Revisiting "Psychoacoustics and amps" thread from '02/'03-Ken Kantor, are you there?

[soundminded]

Ever consider that at least in audio amplifier design, there really isn't much new under the sun? Old designs are routinely dragged out, tweaked, twisted, given a couple of minor refinements and voila, the latest breakthrough is born. As I said in another posting, while I don't completely agree with Ken's opinion that all properly functioning solid state amplifiers sound exactly the same, many are pretty close when operated within their rated power capabilities. I think it's odd that anyone contemplating a high fidelity sound system would give more than passing thought to how an amplifier recovers from overload other than as an indicator of its general conservativeness and soundness of design. One would hope that an amplifier for a serious sound system would be selected to provide sufficient power in its linear region to rarely if ever be overloaded. Most critics of negative feedback contend that this technique makes amplifiers sound poor at any power level, yet it is the reversion to more primitive designs which for me test badly and sound poor. The well designed class AB solid state amplifier has the clarity, neutralness of timbre, dynamic and frequency range, and reliability so that it hardly matters much anymore to me which one I use. I don't see any advantage in practical performance to these multi thousand dollar amplifiers. If there is one area where there might be room for study and improvement, it's the amplifier/speaker interacton. Manufacturers of both use the Chinese Wall philosophy, they've done their job, throw it over the wall and any problems are the other guy's headache. Usually, it's the end user's headache and he is least equipped to solve it. I once heard someone express the idea that once an amplifier reaches a certain level of accuracy, further improvement is of no value and that makes sense to me. Are we there yet? Maybe it's why with far greater capability to analyze the performance limitations and inaccuracies of them than we've ever had before, nobody bothers to use it...because it's now pointless.

[Pete B]

Crest Factor and Peak power requirements: 1-2 watts average, 200-275 watts peak noted for one commercial CD. The average looks low IMO:

http://www.diyaudio.com/forums/showthread....0&pagenumber=50

[kkantor]

>Crest Factor and Peak power requirements: 1-2 watts average,

>200-275 watts peak noted for one commercial CD. The average

>looks low IMO:

>

Damn, the thread that won't die!

It's hard for me to make reasonable comments without knowing in greater detail how "average" and "peak" are defined in the cited case. (Off hand, it looks more like softest-to-loudest passages, not crest factor.) Still, I'm sure you can find a recording with just about any crest factor you want. If not, I can compose something for you......

http://kkantor.spaces.live.com/

[Pete B]

Did you read the thread? I only wrote Crest Factor

because that was the title of the post at the other site.

The post is from Bob Cordell, a highly competent

gentleman.

I know this material Ken just pointing it out for others.

Your comments are welcome, are you familiar with the

Rickie Lee Jones CD mentioned?

Have to wonder if the average was over the entire CD

including the silent gaps between tracks.

>>Crest Factor and Peak power requirements: 1-2 watts

>average,

>>200-275 watts peak noted for one commercial CD. The

>average

>>looks low IMO:

>>

>

>Damn, the thread that won't die!

>

>It's hard for me to make reasonable comments without knowing

>in greater detail how "average" and "peak"

>are defined in the cited case. (Off hand, it looks more like

>softest-to-loudest passages, not crest factor.) Still, I'm

>sure you can find a recording with just about any crest factor

>you want. If not, I can compose something for you......

>

>http://kkantor.spaces.live.com/

[rrcrain]

A couple of comments.

I own a pair of Heathkit 80's era SS amps and due to age, moving, several power surges and the grace of God, they finally required repair. The amps were sent out for repair and upon return, the shop owner auditioned them for a day to test them out. This guy is a hard core tube lover and as a general rule, has no love for SS amps or preamps. He fell in love with my old Heathkit amps; Absolutely fell in love with them claiming they were the bes SS amps he had ever heard.

The point being, some of those old Heathkit SS amps were extremely well designed and can hold their own against some of the best SS amps being built today.

next observation.

