Power amps - how to buy

[noricd]

This month I wrote "Power amps - how to buy", reflecting on my learning journey leading me to Audiolab 8200MB monoblocks for my kit, listening room and music of choice.

I've extracted below the most useful paragraph near the end of the article:

"I learned valuable lessons in what to listen for. For example, sound quality on an amp includes listening for:

(i) resolution - the amount of detail captured
(ii) soundstage - - the height, width, and depth of the recording venue
(iii) soundspace - - the sense of space in the recording venue
(iv) soundfield - deep circle or oblong?
(v) imaging - the three dimensional holographic effect of instruments and performers being presented on the soundstage. Synonym - separation.
(vi) how does it handle dynamic contrasts and transients:
(a) handling of bass, accoustic and electronic
(b) handling of cymbals, triangles and drum brushes"

 

[Phelonious Ponk]

All of that is much more of a function of the recording before the amp and the speakers after it. What the amp can really do is get out of the recording's way and supply enough drive to overcome the speakers' resistance, which is often great and highly variable across the range. And unfortunately, unless you know a LOT more about your speakers impedance load than most audiophiles do (and most manufacturers disclose), the only safe solution is an amp that is pretty grossly over-built. Which is why they're so expensive. A good clue, if not a complete answer, is how well the amp delivers power to 8, 6, 4 and 2 ohm loads, across the FR range, if the manufacturer gives you that information.

Tim

 

[noricd]

Recording Sound Quality

It's good of you Tim to point out the critical role of a recording's sound quality. I did not touch on that in my article. That was because it was partly off-topic and partly ignorance on my part.

I'm learning. Over at The Art of Listening - Before and After thread yesterday I commended Bruce A. Brown on his remarkable case studies in recording art and science. The case studies are here and here. All Bruce's threads are here.

Role of Speakers

As to the role of speakers, in my case I was sold on the same day a Denon 3310 AVR along with 4 ohm speakers. Only months later my research informed me of the importance of the fact that the AVR was rated for only 8 ohm speakers. I had a 2 zone need for the AVR, so it had to stay. I also loved my 4 ohm speakers. So I concluded I needed a power amp. My research led me to realise what you say, ie that buying necessary "grossly over-built" amps is "expensive". So now I have monoblocks rated at 400w into 4 ohm and 250w into 8 ohm speakers. In buying them the local distributor noted that this choice suited also the fact that usually I have to listen to music at lower volumes (though I like it loudish). Even at low volume the monoblocks get in the way of a recording's sound quality features vastly more capably than the AVR.

Pure Music

In passing, trialing the Pure Music software add-on for iTunes in the last week has improved sound more in my circumstances. For example, my lossless ripped version of David Bowie's Ziggy Stardust album is less tinny or thin sounding, there is instead more detail and sustain. Similarly, lead guitar solos on Santana's Caravanserai have longer and fuller treble tone sustain.

I'm using a $10 USB linking my Mac mini to my DAC, so my next text will be to see what impact a USB cable might have. There are so many choices, eg Locus Design Axis USB cable, so research continues.

Thanks again Tim for your important clarification.

 

[Phelonious Ponk]

Recording Sound Quality

It's good of you Tim to point out the critical role of a recording's sound quality. I did not touch on that in my article. That was because it was partly off-topic and partly ignorance on my part.

I'm learning. Over at The Art of Listening - Before and After thread yesterday I commended Bruce A. Brown on his remarkable case studies in recording art and science. The case studies are here and here. All Bruce's threads are here.

Role of Speakers

As to the role of speakers, in my case I was sold on the same day a Denon 3310 AVR along with 4 ohm speakers. Only months later my research informed me of the importance of the fact that the AVR was rated for only 8 ohm speakers. I had a 2 zone need for the AVR, so it had to stay. I also loved my 4 ohm speakers. So I concluded I needed a power amp. My research led me to realise what you say, ie that buying necessary "grossly over-built" amps is "expensive". So now I have monoblocks rated at 400w into 4 ohm and 250w into 8 ohm speakers. In buying them the local distributor noted that this choice suited also the fact that usually I have to listen to music at lower volumes (though I like it loudish). Even at low volume the monoblocks get in the way of a recording's sound quality features vastly more capably than the AVR.

