Do Japanese amps do PRAT?

[DevillEars]

Quite easy really; it's spelt Q U A D.

Hmmm... Makes one wonder about brand names with four letters...
NAIM? LINN? QUAD? LEAK?
PR&T is also a 4-letter word (in more ways than one)...
Any significance?

If we accept that we can all blame Martin Colloms for coining this term and - at the same time - if we can also assume the man had a typically subtle Brit sense of humour, then it's not too much of a stretch to accept the following scenario:

Colloms sits at his desk one evening reading comments on his reviews of audio gear and - after one really irritating comment - yells out "PRAT!!"
Stunned at having been stirred to the use of an epithet, he sits muttering the offending word - "prat, Prat, PRAT, P.R.A.T......... "
"Hmmm.... That's it! PRAT could be turned into acronym, defined, wrapped up in pseudo-scientific jargon and sold back to the real prats". He smirks...
"Now - about the acronym... Pace? Rhythm? Amplifier? Timing? Not quite - my forte is high-performance loudspeakers, not amplifiers, so 'A' will have to settle for 'AND', so it has to be 'Pace, Rhythm And Timing"'- now to sell this concept to a nice gullible audience"...

In an alternative universe, Colloms (this time a motoring journo) sits at his desk one evening reading comments on his reviews of supercars and - after one really irritating comment - yells out "PRAT!!"
Stunned at having been stirred to the use of an epithet, he sits muttering the offending word - "prat, Prat, PRAT, P.R.A.T......... "
"Hmmm.... That's it! PRAT could be turned into acronym, defined, wrapped up in pseudo-scientific jargon and sold back to the real prats". He smirks...
"Now - about the acronym... Performance? Ride? Accessories? Trim? Not quite - accessories are for idiots, so 'A' will have to settle for 'AND', so it has to be 'Performance, Ride And Trim"'- now to sell this concept to a nice gullible audience"... (and maybe I should change my name to Clarkson? )

Just imagine....

In this way, a common-use epithet was turned into

 

[toprepairman]

If the engineers at Naim, Exposure, Densen or anywhere else were to read this thread they'd be laughing their heads off.
The Sales teams, on the other hand would be rubbing their hands with glee, congratulating themselves on the marvellous marketing hype they have burdened the buying public with.

 

[Snufkin]

Hmmm... Makes one wonder about brand names with four letters...
NAIM? LINN? QUAD? LEAK?
PR&T is also a 4-letter word (in more ways than one)...
Any significance?

If we accept that we can all blame Martin Colloms for coining this term and - at the same time - if we can also assume the man had a typically subtle Brit sense of humour, then it's not too much of a stretch to accept the following scenario:

Colloms sits at his desk one evening reading comments on his reviews of audio gear and - after one really irritating comment - yells out "PRAT!!"
Stunned at having been stirred to the use of an epithet, he sits muttering the offending word - "prat, Prat, PRAT, P.R.A.T......... "
"Hmmm.... That's it! PRAT could be turned into acronym, defined, wrapped up in pseudo-scientific jargon and sold back to the real prats". He smirks...
"Now - about the acronym... Pace? Rhythm? Amplifier? Timing? Not quite - my forte is high-performance loudspeakers, not amplifiers, so 'A' will have to settle for 'AND', so it has to be 'Pace, Rhythm And Timing"'- now to sell this concept to a nice gullible audience"...

In an alternative universe, Colloms (this time a motoring journo) sits at his desk one evening reading comments on his reviews of supercars and - after one really irritating comment - yells out "PRAT!!"
Stunned at having been stirred to the use of an epithet, he sits muttering the offending word - "prat, Prat, PRAT, P.R.A.T......... "
"Hmmm.... That's it! PRAT could be turned into acronym, defined, wrapped up in pseudo-scientific jargon and sold back to the real prats". He smirks...
"Now - about the acronym... Performance? Ride? Accessories? Trim? Not quite - accessories are for idiots, so 'A' will have to settle for 'AND', so it has to be 'Performance, Ride And Trim"'- now to sell this concept to a nice gullible audience"... (and maybe I should change my name to Clarkson? )

Just imagine....

In this way, a common-use epithet was turned into

I can imagine this imagining of the origins of PRaT becoming accepted in the future as the real reason behind its adoption by the world of audio. Nice...

