Sounds like you could. Possibly you will want a passive noise filter at the output of the supply.
It would be good to check if there is an internal connection between minus pole and safety earth inside that PSU. If that is the case, when you connect those PSUs in series (to create dual voltage +/-24V PSU for the amp) the "bottom" PSU will be short-circuited and you don't want that to happen...
Very good advice. 🙂
Most of them have V- connected to Earth.
Also applies to people who are contemplating of using virtual earth.
Only safe application in those cases are mono-rail amps with input / output coupling caps.
Here are 2 (different) low-power examples :
https://www.diyaudio.com/community/threads/mini-dcaav-with-dayton-nd91.249372/post-4559002https://www.diyaudio.com/community/threads/mini-dcaav-with-dayton-nd91.249372/#post-6628506
First is split-rail where V- has to be floating.
Second is when V- can be connected to Earth.
Patrick
Most of them have V- connected to Earth.
Also applies to people who are contemplating of using virtual earth.
Only safe application in those cases are mono-rail amps with input / output coupling caps.
Here are 2 (different) low-power examples :
https://www.diyaudio.com/community/threads/mini-dcaav-with-dayton-nd91.249372/post-4559002https://www.diyaudio.com/community/threads/mini-dcaav-with-dayton-nd91.249372/#post-6628506
First is split-rail where V- has to be floating.
Second is when V- can be connected to Earth.
Patrick
This appears to be the datasheet for that unit (or perhaps a slightly later version? Please verify this yourself.) https://products.pulspower.com/us/mwdownloads/download/link/id/1813/
Paragraph 18 shows it’s dielectric limits throughout the various connections and says that the outputs are floating with no connection to earth. I suspect you could use these in series and wire them as a bipolar supply. Test and determine this yourself using proper safety!
Also, make sure the PSU mains are connected to the same switch - something like a power strip where the two PSUs are on the same switched power strip, you do not want them powering up or down separately.
Paragraph 18 shows it’s dielectric limits throughout the various connections and says that the outputs are floating with no connection to earth. I suspect you could use these in series and wire them as a bipolar supply. Test and determine this yourself using proper safety!
Also, make sure the PSU mains are connected to the same switch - something like a power strip where the two PSUs are on the same switched power strip, you do not want them powering up or down separately.
Unless the two SMPS units in question have a feature that allows their switching frequencies to by synchronized to each other, there is a risk that an audio range 'beat' frequency may be present when they are connected in series.
One of the primary advantages of small brick style SMPS units is their simplicity of use and operation. The primary examples of this are the kit ACA and VFET amplifiers. Once the brick SMPS is replaced with larger chassis mount SMPS, output filtration and internal OSC synchronization, then the simplicity aspect disappears, and there may be a number of issues with which the DIY community at large has limited knowledge.
I will also add that in every case where I have substituted a carefully built linear supply for either a brick style or chassis mount SMPS, the linear supply has proven to sound superior. It is possible that a fine sounding example of a Class A compatible SMPS exists, but the jury is still out on that matter.
One of the primary advantages of small brick style SMPS units is their simplicity of use and operation. The primary examples of this are the kit ACA and VFET amplifiers. Once the brick SMPS is replaced with larger chassis mount SMPS, output filtration and internal OSC synchronization, then the simplicity aspect disappears, and there may be a number of issues with which the DIY community at large has limited knowledge.
I will also add that in every case where I have substituted a carefully built linear supply for either a brick style or chassis mount SMPS, the linear supply has proven to sound superior. It is possible that a fine sounding example of a Class A compatible SMPS exists, but the jury is still out on that matter.
I've had absolutely outstanding success with SMPS, and am going to happily try in more amplifiers. Linear is not automatically superior in my experience.
Please try yourself and come to your own conclusions.
Please try yourself and come to your own conclusions.
I have a different conclusion. 🙂
You cannot avoid HF pickup completely even with an external SMPS.
Cheers,
Patrick
You cannot avoid HF pickup completely even with an external SMPS.
Cheers,
Patrick
Worth a try. We use these in industrial machines where I work and I've often thought about trying them in an amp.
Puls is a quality brand and never seen one fail.
