Thread: I replaced a linear power supply with an SMPS

I'm talking about this because a lot of folks firmly believe that a linear supply is pretty much always better than a switching supply. My swap puts that very much in question, at least for me.

OK, the swap was for my backup a Class D Audio SDS-258 module-based DIY amp that I've had for over a decade -- so NOT a critical piece of equipment that I couldn't afford to destroy if it came to that. Actually, my principal objective was to make the amp a lot lighter, not so much to improve the sound.

Unusual for a class D amp, Class D Audio has never offered a SDS-based amp or kit with an SMPS. (A few years ago they offered an SMSP for automotive use, never for AC power).

So I ordered a Connexelectronics SMPS800RE supply with +/- 60 VDC output to duplicate the linear supply. The removal of the linear supply, (also a Connexelectronics model), and replacement was an easy DIY task. Below are Before and After pics.

The sound is just fine: excellent detail, dynamics, and bass, remarkably close to my VTV Purifi amp. A little brighter in the treble than the Purifi, but hey, you wouldn't expect the old CDA to sound quite as perfect. The device has be operating with no problems for several days now. (Beware: neither of the class D amps is going to appeal to any hard-core tube lover.)

i am not a techie, nor do i play one on TV.

certainly agree that SMPS's can potentially wreak havoc on a signal path, particularly when inserting a piece of gear into a system not designed for hifi use (see my active anti resonance platforms....eventually had to switch them to linear power supplies to get the full benefit from the positive things they did).

phono stages are especially sensitive to power supply noise as they take the tiniest weakest signals and have to amplify them to line level. so you would assume that a SMPS would not be a good candidate for a phono stage. however; it turns out that the lowest noise phono stage i have heard uses battery power and a SMPS......the CS Port C3EQM2.

Phono Equalizer Amplifier C3EQM2 | Products | CSPort

so how might that have happened?

well, it turns out that the designer of that phono stage, Toshimichi Machino, was the chief researcher and later CEO for a large maker of industrial power supplies. he likely knows more about power supply design than the whole high end audio industry put together. he started CS Port after retiring from that large power supply company.

http://wales.clsa.com/biosmain.asp?ctrlid=3239

Company Overview | Company Info. | COSEL Co., Ltd.

Originally Posted by Mike Lavigne

i am not a techie, nor do i play one on TV.

certainly agree that SMPS's can potentially wreak havoc on a signal path, particularly when inserting a piece of gear into a system not designed for hifi use (see my active anti resonance platforms....eventually had to switch them to linear power supplies to get the full benefit from the positive things they did).

phono stages are especially sensitive to power supply noise as they take the tiniest weakest signals and have to amplify them to line level. so you would assume that a SMPS would not be a good candidate for a phono stage. however; it turns out that the lowest noise phono stage i have heard uses battery power and a SMPS......the CS Port C3EQM2.

Phono Equalizer Amplifier C3EQM2 | Products | CSPort

so how might that have happened?

well, it turns out that the designer of that phono stage, Toshimichi Machino, was the chief researcher and later CEO for a large maker of industrial power supplies. he likely knows more about power supply design than the whole high end audio industry put together. he started CS Port after retiring from that large power supply company.

http://wales.clsa.com/biosmain.asp?ctrlid=3239

Company Overview | Company Info. | COSEL Co., Ltd.

Hi, Mike. I've been a huge admirer of you system and listening room for many years now, like most everyone else.

I suppose one can't argue with at guy like Machino re. power supplies. But I'd guess the SMPS have their place; they are certainly used nowadays on all class D amps that are regarded as SOTA. Any way, it seems to be doing a good job in my case. I have not noticed any negative effects on my DAC or FM tuner. As far as phono stages are concerned, I haven't listen to vinyl in a decade of more.

I would hazard a guess that the engineers designing and building top-notch Class D amps might know a bit more about SMPS's than most OEM suppliers. Also note that the SMPS Mike mentions does not include an AC to DC convertor, as most implementations do.

It's hard to argue against listening for oneself (probably not in a DBT )

Originally Posted by rbbert

I would hazard a guess that the engineers designing and building top-notch Class D amps might know a bit more about SMPS's than most OEM suppliers. Also note that the SMPS Mike mentions does not include an AC to DC convertor, as most implementations do.

It's hard to argue against listening for oneself (probably not in a DBT )

Sufficed to say I content with the results and it certainly serves my main purpose that was to make the amp easier to tote around, (damned arthritis).

As for DBT, I'm not all sure I could distinguish between the CDA and the Purifi: they are very similar.