 

[LouisB]

And of course the vast majority are.
A number of factors can change the way an amplifier might sound - clipping, slew rate, harmonic distortion, damping factor and phase shifts to name but a few.
However you have to look really hard to find any mainstream amplifier - from any country of origin - which has a problem in any of these areas on music signal.

So what of you show an amplifier slew limits at 20kHz at 100w into the load. Nobody encounters such issues because no music signals demand anything like this power at such frequencies, and no driver could handle it!

The same goes for harmonic distortion. Showing that amplifiers have different levels of distortion and spectra is all very well. Its audibility is another matter entirely.

The question here is around solid state Japanese amplifiers and the comparison with amplifiers which supposedly excel at PRaT, but there are no meaningful differences between them other than power output.

Exactly.
We're basically saying amps with _serious_ design problems or completely unsuitable for their task (load, etc) may suffer problems that could lead to perceived timing issues.
But any decent modern amp should have all these factors well under control.
If you're slew rate limiting for example, you're going to have far bigger issues with general nasty distortion than some prat problems.

Of course, good amp design should allow for proper response to dynamics.

Which goes back to the point I made ages ago, of the factors prat (stupid name) can be about, the tangible thing is good power supply design and ensuring the amp handles dynamics without for example dipping power rails.

Most decent amps have this sorted, with over-spec'd transformers and power supplies. It doesn't need this marketing speak name, it's just smoke and mirrors over basic design principles that should be taken into account in an amp made in Japan, UK, USA or wherever. Now amps from the UK maybe have appealing attributes generally, but it's not like prat is a unique feature designed into amps specifically.

Really if you strip and amplifier right down there's very little to it and most amp designs can be traced back to the days that transistors first appeared on the market.

There is little magic in the box, even if it has a fancy name and price tag on it.

Also, some of the issues that people say cause prat issues will be worse in low powered class A valve amps, yet these typically sound wonderful. No timing issues.

Also when I stick my little radio on, in it's compromised way (frequency response mainly) it also sounds fine. No obvious prat timing issues either.

For me the more important aspect is dynamics and dynamic response. Which is why like for like it sometimes pays to overspec the amp and so on. A good amp is a transparent amplifier of voltage and current, it's not a timing changer. So as always, neutrality & transparency are the key and given those everything else should follow, regardless of what marketing names it has been given to sound more impressive than the competitors.

All the biggest issues I've had with things perceived as timing issues have come from slow bass, that nearly always in my experience comes from the speakers or the speakers + room combination. Sort that out and things will seem faster (really just more accurate). Perhaps amps with a lean bass also will sound 'faster' too, due to less danger of muddle in the bottom end. Getting good tight low extended bass is difficult and is where things can get expensive. Speakers are all a box of compromises and play the biggest part in the final sound you hear in terms of final frequency response and impression of timing (prat) that may be experienced.

 

[Tony L]

Quite easy really; it's spelt Q U A D.

Can't disagree more unless you are trying to use said amp to drive some hopelessly inefficient box with a reactive low impedance crossover. I was thinking only last night about all the music that now makes sense to me via my apparently PRAT-less Quads, Tannoys, JR149s etc etc that I couldn't listen to at all on a fast and lean 'flat-earth' system, e.g. late period Coltrane, Ornette Coleman etc etc.

The album I played that prompted this thought was Coltrane's Meditations. An album I bought back when I had Isobariks and tried again to like later when I had Kans. I couldn't get through the first track, I remember discribing it as real 'fire in a pet shop' stuff. Hearing it again on my humble Cambridge CD player, JC Verdier tube pre, slightly tweaked 303 and JR149s last night was wonderful, I loved it. Ok, you can easily argue that I've changed maybe as much as my system and I'm now open to music that I once struggled with, but I'm certain much is down to the natural, open and spacious way this system presents such recordings. It is just so easy to follow the different strands now they are presented in an unforced and entirely glare-free way.

 

[Sibbers]

I think it depends on your speakers. High end (probably wrong term, what I mean are difficult) speakers will expose the flaws of amp. I wouldn't say all Cambride Audio amplification is that cheap. Perhaps it is when you consider how many buttons and features you have to pay for, but still you're looking at a grand and my 840a had a very obvious lack of control over my speakers, whereas the Rega suddenly gripped a hold of them and gave them energy. In my opinion most amps would not be able to control my speakers as most amp are sold at Richer Sounds and most of them are probably under £300. I ended up spending more again on amplification, then over another grand upgrading it for again more control over the bass and purer signal, and it turned out to be money well spent...

