Historical look at amps

Jsujo, On Mac amps, he means in his opinion to his ears. Millions of people think otherwise and have voted with pocketbooks. At the end of the day it ONLY matters what sounds good to THAT person.

I am not being difficult. I have a long-standing feud with someone that does exactly what I am commenting on. It will just be a matter of time that he finds this through Google, and the feud will spill over to here. So, while it may be beneficial to you, it may give him fodder to slander me even further by using my posts here as ammo.

Trust me.......ok.

Ok.......my company is Analog Research-Technology. We used to have an entire line of electronics, way back when. Way back when we had dealers. The migration to HT put them all out of business, so we went even more underground than usual.

With the recent introduction of the new "self-oscillating" Class D amps (digital amps to some of you............), I decided to gear up and start making 5-channel amps for the HT crowd. Somehow, I have a hard time getting excited about that market, and since we were amazed at how good they sounded, we became sidetracked and made some stereo versions.

One of my customers mentioned here that he has one of amps......well, actually, he has a 5-channel one also......and next thing that you know, my phone is ringing, wanting info, etc. If it were not for that, you never would have heard of me.

Is that help any???

Or do you want:

I live in Texas. I eat really hot peppers and curry. I have a '73 'Cuda hidden away in the garage. I don't drive it much because gas costs too damn much, it rides hard as hell, and I am too damn old to get excited about trying to operate a 4-speed with a clutch that is even stiffer than the suspension.

Or.......

I don't like the sound of feedback. I guess that you have already figured that out. I tend to build stuff that is full of discrete circuitry. Trying to find ways to add all that extra stuff onto a Class D amp module was a minor challenge. The next ones will have even more discrete circuitry. (Hint: it is either power supply, or input stages.)

Anything else that you may care to ask?

This is not the first time poor Ar_t has had to deal with the issue of his business. Audiogon certainly isn't making it any easier. I don't believe Ar_t is trying to hide the fact, it just becomes redundant after a while. All the same for those not in the know, a heads up might be in order.

Ayre's response. I asked Ayre the following question. Please not this is not hype but a reponse from Ayre's president and chief circuit designer.

My question........
> I’ve been corresponding with other
> audiophiles on Audiogon.com in the discussion forum under
> amps/preamps. Lots of discussion and disbelief about whether Ayre
> products are really zero feedback. May say no global feedback but its
> not possible to build an amp or pre without some local feedback and
> that Ayre’s claim is just a sales pitch. The thread is my (Keis)
> thread titled amp history.

Charles Hansen's reply

I briefly read through this thread, and this is basically an argument about semantics. (You will find that the people that argue about topic this generally have an ax to grind.)

The problem stems from the fact that there is no master dictionary that has a list of agreed-upon terms for circuits. So if someone calls a circuit a "current conveyor" or a "transconductance amplifier" or a whatever, you can probably find people that want to argue about the definition of those terms. These arguments can never be settled because there is no master dictionary that can be referred to.

The way Ayre uses the term "zero feedback" is in the context of a complete amplifier circuit and are completely consistent with the generally accepted terminology as used by major semiconductor manufacturers and experienced designers around the world (and not just in the field of audio). For example:

From the Burr-Brown data sheet for the BUF600: "The BUF600 and BUF601 are 3- stage open-loop buffer amplifiers consisting of complementary emitter followers with a symmetrical class AB Darlington output stage.... The amplifiers use no feedback, so their low-frequency gain is slightly less than unity and somewhat dependent on loading." (emphasis mine)

From the Maxim data sheet for the MAX4200: "The MAX4200–MAX4205 are ultra- high-speed, open loop buffers....Since these devices operate without negative feedback, there is no loop gain to transform the input impedance upward, as in closed-loop buffers." (emphasis mine)

Words are used to communicate ideas. (Remember that the map is not the territory.) The circuits in the Ayre products operate differently from the circuits used in other audio products. (This is obvious because they *sound* different than amplifiers that use feedback.) We use the term "zero feedback" to describe these circuits because this is the most accurate, generally accepted way to describe them.

If someone wants to argue about the definition of "feedback", they are welcome to. However, you will probably notice that those people have quite a bit less experience with circuit design than the engineers at Burr-Brown and Maxim.

Hope this helps,
Charles Hansen

Back to a subject touched by Bombay & Bigtee:

I always thought the "High end" was about accurate portrayal of a source. If it's not and it's about "Good sound" then I need to get out because it all becomes a moot point.

I agree -- yet, much of the time we see "pleasing" prime over "accurate". I.e. many audiophiles are searching for the most pleasing to the ears.
Case in point: lately we sat down with friends to audition equipment. As usual, the commentary edged upon "correct", "better", "more realistic" -- all relating to "accurate" rather than pleasing.
The music was electronic w/ some a'phile "girl with double-bass" thrown in. Quality of recording notwithstanding, how are we to gauge "accurate" or "precise" with electronic music??? A violin, say, (whether one listens to classical or not) offers some easy real-life reference -- as do many other sounds -- but electronic, or even electrical instruments???