Anyone own and use Bryston or MOSFET power amp? - Page 2 - AVS Forum | Home Theater Discussions And Reviews
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post #31 of 96 Old 06-09-2020, 02:52 PM
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He was a "good guy"





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post #32 of 96 Old 06-09-2020, 03:06 PM
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But he has a white tie so that overrides hat color, as we all know.
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post #33 of 96 Old 06-09-2020, 03:15 PM
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Originally Posted by alan0354 View Post
I want to get people's opinion on the Bryston power amps, how do they compare with other high end power amps.
Meh, had heaps through here. Nothing special and very generic designs by and large.

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Originally Posted by alan0354 View Post
Another type of amp that I am looking into is power amps with MOSFET power transistors.
Last one I built was an Aussie design called the AEM6000. Good amp, but as always, depends upon the topology and how well that's implemented.

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Bryston has a 20 year warranty. Does that count?
I've always said "big deal" to this. Anyone who's worked in electronics knows of the bathtub curve failure rate. Most devices fail early or they go on to work well for a long time, then fail with age. Bryston have just done the statistical analysis and worked out it can be used as a marketing point, but int the real world, it's irrelevant.
I have many amps that are >>20 years old and even the left over amps I used in my PA that were humped in and out of venues, moved about in trucks and trailers, had the snot beaten out of them most nights, far, far harder than they'd ever get used domestically, and are still working fine.

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post #34 of 96 Old 06-09-2020, 03:16 PM
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No offense but with the protests going on right now I'd suggest we not bring up black and white...and this is a screen cap I took just now on AVS in this post...it's an ad that is on AVS and I'm pretty discussed at this ad....see for yourself...I do not want to see a sexual ad on an audio forum....AVS please look at the ad's you allow and fix accordingly.

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post #35 of 96 Old 06-09-2020, 03:21 PM
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Black hat, black tie.
(But they both probably wore white underbritches)



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post #36 of 96 Old 06-09-2020, 03:23 PM
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Originally Posted by josh6113 View Post
No offense but with the protests going on right now I'd suggest we not bring up black and white...and this is a screen cap I took just now on AVS in this post...it's an ad that is on AVS and I'm pretty discussed at this ad....see for yourself...I do not want to see a sexual ad on an audio forum....AVS please look at the ad's you allow and fix accordingly.

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Rather than reposting... report it.



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post #37 of 96 Old 06-09-2020, 03:24 PM
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Oh, and Alan, if you're not a member of hifi-engine, join. It's basically a repository of owner and service manuals of tons of old and new gear. Free, and never had a spam email etc from them and I was a very early joiner.
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post #38 of 96 Old 06-09-2020, 03:24 PM
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Originally Posted by Ratman View Post
Rather than reposting... report it.
I posted as others can see the crap ad's allowed on here...and instead of responding you can also report.

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post #39 of 96 Old 06-09-2020, 03:26 PM
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I posted as others can see the crap ad's allowed on here...and instead of responding you can also report.

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Reposting doesn't help. You pointed out the Ads. You should report it for removal.

I never saw it until YOU posted.
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post #40 of 96 Old 06-09-2020, 03:27 PM - Thread Starter
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Quote:
Originally Posted by A9X-308 View Post
Oh, and Alan, if you're not a member of hifi-engine, join. It's basically a repository of owner and service manuals of tons of old and new gear. Free, and never had a spam email etc from them and I was a very early joiner.
Yes, I downloaded a lot of schematic from there to study through the years.


thanks


Alan

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post #41 of 96 Old 06-09-2020, 03:29 PM
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Originally Posted by Ratman View Post
Reposting doesn't help. You pointed out the Ads. You should report it for removal.

I never saw it until YOU posted.
I posted for that exact reason...so you and others see it...and now it will be reported.

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post #42 of 96 Old 06-09-2020, 03:30 PM
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Originally Posted by josh6113 View Post
I posted for that exact reason...so you and others see it...and now it will be reported.