I'm sure there are loads of speakers that would be fine with most amps, just not the ones I have and I'm sure a good bunch of others too.

 

[LouisB]

I think it depends on your speakers. High end (probably wrong term, what I mean are difficult) speakers will expose the flaws of amp. I wouldn't say all Cambride Audio amplification is that cheap. Perhaps it is when you consider how many buttons and features you have to pay for, but still you're looking at a grand and my 840a had a very obvious lack of control over my speakers, whereas the Rega suddenly gripped a hold of them and gave them energy. In my opinion most amps would not be able to control my speakers as most amp are sold at Richer Sounds and most of them are probably under £300. I ended up spending more again on amplification, then over another grand upgrading it for again more control over the bass and purer signal, and it turned out to be money well spent...

I'm sure there are loads of speakers that would be fine with most amps, just not the ones I have and I'm sure a good bunch of others too.

Try an 851W, suspect it's very well as good as 'fancy hi-fi'. The cambridge guys now how to design an amp even if a large part of their range is aimed with a budget in mind.

What speakers do you have?

The rega (presume you mean Elicit-R) is meant to be exceptional. Do they marketing-speak PRaT? I tend to glaze over when I hear this term as it's too artsy for me.

 

[Sibbers]

Rega barely say anything ever at all, and they only rate it at 105w's too. Very modest, so no PRAT terms. If I'm honest I still don't recognise the term myself, but the idea that amps only sound bad if they're poorly designed doesn't sit well with me as it was that advice, followed with many engineering logic based arguments that made me stick with the CA so long. Just from the recent upgrade to my LSA amp, I spent about £450 on parts alone to increase capacitance, better resistors etc etc so as basic as an amp is, it still requires expensive parts and well thought out design iterations (expensive minds, expensive trial and error) to make an advancement. If you're only copying another design, well then you still have the parts, the case to pay for.

Speakers are Dynaudio contour s1.4's. Little stand mounts. Don't appear like the kind of thing you'd need an amazing amp for by looking at them, but that said, even my crappy little Eltax speakers reveal the difference between the amp changes (although perhaps not the modification to the latest amp, and it's been too long for me to be able to tell now)

I'm no expert but I know what I've experienced, it's really obvious and I wish I knew before spending so much time enduring the situation. Worst case is I could have easily sold the speakers and never truly discovered them. I would have been ignorant and perhaps not realised but it's heart breaking to think that could have happened and probably I'd be going around saying that my experience of Dynaudio speakers were they were overpriced crap with dark flabby bass and lazy timing.

 

[LouisB]

Rega barely say anything ever at all, and they only rate it at 105w's too. Very modest, so no PRAT terms. If I'm honest I still don't recognise the term myself, but the idea that amps only sound bad if they're poorly designed doesn't sit well with me as it was that advice, followed with many engineering logic based arguments that made me stick with the CA so long. Just from the recent upgrade to my LSA amp, I spent about £450 on parts alone to increase capacitance, better resistors etc etc so as basic as an amp is, it still requires expensive parts and well thought out design iterations (expensive minds, expensive trial and error) to make an advancement. If you're only copying another design, well then you still have the parts, the case to pay for.

Speakers are Dynaudio contour s1.4's. Little stand mounts. Don't appear like the kind of thing you'd need an amazing amp for by looking at them, but that said, even my crappy little Eltax speakers reveal the difference between the amp changes (although perhaps not the modification to the latest amp, and it's been too long for me to be able to tell now)

Rega have it right then.

People love to put labels on things, categorise and put things in boxes.

Yet Rega let the sound and performance speak for itself. If it sounds great (and many people report it does) you don't need buzzword-bingo to justify it. Clearly it has a good, holistic design that is coherent and minimises the problems that all amplifiers strive to reduce.

I don't know about the contours but clearly some speakers are more demanding than others. I don't know about my own, they have been quite happy on the end of a very modest amp. But classic case of don't know exactly what you're missing until something better is put on it. That might be the Rega, and I don't care whether it comes with a PRaT label or not, in fact I prefer not, as we don't need these made up labels to help us predetermine if it's a good product. We just need to try it and hear it and find out for ourselves.

 

[DevillEars]

Maybe there's a case for reviewing the process sequence options when building an audio system...

