Linear vs Switched mode PSU

[Arkless Electronics]

I think you might be referring to a circuit that Hitachi published for their complementary power MOSFETs. Maplin used to sell a very popular power amp kit that used the Hitachi circuit and I made an amp with a pair of them many years ago. It was actually a very good amp but I've heard better since then.

Yes, I agree. Power amp distortion is most often quoted at full - or nearly full - power output, but what about what's happening at the other end of the power spectrum? In my opinion that's more important.

I built those as well. Pretty good amps yes. The commercial Hitachi amps were a little different though. I remember showing them working with a sig gen and scope for a 6th form science open night! That design from Hitachi USA applications department surely has to be the most used/copied in all of hi-fi! Obviously it was put in the public domain to encourage sales of Hitachi power mosfets but it was used by Musical Fidelity, Perreaux, Myst, Inca Tech to name just a few...

On your second point I quite agree. So does Pass Labs with their "First Watt" stuff.

[bumpy]

Jez, are there any components you can hear a sonic difference with. I am thinking capacitors, resistors etc

[montesquieu]

Putting the defeinition of "voicing" to one side, I think you missed the point about the extra resistor in the Naim/NCC circuit. It adds even order distortion (actually it's rather clever, it makes the LTP act more like a singleton input at ac whist retaining the excellent dc characteristics of an LTP) and alters the sound significantly. All this is at a level below the supposed audibility level for distortion. I cettainly the prefer the higher distortion version and I suspect >90% would if they did the experiment.

How does that fit with your research?

BTW, I also have a compoung chip amp with ppm levels of THD. It's far from my favourite amp.

Trust Naim to build a nice bit of kit then stick a resistor that buggers the sound up ... I suppose there's a £££ 'upgrade' to take it out again? :P

... I'll get ma jaikit ....

[Yomanze]

Good point. If you listen mostly to artificially created (electronic) music, for instance, then the traditional notion of 'accurate' goes out of the window, so how can one then use it as an arbiter for such?

For me, it's dead simple: the better my hi-fi system reproduces the real sound of instruments and voices (as perceived by my ears), the more I enjoy listening to recorded music featuring such. Ultimately, it's all about experiencing my notion of musical realism, and therefore what's heard in that respect, can only ever be judged subjectively by me, or perhaps also by others whose notion of such is similar.

Therefore, the enjoyment I derive from my hi-fi system is directly proportional to how well it achieves the above. I'd imagine that it's the same for most people

Marco.

In electronic music there are still a lot of recognisable sounds, an 808 kick, the infamous 808 cowbell, Yamaha FM basses (Lately Bass especially), AKAI samplers had their own stamp on the sound, use of Roland Juno synths for dance music etc. Some people still use hardware to make electronic music, all the better for it, once in software it all changes, and so do the reference points - 'cleaner' and more clinical too in software.

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[Yomanze]

Jez, are there any components you can hear a sonic difference with. I am thinking capacitors, resistors etc

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[Arkless Electronics]

Jez, are there any components you can hear a sonic difference with. I am thinking capacitors, resistors etc

90% of nth degree changes audiophiles claim to hear are non existent and due purely to the imagination.
How many % distortion does there need to be from your SET's before you hear it?

[Marco]

In electronic music there are still a lot of recognisable sounds, an 808 kick, the infamous 808 cowbell, Yamaha FM basses (Lately Bass especially), AKAI samplers had their own stamp on the sound, use of Roland Juno synths for dance music etc. Some people still use hardware to make electronic music, all the better for it, once in software it all changes, and so do the reference points - 'cleaner' and more clinical too in software.

No worries, Neil, and noted. My point was simply that it's ultimately all artificially created, unlike say, the sound of an acoustic guitar.

Marco.

[Marco]

90% of nth degree changes audiophiles claim to hear are non existent and due purely to the imagination.

That's good then because most of the time I've compared the best caps and resistors, with standard types, in any equipment I've used, the changes (improvements) heard have been of the patently obvious, rather than nth degree variety!

Marco.

[Starterman]

Trust Naim to build a nice bit of kit then stick a resistor that buggers the sound up ... I suppose there's a £££ 'upgrade' to take it out again? :P

... I'll get ma jaikit ....

The resistor effects a more natural balance of harmonics in the distortion profile - more like valve amps tend to have. As far as I can tell Naim has always provided this for no extra charge.
Also, FWIW the modest output impedance of Naim amps means they might have a lot more in common with your STA100 than you realise.

[MrRadish]

So grateful to hear of anyone's experience when switching from a switched PSU to a linear PSU (or the other way round) on an audio item?

I feel like I'm drifting off topic answering this, given where the rest of the thread has gone :-)

I've had or have some Maplin test bench LPSU, HDPlex LPSU, iFi iPower SMPS, Russ Andrews PowerPak 2 SMPS, Longdog Audio LPSU, cheap Maplin SMPS and SoTM mbps-d2s battery pack. I used them to power either a PPA v2 card, SoTM PCIe card or a Hi-Face EVO converter. I didn't have them all at the same time, but the Maplins and HDPlex provided a constant reference point. I had two of most of the units to handle 5v and 9v, but found the results (comparisons) were the same regardless of what I was powering. I mostly swapped them over in pairs, where feasible.

The cheap Maplin SMPS was awful, noisy and just yeeuch...
The Maplin test bench were mediocre with poor transparency, poor liquidity and a slight treble roll off, though they were reasonably musical and had decent bass weight.
The HDPlex was almost identical to the Maplin LPSU but a little more rolled off in the treble and slightly more musical. Pleasant but low-fi.
The iFi were technically fine (no roll-off), reasonably transparent and didn't draw attention to themselves, but they weren't particularly musical. I just got bored listening to them.
The Russ Andrews SMPS was beautifully sweet, open and transparent with excellent treble purity and very musical, but slightly lean in the bass. I only had a 9v one of those, so that was testing with the EVO.
The SoTM battery pack was a good all-rounder with no deficiencies and reasonably musical, but not as transparent or enjoyable as the RA (testing with the EVO).
The Longdog supplies are the best of the bunch, with a musical, liquid, well-balanced sound that doesn't draw attention to itself. I don't know if they're as open as the RA, but it's not something I can compare any more.

I should also add a couple of riders:
1. All my testing used substantial mains filtering or regeneration. The SoTM battery supply's main strength is that it doesn't need any of that (for itself), so the other supplies had a helping hand.
2. I've used both SMPS and LPSU ATX power at various points and on one occasion devoting an AG1500 just to the SMPS ATX unit and running the USB card and everything after that from a different regenerator produced excellent results. That was with the Maplin LPSU in place, so the quality and cleanliness of the AC feeding these supplies seems to matter a lot.