OK. I see where you are coming from.
FWIW my optician wears glasses. Does that make him unable to sort my vision as his vision is not as good as the machines he uses to measure my eyesight? I would not want a subjective optician!
I will repeat: Choice is good for everyone. I personally gave up with tweaky stuff and magic components 20 years ago and wanted 'build to BOM gives SOTA performance'. I also embrace the fact that some like to agonize over the choice of one capacitor. It all makes for a healthy community.
You however seem to have something against Tom?
FWIW my optician wears glasses. Does that make him unable to sort my vision as his vision is not as good as the machines he uses to measure my eyesight? I would not want a subjective optician!
I will repeat: Choice is good for everyone. I personally gave up with tweaky stuff and magic components 20 years ago and wanted 'build to BOM gives SOTA performance'. I also embrace the fact that some like to agonize over the choice of one capacitor. It all makes for a healthy community.
You however seem to have something against Tom?
So they're both very technically competent and, not knowing how they behave in clipping, *probably* sound more alike than different. Hopefully that means we DIY'ers have more opportunities to build something great.
I can appreciate that Tom's (dry) narrative is nowhere near as compelling as Mauro's (No intended slight to either--I'm a dry engineering type, and realize I rub some folks the wrong way by sticking to the "facts"), and we humans love a good story, but there's a dangerous assumption that simply because the MyRef was "tuned" by ear that it must be "better". That's a sighted bias and is nothing more than special pleading. I'm glad you're happy with your choice, nonetheless!
Lacking any sort of unbiased comparison, it seems wildly unfair to either design to call it "better". Both designs seem very good and most would benefit from either (hence the caveats/etc. that I tried to ask earlier about ease of fabrication).
I can appreciate that Tom's (dry) narrative is nowhere near as compelling as Mauro's (No intended slight to either--I'm a dry engineering type, and realize I rub some folks the wrong way by sticking to the "facts"), and we humans love a good story, but there's a dangerous assumption that simply because the MyRef was "tuned" by ear that it must be "better". That's a sighted bias and is nothing more than special pleading. I'm glad you're happy with your choice, nonetheless!
Lacking any sort of unbiased comparison, it seems wildly unfair to either design to call it "better". Both designs seem very good and most would benefit from either (hence the caveats/etc. that I tried to ask earlier about ease of fabrication).
Just for sake of technical correctness: Mauro's and based on it, Dario's design does include limiter features for a more controlled clipping.
And I forgot to mention that all Myref designs are coming with a built in for free speaker protection. Working very effectively, I had thanked God several times in these past 10 years of experience with it. The myref design is close to be 'indestructible', and saved my speakers several times.
And Mauro is a very technical, sober person himself. His customers are contributing with these 'human' concepts.
And I do esteem highly Tom's technical expertise. I would be just as proud as he is, when showing his really fantastic results.
Still I can not stand the applied blunt marketing strategies appearing in his threads.
Immagine now that all familiar, metallic voice coming from your flipper device:
"Insert more coin for your even lower THD"
Ciao, George
And I forgot to mention that all Myref designs are coming with a built in for free speaker protection. Working very effectively, I had thanked God several times in these past 10 years of experience with it. The myref design is close to be 'indestructible', and saved my speakers several times.
And Mauro is a very technical, sober person himself. His customers are contributing with these 'human' concepts.
And I do esteem highly Tom's technical expertise. I would be just as proud as he is, when showing his really fantastic results.
Still I can not stand the applied blunt marketing strategies appearing in his threads.
Immagine now that all familiar, metallic voice coming from your flipper device:
"Insert more coin for your even lower THD"
Ciao, George
"It has been invented, with a lot of creativity, 10 YEARS AGO."
"This year is in fact an occasion to celebrate a beautiful design.. "
May I add, more like 23 years ago!!
What we have witnessed here is an evolution and growth of a Great and Ingenious Design Idea from the early 90's .
https://ia601701.us.archive.org/15/...s_1992-11/Radio_Electronics_November_1992.pdf
http://www.diyaudio.com/forums/chip-amps/197384-composite-amplifiers.html#post2725392
Cheers !!!
Jer
"This year is in fact an occasion to celebrate a beautiful design.. "
May I add, more like 23 years ago!!
What we have witnessed here is an evolution and growth of a Great and Ingenious Design Idea from the early 90's .
https://ia601701.us.archive.org/15/...s_1992-11/Radio_Electronics_November_1992.pdf
http://www.diyaudio.com/forums/chip-amps/197384-composite-amplifiers.html#post2725392
Cheers !!!
Jer
I somehow missed that thread, very nice!
Now, may I be obstinate and claim that the introduction of the chip based current pump into the composite loop, based on the good experiences with the solid state discrete current output A370, merits to recognize it's originality?
Or i'm just ignorant of possible predecessors? happens to me a lot, just being ignorant..
Ciao, George
Now, may I be obstinate and claim that the introduction of the chip based current pump into the composite loop, based on the good experiences with the solid state discrete current output A370, merits to recognize it's originality?
Or i'm just ignorant of possible predecessors? happens to me a lot, just being ignorant..
Ciao, George
Neither. Was. Mine.