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Thanks... I didn't need to see it. But glad you have decided to take my suggestion.



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post #43 of 96 Old 06-09-2020, 03:33 PM
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Thanks... I didn't need to see it. But glad you have decided to take my suggestion.
Didn't need your suggestion to report the obvious...and now you know money Trump's all even on an audio forum...my 4 year old son reads on here with me so the last thing I need to see is a sexual ad like that.

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post #44 of 96 Old 06-09-2020, 03:39 PM
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Dude... get over it and report offensive material(s).



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post #45 of 96 Old 06-09-2020, 03:40 PM
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Dude... get over it and report offensive material(s).
I have...how about you back off buddy?

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post #46 of 96 Old 06-09-2020, 03:57 PM
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That's a Tapatalk ad... https://www.tapatalk.com/contact_us

Please use the report post button to alert staff to problematic posts. Never quote or respond to them yourself.
Always post about products, never post about other members.
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post #47 of 96 Old 06-09-2020, 04:04 PM
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That's a Tapatalk ad... https://www.tapatalk.com/contact_us
Ok but when I click it states it's not available...I use my phone for many forums and only on this forum have I seen an ad like that...but thanks for stating it has nothing to do with AVS...I'll investigate more.

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post #48 of 96 Old 06-09-2020, 04:06 PM
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I use my phone for many forums and only on this forum have I seen an ad like that.
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If you Google, you'll find no shortage of complaints from their users about offensive ads.

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post #49 of 96 Old 06-09-2020, 04:07 PM
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If you Google, you'll find no shortage of complaints from their users about offensive ads.
Will do...it's a shame that this happens.

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post #50 of 96 Old 06-09-2020, 04:56 PM - Thread Starter
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Originally Posted by A9X-308 View Post
Oh, and Alan, if you're not a member of hifi-engine, join. It's basically a repository of owner and service manuals of tons of old and new gear. Free, and never had a spam email etc from them and I was a very early joiner.
I have been reading and analyzing the Bryston output stage for a few days. The more I doubt it's worth the while to even get into it. It's too complicate, usually from my experience is not good. Things are intertwined together, usually it's asking for instability. I attached the schematic. It's basically a Quazi-Complementary-Feedback Pair that is well studied. This is my observation, see whether you agree or not:

1) the signal from VAS(second gain stage) goes through Q27(inverter), to Q16(buffer), to Q18(phase splitter) before driving the output transistors Q2 and Q1. Then because Q2 is CE stage with gain, frequency response is a lot lower than Q1 which is EF. There is a big mismatch right there that might cause problem. Signal goes through 4 stages to the output, I don't like it.

2) My big concern is Q18 driving Q1. Input capacitance of Q1 increase with increase collector current. a pole is formed as shown in the RED markup with R15.

3) You can see the BLUE circles, there's a lot of BANDAID RC network around, must be last minute add on to stabilize the amp. You look at the RC value, the pole/zero are all in hundreds of KHz to MHz. Those are definitely not for audio frequencies, it's taming the oscillation.

4) Because of the Quasi Comp, TWO current limiting transistors needed Q16 and Q17, this further complicate the design.

5) The use of 2uH inductor L1 is a sure indication the amp cannot withstand higher capacitor load. An inductor has to be used to isolate the output from the capacitor load. Inductor should be avoid at all cost. I had a lot of test, that inductor destroy linearity when driving a non linear load.

Just too too much crap going on. Like I said, a good circuit is always very simple, you can see very distinct individual stage that perform a specific function. This one is all mumble jumbo together.

See what you think.

Alan
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post #51 of 96 Old 06-10-2020, 12:57 AM
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I would like to answer the OP - @alan0354 - if that won't hijack the thread from other matters.

I am using a Bryston 4B3 and think it is a great amplifier. I used a 14BSST years ago and also thought that was great. The associated speakers are Janszen Valentina P8, which are hybrid electrostatics and rather revealing.

