Challenge From Harbeth - Free M40.1 For Those Who Can Identify Amplifier Differences
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Elephantears
Trunkated Aesthete
Yes, I know that, and I have all due respect for this. But that doesn't help us talk about music and the varieties of musical reproduction. You might be able to explain why a Croft amp sounds totally different to a Krell by science, but if you want to convey that to anyone you're stuck with hints and metaphors. Which is fine by me.
Robert
Tapehead
I wouldn't bet on it either since you appear to have chosen a valve amp. The reasons why some of these sound different are well understood (by technocrats at least
).It would be necessary to see just how far your amps fail in terms of being transparent. They might just be good enough.
As for choosing the four mentioned as representative, someone else here mentioned them but all have a technical specification not dissimilar to models from Cyrus, Arcam, Pioneer, Marantz, Linn, Naim, Quad, Audiolab, Technics etc.
In other words, products form companies selling hundreds of thousands to the public over many years, as apposed to hair shirt valve stuff selling in minute quantities into a tiny sector of the audio buying public.
Paul R
pfm Member
I don't see that as 'rigged', I see this as wriggle.
If you want to do it differently then make a proposal, the basic requirement must be statistically audible discrimination between competent amps that would be expected to sound the same on conventional criteria. It wouldn't be interesting to do the test using background noise levels, or with a stunt signal that trips the protection on one of the amps. Human sensible sounds, amps that measure acceptably and similarly.
Perhaps you could propose a pair of amps that meet the criteria of similarity yet which you believe sound different? You had your amp upgraded recently at significant cost, IIRC, did it sound different after? Does it measure well enough to be considered 'transparent'? Why not a couple of those in different states of tune?
Paul
Evil Emperor
Taller Than Stalin
But, within their operating parameters and carefully level-matched, they don't sound different. That's the point. Unless one of the two amps has a radically different frequency response, or unless one of them has several orders of magnitude distortion at any real-world volume level or one is broken and one isn't they should sound the same.
OK, so the Croft lacks the headroom on offer to the Krell and that will dictate a lot of the comparison (including probably the type of speakers used), but under an all-things-being-equal test, they should sound the same.
YNWOAN
100% Analogue
Yes, but this isn't the view at Quad any more. Even then, he was very much in the minority of amplifier designer/manufacturers to hold this belief.
Can I remind you that I am happy to take the test using my method. I wonder how flexible the test is? Does it have to use Harbeth speakers etc? Picture this, you are a speaker designer such as Robert Audio Smile, would you make crucial design choices with kit you werent familiar with, in a room you didnt know, music you didnt know and listening in a method you werent happy with? If you could I think hi-fi design would be very different. And this is absolutely no offence to your design or technical skills- I heard the full Smile-system at Whittlebury and rated it but I am sure it wasnt designed in the same way we have to take this test.
Why cant this take place at my house? I have a nice spur for my amps, NAIM friendly cable and a system I have lived with for years (a new cartridge though). I am happy for a modern(ish) amp to be used, a Pioneer A400 or an Audiolab will do (stick them on the dirty mains and plug in all the SMPS chargers I can find- why not? the amps will measure the same within reasonable limits) and I will have the 552/500. A SPL meter and some tape on the volume control to give me options on listening level. I dont know what is so tricky here??????
Why cant this take place at my house? I have a nice spur for my amps, NAIM friendly cable and a system I have lived with for years (a new cartridge though). I am happy for a modern(ish) amp to be used, a Pioneer A400 or an Audiolab will do (stick them on the dirty mains and plug in all the SMPS chargers I can find- why not? the amps will measure the same within reasonable limits) and I will have the 552/500. A SPL meter and some tape on the volume control to give me options on listening level. I dont know what is so tricky here??????
Joe P
Memory Alpha incarnate | mod; Shatner number = 2
Take four well-regarded amps all with respectable specs and power output — Bryston 3B, Linn Klout, Naim 250-2 and Berning 270.
