AudioCircle

Industry Circles => Digital Amplifier Company => Topic started by: AmpDesigner333 on 3 May 2021, 09:28 pm

Title: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: AmpDesigner333 on 3 May 2021, 09:28 pm
I recently simulated the circuitry for a new spin on our amp technology....

With very realistic component values and some clever tweaks, I was able to get THD at rated lower down to 0.00002%.  Yes, that’s FOUR zeros.

Interestingly, the original purpose of the changes was to increase damping factor at high frequencies, which these new circuits also do quite well.  The simulations take a long time, some more than an hour for a very particular scenario, so I run them in the background when there’s time.

What amount of THD (or lower) do you believe is “essentially distortion free”?
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: jjss49 on 3 May 2021, 10:12 pm
lower distortion is good if it leads to good sound

it should not be an end to itself

sympathetic distortion can be a positive in the pursuit of lovely sound
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: Scroof Neachy on 3 May 2021, 11:08 pm

What amount of THD (or lower) do you believe is “essentially distortion free”?

.00000000000000000000000000000000000000 0000000000000000000001%
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: Docere on 4 May 2021, 05:41 am
What is the benefit?

At what level is distortion audible? What orders of distortion are responsible for what psychoacoustic effects? Do the ratios of the orders matter?
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: navi on 4 May 2021, 12:07 pm
.00000000000000000000000000000000000000000000000000000000001%

I think you are missing a '0'
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: JLM on 4 May 2021, 12:16 pm
Do we know how to measure distortion that collates to what we hear at very low levels?
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: NoDisco on 4 May 2021, 02:44 pm
What natural processes contribute to distortion? What is their threshold under standard conditions? There’s your limit.
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: opnly bafld on 4 May 2021, 03:56 pm
Someone must have felt it was a little slow on the Cherry Amps forum.
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: AmpDesigner333 on 6 May 2021, 01:27 pm
Do we know how to measure distortion that collates to what we hear at very low levels?
NO, but realistically speaking, people in high-end claim a lot of things than are simply BS.
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: opnly bafld on 6 May 2021, 01:54 pm
Audio companies have been there a lot longer.  :wink:
THD has been a known measurement for years and yet there is no correlation* between it what people hear.
It is used (and has been for decades) by many as marketing to sell product to "number buyers".

*Obviously very high distortion can be heard, but I think we all know that is not what I'm referring to.
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: RDavidson on 6 May 2021, 06:15 pm
NO, but realistically speaking, people in high-end claim a lot of things than are simply BS.

Right. So wouldn't claiming "essentially distortion free" just be more marketing hyperbole?
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: rollo on 6 May 2021, 06:44 pm
Yes you can very well done.  :D Just like a Japanese Reciever now  :rotflmao: :rotflmao: :rotflmao: I'm sure your stuff sounds better sorry could not resist  8)


charles
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: opnly bafld on 6 May 2021, 07:04 pm
On another forum someone wrote off an amp as being "junk" even though he really didn't know anything about it.
The reason? The manufacturer rated the power at 1%. 
 :roll:  :duh:

Edit: Moved the emojis to below the last sentence since I'm not faulting the manufacturer at all for their "specs".
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: RDavidson on 6 May 2021, 07:13 pm
And that's fine. Numbers folks have their opinions and can buy what they like. If the manufacturer was really concerned about this audience, I'm sure they could've come up with a different way to write their specifications that would still be accurate and satisfy said audience. But yeah, to dismiss a piece of gear without listening is... :slap:
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: Scroof Neachy on 7 May 2021, 12:49 am
I think you are missing a '0'

You’re absolutely right. I’ve gone back to my post and made the correction.
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: Tyson on 7 May 2021, 12:53 am
And that's fine. Numbers folks have their opinions and can buy what they like. If the manufacturer was really concerned about this audience, I'm sure they could've come up with a different way to write their specifications that would still be accurate and satisfy said audience. But yeah, to dismiss a piece of gear without listening is... :slap:

It's like buying a meal based on how it measures. 
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: RDavidson on 7 May 2021, 02:34 am
It's like buying a meal based on how it measures.

 :lol: Maybe more like not buying a can of soup based on a moderate amount of sodium listed on the label. :lol:
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: Tyson on 7 May 2021, 05:24 am
:lol: Maybe more like not buying a can of soup based on a moderate amount of sodium listed on the label. :lol:

Well, based on sodium content measurements, the inexpensive soup actually outperforms the expensive soup.  Don't fall for snake oil soup!
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: Letitroll98 on 7 May 2021, 10:43 am
:lol: Maybe more like not buying a can of soup based on a moderate amount of sodium listed on the label. :lol:
Although I'm careful about any sodium in the food I buy, I don't really care if the level is pretty low or vanishingly low.  I am concerned about high levels of sodium.  Same with THD.
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: planet10 on 7 May 2021, 11:26 pm
With very realistic component values and some clever tweaks, I was able to get THD at rated lower down to 0.00002%.  Yes, that’s FOUR zeros.

