Sound Quality Vs. Measurements

[dvv]

Originally Posted by a.wayne

Sy,

He meant 600 watts @1 ohm use as much negative feedback as necessary , give it your best shot ...

"Best shot"?

That also is not at all scientific, Wayne, you old rogue. You should know by now that here, only science works.

[a.wayne]

Originally Posted by SY

Being a tube guy, I tend to avoid 1 ohm speakers.

What ..? You need Carver to show you how , his tube amp has a 1 ohm tap..

Originally Posted by dvv

"Best shot"?

That also is not at all scientific, Wayne, you old rogue. You should know by now that here, only science works.

Yeah we should have Carver send an amp over to Sy , I think too much flea power has killed his zeal ..

On another note we have one of John's halo amplifier's runRning in now for a few weeks, while its protection circuit didn't like the Big bembeh , it's doing very well on the Maggie's (3.6) listening session last weekend was impressive , this is a very good amplifier sonically , I'm now tempted to try the JC-1's , well if I get one of the kids to pay their way thru College ..

Cheers ...

[DF96]

People on here used to be (wrongly) accused of always using THD, which our (absent) friend told us was meaningless. Now people are being criticised for refusing to use THD.

2% THD might be acceptable. 0.02% THD might be unacceptable. It all depends. Perhaps I should clarify for those who are confused by numbers, feedback, Ohm's Law etc. : I am not implying that higher THD is necessarily an advantage!

Does that answer the question?

[M Gregg]

Well,

Have you tried a mono signal into head phones one in each side from different sources or through different "signal paths and components" playing the same music?...Then reverse the HP on your head and compare...Just for fun of corse..Direct comparison...
I think our sonic short term memory is not so good..

Regards
M. Gregg

[a.wayne]

"our" ......


Thorsten is out study and eating distortion thd is not a lone wolf causes and effects play a bigger role ...

[Wavebourn]

Originally Posted by dvv

I didn't ask for your analysis of my amp or my sex life, just a simple, easy question, and you let me worry about the philosophical side of things.

Ok, similar question: what is bigger, kilogram or kilometer? Please answer simply: yes, or no.

[a.wayne]

Yes ......

[dvv]

Wave, what's wrong? Why the ridicule? What's wrong with classic measurements? They don't tell the whole story, to be sure, you could even say they tell relatively little of the whole story, but is that reason enouugh to make someone asking about it a pariah?

What's happening here? Did I chance upon a question which the tube group, as they are the only ones showing signs of life (as well as DF96) and agitation, ask a question which must never be asked? Because the answer might be something like - yeah, it has 5% of THD, but it's the NICE 5%?

Will any of you, or rather CAN any of you tell why is my question so repulisve to you?

[SY]

As I explained in some detail earlier, your question wasn't "repulsive," it was meaningless.

[dvv]

Originally Posted by DF96

People on here used to be (wrongly) accused of always using THD, which our (absent) friend told us was meaningless. Now people are being criticised for refusing to use THD.

2% THD might be acceptable. 0.02% THD might be unacceptable. It all depends. Perhaps I should clarify for those who are confused by numbers, feedback, Ohm's Law etc. : I am not implying that higher THD is necessarily an advantage!

Does that answer the question?

Quite agreed.

Since you were the only with the decency of giving a fair answer, let me tell you why I asked in the first place. After a lot of experimenting, I managed to get the 1 kHz THD, at 100W/8 Ohms and no global NFB, to 0.08%. On a 20-20,000 Hz level, this was 0.245%, and at 50 kHz, THD was 0.39%.

The amp has a cascoded FET front end, buffered second stage and cascodes in the second stage. Output devices are Motorola/ON Semi MJL 3281/1302. Open loop power bandwidth was 94 kHz/8 Ohms.

I probably overcompensated it, meaning there's still a lot of work to be done, but overall, I thought the initial static distortion results were rather good. For a moment, I though almost too good to be true, but upon several bouts of checking and rechecking, I kept getting the same results.

Nevertheless, I thought I might check here as well. Always good to hear other people's experiences.

I am certainly not claiming that the amp will sound great, or anything like that, despite its promising results in basic and not so basic tests, it is after all an ongoing project. I am waiting for the delivery of those trannies now, they should be here by the end of next week.

Anyway, thank you for offering your view, and thanks go to M.Gregg as well.

Oh, BTW, I am well aware that more than its absolute value, the distribution of the harmonics and their THD rates are far more important. But that fact should not prevent anyone answering the basic question.