The Brystons have a long warranty and excellent customer service. As audio equipment has become more expensive overall, Bryston have not been shy about raising their prices, too. What used to be a less expensive brand is now up there.

I tried several amps in my system before choosing the 4B3. The Pass X250.8 was great, but it gives off too much heat for my room (as much as the small heater I use in the winter). The Classe CA-2300 sounded beautiful, but it has a fan that I could hear running. I tried a few others, too, that I didn't like that much. I thought the Bryston had the best combination of sound, good build quality, and silence.

As to your question about MOSFET transistors, I think it's a poor idea to select a piece of audio gear based on the technology used. A good designer can get great performance from many types of technology. A poor designer can't get good performance from much. I think some audiophiles like to use class A, or a specific DAC chip or design, or a type of transistor as a marker to save them from having to consider the sound and design and measurements of actual equipment. It is pointless.

Good luck, and have fun with it!

PS: I see from your profile you are an amp designer, so that puts your question in another light. I have had a couple of power amps with MOSFETs -- a Conrad-Johnson MF-2300 and later, an Audio by Van Alstine Fet-Valve 400R. I thought the AVA amp was very good, not much different in sound from my Bryston 4B3. The older cj amp was replaced by the Bryston 14BSST, which was better in every way. To be fair, solid state is not conrad-johnson's forte.
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post #52 of 96 Old 06-10-2020, 02:10 AM - Thread Starter
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Thanks Mike In NC for sharing.

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post #53 of 96 Old 06-13-2020, 09:45 PM
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Quote:
Originally Posted by alan0354 View Post
Yeh, but some salesman keep saying all amps sound the same as long as it's not clipped.



Yes, I agree with you everything matters. Power supply, grounding, everything matter. I experimented a lot. Here I am concentrating on the output topology. You into DIY amplifiers?
I am not quite there yet............... but i have been around the block and I am certainly not tone deaf in regards to amplifiers and how to go about making a good one. Unfortunatly my skill set is not quite high enough to actually design an amplifier......... But it is high enough to buy the necessary assembled parts, to put a nice one together cheap....

Mr. Randy sloan who is dead now...... wrote many nice books and supplied many very good simple designs , where people could put together high quality amplifiers with very good all round specifications, for peanuts. Some of the stuff he taught,,,,,,,, made him a person that would never be hired by an audio company to design amplifiers, because he was honest and disclosed all the secrets, as well as any bad Karma, that audio companies in general were up too... No surprise his only way to earn a living was starting the business. "Tab electronics", where people could buy ready to assemble modules for high quality home made amplifiers.

Most of what I know, was taught to me, buy reading his works, and there is no better person to learn from than an audio engineer!!!.

I know adcom has some old designs, but old is not bad when it performs like Adcom does. The new 585 575se etc, are just killer amplifiers, really well built..... Sure one can complain about price............. but they are certainly way cheaper than Bryston, and look quite steller in comparison.

People could do well...... by paying less attention to Fad followers, and actually trying to learn something about amplifier design....... Then they would actually know what they are buying.

Check out this guy.... look at those modules he made for screw top caps..........
https://www.facebook.com/pg/HoppesBr...=page_internal
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A Good amplifier requires a adequate power supply, It does not matter what the amplifier is capable of if the power supply will not provide the power required. Most amplifiers have under rated power supplies. It is up to you to make sure you get the ones that are least under rated if at all.

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post #54 of 96 Old 06-13-2020, 10:10 PM
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The Hafler DH-500 was a MOSFET design that touted very high slew rate as an important feature of its design. It used a massive transformer and was built like a tank with wind tunnel cooling for the heat sinks.

Mike

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post #55 of 96 Old 06-14-2020, 01:03 AM - Thread Starter
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Quote:
Originally Posted by johnplayerson View Post
I am not quite there yet............... but i have been around the block and I am certainly not tone deaf in regards to amplifiers and how to go about making a good one. Unfortunatly my skill set is not quite high enough to actually design an amplifier......... But it is high enough to buy the necessary assembled parts, to put a nice one together cheap....

