Who is using amps/preamps with SMPS power supplies?

[rabski]

Smps have a potential sonic advantage for audio use over linear supplies ( in one application at least) in their lack of low frequency noise ie hum. Valve designs particularly zero global feedback ones seem to benefit from this, at least in my experience. Ive built valve headphone amps and phono stages using smps for the heaters and  HT which show no sign of LF noise on a noise plot unlike linear supplies, nor any downband modulation into the audio band from the switching noise.  This is with only a simple noise filter.  I think they sound better than my linear supply versions particularly in the bass with no added harshness etc . A power amp is next but not an 845 ! 

I imagine an SMPS producing around 1500 volts at 300 mA or so may offer some design challenges. It's bloody difficult enough with a linear supply. Basic things like insulation and component spacing get a bit 'fun' at 1.5 kV.

 

[Warszawa]

Have you heard well-made LPSU vs well-made SMPS on anything? If so, what? I would urge those who fight the corner of SMPS in general to do so. No-one is promising a revelation here, but others have been surprised by what should, in theory, not make anything like the difference it does. I'm talking digital front-ends here, not amps, so may well be off-topic.

I haven’t had the need/opportunity with my kit as it’s all LPSU or battery powered. I am not denying people are hearing differences either, just suggesting that SMPS are not the devils work that some marketing would have you think. 

We are veering off topic here, and I hate to bring up the extreme example of the Chord DAVE yet again (particularly as a certain member might assume I’m pointing fingers), but there lies a case where cost was not an object and the designer chose a SMPS. And whilst admitting a LPSU may change the sound, he remains adamant it can only be for the worse and in detriment to the way the product is designed. 

 

[TheFlash]

I haven’t had the need/opportunity with my kit as it’s all LPSU or battery powered. I am not denying people are hearing differences either, just suggesting that SMPS are not the devils work that some marketing would have you think. 

We are veering off topic here, and I hate to bring up the extreme example of the Chord DAVE yet again (particularly as a certain member might assume I’m pointing fingers), but there lies a case where cost was not an object and the designer chose a SMPS. And whilst admitting a LPSU may change the sound, he remains adamant it can only be for the worse and in detriment to the way the product is designed. 

On your first point, that's good to know, thanks. And I agree they are far from the devil's work!

It's only off-topic because it's a DAC not an amp . I know you're not having a pop.  I guess if people have money to spare and like the change an aftermarket LPSU makes to the DAVE then that's their prerogative and not to be judged by us.

You do raise an interesting point though, which was touched on earlier by @hifinutt: it would be great to see a list of the manufacturers (and, if relevant, models) which come as standard with:

• internal linear PSU
  
• internal SMPS
  
• external linear PSU
  
• external SMPS.
  

The broadly (beyond hifi) ubiquitous external SMPS makes life so much easier for a manufacturer: swapping from 110v to 230v simply means shipping a different accessory. If internal, a switch on the back can do the same thing.

But linear PSUs (the best ones, anyway) are designed to work at a fixed voltage. Makes life a little harder.

 

[jobseeker]

My Mytek Brooklyn Bridge has  an inbuilt socket to connect a Linear Power Supply, but I’ve never felt the need to be honest. The lack of bulk, weight and potential transformer buzzing is quite convenient in many ways (I’ve had transformer noise with a lot of amps). Which all would be for nought if it didn’t sound good but, fortunately, it does. 

 

[Blzebub]

I now have a total of three Audiolab DC Blocks in my system, thanks to transformer humming from various power-supplies. The SMPS on my DACMagic is by contrast totally silent.

I don't buy this mantra that SMPS are inherently "noisy". The opposite is true, IME.

 

[rabski]

I now have a total of three Audiolab DC Blocks in my system, thanks to transformer humming from various power-supplies. The SMPS on my DACMagic is by contrast totally silent.

I don't buy this mantra that SMPS are inherently "noisy". The opposite is true, IME.

I think most people are using 'noise' here to refer to electronic 'noise' in the sense of interferfence on top of the basic DC output of a power supply. It's a good point though. In general, SMPS are liable to cause electronic noise, but linear supplies are prone to mechanical noise.

Designing and building a (good) linear supply is not as simple as people may believe. It's also something I've pointed out a number times, that there is no such thing as a 'universal' power supply, as the requirements of a circuit will differ. There are many applications where an SMPS makes perfect sense, as what it's powering may be designed to reject or filter any high-frequency noise, or it may be anyway irrelevant.

 

[TheFlash]

I think most people are using 'noise' here to refer to electronic 'noise' in the sense of interferfence on top of the basic DC output of a power supply. It's a good point though. In general, SMPS are liable to cause electronic noise, but linear supplies are prone to mechanical noise.

A really important clarification. We risk using a single word to talk about two very different things.
 

The DC3 LPS I have powering my Node hums, audible from 1-2 feet away but no further. By contrast, the electronic noise floor is lower than ever and the music sounds better than ever.