This wasn't a tightly controlled test, but many times, I have heard very major differences between amps driving the same set of speakers. Most of the time, the differences were due to the amps differing in size or a gross missmatch between amp and speaker. Some amps have problems with sibilance even at low volumns but work perfectly with another set of speakers. Other amps simply don't have the muscle to reproduce decent bass.

Can I state clearly that I hear major differences between two SS amps of the same size and design? No, I can't. but...

Oddly and without explanation, I've discovered my two, supposedly identical SS amps sound ever so slightly different. One is ever so sightly "brighter" than the other. The only explanation I can think of is their difference in age. The oldest was one of the first 500 if the series while the second amp is from the end of the products production run.

[soundminded]

Ken, I'm coming around to your way of thinking. After a great deal of experimentation during the past year with various speaker rebuild projects and a bunch amplifiers, I'm coming to the conclusion you stated all along, that all solid state amplifiers functioning properly and operating within their linear limits sound alike. What threw me is that for many of them with integral preamps, their nominally indicated flat tone control settings do not always result in their flattest response. Someone on another board documented this for a bunch of them but when the preamps are truely set flat or the tone controls bypassed, they all perform pretty much the same. Therefore, in a conventional 2 channel sound system, it would seem that the loudspeakers (and phonograph cartridge if there is one) is the only variable other than equalizer settings and speaker placement which affects subjective performance. So then the only criteria for selecting an amplifier are having sufficient power for a particular requirement, cost, size, weight, heat evolved, and reliability.

[kkantor]

Hi... my first reply to this post, which was more comprehensive, seems to have evaporated somewhere between my hotel in Korea and the BBS server. Oh well...

No, I couldn't make it through more than about 30% of the cited thread. Torture.

But, I do have that RLJ CD around somewhere, and will run the numbers on it when I return. I'll be careful about inter-song gaps, etc.

-k

http://kkantor.spaces.live.com/

[kkantor]

Thanks, I appreciate the input!

You bring up one of the reasons why I personally like fairly minimalist gear for my critical listening. It's not (to my mind) that extra circuitry causes degradation, per se. It's that any additional complexity reveals more possibilities for the local mishandling of the signal, for example, as you have discovered.

-k

http://kkantor.spaces.live.com/

[Carlspeak]

>Ken, I'm coming around to your way of thinking. After a

>great deal of experimentation during the past year with

>various speaker rebuild projects and a bunch amplifiers, I'm

>coming to the conclusion you stated all along, that all solid

>state amplifiers functioning properly and operating within

>their linear limits sound alike. What threw me is that for

>many of them with integral preamps, their nominally indicated

>flat tone control settings do not always result in their

>flattest response. Someone on another board documented this

>for a bunch of them but when the preamps are truely set flat

>or the tone controls bypassed, they all perform pretty much

>the same. Therefore, in a conventional 2 channel sound system,

>it would seem that the loudspeakers (and phonograph cartridge

>if there is one) is the only variable other than equalizer

>settings and speaker placement which affects subjective

>performance. So then the only criteria for selecting an

>amplifier are having sufficient power for a particular

>requirement, cost, size, weight, heat evolved, and

>reliability.

It's my turn to weigh in with post #133.

For the most part, I agree with your last sentence above. However, some would argue there are listeneable differences between amps. Of course, one could dredge up a $59.95 amp with lots of AC hum in the backgrould to proove a point. But we're talking about the bulk of amps which are pretty decent and simply transmit and sometimes filter electrons.

My experience has shown the most important components in the recorded audio chain from performer to listener are the transducers. More specifically, they are the recording microphone, phonograph needle (as you pointed out) and of course, lastly, the loudspeaker. These are what I call the garbage in-garbage out components. They perform the key role of converting analog-to-electrical signals and vice-versa functions.