Mr. Randy sloan who is dead now...... wrote many nice books and supplied many very good simple designs , where people could put together high quality amplifiers with very good all round specifications, for peanuts. Some of the stuff he taught,,,,,,,, made him a person that would never be hired by an audio company to design amplifiers, because he was honest and disclosed all the secrets, as well as any bad Karma, that audio companies in general were up too... No surprise his only way to earn a living was starting the business. "Tab electronics", where people could buy ready to assemble modules for high quality home made amplifiers.

Most of what I know, was taught to me, buy reading his works, and there is no better person to learn from than an audio engineer!!!.

I know adcom has some old designs, but old is not bad when it performs like Adcom does. The new 585 575se etc, are just killer amplifiers, really well built..... Sure one can complain about price............. but they are certainly way cheaper than Bryston, and look quite steller in comparison.

People could do well...... by paying less attention to Fad followers, and actually trying to learn something about amplifier design....... Then they would actually know what they are buying.

Check out this guy.... look at those modules he made for screw top caps..........
https://www.facebook.com/pg/HoppesBr...=page_internal

Power amp design is very my like IC opamp design. I don't know exactly who copied who, but if you look at the circuit of IC opamp, they are very much alike. Plenty of books talked about Analog IC design and opamps. I designed analog IC before including opamps, so it's an easy transition for me. Check out the book by Bob Cordell.
https://www.amazon.com/s?k=bob+corde...wer+amplifiers


He has a new edition out, I only have the old edition that is a lot cheaper on Amazon. He was an analog IC designer like me before, I actually communicated with him before. The book details the theory of each stage and options and all. You study that book, you can design power amps. I verified most of the formula in the book, it's accurate.



I also have the book by Doug Self, it's a good supplemental book, but not a book that teach you theory, just give you results.

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post #56 of 96 Old 06-14-2020, 01:16 AM - Thread Starter
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Quote:
Originally Posted by mhutchins View Post
The Hafler DH-500 was a MOSFET design that touted very high slew rate as an important feature of its design. It used a massive transformer and was built like a tank with wind tunnel cooling for the heat sinks.

Mike

I looked at the circuit, mostly is good, very similar to one of my design. The IPS is complementary Long Tail Pair design, the one exceptional part is darlington VAS ( second stage) with anti saturation diode D9 and D10 as shown in 1 and 4. I use both in my design which helps a lot. In my design, I use cascode on the Long Tail Pair and replace R17 and R10 with active current source as circled in 2. Of cause I use BJT as output transistors instead of MOSFET. In my design, I use 3EF instead of only Q12 and Q13 as buffer in the DH500.



The only thing I don't like is the inductor L1 used as shown in 3. This hurts the THD a lot with real speakers. That's the reason most of the high end amps don't use it. Problem is without the inductor, you really have to know what you are doing as it's like an isolation barrier from the capacitance of the speaker cable and the reactance of the speaker from kicking back to make the amp unstable. But it really hurts the sound quality.


I have plan on something like this but a much improved output stage than this already.



You ever heart the DH500? How does that compare to other regular power amps?
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post #57 of 96 Old 06-14-2020, 10:39 AM
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Originally Posted by alan0354 View Post
.
.
.
You ever heart the DH500? How does that compare to other regular power amps?
I've owned the DH-500 since I built the kit in '81 and I bought the DH-110 preamp kit soon after. Unfortunately, the potential of such fine equipment was hampered by the crappy speakers I've always owned. The original RCA input connectors have corroded and need replacement, but otherwise the gear has been flawless to my tin ears.

I'm not an amplifier designer, so most of your circuit comments were over my head, but it seems like you must have some very good amplifiers. Hopefully they perform like the proverbial "straight wire with gain".

Mike
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post #58 of 96 Old 06-14-2020, 04:34 PM - Thread Starter
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I've owned the DH-500 since I built the kit in '81 and I bought the DH-110 preamp kit soon after. Unfortunately, the potential of such fine equipment was hampered by the crappy speakers I've always owned. The original RCA input connectors have corroded and need replacement, but otherwise the gear has been flawless to my tin ears.