Pure Music

In passing, trialing the Pure Music software add-on for iTunes in the last week has improved sound more in my circumstances. For example, my lossless ripped version of David Bowie's Ziggy Stardust album is less tinny or thin sounding, there is instead more detail and sustain. Similarly, lead guitar solos on Santana's Caravanserai have longer and fuller treble tone sustain.

I'm using a $10 USB linking my Mac mini to my DAC, so my next text will be to see what impact a USB cable might have. There are so many choices, eg Locus Design Axis USB cable, so research continues.

Thanks again Tim for your important clarification.

There is no logical reason to believe that there would be an audible difference between properly-spec'd USB cables. Against all logic, I have an Audioquest USB cable. It is a lovely green, but sounds exactly like the black one that I now use to connect a printer to my wireless router.

Tim

 

[MylesBAstor]

This month I wrote "Power amps - how to buy", reflecting on my learning journey leading me to Audiolab 8200MB monoblocks for my kit, listening room and music of choice.

I've extracted below the most useful paragraph near the end of the article:

"I learned valuable lessons in what to listen for. For example, sound quality on an amp includes listening for:

(i) resolution - the amount of detail captured
(ii) soundstage - - the height, width, and depth of the recording venue
(iii) soundspace - - the sense of space in the recording venue
(iv) soundfield - deep circle or oblong?
(v) imaging - the three dimensional holographic effect of instruments and performers being presented on the soundstage. Synonym - separation.
(vi) how does it handle dynamic contrasts and transients:
(a) handling of bass, accoustic and electronic
(b) handling of cymbals, triangles and drum brushes"

Have to say that sounds like a AHC checklist. Bottom line is that reductionism eg. reducing everything to the LCD, doesn't work because there are unpredictable synergies that occur in real life.

For example, no where do you talk about the quality of vocals. If you don't get the tonality and harmonic structure correct, forget al the detail, bass, etc. Or in other words, if the DUT doesn't get the midrange right, forget the bass, the dynamics, and soundstaging!

 

[noricd]

So that I can learn or comment in response, Myles please indicate what the acronyms AHC, LCD and DUT stand for. Thanks.

 

[MylesBAstor]

So that I can learn or comment in response, Myles please indicate what the acronyms AHC, LCD and DUT stand for. Thanks.

OK

AHC = Tony Cordesman
LCD = least common denominator
DUT = device under test

 

[noricd]

Myles, I now accept those parts of your valuable comments which I understand. At the end of this post I note that there are parts I don't know how to listen for, eg tonality and harmonic structure. It's always delightful to have clear thinking to see gaps as you've done.

Drawing on what you've said about my short checklist (I drew the content from various writers), for me it follows that your first point could usefully comprise a rider at the start of end of the checklist. I'm seeking to consolidate my thinking and learning, where most audiophile forums, articles and other literature have random, albeit useful, observations.

Here's a draft of what I'd have in mind.

However, this checklist is merely indicative and not definitive of sound quality considerations. For example, reductionism, eg reducing everything to the least common denominator, may lead to false conclusions because there are unpredictable interactions in reality. To illustrate, those interactions might be between equipment, cables, speaker placement or the listening room or in any of those sub-components. They are interactions because they may not be working in synergy.

I'm not capable enough to capture what you had in mind in your second point, your phrase "tonality and harmonic structure", so I leave the door open for additional riders, clarifications and details.

Do let me know if you see yet more gaps or issues in the rider.

Definitions are useful to the extent to which the audiophile experience is science; recognising that a lot is art. All feedback welcome. Thanks again Myles!

 

[A.wayne]

Have to say that sounds like a AHC checklist. Bottom line is that reductionism eg. reducing everything to the LCD, doesn't work because there are unpredictable synergies that occur in real life.