...What amount of THD (or lower) do you believe is “essentially distortion free”?

It is pretty well established that single number THD is next to meaningless, what does the spectrum look like? IMD? And Class D, IIRC, how well suppressed is the HF modulation.

dave
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: SET Man on 8 May 2021, 01:33 am
Hey!

    Might as well go for the Guniness World Records for amp with the lowest THD at a given wattage commercially available 8)

     When I started out interested in Hi-End audio in my mid teens I was fascinated by megawatts amps, giant speakers with many drivers and yes measurement specs. Well, funny that I ended up with 18wpc SET amps and 6" Fostex based Single Driver speaker now :lol:

    Anyway, I've never heard any DAC amps, so I'm not in a position to comment if DAC amps with super low THD sound better than my highly distorted ancient tech SET amps. After all we buy audio to listen with our ears and not watching it through a measurement scope. Well, at the end of the day... whatever floats your boat man!

Buddy

Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: sumoking on 8 May 2021, 03:37 am
The DAC amps are extremely clean and less distortion can be a really good thing. It's already amazing sounding amp line.  If its now a better sounding amp, it is a good thing for the audio world.

Tommy- Specs aside, can you share if the amp sounds better with this change?

Cheers.
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: Shear Bliss VMPS on 8 May 2021, 06:10 am
Tommy does a extra zero or two matter in this day and age ? I think not. Sounds like a 1970s era rehash of specs & power on big massive receivers wars of the day. What should matter most is tonal quality and the most natural midrange that can be wrought from a Class D design.

I feel there is still room there in this regard to make the entire midrange more natural in human warmth terms. Yes a very tough nut to crack for sure, but one that would give the greatest returns tonally and sound wise. Also shut critics of Class D design UP !!

Your MEGAschino mk2.5 upgrade is stellar and totally awesome sounding. It has a beautiful grip and control of my Tekton Electron SEs. But believe improvements in human vocal warmth would/could reveal a new revolution in your amps and perhaps Class D designs too. Tommy shift your restless energy out of extra zeros which mean absolutely nothing, and make your designs throughout the entire midrange area a little bit more natural sounding. And also saying this, becoming the first to do so perhaps.

Sincerely, Doug West
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: RonN5 on 8 May 2021, 01:37 pm
Doug,

I agree that the chase for zeros matters less than the chase for tone (and soundstage and realism).

For me, one of the benefits of getting the voices right is eliminating sibilance...which was a big improvement when I switched from the Halo to the 2Cherry.

One of the great things about Tommy's amps is the tone but you will also hear that said about some of the tube amps that have far more distortion....meaning that the chase for zeros won't be an acceptable standard for many. 

Also, it seems pretty common that an amp can have great tone with one pair of speakers but not as good with another pair...and change up the room setting and the tone may improve or lessen again....meaning there is always the aspect of how equipment plays together and how it sounds in a specific room.

Finally, there is the whole issue evolving amplifier technology and how do you find a way to stand out with your product in a way that people are willing to give you a try vs the latest new technology product that is getting a lot of hype?
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: Barry on 11 May 2021, 03:46 pm
I recently simulated the circuitry for a new spin on our amp technology....

With very realistic component values and some clever tweaks, I was able to get THD at rated lower down to 0.00002%.  Yes, that’s FOUR zeros.

Interestingly, the original purpose of the changes was to increase damping factor at high frequencies, which these new circuits also do quite well.  The simulations take a long time, some more than an hour for a very particular scenario, so I run them in the background when there’s time.

What amount of THD (or lower) do you believe is “essentially distortion free”?

I’m using cherry amp (bi-amp). Very happy with it.  They present good micro details and very musical.  Whenever I change the components or having new tweaks.  They tell me if it sounds better or worse right away. 

There are amp which make things sounds better.  Cherry amp make good sources sound great, and bad source sound ugly.  I prefer amp presenting the truth instead of hiding or beautifying it.  Only this way we could set up the system to the next level.

Of course, having good measurement does not mean good sound.  There are many other factors to take care of.   As a user for 5 years with continuous fine tuning, I would say cherry amp reference class gear.  They are as musical as your source could deliver.

I’m interested to hear the next gen cherry amp soon.
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: Shear Bliss VMPS on 12 May 2021, 01:20 am
Wanted to re-visit my May 8th post. I hope it did not come across as sounding or appearing as being unhappy! Nothing of the sort here as its just simply the finest amplifier I have ever owned.

We all have our own biases whether it be room size or acoustic damping / defusing panels etc. For instance I have always had a problem with the power band of music around the 1Khz range, before and after. When I mention midrange warmth its in this area I like more recessed and laid back. Different speakers can change this as we know.