I don't think anyone in this discussion group would argue against the loudspeaker's role at the end of the audio chain. At the front end, recording microphones are also important as demonstrated in Sterephile's first test CD (track #5). Founder J. Gordon Holt reads text that's been recorded with 18 different studio grade microphones. You CAN hear differences between them

Lastly, there's the speaker wire. Roger Russell, a very well regarded audio engineer makes his case agains high priced wire at the following link:

http://www.roger-russell.com/wire/wire.htm

Oh yeah, there's more. The recent issue of Stereophile magazine contains a review of $14,900 interconnects. I almost fell out of my chair when I saw that one. And the list goes on............

Remember, it's all about the music

Carl

Carl's Custom Loudspeakers

[dynaco_dan]

Hi Carl;

Does that price of $14,900.00 includes all taxes?

Is shipping and handling included or extra?

That price of course, includes the house as well?

Sounds like a good price from here. lol lol

If I move the decimal point a few places to the left, I think I can even afford them.

[soundminded]

>Thanks, I appreciate the input!

>

>You bring up one of the reasons why I personally like fairly

>minimalist gear for my critical listening. It's not (to my

>mind) that extra circuitry causes degradation, per se. It's

>that any additional complexity reveals more possibilities for

>the local mishandling of the signal, for example, as you have

>discovered.

>

>-k

>

>http://kkantor.spaces.live.com/

>

I take the opposite view. Tools such as equalizers are extremely powerful devices which when properly used can enhance the performance of a sound reproduction system. In my best system, I use two, a 10 band which equalizes the system for the "average" recording and a 5 band which further equalizes it for recordings which deviate from average. I feel this affords me the most accurate reproduction with the greatest number of recordings. Interestingly, the 10 band equalizer can take years to tweak, once that's done the 5 band just a few seconds or a minute or two.

[rrcrain]

A number of years ago, I read an article concernng different interconnects and if they could or could not make a difference. The author focused strictly on measurable attributes, DC resistance, inductive and capacitive reactance.

After digesting all of the mathamatics and examples he offered, the answer was as clear as mud. Tube equipment runs the highest possibility of benefiting from some of the more esoteric interconnects, and even then, it really depended on a gross mismatch between amp and preamp input and out impedance.

In those few instances where they made a clear improvement, he was using either highly capactive or highly inductive interconnect wire to match amps and preamps togehter that otherwise did not like each other. his point was that there "can" be uses for exotic wire configurations, but generally it doesn't make any difference at all.

Personally, it would be cheaper and easier to buy equipment that actually matched and worked properly together than buy sutpidly priced wire.

[Carlspeak]

Postscsrip to my post #133:

I have been a member of the CT. Audio Society for many years now. Over that time I've had occasion to witness interconnect 'shoot-outs', speaker wire 'shoot-outs' etc.... and some very high-end systems costing well over $100,000.

The conclusion I've reached is the more high end the system, the higher likelyhood will be that it will be able to descriminate minor differences (or changes if you will) in individual components. Whereas low, or mid-fi systems generally will not.

Take it for what's it's worth. I have no measurements or technical databases to support my conclusion - just what I've personally expereienced.

Remember, it's all about the music

Carl

Carl's Custom Loudspeakers

[soundminded]

"For the most part, I agree with your last sentence above. However, some would argue there are listeneable differences between amps. Of course, one could dredge up a $59.95 amp with lots of AC hum in the backgrould to proove a point."