The outputs are floating so you can create a dual rail supply no problem, and they're adjustable so you can dial it up to about 28V if needed and/or balance the two to be equal.
The "DC OK" output is just a dry relay contact to be used for monitoring the output voltage if you wish.
Details in the attached data sheet.
Puls is a quality brand and never seen one fail.
The outputs are floating so you can create a dual rail supply no problem, and they're adjustable so you can dial it up to about 28V if needed and/or balance the two to be equal.
The "DC OK" output is just a dry relay contact to be used for monitoring the output voltage if you wish.
Details in the attached data sheet.
I've always wondered in the smps supplies in older (1990s vintage) servers would work. Like the Sun Sparcstation line. These things were engineered really well, from what I heard back then, and cost a small fortune. My guess is that they would need a very clean Power supply to push the limits of processing power (a whopping 50Mhz!)
As TungstenAudio mentioned the possibility of beat frequencies smack in the audible band is a risk. If you have one running at 101kHz and one at 99kHz you have 2kHz... The high power rating of the SMPS also gives a risk of skipping frequencies, which may be even worse. But with a class-A circuit pulling a relatively large amounts of power this is unlikely to happen.
There will be loads of HF 'hash' in your circuit tho. This may or may not be a problem. There is no way of eliminating all the switching currents and the multiple frequencies they produce. If unlucky some may intermodulate with some audio frequencies. Perhaps not a real issue either.
Antennae are two-way. They receive as well as they transmit. Your layout is a collection of antennae from all the components, connecting tracks and wires, and everything that makes up the circuit. If you want the circuit to pick up as little HF as possible, the layout (physical design) must be per 'high speed design rules'. Every signal trace needs a tightly coupled return path, all loops as small as possible, etc. Even tho the audio circuit is regarded as low frequency analog, it needs to be treated as high speed when placed near other high speed circuits (which SMPSs are).
That is if yo are nitpicking the EMI and HF issue. It may not be a problem at all.
Also, most SMPS units are just the power supply. It is intended to have filters pre and post, and some long legged electrolytic cap is not suitible for any frequencies above a few kHz. You must use filters designed for the high frequencies.
I have had success with my limited experience with SMPS. To avoid skipping I've used SMPS sized so they are running at 75-90% of max rating. It is not like linear supplies where oversize is good.
Another issue is most SMPS are made so small they all need force air cooling, and those fans are annoying.
I have some brick I intend to try out and they can be mounted on heatsinks. If possible, only use SMPS that can be mounted on heatsinks.
But, after all my rants, hope you try em out and that they work fine.
There will be loads of HF 'hash' in your circuit tho. This may or may not be a problem. There is no way of eliminating all the switching currents and the multiple frequencies they produce. If unlucky some may intermodulate with some audio frequencies. Perhaps not a real issue either.
Antennae are two-way. They receive as well as they transmit. Your layout is a collection of antennae from all the components, connecting tracks and wires, and everything that makes up the circuit. If you want the circuit to pick up as little HF as possible, the layout (physical design) must be per 'high speed design rules'. Every signal trace needs a tightly coupled return path, all loops as small as possible, etc. Even tho the audio circuit is regarded as low frequency analog, it needs to be treated as high speed when placed near other high speed circuits (which SMPSs are).
That is if yo are nitpicking the EMI and HF issue. It may not be a problem at all.
Also, most SMPS units are just the power supply. It is intended to have filters pre and post, and some long legged electrolytic cap is not suitible for any frequencies above a few kHz. You must use filters designed for the high frequencies.
I have had success with my limited experience with SMPS. To avoid skipping I've used SMPS sized so they are running at 75-90% of max rating. It is not like linear supplies where oversize is good.
Another issue is most SMPS are made so small they all need force air cooling, and those fans are annoying.
I have some brick I intend to try out and they can be mounted on heatsinks. If possible, only use SMPS that can be mounted on heatsinks.
But, after all my rants, hope you try em out and that they work fine.
You may need to stack a few of them together to get the voltage, but as far as quality goes, you are correct, they were exceptional. I had many Sun products from that time, all with Sony power supplies. Good stuff, no failures.