New Class D amplifiers

@niodari 

My V chassis is all metal. My system is all XLRs, so never tried the RCAs. Maybe shoot Ric a couple of photos pointing out the situation

Good Luck

kuribo

... you are another example of someone who can't deal with an opinion contrary to your own. Feel free to ignore that which causes you grief.

Ahhh, the classic ad hominem, the laziest of all logical fallacies.

@tweak1 This makes sense, that unit is non-functioning for me anyways.

Wow has this thread gone off the rails! All b/c of one member. 

Do I really need to explain the difference between subjective preferences and objective performance again?

There should be no difference at all! If you think there is, then you are convinced that we can't make the measurements for everything we hear (which, since about the early 1990s, we can) and also that the human perceptual rules that are shared by everyone on the planet are of no consequence, making things like deciBels irrelevant.

Of course I've found that both the objectivist and subjectivist camps don't like this heretical view. I subscribe to Daniel von Reklinghausen's take on the matter of measurement and what we hear. 

Obviously anecdote isn't reliable, but it can provide data points over time, especially if everyone's anecdote, independently of one another, describes the same thing.

Similarly, the guys that only look at measurements are notorious for their bias confirmation, and their striking ability to assemble dreadful sounding systems.

Neither side is right; both suffer bias confirmation.

@tweak1 With XLR inputs, you may try all four possible positions for the back switches and see if this affects SQ

Yes, I AM convinced that we cannot measure everything we hear......in fact, most things we hear cannot.....at all....be measured. All wires, direction of wires, all jacks, all fuses, all capacitors, all brands of solder, etc. into infinity sound different yet they do not measure any different. Just a few days ago I put a piece of cardboard underneath my streamer and it sounded better.......please measure that! The mods I just completed to the Peachtree GaN1 transformed the sound but will NOT in any way affect any measurement you can do. Our ears are way more sensitive to what things "sound like" than any scope or distortion measurement device. I just swapped two different 6 inch pieces of twisted wire on the digital input of the amp and you get a completely different sound.......this is everywhere.....every single thing you do has a sound. There is no such thing as a pure thing. This is why the first rule of tweaking is to eliminate as much of the signal path as possible......these new digital amps do just that.....of course, there will be better digital amps......most of us will have digtial amps within 10 years....this, I have no doubt about.

I have had Walter's Voyager Amp in my system for a couple weeks.

The sample was eventually sold to another audiophile with a great system.

I compared it to my Pass Labs INT25. The extra power did improve the bass

response. I think overall it is a great value. I may get a class D Ganfet for 

bi-amping.

I have heard the Aavik, Orchard, Atmas, Bel Cantos, LSA Class D sound.

If the Borresen people find it palatable, I can't imagine we are far from

seeing it everywhere. 

But for now I will stay with my friend Nelson.

@jeffseight ​I have heard the Aavik, Orchard, Atmas, Bel Cantos, LSA Class D sound

Can you explain the differences between all those class d amps you heard? Which was the most musical?​​​​​​

No I can not sorry. I was interested in knowing if any were better for my ears

than my Pass amp. Except for the Bass punch that was a no.

As I hear it Pass and Luxman Class A solid state amps

still hold the most magic. 

But Class D Ganfet is making the differences subtler.

I would like to hold a shoot out of Class D Ganfet amps

to include: Technics, Atmosphere, Orchard, AGD, Bel Canto, LSA,

and possibly others. In an A/B format. Audience voting preferences

would decide which moved up to go against the next.

Starting with the lowest MSRP seems most logical.

If Aavik agreed to provide one it could be last.

At 2-3 times the MSRP it should win. 

Refinements?? Suggestions?

I could hold this in either Seattle or the Bay Area. Or both.

@niodari

I can't try anything as I had an accident when I was moving it with the lid off, but resting sideways on top (plugged in f course... the top fell in and it crashed into one module  creating BIG sparks. Fortunately, I was able to drop the EVS1200 in its place until I get it fixed. Im not in any hurry as the EVS sounds amazing

If Aavik agreed to provide one it could be last.

At 2-3 times the MSRP it should win. 

...and therein lies the problem.

We need a formula with a number of parameters (including the price, and a few parameters that measure the SQ, and a few parameters more like the weight, the size and the power consumption of the amp, etc) to measure the overall benefit/performance of each amp. We may easily construct that formula if someone will carry out experiments and put the corresponding parameters into the formula. @jeffseight , does it look good to you? 