Connect each in turn to a pair of 40.1s. Level match. Do the test double blind.
Let's not worry about trying to identify by ear which amp is which.
Do you think that if the amps aren't clipping you wouldn't hear differences between them?
Joe
Connect each in turn to a pair of 40.1s. Level match. Do the test double blind.
Let's not worry about trying to identify by ear which amp is which.
Do you think that if the amps aren't clipping you wouldn't hear differences between them?
Joe
sergeauckland
pfm Member
If not, then more's the pity! Once Quad developed products on engineering criteria, it brought out new products when they were an improvement on what went before. At each new product stage, they had operational benefits over what went before. Now, who knows. They seem to bring out new products for the sake of bringing out new products, not because they're any better than what went before. It's no longer acceptable to keep a product in manufacture for 28 years (Quad ESL 1957-1985) or even 18 years (Quad 303, 1967-1985). The HiFi world has changed, and not for the better, in my view.
S.
sergeauckland
pfm Member
Don't know about the Berning, but the other three, no, I would not expect to hear any difference. Why would there be when the specs all indicate transparency?
S.
sergeauckland
pfm Member
I have carried out this experiment exhaustively over the years, and my statement above was of my expectation, based on my experimental experience.
In most scientific experiments there is an expectation, the predictions that come out of a theory, that is being tested. In this case, it is the theory that amplifiers whose measurements indicate transparency will sound the same when listen to blind and level matched, and below clipping.
S.
Cereal Killer
432
That simply mean the 40.1 are to coloured/voiced to tell the amps apart - IMO
YNWOAN
100% Analogue
Well, that is the case (Quad have since gone on to re-release valve amplifiers) and yes, I realise that is your view.
To be honest I used to deal with Quad back in the day when the 'all amps sound the same' was Peter Walker's stated view. Frankly, they sounded so obviously different to some of their competitors that I struggled to give such a view credibility and people with no hi-fi expectations, or experience, had no difficulty differentiating between different amplifiers.
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sergeauckland
pfm Member
The SPL meter is not suitable for volume matching as even using tones, it's pretty difficult to get consistency better than 1dB. For accuracy in amplifier evaluation 0.1dB matching is needed. The reason is that even if 1dB difference isn't appreciable as a volume change, although it can be depending on the programme content and the listener's sensitivity, in any measurement, the measuring instruments and accuracy of set-up should be 10x the minimum one is trying to measure.
The way to ensure level matching is to put a tone into the load, from a CD player. Level match each power amplifier to 0.1dB using an audio millivoltmeter across the loudspeaker. The volume control that sets the listening volume then comes before the individual amplifier adjustment controls such that whatever the volume used for the listening tests is the same regardless of which amplifier is playing.
S.
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sergeauckland
pfm Member
And yet, and yet; the Martin Collums tests couldn't find any difference between a Quad 405 and a Naim amplifier. Everyone knows that a Quad is different to a Naim,until they have to distinguish them blind.
S.
Tony L
Administrator
In their natural habitat there is little crossover between a Naim and a Quad 405, e.g. chances are the type of Naim amp Collins is on about would normally be partnered with inefficient reactive low impedance speakers like Isobariks or Saras, the 405 sings it's best into ESLs or other high impedance speakers like LS3/5As. As such you'd have to move both amps out of their comfort zone / design parameters to make a comparison, and wouldn't that make the whole thing utterly pointless? It's almost the equivalent of concluding that the common ground between a Nikon F SLR and a Boss DS1 distortion pedal is that you could use either to drive a nail into a plank of wood, so lets assess them on that.
sergeauckland
pfm Member
The loudspeakers used by Collums were KEF R105s, the panelists having been given the choice of those or Spendor BC1s. There was a third amplifier being compared, the TVA Export valve amplifier. The results showed that the three amplifiers were indistinguishable.
S.
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