 

[Warszawa]

Personally, if I had five figures to spend on a DAC, I would only be spending that money on peripherals such as external power supplies and clocks if they were made, or at least endorsed by the manufacturer. Plus I tend to give more consideration to how things look on the rack these days and I don't fancy having lots of big metal boxes hanging out of the arse of everything. Each to their own though. If it brings to user sonic bliss or peace of mind then great.

Anyway, enough waffle. In response to the original question. Just because a Node can be improved by replacing the SMPS, doesn't mean an SMPS based amplifier is inherently inferior to other designs.

 

[TheFlash]

Anyway, enough waffle. In response to the original question. Just because a Node can be improved by replacing the SMPS, doesn't mean an SMPS based amplifier is inherently inferior to other designs.

Agreed 100%.

 

[It Cost How Much!?!]

The only SMPS component I have is the Velodyne sub, I think it has one. 

I avoid SMPS as much as I can. 

 

[TheFlash]

The only SMPS component I have is the Velodyne sub, I think it has one. 

I avoid SMPS as much as I can. 

That will be because it’s well known how noisy they are then…

I”ll just get my coat.

 

[dave]

I have quite a few smps in regular use in my stereo, now I come to think about it, Denon DVD2900 and Behringer DEQ2496, and probably Sony tv tuner. In my lampizated Dynaco PAT4 I use a boost converter to generate the HT. Also in my home made valve CD player(s) I use linear power supplies for everything except the HT, which uses a boost converter, again of my own design (leftover day job). I don't have any audible problems that I am aware of. I did have some HT boost converter smps noise problems in my valve cassette deck with the boost converter. I had to do some extra filtering, but that is like a MC head amp type of sensitivity.

I am going to make a 100ish watt 400v smps for an SE amp I am going to build, and I just see advantages of adjustable voltages and smooth DC, but it will be a bit scary, big bang in the case of the short circuit, but that should be no different from a linear, and current limiting is easier.......... so maybe it is better...

Filtering is key and sensible physical design. never bolt a switching device to a chassis (even with a silpad), always an isolated air cooled heatsink.

 

[Steveh]

From the vaults(2011)

Chord SPM800

This from Gramophone 1995(annual shortlist of recommendable hi-fi products)

Very high quality power amplifier using a switched-mode power supply. The power supply is arguably the most important part of a modern amplifier and this one is extraordinarily good. The result is a compact unit of remarkable anonymity and an ability to control almost any load. Superbly finished, like all Chord products, it has made deservedly substantial in-roads into both the professional and domestic markets.

 

[Fourlegs]

From the vaults(2011)

Chord SPM800

This from Gramophone 1995(annual shortlist of recommendable hi-fi products)

Very high quality power amplifier using a switched-mode power supply. The power supply is arguably the most important part of a modern amplifier and this one is extraordinarily good. The result is a compact unit of remarkable anonymity and an ability to control almost any load. Superbly finished, like all Chord products, it has made deservedly substantial in-roads into both the professional and domestic markets.

I had the Chord SPM1200Mk2 on home demo for a few weeks which also has a smps. It was knocked into a cocked hat for musicality and general sound quaity compared to the Pass Labs XA30.8 with its lps and which I bought instead of the Chord amp.

Just sayin’.

 

[dave]

It was knocked into a cocked hat for musicality and general sound quality compared to the Pass Labs XA30.8 with its lps and which I bought instead of the Chord amp.

That could be because Nelson Nass knows how to design an amplifier (imho  )

I haven't done it yet recreationally but I feel there could be definite synergies with a designed for purpose smpu and a class ab amplifier.

 

[rabski]

Yeah. I was going to suggest that if you're looking for the cause of sonic differences between a Nelson Pass design and a Chord design, I'd look a lot further than the type of power supply.

 

[Fourlegs]

Richard and Dave, i agree with you but I was really responding to the post with the quote from Gramophone saying this in relation to the SPM 800, “Very high quality power amplifier using a switched-mode power supply. The power supply is arguably the most important part of a modern amplifier and this one is extraordinarily good.”

 

[TheFlash]

I had the Chord SPM1200Mk2 on home demo for a few weeks which also has a smps. It was knocked into a cocked hat for musicality and general sound quaity compared to the Pass Labs XA30.8 with its lps and which I bought instead of the Chord amp.

Just sayin’.

And you say this as a signed up member of the Chord Fanboy Club!

Actually, according to my records, you're actually a signed up member of the Chord Fanboy Club: Digital Front-End Chapter. That figures.

 

[Warszawa]

I had an SPM1050 Mk II for a while. It was a lot of fun. Preferred it to Bryston. 

 

[Camverton]

Currently trying an Ultima 6 Chord amp. It goes very well with their digital front end in that it is incredibly detailed and without any added colour. The neutrality does take a little bit of getting used to, but on switching back to my other amps I discovered that I didn’t want to go back to them! Rather like using Chord DACs, at first they sound almost too “perfect” but there is no going back to more traditional designs.

Whether the detail and neutrality is down to the power supply I don’t know. Of course, everything depends on how they match the speakers they drive and the taste of the listener. Could the Chord amp do with a touch of 2nd harmonic distortion? Maybe, but hearing music so cleanly reproduced is certainly addictive.