Will be rolling my Acoustat 1100s back in soon for hopefully a short listen. Will be bi-wired like my Electron SE are now, same cables etc. Lets see how the precieved difference in DB plays out.

Thanks Tommy for your stellar products!!
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: morganc on 12 May 2021, 01:45 am
Wanted to re-visit my May 8th post. I hope it did not come across as sounding or appearing as being unhappy! Nothing of the sort here as its just simply the finest amplifier I have ever owned.

We all have our own biases whether it be room size or acoustic damping / defusing panels etc. For instance I have always had a problem with the power band of music around the 1Khz range, before and after. When I mention midrange warmth its in this area I like more recessed and laid back. Different speakers can change this as we know.

Will be rolling my Acoustat 1100s back in soon for hopefully a short listen. Will be bi-wired like my Electron SE are now, same cables etc. Lets see how the precieved difference in DB plays out.

Thanks Tommy for your stellar products!!

Nice.  What amp are you running?
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: AmpDesigner333 on 13 May 2021, 03:07 am
The DAC amps are extremely clean and less distortion can be a really good thing. It's already amazing sounding amp line.  If its now a better sounding amp, it is a good thing for the audio world.

Tommy- Specs aside, can you share if the amp sounds better with this change?

Cheers.
So far, this result is only from a simulation, but we've come to the point where sim results are very close to real life -- with the right components and layout.

More importantly, the output impedance is close enough to zero that damping factor over 1000 is easily exceeded.  That's where trace, wire, and connector resistance actually make a difference.

Sound quality wise, we've found that you can hear the difference, but more from the way the amp handles transients and arbitrary waveform tracking toward the extremes of current draw.  So much is in the implementation and not the specifications, per se.  Items like power supply rejection ratio and the noise floor shape play a part in what you hear as well.

There's no such thing as a "perfect amplifier", but we're getting closer!
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: planet10 on 13 May 2021, 06:25 am
the output impedance is close enough to zero that damping factor over 1000 is easily exceeded.  That's where trace, wire, and connector resistance actually make a difference.

And by the time you put a voice coil in series (not to mention that oft seen first inductor), the real damping factor is somehwere 20-40ish. Why not just specify Rout. Damping is a marketing dept creation to make a small number look big.

Quote
There's no such thing as a "perfect amplifier", but we're getting closer!

A step closer would be variable out so you could dial in the amount of electrical damping applied to the loudspeaker. Too low is only an asset if you have a speaker with an ugly/significantly non-flat speaker impedance. It is possible to overdamp the loudspeaker.

dave
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: AmpDesigner333 on 13 May 2021, 06:46 am
And by the time you put a voice coil in series (not to mention that oft seen first inductor), the real damping factor is somehwere 20-40ish. Why not just specify Rout. Damping is a marketing dept creation to make a small number look big.

A step closer would be variable out so you could dial in the amount of electrical damping applied to the loudspeaker. Too low is only an asset if you have a speaker with an ugly/significantly non-flat speaker impedance. It is possible to overdamp the loudspeaker.

dave
The voice coil is what’s being driven. The source impedance under certain conditions can be calculated with damping factor. I find it hard to be biased against any useful performance measurement regardless of how some companies choose to use it.

A loudspeaker that can be overdamped by lack of drive strength is not my type of loudspeaker.  Truly good designs sound better and better with lower impedance drive.  Low impedance drive also overcomes the reactance of the drivers PLUS crossover.  That’s a circuit that is designed assuming voltage source drive.
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: planet10 on 13 May 2021, 04:57 pm
I will beg to differ.

dave
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: opnly bafld on 13 May 2021, 06:40 pm
I will beg to differ.

dave

+1

Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: Nsm1979 on 13 May 2021, 09:41 pm
+1

I am all for people having a difference of opinion.  I am even more in favor of people having strong convictions.  That’s what makes this forum what it is.

That said, have either of you heard one of Tommy’s Cherry amps?  I own one that I picked up off the preowned market.  So really, no affiliation with DAC. The mono amp I own is easily the best I have owned and possibly the best I have had the pleasure to listen to.  He has come out with quite a few new models since mine came out of his factory. I hope to acquire one of his newer creations in the future.  As for now, I have no desire to look elsewhere for my amplification.

Curious to what you “differ”?
Title: Re: 0.00002% THD — Can we say “essentially no distortion” yet?
Post by: opnly bafld on 13 May 2021, 11:57 pm
I am all for people having a difference of opinion.  I am even more in favor of people having strong convictions.  That’s what makes this forum what it is.

Curious to what you “differ”?

The same thing as planet10.  :wink:

Never experienced a Cherry amp and probably never will, never said anything good or bad about the amps, even defended Tommy a time or two when he was new to the forum.
I just have a different opinion as to what makes a good speaker, matching amplifiers to speakers, and at what point damping factor becomes a non factor.