My goal of the Modulus-86 was to design the best amplifier I could with readily available parts. My reason for this is simple: I wanted an amplifier that provided the best performance possible. As I've pointed to many times, there's an overwhelming body of evidence that supports the theory that equipment that is perceived to have good sound quality also has good measurements. See the work by Sean Olive and Floyd E. Toole for example. I used measurements to quantify the performance level of the amp.
The main performance parameter is actually the loop gain - in particular the loop gain at 20 kHz. However, it doesn't work well on a sell sheet to put "50 dB loop gain at 20 kHz" because you can't compare it to anything. No one else specifies or even mentions the loop gain of their amps (perhaps Bruno Putzey excluded). The high loop gain has the advantage of lowering the THD and that is something most people can relate to. Hence, the vanishingly low THD is the main selling point.
Maximizing the loop gain with a composite amplifier architecture provided many other advantages as well. The high power supply rejection is certainly attributed to the composite amplifier. The Modulus-86 performs as well on a well-regulated laboratory supply as it does on a standard unregulated linear supply (trafo + diode bridge + cap) as it does on a switch mode supply (Connex SMPS300RE).
I then added a differential input to move the ground circuit out of the signal path. No more hum from ground loops!
I will always strive for the highest performance possible. To me that's not a "stupid number's game". That's circuit design.
Tom
Actually, composite amplifiers are even older than that. They date back to the early days of opamps. Composite amplifiers were commonly used to get good DC performance from a high-speed amplifier.
High-speed amps tended to not have good DC performance. High offset voltages and such. So someone decided to throw a high-speed amp in a loop with a low-speed amp with good DC specs and the composite amp was born. The composite amp had both the high speed and good DC specs - at the expense of more complicated amplifier compensation design (stability).
Tom
I've posted KSTR's distortion measures just to point out that the FE it's actually a very good performer also by crude numbers and shouldn't be discarded so fast.
And those measures were made on a beta board which misses some refinements that should improve performance further.
I'm also sure that Tom amp measures even better, this doesn't necessarily mean that it sounds better too, maybe it does, maybe not.
Just one side note...
Mauro Penasa, apart being a very competent designer, is also very skeptical about parts contribution or 'sonic signature' of parts.
Obviously I don't agree with him on this point.
Links to Mauro's measurements on Rev A:
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach.html#post610143
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach.html#post610185
Joseph, do you have any measurement of Rev C?
And those measures were made on a beta board which misses some refinements that should improve performance further.
I'm also sure that Tom amp measures even better, this doesn't necessarily mean that it sounds better too, maybe it does, maybe not.
Just one side note...
Mauro Penasa, apart being a very competent designer, is also very skeptical about parts contribution or 'sonic signature' of parts.
Obviously I don't agree with him on this point.
Links to Mauro's measurements on Rev A:
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach.html#post610143
http://www.diyaudio.com/forums/chip-amps/54571-my-audiophile-lm3886-approach.html#post610185
Joseph, do you have any measurement of Rev C?
I think we resolved several pages ago that the two approaches both give very very good performance. This is not a d**k waving thread and the OP has already made his decision. We should just rejoice that there are multiple approaches to high performance composite amplifiers and leave it there.
This was not my intention and I'm perfectly fine with opener's decision.
Simply I felt that Mauro's work (and mine, with a MUCH lesser extent) were somewhat dismissed here (not by Tom) and this is the only reason that lead me to post measurements.
I almost feel like I should apologise for asking the question in the first place! FWIW anyone who owns the Ncore amps (as I do) can be in no doubt that measurements play a significant role in SQ. However I don't think even Bruno relies entirely on measurements and my suspicion is that we haven't yet identified all the factors that affect SQ.
I have little doubt that both amps sound really good.
I have little doubt that both amps sound really good.
Agreed, absolutely a legit question. And I do apologize if I slighted the MyRef in any way--my allergy to one-sided subjectivism might have suggested otherwise.
I feel that we had at least 7 pages of honest discussion with various pros and cons listed. But suddenly things got defensive. I don't recall Mauro's work being dismissed, in fact look back to the first page and you will see glowing reports of it.
There is no need for contention in this subject either. Some people like the idea of one design, some like the idea of the other. Both sound great. Lets put on music and have fun!
@Studley: Don't be. It's all part of the Craic here!
1.) It really seems that you could enjoy, based on your listening background, this type of sound, of a well executed chipamp.
2.) All my best memories of listening to very enjoyable, not, desperately desireable setups.. were about Nelson Pass or Bartolomeo Aloia designed, low or zero global feedback designs.. which are all about correct measured parameters, but many orders of magnitude worse than the levels discussed here..
Nothing to apologize too, I can't find nothing offensive in your posts.
Simply can't wait
Yeah the Ncores are the most neutral and transparent amps I've ever heard. Closest thing to a straight wire with gain you will find. I suspect the Modulus has similar genes. On the other hand, I also really like a well implemented SET amp. This is no different to enjoying a G&T (made with Tankerey of course) but also being able to enjoy a pint of hand pulled Timothy Taylor's. ( For those of you who have never tried the latter, suffice to say it's the best beer in the world. As measured objectively by my taste buds.)
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