I've long believed that the listening environment has the largest impact on the eventual "sonic signature" of any audio system, so some effort, funds and time need to be spent on eliminating the most serious environmental obstacles to good sound. For me, these have largely involved the prevention of secondary reflection surfaces by way of adding carpets/rugs for the floors and the use of heavy curtains or tapestries for the walls. Secondary reflections tend to "add" phase-shifted elements to the overall "sound" as perceived at the listening position - something that tends to smear transients in particular.

Next in line has to be loudspeakers which need to interface with the listening environment and complement the environment to produce "sonic harmony". (There's no sense in picking speakers with characteristics that magnify any room problems). Obviously, any speakers selected also need to complement the personal musical preferences of the listener.

Then, the amplification needs to be selected to complement the downstream combination of speakers and room. The complementary aspects will be electrical (for compatibility with the speakers' load characteristics) and "voicing" for more subjective aspects such as preferred musical genres and room characteristics.

Finally, the source component(s) need to be selected to complement the rest.

NOTE: This sequence does not imply any budget allocation priority!

For around 12-15 years (way back when) I was quite satisfied with an analogue-only system comprising a Thorens TD160C/TP16, a B&O Beolab 5000 integrated amp and a pair of Kef Cadenzas. This system was largely there for two categories of usage: one, background music at parties/dinners/etc; and two, foreground music when reasonably serious listening was possible (with kids growing up, that was rare).

About 20 years ago, the opportunity and funding coincided to permit a "system refresh" and I wound up with a Rotel RCD965BX Discrete, an Audiolab 8000A plus a pair of Tannoy 613s. An opportunity arose which was grabbed with both hands - obtained a pair of Tannoy D700s. Various burglaries resulted in a sawtooth upgrade path: first, 8000P added, then (when both Audiolabs were stolen) amps were replaced by Classe' pre/pwr (CP50 & CA100) which were also stolen resulting the current amplifier setup (Classe' CP500 plus Jeff Rowland Model 201 monoblocks).

The D700s only really blossomed with this latest pre/pwr combo - the Audiolabs quite frankly battled to drive them and the CP50/CA100 lacked control. With the CP500/201 combo, the D700s are adequately controlled (but not overly so) and the 201s are able to drive the D700s to ridiculous levels while remaining well within their "comfort zones". To summarise, there is a hefty unused dynamic headroom available - both in terms of current delivery and power - so that the amplification, at normal listening levels, is unstrained.

Sources are LP12/Hercules/Ittok/Kontrapunkt 'h' plus a Theta Data Basic II feeding a Bryston BDA-1 DAC. The LP12 feeds into an in-built and bespoke Classe' phono stage which is surprisingly competent for a bolt-on.

Finally, a note on noise floors. When this latest system was built, we were living in a house with poor wiring isolation and electrical noise over the 240v AC supply was significant and detrimental to the overall sound - introducing a level of hash that was only unmasked when offered a mains filter for home trial. Subsequently, on a step-by-step basis with careful A:B:A testing, the mains feed has been refined by buying a passive mains filter and adding decent mains cables for each component. Next in line was a systematic replacement of my old Cable Talk signal cables with a one-brand set of silver mono-crystal cables. The end result of wiring changes? Background electrical hash level driven down significantly, and - in the process - unveiling low level detail that had not previously been audible. The main area of sonic improvement lay in spatial information - typically imaging and soundstaging which rely heavily on low-level phase information.

The point of the above has been to illustrate the various interdependences that exist in any "system" and cannot be realistically isolated as being down to any single component. What really works lies in the area of synergy or how everything works together in a mutually-complementary fashion to deliver a total impression to the listener.

Nowadays, I don't bother about the system - I just try to find more music to enjoy...

 

[Sibbers]

I fully agree with all the above, but one thing I noticed going up the amplifier chain was that each step made my speakers much less fussy about placement. I don't know why, and I have a small room. Everything I read suggested paying attention to the room and although it made differences, it didn't fix the resonance that was fixed by a decent amp.

I can see why the acronym YMMV is so often used

 

[Markus S]

Presumably, the better amps better controlled the bass resonance of your speakers, bringing the resonance into a more sharply defined, narrower window so that fewer of the room modes coincided with speaker resonance modes, giving you more latitude in placing your speakers.

An amplifier designer once told me that one of the more arcane differences between amplifiers was the ability to absorb the current from the speaker's back-EMF without influencing the amp's zero voltage point.

 

[LouisB]

@DevillEars - very good post and I agree.

There are _so_ many factors. And really important factors that rarely get mentioned because they are harder to tackle than popping to the shop or online and ordering a new shiny impressive box.