I'm not an amplifier designer, so most of your circuit comments were over my head, but it seems like you must have some very good amplifiers. Hopefully they perform like the proverbial "straight wire with gain".

Mike
A wire with gain is the ideal goal, no amp is ideal, all the graph testing of THD, gain flatness and all don't mean a thing when comes to real life driving a real speaker. All test amps with a resistor, not real speaker that is reactive and can kick energy back and cause phase shift. For resistor load, a cheap amp can easily measures as good as the high end amps, it's only when your speaker is very reactive, you need an amp that can really control the speaker. That's where all the big transistors, large heatsink, big capacitors and transformer come into play. Look at the DH-500, so many big transistors.


And this has nothing to do with how much power, it's the quality of the watts that matter. A 60W amp with good and beefy design can sound a lot better than a 200W cheap amp. My smaller amps are all [email protected], the difference is they are [email protected] and [email protected] This is very important to be able to drive very low impedance load. Look at the picture of my 60W amp, inside is full to the brim and is running hot. I have to limit to 60W because it'd get too hot if I increase the power without sacrificing the quality.


Being non-ideal, different amps do sound different, just changing the frontend of the power amp can change the sound and is noticeable even though measuring THD are both very low and both have flat gain from 20 to 100KHz. that's why measurement don't mean a thing.
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post #59 of 96 Old 06-14-2020, 05:36 PM
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Originally Posted by alan0354 View Post

Being non-ideal, different amps do sound different, just changing the frontend of the power amp can change the sound and is noticeable even though measuring THD are both very low and both have flat gain from 20 to 100KHz. that's why measurement don't mean a thing.
I have heard for many years from audio engineers about the real-world limitations of measurements and why extensive listening tests (sighted and sometimes blind as well) are the most important aspect in finalizing a product design. Voicing is the last part of the process. I have posted on this subject many times.

It is not about power amplifiers, but take a look at the new article and a brief video linked below about measurements from a product designer's perspective. In this case focusing too much attention on achieving the lowest possible distortion measurements did not result in the best possible sound.

https://darko.audio/2020/06/podcast-...-measurements/

Music room: Cary SLI-80 tube integrated amplifier, McIntosh MA6500 integrated amplifier, Quad 99 preamp, Quad 909 power amp, Acoustic Research AR9 loudspeakers, Yamaha CD-N500 CD player, Teac UD-503 DSD DAC, Phase Linear 8000 II linear-tracking turntable.
Theater room: Panasonic 65S60 plasma television; Yamaha RX-A2020 (preamp section); Adcom GFA-5503 and GFA-5400 amplifiers; Polk LSi25, LSiC, and LSiF/X loudspeaker system; Velodyne FSR-18 servo-subwoofer.

Last edited by Alex F.; 06-14-2020 at 06:51 PM.
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post #60 of 96 Old 06-14-2020, 07:00 PM - Thread Starter
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I have heard for many years from audio engineers about the real-world limitations of measurements and why extensive listening tests (sighted and sometimes blind as well) are the most important aspect in finalizing a product design. Voicing is the last part of the process. I have posted on this subject many times.

It is not about power amplifiers, but take a look at the new article and a brief video linked below about measurements from a product designer's perspective. In this case focusing too much attention on achieving the lowest possible distortion measurements did not result in the best possible sound.

https://darko.audio/2020/06/podcast-...-measurements/
But some salesman that knows nothing about science always quote measurements and said they are scientific.

Own designed power amps, own designed preamps, JM LAB Focal Alto Utopia and Spectral 913.1 speakers, Rythmik F12SE sub.
Not hooked up: Nakamichi Stasis PA-7 power amp, Velodyne VA1210 sub, Kef Reference Series center, Kef Bookshelf speaker, Monitor Audio bookshelf speaker, Infinity rear speakers. Acurus 3X200W amp.
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