Ever hear of the "T-amp?" I think it is offered by a company called Sonic Impact. It sells for about $30 at Wallmart and puts out about 10 to 15 wpc. In an article in an audiophile magazine some months back, some of the "cognesenti" who consider themselves amplifier mavens were comparing it to SET amplifiers costing tens of thousands of dollars and considered it their equal or superior. Even the manufacturer was astonished at the reviews and demands for it because it was never intended to be a high fidelity amplifier in the first place. They had it in mind for home video games. Whatever ultra subtle differences some people claim to be able to hear, I am not aware of any proof that they have been borne out by DBTs. In fact, I defy anyone to walk into a room in which a sound system is playing and state what amplifier is being used without knowing or seeing it. However, I was surprised myself last May when visiting the VTV (vacuum tube valley) show in Piscataway NJ that I was able to correctly guess that the one solid state amplifier at the show was in fact solid state strictly on its sound and I must say it seemed to me to be considerably superior to all of the tube amplifiers I heard, at least for the sound systems using them. Of course there was no way to make a direct AB comparison but it reminded me of why I bought my first solid state amplifier which happened to be the AR amplifier and never looked back. I really really don't like the sound of tube amplifiers given a choice but if I had to, I'd live with one. While I was there I asked the people demonstrating McIntosh equipment which they preferred since their employer sold both and they unanimously agreed that they preferred solid state amplifiers. That also surprised me.

[rrcrain]

I've only listened to one tube amp that I've liked as well as, perhaps better than my solid state amps and that was the Rogue Zeus.

On the other hand, I seriously like the sound of a tube preamp driving my solid state amps and hope to procure one in the near future.

[kkantor]

Could be:

They have super-accurate response, which allows the listener to hear sonic details that more pedestrian systems mask.

Or,

Designers of mass-market audio equipment are typically constrained by normative notions of loudspeaker impedance, while makers of ultra-expensive gear are more likely to venture into stressful extremes in the pursuit of other goals.

Or,

When we hear something odd come out of a $1,000 loudspeaker, we generally recognize that it originates from the speaker. When we hear the same odd effect from a $50,000 loudspeaker, we are subtly inclined to assume we are "hearing" the cables or amp.

Or,

Seated in front of a super-system, we unconciously listen more carefully. Our hearing acuity and focus of attention actually goes up slightly.

Or,

Some combination of the above.

[soundminded]

Or it just might be that the fact we know it is a $100,000 super system with $50,000 speakers has us mentally conditioned to expect something which isn't there. I've become immune to all this hype having seens many many scams in all types of expensive equipment including industrial equipment over a lifetime. I heard a system at the VTV show in Piscataway NJ last May which cost around $500,000 and I wasn't impressed in the least. Judging from what the owner of the company who was demonstrating it played (loud hard rock before he as I in, vinyl reissues of 1940s Bing Crosby recordings as I left) and his general demeanor, I'd say he wasn't particularly impressed either, in fact he seemed rather bored. As for my test disc (one of many I brought with me) reproduction of it was pathetic. It was a recording of Marian McPartland the well known jazz pianist performing at Maybeck Hall and it sounded as though she'd suffered the effects of polio in her left arm. Amazingly, as far as I could tell, not one other visitor to this show brought even a single disc with them to hear. So much for audiophiles.

[kkantor]

You are right, I should have added that to my list of alternatives. I was alluding to it in #3, but you stated it more definitively. Thanks.

[soundminded]

Having had more than a passing experience with live unamplified music, I have definite ideas about how sound reproducing systems which claim high fidelity should sound. And having had more than a passing experience with engineering and manufacturing, I have definite ideas about what things should cost. Also being aware that there is usually more than one engineering route to the same or equivalent results, I am impressed by the most efficient method of designing and fabricating things, not the least efficient. Why should I pay lots of money for someone elses lack of skill or shortcomings? If they can't build an acceptable product at an acceptable price, they won't get my patronage no matter who says what about the designer or his product. Putting 50 3 1/2" Tymphany drivers in two size 1000000 AAAAAAAAA wooden shoeboxes with an equalizer the way Roger Russell has and selling them for $19,000 doesn't impress me. Line source array speakers have been around a very long time. Build a similar product using Tang Band drivers with a $100 equalizer and sell it all for about $500 to $1000 or less and I might be very impressed.

