Does designing an amplifier by ear really work?

[tube fanatic]

 A friend saw this on AA and sent it over.

 

This treatment raises some thoughtful points about why amps which measure extremely poorly often sound phenomenal, and why some amps which measure well can sound like crap:

 

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.497.2126&rep=rep1&type=pdf

 

It is well worth reading.

 

 

Maynard

[Schu]

I think this idea transcends just Amplification... Practical trumps Theoretical every time no mater what the discipline. 

Another thing is... a designer may  NOT be the best judge of the design in the same way that a race car designer is not the fastest driver/pilot.

[seti]

Sakuma San prime examples his stuff looks like he is having a laugh.

http://www5.big.or.jp/~dh/

 

[CECAA850]

11 hours ago, Schu said:

I think this idea transcends just Amplification... Practical trumps Theoretical every time no mater what the discipline. 

Another thing is... a designer may  NOT be the best judge of the design in the same way that a race car designer is not the fastest driver/pilot.

And an amp designer creating something that sounds good to him may sound like crap to me.

[moray james]

13 minutes ago, CECAA850 said:

And an amp designer creating something that sounds good to him may sound like crap to me.

Everything is like that. I am not sure that I understand the point you are making. A chef makes a desert that tastes good to the chef but to you, who knows what you like.

[CECAA850]

1 minute ago, moray james said:

Everything is like that. I am not sure that I understand the point you are making. A chef makes a desert that tastes good to the chef but to you, who knows what you like.

Just pointing out that in the greater scheme of things you need to listen to different amps to see what you like.  Going off of reviews or what amp designers create, whether it was designed by ear or specs really doesn't matter.  Granted it might be slightly off Maynard's point.

[kevinmi]

Very interesting read. Although most of it is way to technical for me, I get the gist of what the author is saying. It has always been my belief that the music you hear far outweighs the specs printed on paper!

[Dave1290]

Nice thread Maynard and yes I started the read and will finish it.

 

First thoughts seeing, or trying to "see," all the aspects this forum has to offer is truly mind boggling to me.  I've always been a "plug n play" kinda guy and will most prolly remain that way.  

 

Second thought was you guys are TOTALLY out to lunch even though I find all of it interesting.  So yea. a lot of pieces of the pie in here.  Maybe someday I'll get it all figured out.  Never happen but ya start somewhere I guess and gleen what you can.  It'll sort itself even though I leave the tech/mod/building to other people I find it all very interesting.

 

Almost "lunch" time!

[babadono]

 

Ok I am trying to quote the sentence the starts with "On all the elements........and sound quality".

So we are all agreed? That everything except the power amp is well defined and the sound quality standardized? Huh? Is this a Klipsch speaker forum?

 

 

 

 

 

[babadono]

But on the Introduction page of a Doctoral Thesis an unproven generalization that there is general agreement that the standard fidelity objective as pertains to the resulting sound quality of everything in the reproduction chain except the Power Amplifier is already understood? If I were one of the reviewing Profs I would have brought out the button.

[kevinmi]

18 minutes ago, babadono said:

But on the Introduction page of a Doctoral Thesis an unproven generalization that there is general agreement that the standard fidelity objective as pertains to the resulting sound quality of everything in the reproduction chain except the Power Amplifier is already understood? If I were one of the reviewing Profs I would have brought out the button.

What is it that you think isn't understood?

[babadono]

Yea sorry everything is understood except power amps. My bad.

Just not by me I guess.

[tube fanatic]

6 hours ago, Jeffrey D. Medwin said:

I am fully under the impression that an amp that sounds really really good, ................will measure really really good !!! 

 

Jeffrey

 

I don't agree with this.  There are many amps out there which measure poorly but sound wonderful to particular individuals.  I always come back to the example of the original Darling SET which has around 15% 2nd harmonic distortion at full output (if I recall correctly)- there are guys who will not listen to any other amp after hearing one.  And, Jeff, didn't you agree that the ripple of your LSES filter is fairly high and can result in some audible hum (please correct me if I'm mistaken)?  Wouldn't the former be an example of poor measurement?  

 

As to using neg. fb, I'm one of those who does not consider it to be problematic at all.  After all, it does extend bandwidth and lower output impedance.  Personally, I don't like or use a global loop.  Yet, when one looks at all of the renowned vintage amps which use the latter and sound outstanding it's difficult to reject the methodology out of hand.  

 

What I found most interesting about the guy's thesis is the discussion of the response of our own auditory systems to harmonic distortion and our built in cancellation effects.  That's a subject which I'll have to research more when time permits.  It's something which I haven't thought about previously. 

 

I understand Cheever's point about the amp being the determining factor in what we hear.  As the last element before the speakers, its influence will be significant based on its output impedance and how it interacts with the speakers' impedance variations.  I've always felt that preamps don't do all that much to alter the sound of a system. 

 

 

Maynard

[mike stehr]

6 hours ago, tube fanatic said:

What I found most interesting about the guy's thesis is the discussion of the response of our own auditory systems to harmonic distortion and our built in cancellation effects. 

 

That's the part that caught my interest, although I'm only half through the article.

[tube fanatic]

Jeffrey, I did not make any statement about the sound of your or Dennis' amp.  As you astutely observed, I have not heard either.  I simply questioned your statement that an amp which sounds good measures good.  So, I must ask you what constitutes good measurements? 

 

I am a bit confused here as I had the impression that you and Dennis (since you have included him in this discussion) design totally by ear and eschew measurements since they will not influence any design changes.    

 

I look forward to your clarification when you have a free moment.

 

 

Maynard

[Dave A]

It all depends on what gage wire is used for the amp build.

[CECAA850]

10 hours ago, Jeffrey D. Medwin said:

Are you actually able to wrap your head around that concept Maynard ??  

Condescending statements like this won't get you far.

[CECAA850]

3 hours ago, awsjr said:

 

 

Moderator - how about stopping Medwins continual promotion of his friends products ... ALK couldn't do it... Dean doesn't... NOS Valves doesn't... BEC doesn't... 

I take it as he's excited to go.  If I were going to the McIntosh factory I might be a little over the top too.  You can take his statement about "best ever" with a grain of salt.  I certainly do.

[polizzio]

Here we go again.........

[babadono]

The latest news....hum is good...if you have 60Hz noise in your system it means its ready to pounce on other frequency signals. MALARKEY!

What it really means is:

A. You have yourself some poorly designed and built audio equipment.

B. You have ground loops in the inter connection of said equipment.

or

C. You have common impedance coupling in the inter connection of said equipment.