, needing guitar power that does not require its own airline tickets to travel ... The one pictured has not been final assembled as yet nor undergone burn in or amp bias tweak ... My 'scope pictures look about as good as these: http://aussieamplifiers.com/nx500ln.htm
(I'm working up a vacuum tube pre-amp with switching supplies = a serious violation of audiophile conventional wisdom ...
)
Anyone know where to get thin sheets of teflon?? about 8 1/2 x 11" ??
? Resources: costs each manufactured supply module ~ US$180.00 delivered (X 2) ... (DIY SMPS's from ground up would have cost much more, considering design time, mfger time, assembly time, parts ...). These supplies are "hospital grade" intended for industrial applications like running motors & ultra sound scanners, etc. Note also lab equipment grade EMF filter on line cord and circuit breaker / power switch (usually a no - no for golden ear gear), but no EMF allowed in or out of the box. I am using my own "secret sauce" on the supply outputs = those counter wound humbucking torrids knock almost all of the residual switching supply noise off of the power rails. The interconnecting power & speaker wiring is fine strand #12 AWG silver, teflon coated, likewise input signal wires are of shielded stranded silver / teflon wire from the gold plated RCA connections to the gold plated amp module connections ... which rmay or may not do much, but the customers love it. (The interconnects and amp modules are more co$tly than the power supplies.)
" .. And what if it needs debugging after assembly? .."
? So far all switching supplies have passed muster = no worry mate, no failures, no excessive heat, no bad news ...
This dual channel amp is for a special project to be sold when (or if) it passes all the tests. These are 500 watt into 4 ohm MOSFET amp modules, downgraded in output to about half that for thermal reasons, mostly = to be run 24/7/365, hopefully without any hangups, ever. Another model will use open frame + 60 VDC X 2 SMPS modules for +/- 60 VDC rails and closer to 350 watts per channel ... but weigh a little less = 14 to 15 pounds (!)
" .. And then will it sound OK? ..."
So far they sound just great = healthy, plenty of guts, tight bass, clear highs. The ultimate customers are professional musicians, needing guitar power that does not require its own airline tickets to travel ... The one pictured has not been final assembled as yet nor undergone burn in or amp bias tweak ... My 'scope pictures look about as good as these: http://aussieamplifiers.com/nx500ln.htm
(I'm working up a vacuum tube pre-amp with switching supplies = a serious violation of audiophile conventional wisdom ...
)Anyone know where to get thin sheets of teflon?? about 8 1/2 x 11" ??
" ... The resources necessary include that expertise (not the money). ... Without it, one is struggling. ..."
Re: The Money.
"Anything worth doing, is worth doing for money ..." - Alfred E. Newman / Mad Magazine.
The way I do it is I find a market that is intriguing or very interesting, first. Then I try to build what I would want if I were a customer interested in the market. Then I try to make it better and better, hang the initial costs, 'cause there is always a market for quality (see Forbes Life Magazine). Then I just go ahead and build it ... "If you build it and it doesn't stink, they will come ..." Then I work with it for a while ... I do have a modest R & D budget with my company 'cause that's the way the US income tax is structured (spend it on your hobbies and call it R & D for the business ... see: http://sailboatstuff.com = this paid for my sailboat and slip rental, almost all tax free, for several years until I sold that business, then capital gains taxes of <20%).
Re: The Expertise.
I may write a book on how this is done, legally, without pain and plenty of joy and a modest reward for the piggy bank at the end. My expertise was physics and engineering then computers and networks, now, eCommerce ... its basically doing with instead of without and having fun while doing it.
Re: The Money.
"Anything worth doing, is worth doing for money ..." - Alfred E. Newman / Mad Magazine.
The way I do it is I find a market that is intriguing or very interesting, first. Then I try to build what I would want if I were a customer interested in the market. Then I try to make it better and better, hang the initial costs, 'cause there is always a market for quality (see Forbes Life Magazine). Then I just go ahead and build it ... "If you build it and it doesn't stink, they will come ..." Then I work with it for a while ... I do have a modest R & D budget with my company 'cause that's the way the US income tax is structured (spend it on your hobbies and call it R & D for the business ... see: http://sailboatstuff.com = this paid for my sailboat and slip rental, almost all tax free, for several years until I sold that business, then capital gains taxes of <20%).
Re: The Expertise.
I may write a book on how this is done, legally, without pain and plenty of joy and a modest reward for the piggy bank at the end. My expertise was physics and engineering then computers and networks, now, eCommerce ... its basically doing with instead of without and having fun while doing it.
Surplus switch mode power supplies are so common and so cheap there is little point in rolling your own unless you want a long, slow, painful, and expensive learning experience.
Check some of the on-line surplus dealers. You'll find new and used surplus supplies for less than you can build an unregulated linear supply.
I_F
Check some of the on-line surplus dealers. You'll find new and used surplus supplies for less than you can build an unregulated linear supply.
I_F
Yes!!
Look for "isolated output" = output negative (-) not connected to power line ground., but there should be provisions for power line (third wire) grounding ... so you can make the chassis a shield and protect prying fingers from shock.
Look for supplies that use chopping / switching frequencies greater than 100K Htz. Usually these run at around 200K to 250K Htz. ... this noise is much easier to filter off than switch frequencies close to the audio range. (Don't bother with computer switching supplies = the manufacturers lie about the power ratings and the noise rejection = 250 watts will be lucky to produce 100 watts of useful audio power.)
Look for "open frame" supplies that are "U" shapped = these will have a wall of aluminum that will reduce noise and EMF influences "attacking" your audio parts. (These should be mounted / oriented so a wall is between the PSU and the audio parts, like a fence.) Completely enclosed supplies are even better ...
Even thoiugh switching supply makers claim good power to noise ratios, be prepared to add the ol' reliable filter modules = thousands of uF worth of external capacitance.
Look for "isolated output" = output negative (-) not connected to power line ground., but there should be provisions for power line (third wire) grounding ... so you can make the chassis a shield and protect prying fingers from shock.
Look for supplies that use chopping / switching frequencies greater than 100K Htz. Usually these run at around 200K to 250K Htz. ... this noise is much easier to filter off than switch frequencies close to the audio range. (Don't bother with computer switching supplies = the manufacturers lie about the power ratings and the noise rejection = 250 watts will be lucky to produce 100 watts of useful audio power.)
Look for "open frame" supplies that are "U" shapped = these will have a wall of aluminum that will reduce noise and EMF influences "attacking" your audio parts. (These should be mounted / oriented so a wall is between the PSU and the audio parts, like a fence.) Completely enclosed supplies are even better ...
Even thoiugh switching supply makers claim good power to noise ratios, be prepared to add the ol' reliable filter modules = thousands of uF worth of external capacitance.
AndrewT said:
Sometimes one must stuggle on. It can be necessary to improve knowledge and gain experiance
ssanmor, the coldamp site says only voltages from +/-40V to +/-60V on request.
One of the things that appeals to me about DIY audio is that you can save a few $$$ compared to comercial stuff. That is lost with the SPS30 becasue of its price. So I'll be on the lookout for a suitable SMPS as described by fast eddy.
Yes, we have to change that. We can now supply unipolar from +24V/10A to +120V/3.5A and symmetric from +/-13V to +/-60V on request.
I understand perfectly your appeal for investigation and DIY, just wanted to let you know. Sometimes one wants to concentrate his efforts on a part of the system (for example, the amplifiers) and buy a ready-made supply, or vice-versa.
Keep on, but, above all, be very careful with line voltage, it can kill you!
Best regards,
Sergio
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