For example, no where do you talk about the quality of vocals. If you don't get the tonality and harmonic structure correct, forget al the detail, bass, etc. Or in other words, if the DUT doesn't get the midrange right, forget the bass, the dynamics, and soundstaging!

If the bass is wrong nothing will sound correct including the midrange....

 

[MylesBAstor]

If the bass is wrong nothing will sound correct including the midrange....

Absolutely. In oh so many ways!

Yet still some bass limited speakers can have a darn good midrange.

 

[LL21]

Absolutely. In oh so many ways!

Yet still some bass limited speakers can have a darn good midrange.

SF Guarneris are one...but still, with a well set-up sub...the midrange does change quite dramatically...or perhaps i should say voices change quite a lot and something gets filled in relating to the mids (but it could be lower down)...never measured, but certainly feels that way.

 

[DonH50]

I suspect the effect is similar to speaking in the living room compared to the bathroom. My vocal output does not change, but the sound is certainly different. We miss the lower-frequency content of the music and voices sound anemic without context.

All IMO - Don

 

[LL21]

I suspect the effect is similar to speaking in the living room compared to the bathroom. My vocal output does not change, but the sound is certainly different. We miss the lower-frequency content of the music and voices sound anemic without context.

All IMO - Don

Having owned Celestion SL6si and then Guarneris...i did not [at all] appreciate the weight of proper midrange until the SF Strads...changed everything for me in terms of my understanding of that very important 'weight'. The sub helped a lot...but a full range speaker was far better...as the sub did not go anywhere near that high up the range.

 

[Bill Hart]

I guess part of it is priorities and listening bias. I could live much easier with a system that was a great midrange delivery package, and trade off real bass (alot of weight isn't the super deep stuff, i think it comes up a bit higher in the range), than have a full range system that sounded lackluster in the mids. Thus, my love of the old Quad. My current system does have bass problems, largely relating to the discontinuity between the self-powered woofer box and the horns (Avantgarde Duo). It does bug me more than a little- on some recordings it isn't a problem at all, but those seem to have closely miked acoustic bass and would probably sound pretty good on almost anything. I think good bass is really hard to do, given the whole interaction with the room, assuming the equipment and source material can otherwise deliver. Sometimes, it is the program material- I'll listen to some record and think, damn! No bass. And there probably isn't much on that recording, compared to the next one that sounds just fine.
As to 'how to buy an amp' I haven't the slightest idea how you can do that in a vacuum, without regard to the system as a whole. The descriptors, to me, relate to what the end product is, including the front end, the electronics and of course the loudspeaker. Just my blithering insight into the obvious, I guess.
Nice thread revival, BTW.

 

[GaryProtein]

There is no logical reason to believe that there would be an audible difference between properly-spec'd USB cables. Against all logic, I have an Audioquest USB cable. It is a lovely green, but sounds exactly like the black one that I now use to connect a printer to my wireless router.

Tim

I am SO GLAD to hear someone say that!

 

[GaryProtein]

If the bass is wrong nothing will sound correct including the midrange....

Absolutely. In oh so many ways!

Yet still some bass limited speakers can have a darn good midrange.

You can have a great midrange with NO bass. BAD bass can ruin the sound just like bad midrange or bad treble can ruin the sound.

If I turn off my woofer and/or tweeter amplifiers, I can still enjoy the great midrange.

The good parts are good parts. Other parts like limited good bass or limited good treble don't ruin the good parts. BAD parts can ruin the good parts.

 

[Gregadd]

Originally Posted by Phelonious Ponk
There is no logical reason to believe that there would be an audible difference between properly-spec'd USB cables. Against all logic, I have an Audioquest USB cable. It is a lovely green, but sounds exactly like the black one that I now use to connect a printer to my wireless router.

Tim
I am SO GLAD to hear someone say that!

Yes it sounds good every time he applys the same logic to so many topics. Which is is not say it is never true.
gregadd

 

[Gregadd]

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