ELEKTOR September article

[The golden mean]

We ; the consumers have a lot of power if we can unite! A cost/benefit analysis of traditional measurements would probably be very negative. In science; who would publish something like: our measurements show no correlation between what we wanted to measure and our actual measurements! Indeed a result but probably of less value...
Or ; we don´t now anything about if this substance(medicine) is dangerous to human beings, our research don´t show anything at all; it can be dangerous but further investigations will likely be worthless."

Still (from Elektor) a quote "Of course, it´s difficult to judge sound from these three amplifiers from the measured result, so we would like to hear from readers who have experiences with one or more of these modules."

Compare to: "we don´t now anything about secondary effects of this medicine, in case you encounter any negative effects please let us know."

When it comes to research some of it are administrated by the public (taxes) in most (developed) countries.
In science results are only preliminary (preliminary valid until they are falsified) but
we want to seek evidence for a hypothesis or a theory , so astrology or something like that can be left behind.
That is, evidence based research is the norm.

Then there is a society called AES maybe better than CES.

http://www.aes.org/

[Eva]

Originally posted by Bas Horneman

There must be many reasons. But one reason I think simply has to do with the amount of research that that would take. Who would pay for that?

Certainly most big players won't...there is zero requirement for that kind of research (not from the engineering department or marketing department).

Most people are convinced that a home theatre receiver with cd or dvd player is already perfect sound forever. So we've come to the end of history as far as most people on earth are concerned.

So the research for better measurements would be for a couple of freaks like us in the fringe. Hopefully most of us will continue to use our ears to be the final judge in any case.

CD/DVD players and amplifiers *are* perfect nowadays, even the lower cost ones, at least they are perfect in comparision with the rest of the stuff that we routinely have in the audio chain. There is a lot to improve in (commercial) recordings, (low cost) speakers and particularly in listening environment acoustics.

[Tolu]

@Lars Clausen
At the end of your product page (What you need to build a complete amplifier.) you have written that for 2x200W one need 2 x 40-42V transformers and not 63V. So Elektor did what you say!

Has anybody listened to the Velleman VM100 or the NCD1 module?

The Velleman is very cheap (55 Euro)!

Regards

Tolu

[The golden mean]

Originally posted by Tolu
@Lars Clausen
At the end of your product page (What you need to build a complete amplifier.) you have written that for 2x200W one need 2 x 40-42V transformers and not 63V. So Elektor did what you say!

You obviously mix up AC and DC voltages! To get the proper DC voltage after the rectifier bridge multiply with the root of 2 ; approx. 1.4 and deduct a small loss by the bridge (a bit less so if Scottky diodes are being used). The AC voltage is measured by "weighing" it in so called RMS (Root mean square). The peak value of 220 V AC is more than 300 V.

A 2*42 V transformer will give about 59 V DC, (and there is a thing called regulation which has to do with the inner resistance of the primary and secondary windings and the core, thus a 1000 VA rated transformer will "drop" it´s voltage less than a 300VA transformer while delivering the same current which must of course be within the limit of the 300 VA transformer´s capacity). Using a regulated lab supply may affect measurements a bit compared to the usual unregulated supply. A regulated supply usually is a servo system that tries to keep the voltage constant while the current draw from the supply varies. Being "a too fast"
system may lead to instability and being "a too slow" system may introduce IM distortion in the amp. Thel had some objection about using a lab supply.


In the article and the presentation of the NCD 1 module the author says it can be driven up to +/- 60V DC ( I don´t have the article in front of me but read it today) thus driving it by +/- 40V DC doesn´t make sense to me.

I don´t agree to Eva´s claim about (nearly) "perfect" players and amps. The better speakers you are using and the better room treatment you have achieved, the more obvious differences in both amps and players are perceived.

[ekaerin]

Hi,
I shall not answer on the behalf of Eva but.....

"in comparision with the rest of the stuff that we routinely have in the audio chain"

...the two words comparison and routinely caught my attention and I agree.
I also believe that the lucky guys among us that have the right proportions of
and treatment of their listening environment are quite few.

Listening room acoustics shall not be underestimated.

/ Mattias

[Bas Horneman]

CD/DVD players and amplifiers *are* perfect nowadays, even the lower cost ones, at least they are perfect in comparision with the rest of the stuff that we routinely have in the audio chain.

Maybe you should listen to my dvd player (Pioneer DV-585A)with the European home theater amplifier of the year 2006/7 (Yamaha RX-V659) the word perfect won't cross your mind.

[ekaerin]

Bas,

I have an even smaller and quite older Yamaha reciever driving my
4 Ohm Dynaudio....
Not an ideal case for sure.

btw. I had a good laugh reading your DIY-mag / 2006_1 / you might be a tube-neck or bottlehead...

/ Mattias

[Bas Horneman]

btw. I had a good laugh reading your DIY-mag / 2006_1 / you might be a tube-neck or bottlehead...

Glad you liked it! (It was plagiarism though) My favourite was
"You hear someone say Marshall on a late nite Western, and you wake up!"

[The golden mean]

There is no such thing as relatively perfect. Eighter an item is perfect in some sense or it isn´t.
If you say that speakers contribute more to bad sound than amps
it can be possible to try to investigate into it. But in my opinion this statement has to much of generalization to it.

Thus, maybe some speakers contribute more to bad sound than some amps. But this seems trivial indeed. Even more so as some amps can contribute more to bad sound than some speakers.

Conclusion; we need to investigate most speakers and amps (and CD/DVD players) or at least a great sample that could be considered representative and compute the statistical outcome. In addition we need to consider acoustics in the listening rooms.
This seems to be a huge project in order to prove a statement that perhaps was a bit easy-going IMHO.

[ekaerin]

Yea.
Maybe there is even nosuch thing as perfect in itself.
I agre that it is easy to generalize. You often take an average of
ypur own experiences and "generalize" based on this.

In my own case, it's the amp, hooked up for now, on highs and the room in the lows
that sets the limits for my listening experience.

/ Mattias