@tweak1 I am sorry for that accident. Something similar happened with my Megaschino, but it was finally repaired (just 10 days ago). Now neither am I in an extreme hurry to repair my 5.5 watts SET amp (earlier the left channel  EL34 tube of the amp was blown up and damaged  the 50 v 470 capacitor which is just below the amp. The amp still worked but the left channel was a bit weaker. Finally, I decided to replace the capacitor. We touched just this small part of the amp, nothing else. Surprisingly, no sound coming out of either channel anymore. I have no idea what could happened. The amp has a blocking system, which now does not unblock). 

Wow has this thread gone off the rails! All b/c of one member.

Well this person also tends to not practice what he preaches. Below is what he posted in September last year:

Sadly, there are many small minded people who can't accept that their opinions on the matter are unimportant to a great many.

Based on this, it tells me that this person not only has a small mind, but an even smaller brain!

Honestly, i don't see a point in personal insults. 

@ricevs , if I understood it correctly,  does an essential part of your moding consist of verifying and replacing wiring,  capacitors and resistances, or something similar? Do you rely on your personal sonic preferences, how you attain a better sound reproduction? 

Nio,

I am out of this thread.

I will begin another to carry on the proposal.

@ricevs mentioned this new brand to me a few days ago. Ric is modding my Peachtree GAN1 (to his preferences of course). This other amp he mentioned is the same as the GAN1 in spirit. It is more robust in that it has a volume, analog inputs, likely better software, and USB and SPDIF. It also has some audiophile name recognition and cost a lot more money (which makes some happy).

Maria Amplifiers – Daniel Hertz SA

Not sure if it has a remote.

@jeffseight I'd be up for a shootout in the Bay Area.

More than happy to bring:

Class D Mini GaN 5

Peachtee GaN 1

Purifi 

HiFi Rose RA 180

Marty

Marty,

Very good. I just started a new thread on this idea.

Please pm me tomorrow for more discussion.

Niodari,

Please see the Gan 1 thread for a description of the mods.  Of course, we all use our own sonic preferences......there is no objective reality in audio....everything sounds different and there is no consensus.  However, all those (95+%) who listen to what I do (since the late 70s) like it.  Those that don't listen....well, they just have opinions......based on no real knowledge.

The real FUN is in experiencing things......try expeiencing joy and love......you can experience it right NOW.......we create our own reality.....What do you want?  It is all right here.....right now.  Blessings for everyone!

The real FUN is in experiencing things......try expeiencing joy and love......you can experience it right NOW.......we create our own reality.....What do you want? It is all right here.....right now. Blessings for everyone!

Ric, depends on what things we experience and if they really give us a joy. Right now i am experiencing a joy that gives me my Megaschino on jazz vocals. Hope soon will experience another joy with your moded *Voyager*. I am sending an email message to you (soon). 

Atma Sphere Class D mono blocks 

I’ve only had them in my rig for a day, but I am very impressed. It blows the doors off my Willsenton R8. And I’m simply running balanced direct from my Pontus II. 
 

The bass is soooo much grippier and textured. I thought my soundstage was more or less limited by my Tecktons and my room boundaries. I was wrong. The AS’s fill the room with energy that gave me goose bumps and pushed to soundstage in every direction. I finally have speakers that disappear. I’ve been told they need 200hrs of break in. Vocals are gorgeous. I’m not missing tubes one bit. I feel like I’ve finally pierced above the clouds and my system is performing at a true “audiophile” level. 

I’m going to demo the Gold Note stack next weekend.

@yyzsantabarbara 

Thanks for the 411 on Daniel Hertz, aka Mark Levinson

Here's a 16 minute overview by ML on his new kit

Just came across this new review of the Technics SU-G700M2 from The Absolute Sound on YouTube:

It's nice to have this deep dive into the inner workings of this amp. He even goes so far as to say it's a taste of the Ultra High End for a tenth of the price. Not perfect, or everyone's cup of tea, but it's got the goods.

All the best,
Nonoise

@rsf507 

Not as yet. Still trying to follow this thread even though it seems to have taken on a life of its own. There are several I would like a chance to listen to first. Difficult to arrange.

D-Class are exceptionally good.  Lots of power, cheap. Here are two different reviews I did and are different prices.  One can be bought under $100, and the other around $600 as they Hypex amps.

