Can anyone with knowledge of DBTs between live acoustic instruments and a recording of them in the same environment played through different equipment supply some details? A number of us have referred to this, and there must have been tests of this nature.
I can only comment on the RLD I heard in a DIY amp shoot out I attended - it didn't fare well.
Out of interest to others it was up against my own amp the DC7 Mk 1, a F5 and a Baby Huey. It was a close run thing between mine and the F5 - with the F5 coming out a nose ahead. The Baby Huey was well recieved despite some technical issues and poor OT's. No one rated the RLD well.
Shoog
Last edited:
It's a tube amp of my design which will not satisfy the desires of people wanting an effects box.
Nelson Pass will be very interested in your comment 🙂
If the people disagree - then the people must be wrong 😉
Shoog
If the people disagree - then the people must be wrong 😉
Shoog
was it run on a DBT?
when people ask me about amps i build, i resist to comment on how it sounds,
i always leave that to the user to decide...
but i tell them that my amp does not hum, and does not come up in smoke prematurely,
i also advise then as to power consumption they are up against....
I made a small mistake, my amp was not the DC7 Mk1, it was a Gary Pimm Tabor clone.
Unfortunately it was just a bunch of DIY enthusiasts doing an afternoon shoot out so this is an anecdotal account. However I think its important to observe the reactions people have to different design approaches when such big claims are been made for one particular design philosophy. I have a strong suspicion about why the particular amps performed the way they did, and I have taken those ideas and applied them to all my subsequent designs.
Shoog
Last edited:
I'm not a scientist, I'm a technician. That means I get stuck between the engineers who design clumsy, impractical devices, and the client who wants it to do impossible things. "I want to see the shadows without the light around them."
Engineers are great - I'm amazed by them, but they often aren't great at making stuff that's easy to use for anyone else. Often there is a buffer designer who at least attempts to make the device user friendly.
I like engineers, they built the modern world (taking what the scientists told them), but sometimes they over state their case and lose credibility.
Shoog
Shoog
A highly acknowledged scientist I knew quite some years ago, gave the following comment , as we were scratcing our heads over some strange looking data on that large Tektronix color terminal I had set up....
" I'm not sure I like this machine....I doesn't do what I want - it only does what I tell it to do...."
" I'm not sure I like this machine....I doesn't do what I want - it only does what I tell it to do...."
Firstly - I was not aware of any severe or otherwise disagreement on sufficient tests for amplifiers! You mention 'rely on measurements' as if such is lacking in the case of amplifiers. Admittedly many quoted measurements omit more than they state - but I presume we might accept that we are talking of correct/meaningful tests! (One cannot qualify the validity of something per se, by using inferior examples?)
Then I would like to see mention of the shortcomings of current amplifier tests?
Again I can only agree with your first sentence. But what adverse influences are you meaning in the thereon following sentences? And to quickly add, before you (rightly) consider me brain-challenged (don't comment!) - again hopefully we are talking about properly designed amplifiers; not some of the caricatures on the market passing as 'amplifiers'. (Again, we can surely presume we are not defining the 'state of' by the worst examples ...) This is not a facetious question; simply trying to sort out real aspects from those some believe to be real.
Thanks!
I'll reply to to this, and Johan in one go ... 🙂
No, I don't use DBT - the method I use is the same as assessing how loud, say, a kitchen radio will reasonably go, something that everyone does on occasion. So, how does the normal consumer know that the radio is giving as much as it's capable of? Because, it starts to obviously distort - blind Freddy and all that sort of thing ...
But, everyone "knows" good audio doesn't distort! Wrong!! It's easy to hear it misbehaving, but 'audiophile' tracks typically won't reveal it easily, or obviously. Over the years I've accumulated dozens and dozens of albums, and tracks, which easily provoke conventional hifi into clearly audible distortion, and that's all I worry about - the same principle as the kitchen radio being asked to play loud, when it's clearly over its head ...
As an example, over 25 years ago I used a Status Quo Greatest Hits CD, as an instant barometer. Most of the tracks contain well recorded regular striking of cymbals throughout the song, and the majority of systems back then struggled to even do a half decent rendition of this sound. Things have improved over the years, but it still serves the purpose well - as you increase the volume, at a certain point the quality of the cymbal sound starts to collapse, because the amplifier has reached the point where it starts to generate very obvious distortion. Some people might say, "No, that's the speaker misbehaving!" - wrong!! Because, I "fix up", improve the electronics in the chain, and then, using the same speakers, play that track again - no distortion!!
It's a simple process I've used over and over again - and it's convinced me that the villain in the piece is always misbehaving electronics - because focusing on, and improving that has always given me real progress ...
Edit: I might just mention again that the top of the line Bryston amp is the first one I've come across recently that has checked all boxes, in a positive sense - because I heard none of the misbehaviour of "lesser" amps ...