As always, the final outcome is a synergy of all the factors in the system, the room and the listener preferences (and biological factors/age).

PRaT to me is a terrible name. However getting a dynamic system, well I can relate to that. There are many factors that affect this, speakers and room being a really big factor. For me my priorities are source and speakers, I think any modern competent hi-fi amps are already very close. Icing on the cake is to really push the amp up in quality. When I think about the very modest sources and speakers some people do use, I really wonder whether spending 1k+ on a new amp is the right priority, at least until these other parts are sorted. Get your source and speakers right, if they are not, all else is a bit of a moot point.

 

[LouisB]

Presumably, the better amps better controlled the bass resonance of your speakers, bringing the resonance into a more sharply defined, narrower window so that fewer of the room modes coincided with speaker resonance modes, giving you more latitude in placing your speakers.

An amplifier designer once told me that one of the more arcane differences between amplifiers was the ability to absorb the current from the speaker's back-EMF without influencing the amp's zero voltage point.

That's damping factor isn't it? Many modern amps have very high damping.

I recently upgraded my woofers to higher damping upgrade versions of the same basic design.

It's made the base tighter, more accurate. Attack and decay are better controlled. I suspect this change along is far greater than any amp swap I could make. I could easily see how the bass accuracy could be thought of as timing or prat. In reality the timing has not changed, but the dynamics, the attack and decay control is improved. It's hard to talk about PRaT as it's a very wishy-washy term, but you can see I had no problem describing improvements in terms of damping, accuracy, transient responses, attack and decay. These are all concrete, objective things that can be discussed with some degree of understanding about what they are and what they mean.

 

[Markus S]

No it's not damping factor, which is a function of the output imedance of the amp. It's more to do with clean earthing arrangements.

 

[Sibbers]

Presumably, the better amps better controlled the bass resonance of your speakers, bringing the resonance into a more sharply defined, narrower window so that fewer of the room modes coincided with speaker resonance modes, giving you more latitude in placing your speakers.

An amplifier designer once told me that one of the more arcane differences between amplifiers was the ability to absorb the current from the speaker's back-EMF without influencing the amp's zero voltage point.

Sounds like a reasonable explanation to me. I don't understand it, but I know the significance and the logical bit of my brain still has trouble accepting it, as it seems to defy physics. Again, more ignorance in my part I'm sure but I don't think I'm in the minority. I think most people would share my sense of surprise.

I imagine the huge magnets and infinite baffle setups associated with a good number of expensive speakers make for difficulties that require big loads to control. I have no idea what challenges crossovers present to amps, that's probably another 5 page thread if this is anything to go by.

My view is if prat is a term that people understand the meaning of, then marketing fluff or not, it communicates something and that what words are meant for. Tomato tomato. Hehe, that doesn't work so good in text.

 

[LouisB]

No it's not damping factor, which is a function of the output imedance of the amp. It's more to do with clean earthing arrangements.

I believe that'll be measured as a combination of output impedance / current capacity and damping factor.

Happy to be corrected. But clean earthing arrangements is just another wishy-washy.

Star-earthing etc an all be measured in SNR, impedance etc.

 

[davidsrsb]

Can't disagree more unless you are trying to use said amp to drive some hopelessly inefficient box with a reactive low impedance crossover. I was thinking only last night about all the music that now makes sense to me via my apparently PRAT-less Quads, Tannoys, JR149s etc etc that I couldn't listen to at all on a fast and lean 'flat-earth' system, e.g. late period Coltrane, Ornette Coleman etc etc.

This is all pointing at high PRAT amplifiers adding something, rather than accuracy.
Many people like this spice, but is not suitable for all music or ears.

The damping factor argument makes little sense once you exceed a factor of ten, as further improvements have negligible effects on cone resonance

 

[LouisB]

This is all pointing at high PRAT amplifiers adding something, rather than accuracy.
Many people like this spice, but is not suitable for all music or ears.

The damping factor argument makes little sense once you exceed a factor of ten, as further improvements have negligible effects on cone resonance

that's my view also. Damping factor in your speakers + room resonances will likely far exceed any issues in a decent solid state amp with sufficient output current to drive the expected speakers.

Sure, a bad amp and speaker combo may not work well but well, that's always been the case hasn't it.

 

[abbydog]

This is all pointing at high PRAT amplifiers adding something

Like great gobs of capacitance on a basically under-specced amp, you mean?