I'd design my own from scratch but I'm having so much fun taking other people's fine ideas and efforts, figuring out where their shortcomings are, and "improving" them that I don't really see any need to reinvent the wheel. For a while when people stopped wanting them or even knowing what they were, they'd sell them for a song. Now a lot of it is being thrown out like so much trash. 3 Empire 9000Ms, 2 KLH Model 6s, 2 AR2as, 2 AR2axs, 2 EV Wolverine enclosures with 1 12" EV two way speaker, and a couple of JBL 15" subwoofer enclosures all for free last summer. It was my basement workshop or curbside for the trash collector. And what a lot of fun I've had with all of it. Much more than I'd have gotten out of the longest skinniest shoe boxes in the world. Besides, if I wanted a pair of Bose 901s put though a linguini machine, I could have just as easily built them myself. Given the availability of a vast array of very high quality low cost parts and electronic components and knowledge which is so readily available, IMO most popular high end speaker systems could be successfully reverse engineered or close to it by many hobbyists at a very small fraction of the retail cost. And if I hear one I like, I might just give it a go. Building an equivalent AR9 using modern readily available parts as PeteB suggested strikes me as a very good way to spend some time and a little money.

[Pete B]

A nice summary of the Carver Challenge, you have to give JGH credit for his honesty:

http://www.diyaudio.com/forums/showthread....2392#post152392

This also:

http://www.diyaudio.com/forums/showthread....2546#post152546

[Mexicomike]

I don't agree that amps sound the same. There can be an obvious difference in Amplifiers. Back in the mid '80's 3 of us did listening tests between a Moscode 600 and a Phase Linear 400. It was blind testing with none of us knowing which amp was in or out. The identification of the difference was literally 100 percent with all three participants able to identify that there was a difference every time they were switched and with every particiapnt preferring the sound of the Moscode. This demonstration - conducted at home and without any represntatives of a stereo shop, through a set of Nestorovic 5as speakers - convinced me to buy the Moscode which I still own.

I am not saying that you might not be able to tell the difference in amps most of the time but sometimes it is quite obvious. I am also NOT saying that the Moscode is/was more accurate, just that we all preferred the sound.

[Guest matty g]

Hi -

Amps do not sound the same in my opinion. I have spent many hundreds of bucks to come to this conclusion. There can be no doubt that circuit design has a profound effect on the final sound of an amp. Not all amplifiers are meant for home use, such as sound re enforcement amplifiers. I do not agree that a watt is a watt.

In the original post, Ed was referring to an integrated receiver, so now we are talking about the pre-amp section as well as the power amp section. The pre-amp section will absolutely change the sound, even when set "flat". But beyond that, let me say that just because a given electronics manufacturer has a reputation for robust electronics or a great tuner section or a dynamite phono preamp section doesn't mean that their product won't SUCK when you drop a bundle on it and hook it up to your system. You may even discover that the one you got for nothing and repaired sounds much much better than the one that you just dropped $650 bucks on, even though the $650 buck unit is rated at twice the power and you wish you hadn't walked into the store that day....the veins in my neck are bulging, I'd better stop.

Matt

[Carlspeak]

Aaaaah, here we go again, the subjectivists vs the engineers debate.

What's next? Resistors? diodes? wire? connectors? ..........

It's all about the music

Carl

Carl's Custom Loudspeakers

[Pete B]

No where in there does it say that all amplifiers sound the same. The fact is that "good" (see my definition of good here: http://www.classicspeakerpages.net/dc/dcbo...8&mesg_id=6668) amplifiers, operated in their linear region sound the same.

And Carver showed that a good amp, his, could be made to sound like a not so good amp, the very expensive tube one, with about 10 dollars worth of parts from Radio Shack. He nulled his amp to the sample provided in a hotel room over the course of a few days, and he won the challenge.

The fact is that you have to match levels, match frequency response to within about .1 dB, and match output impedance. Otherwise, yes, even low distortion amplifiers will sound different.

I'm not going to debate anyone, it's all there in the literature and history, you just have to find it and study it.

[kkantor]

What if you changed the model of speaker, and your preference which amp sounded "better" changed? What would that tell you?

-k

"Monday sounds different from Tuesday, and you can't prove me wrong!"