Last edited:
And the second time, a "certain point" is never reached?
And BTW, I hope you'd agree that certain point = measurement. Only the scale is undefined.
And BTW, I hope you'd agree that certain point = measurement. Only the scale is undefined.
Correct. The sort of equipment I've been playing with recently is quite limited, in terms of the voltage rail size, and ability of the heatsinks to dissipate. In fact, I managed to 'kill' the amplifier module, a slow process taking a week or so, the heat stress finally wore it out, it seems. But while functioning correctly there wasn't an issue with distortion intruding at a certain volume level ...
The Bryston very much impressed me - it obviously has huge headroom compared to many amplifiers, but particularly noteworthy was that that "certain point" was not reached, to as loud as the demonstrator was prepared to drive it.
The "certain point" would be measurable, there would be a distinct kink in a graph of the level of distortion of the high frequency components, when plotted against power levels. In fact, that is typically seen, many times in testing of amplifiers: the high frequency performance deteriorates very significantly beyond a certain power level -- but this is then brushed aside as not being particularly significant or important in the overall picture ... well, IME it is important ...
The Bryston very much impressed me - it obviously has huge headroom compared to many amplifiers, but particularly noteworthy was that that "certain point" was not reached, to as loud as the demonstrator was prepared to drive it.
The "certain point" would be measurable, there would be a distinct kink in a graph of the level of distortion of the high frequency components, when plotted against power levels. In fact, that is typically seen, many times in testing of amplifiers: the high frequency performance deteriorates very significantly beyond a certain power level -- but this is then brushed aside as not being particularly significant or important in the overall picture ... well, IME it is important ...
Last edited:
Well Fas42,
Thanks for reply - but I fear you have not answered my question. Not to belabour, but what you described above ... why have you previously stated that it was not tested for that? With the kitchen radio the problem was clearly partly overload - how is that not tested for? It is contained in the most basic of specs: The maximum capability of an amplifier. That it performs blameless within that 'limitation' is contained in another test: Distortion which ideally should be below audible level (No, not perfect. Nobody spoke of perfection, as was the allegation against SY and friend. That is part of the problem with much of this thread; argument about what was never said/implied. But I interrupt myself ...) You did not indicate where tests failed, unless the same were incomplete etc. - as before.
So still: What other links' performance are degraded by the amp and how, which was not tested for? What aspect of the environment will degrade the amplifier's performance?
Not directed at you personally and with no disrespect; your questions 'verbalise' factors which have frequently been misunderstood/misinterpreted despite posts explaining the reality of designing/testing.
(And I have another question about this repeated referring to "real world amplifiers" as if engineers did not also design those - but that at another time.)
Thanks for reply - but I fear you have not answered my question. Not to belabour, but what you described above ... why have you previously stated that it was not tested for that? With the kitchen radio the problem was clearly partly overload - how is that not tested for? It is contained in the most basic of specs: The maximum capability of an amplifier. That it performs blameless within that 'limitation' is contained in another test: Distortion which ideally should be below audible level (No, not perfect. Nobody spoke of perfection, as was the allegation against SY and friend. That is part of the problem with much of this thread; argument about what was never said/implied. But I interrupt myself ...) You did not indicate where tests failed, unless the same were incomplete etc. - as before.
(My colouring)
So still: What other links' performance are degraded by the amp and how, which was not tested for? What aspect of the environment will degrade the amplifier's performance?
Not directed at you personally and with no disrespect; your questions 'verbalise' factors which have frequently been misunderstood/misinterpreted despite posts explaining the reality of designing/testing.
(And I have another question about this repeated referring to "real world amplifiers" as if engineers did not also design those - but that at another time.)
We can focus on frequency response 20Hz – 20Khz and varying degrees of harmonic distortion etc. But this is not the only spectrum of sound
I was wondering..
What about an amps ability to replay micro and macro variations in amplitude. Is there a measurement/parameter specific to an amp (independent of a speaker), for this?
Is it 'dynamic range'?
Could it be that amp A is sensitive or by nature is 'inherently optimised' to micro dynamics and amp B is sensitive to or inherently optimised for macro dynamics?
Again neither can ever be quite good as as the other
Can we even measure micro dynamic range?
an amps 'expressive voice' be partly determined by it's compressive response or how linear it's response is, to subtle variations in amplitude
I was wondering..
What about an amps ability to replay micro and macro variations in amplitude. Is there a measurement/parameter specific to an amp (independent of a speaker), for this?
Is it 'dynamic range'?
Could it be that amp A is sensitive or by nature is 'inherently optimised' to micro dynamics and amp B is sensitive to or inherently optimised for macro dynamics?
Again neither can ever be quite good as as the other
Can we even measure micro dynamic range?
an amps 'expressive voice' be partly determined by it's compressive response or how linear it's response is, to subtle variations in amplitude
Last edited:
- Status
- Not open for further replies.