This guy doesn't have Golden Ears . . . . . I think they must be Platinum
Actually I can't help being worried that you will build this and be disappointed. I know I'm as susceptible to the placebo effect as anyone, and I want the amp to sound good! Maybe the sound isn't as good as I say...I've never heard a krell or high end musical fidelity amp to compare it to. As for golden ears....well a self test suggests that I can't hear above 15kHz, so I'm the first to admit I'm flawed!
Testing the bass is easy though. I have one track, Katie Melua - the flood. I have set the volume on my source. The quality of the bass immediately becomes apparent as soon as the track starts.
Really though, why would you be surprised? Today I said the bass with the bootstrap was worse. You simmed it and demonstrated I had a large rolloff at low frequencies.
So, quite neatly, the objective and subjective measurements aligned very well in this case.
Design the amp according to modern trends and lowest possible THD and it will sound clinical, dry and unengaging.
Design it using CFB and the principles espoused all those decades ago by John Linsley Hood and here demonstrated ably by SWF and the amp will sound musical, engaging, and fulfilling.
There lies the rub. You choose. If you think an amp design is pure engineering, then think again. There is art to this craft, subtly communicated by the status with which capable designers like Nelson Pass and most of the tube guys are presently held.
Good engineering is necessary, but one eyed, THD based design which considers only the aggregate and not the individual artefacts is lazy and plain wrong.
I hope sincerely this post does not start a flame war and stall the thread, but I feel quite strongly it has to be said. If you want the best possible amplifier to rise from the ashes, leave SWF to do his wonderful job - designing unfashionably by ear to a large extent - and you will have it.... gee, it's almost there already.
Hugh
Design it using CFB and the principles espoused all those decades ago by John Linsley Hood and here demonstrated ably by SWF and the amp will sound musical, engaging, and fulfilling.
There lies the rub. You choose. If you think an amp design is pure engineering, then think again. There is art to this craft, subtly communicated by the status with which capable designers like Nelson Pass and most of the tube guys are presently held.
Good engineering is necessary, but one eyed, THD based design which considers only the aggregate and not the individual artefacts is lazy and plain wrong.
I hope sincerely this post does not start a flame war and stall the thread, but I feel quite strongly it has to be said. If you want the best possible amplifier to rise from the ashes, leave SWF to do his wonderful job - designing unfashionably by ear to a large extent - and you will have it.... gee, it's almost there already.
Hugh
Hugh, that is a myth
but it could reveal if you have poor speakers
but still 'half way right', as too many may not have good enough speakers
because that's what it takes
and yes, no good for FR wideband drivers either
Tinitus,
The dogmatic assertions by both pure engineers and subjectivist audiophiles have led to this gaping chasm of opinion which extends over about four decades now..... and it ain't changin' any time soon.
I would rather not get involved with arguing the case at all, too many peoples egos, including my own, at stake. Rather, I invite others to build amps according to both schools of thought and compare. This is very rarely done, of course, because it is difficult, exacting, and requires a great flexibility of thought along with some intellectual rebelliousness.
Thank you Tinitus for your courtesy, but this argument leads only to acrimony and intolerance. I will back off and simply smile engagingly....
Hugh
The dogmatic assertions by both pure engineers and subjectivist audiophiles have led to this gaping chasm of opinion which extends over about four decades now..... and it ain't changin' any time soon.
I would rather not get involved with arguing the case at all, too many peoples egos, including my own, at stake. Rather, I invite others to build amps according to both schools of thought and compare. This is very rarely done, of course, because it is difficult, exacting, and requires a great flexibility of thought along with some intellectual rebelliousness.
Thank you Tinitus for your courtesy, but this argument leads only to acrimony and intolerance. I will back off and simply smile engagingly....
Hugh
LuGit,
I guess it s very early in Sweden and that you posted even
before having a few cups of coffee....
Beware that such an inverted opinion can only bring you some
kind of negative feedback, wich i know you dont appreciate
at its fair value...
Last edited:
Lineup has a very interesting little amp here. I have commented (less frequently) lately because of the "pure engineers and subjectivist audiophiles" and the ego's that accompany them . To even state subjectively that choice devices or something less than a PPM design can sound better is immediately shot down as lunacy. In my short experience I will admit the blameless is less than totally exciting. Listening through a triple OP , some of the "lesser" designs (higher thd) are more to my liking than others. To combine the engineering (rock solid electrical and thermal stability) along with sonic excellence and ease of construction is not something one can do overnight.
Instead of building two amps in "both schools of thought" to compare (done that) , why not build one combining the two ? I suppose on one end of the spectrum we have "clinical" (like some say a CD is ... as opposed to Vinyl ? ) , and then we have "warm".
, different spectra/rolloff .... produces a more pleasing sound. Why ?? just the "masking effect" of increased low order distortions. PIM and impedance changes with frequency/ load are more "at work" than either lack of distortion or more of it.
"Modern trends" can be made more modern. "think outside the box" - a new design does not have to be PPM just to be modern. Just to be different , I will try a mosfet hawksford cascode (the VAS) ... why not? , even if it does not simulate as good. (change/difference in early effect(s) = change in sound).
I don't really "believe" in either camp , to do so would limit the options ... design the amp for audio , not lab tests.
PS - how can one have a "subjective measurement" ? THAT would be a real breakthrough !
OS
Instead of building two amps in "both schools of thought" to compare (done that) , why not build one combining the two ? I suppose on one end of the spectrum we have "clinical" (like some say a CD is ... as opposed to Vinyl ? ) , and then we have "warm".
Well said , swordfish. This would satisfy at least some objectivist's/rejectivist's
, different spectra/rolloff .... produces a more pleasing sound. Why ?? just the "masking effect" of increased low order distortions. PIM and impedance changes with frequency/ load are more "at work" than either lack of distortion or more of it."Modern trends" can be made more modern. "think outside the box" - a new design does not have to be PPM just to be modern. Just to be different , I will try a mosfet hawksford cascode (the VAS) ... why not? , even if it does not simulate as good. (change/difference in early effect(s) = change in sound).
I don't really "believe" in either camp , to do so would limit the options ... design the amp for audio , not lab tests.
PS - how can one have a "subjective measurement" ? THAT would be a real breakthrough !
OS
Last edited:
Agree, WuYit!
A very good goal is to ensure that H2, H3 and H4, all musical, comprise 98% of the THD.
Remember that when adding amplitudes, always use root mean square calculation, that is, square each amplitude, add together, then take the square root. Compare this figure to the THD as a ratio, looking for >98%.
This is a worthy goal, one I use myself.
Hugh
A very good goal is to ensure that H2, H3 and H4, all musical, comprise 98% of the THD.
Remember that when adding amplitudes, always use root mean square calculation, that is, square each amplitude, add together, then take the square root. Compare this figure to the THD as a ratio, looking for >98%.
This is a worthy goal, one I use myself.
Hugh
But does it really matter if total THD is say less than 100ppm.?..
That s right but only statistically because it is assumed that
the harmonics phases are not correlated.
In case the harmonics are phase aligned, the figure might
be quite more ugly..
I have a soft spot for tube amps.. they seem to produce a more airy and liquid type of sound...that i really like.and to state that it's just a matter of haveing good speakers to enjoy the low THD designs is just plain wrong.. they still sound sterile lifeless and dry..!!
Could be that the injection of lowish order THD is just the right medicine to get the bloom and liquidness that brings it all to life..have seen the same thing in designing loudspeaker units...things like rear wave reflection seems to matter more than low THD to produce natural sound..
Could be that the injection of lowish order THD is just the right medicine to get the bloom and liquidness that brings it all to life..have seen the same thing in designing loudspeaker units...things like rear wave reflection seems to matter more than low THD to produce natural sound..
Last edited:
I don't know why everyone is so concerned.
The bottom line is that in this design we have a simple, reasonably high bandwidth and easy to construct amplifier that has a low enough THD to not sound unpleasant.
As a bonus it has a distortion spectrum that some people, right or wrong, think sounds better. This can't be a bad thing.
Personally I also think it sounds better than many I have heard with far lower THD.
Let's appreciate it for what it is.
The bottom line is that in this design we have a simple, reasonably high bandwidth and easy to construct amplifier that has a low enough THD to not sound unpleasant.
As a bonus it has a distortion spectrum that some people, right or wrong, think sounds better. This can't be a bad thing.
Personally I also think it sounds better than many I have heard with far lower THD.
Let's appreciate it for what it is.
Last edited:
When it comes to this design, Fetzilla
it is easy to go for high or low OLG, much or less negative feedback
and so get different numbers on THD.
It is up to each one what one prefer.
With or without bootstrap is one choice.
MOSFET or BJT VAS.
Because the simplicity of circuit any choice wont upset the amplifier.
It is easy to modify to suit any desire and belief.
What I like us to not change is
1. JFET input
2. Lateral or vertical MOSFET output.
3. Only 3 stages as shown in schematic.
it is easy to go for high or low OLG, much or less negative feedback
and so get different numbers on THD.
It is up to each one what one prefer.
With or without bootstrap is one choice.
MOSFET or BJT VAS.
Because the simplicity of circuit any choice wont upset the amplifier.
It is easy to modify to suit any desire and belief.
What I like us to not change is
1. JFET input
2. Lateral or vertical MOSFET output.
3. Only 3 stages as shown in schematic.
I am glad.
I know yoou are pleased with Fetzilla.
And you have the knowledge to try different modifications.
It is an excellent basic circuit for experimenting somewhat.
swordfishy
Change one thing at the time, makes it easier to see what is an effect.
If you change several things, how do you know what did effect a change in sound?
You have to guess.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.