And

@atmasphere: Your quote earlier:

There should be no difference at all! If you think there is, then you are convinced that we can't make the measurements for everything we hear (which, since about the early 1990s, we can) and also that the human perceptual rules that are shared by everyone on the planet are of no consequence, making things like deciBels irrelevant.

In the interest of my own learning, would you please point out which measurements correspond to what people hear? It would also be interesting to know how the type of measurement is performed and deemed to correlate to how our hearing works. Thanks.

In the interest of my own learning, would you please point out which measurements correspond to what people hear?

Sure- two measurements that have not got the attention they deserve- first, distortion vs frequency, which ideally should be a straight line or decreasing with increased frequency.

If the amp has problems with feedback due to insufficient Gain Bandwidth Product, the distortion will rise with frequency above a certain point (often between 1 and 3KHz). If this happens the amp could be perceived as bright due to how our ears perceive higher ordered harmonics and the Fletcher Munson curve.

The other measurement is the distortion spectra. Its not enough that the distortion be low. The ear has a masking principle; the way that tube amps sound nice and smooth is because they have enough 2nd and 3rd harmonic that those harmonics are able to mask higher orders. If those harmonics are insufficient, the amp may be perceived again as harsh and bright. This measurement is a bit open to interpretation as you have to know what you are looking at to be able to say how the amp is going to sound when you listen to it.

Quite often this last measurement is done with the fundamental at a low frequency - like 50 or 100Hz. If this is so and there isn't a measurement with the fundamental at 1KHz or higher then the measurement isn't all that helpful if distortion rises with frequency! IOW at a low frequency the distortion spectra might appear benign but above a certain frequency things could be considerably different.

So now you can see how an amplifier with 0.005% harmonic distortion might sound harsh and bright if those harmonics are not masked and the THD was measured at a low frequency- this can hide problems in the design. OTOH a zero feedback tube amp might have much higher distortion, but because it does not rise with frequency and the lower orders dominate, it might sound smooth and musical.

Class D offers a means to eliminate the first problem of rising distortion as well as allowing for a more benign distortion spectra.

@atmasphere , your thorough thoughts and comments are always highly appreciated.

How the measurements reflect the sound that we perceive? This is very interesting question somehow relating theory with practice. I still cannot put these two things together. For example, I have never heard a more complete, realistic and clean sound than my 5 watts SET tube amplifier gives (which unfortunately was broken due to a defective output tube). It has very high distortion including at high frequencies (up to 5%). I perceive no distortion on normal listening levels. On the other hand, i am not sure whether the distortion per se (as it is commonly defined in electric engineering) is that important. Again i perceive no distortion with my LSA GaN Voyager 350, neither at low nor at high frequencies, independently of speaker load. I think the frequency response is adequate.   I would not say that it has no soundstage or it is harsh. Apparently all is good but the sound is not alive, realistic and joyful. You see a wax figure, apparently all looks beautiful, but something is missing (you cannot make any real relationship with a wax figure). Perhaps , the problem is not that this and other amplifiers do not do something well, but that it doesn't do something that it should do? You may say that  second and third order harmonics are missing. But if there is no distortion, what needs to be masked? 

How the measurements reflect the sound that we perceive?

I described that above.

Since the ear uses higher ordered harmonics to sense sound pressure, its keenly sensitive to them since the ear has a +120dB range. If these harmonics are not masked by the lower orders (2nd and 3rd) they will contribute to harshness and brightness, since the ear assigns tonality to all forms of distortion.

That is why you don't hear it outright as breakup in any amplifier that isn't being overloaded. You sense it as tonality instead. For example, the 'dry' quality some amplifier have is due to their distortion signature, which audiophiles call the 'sonic signature' of the amplifier.

I don’t understand why Roon requires having your amp on all day, but putting that aside, going from A all the way to D strikes me as somewhat extreme for one who is used to the Pass. Why not look into a good A/B first? 

going from A all the way to D strikes me as somewhat extreme for one who is used to the Pass. Why not look into a good A/B first? 

The main reason AB exists is to reduce heat and power consumption, with some of the benefit of class A operation.

Class D allows a good designer to sidestep some of the reasons for class A operation in the first place- a classic example being that of crossover distortion. Most class D amplifiers are literally incapable of this kind of distortion. In addition, the distortion of the output section isn't made in the same way that it is in a class A or AB design. The result can be that the distortion the class D amp generates can be far more benign to the ear. 

I've heard class D amps that compare more than just favorably to a Pass Labs amplifier. These days its not about class of operation, it simply about the sound.

Roon has an option to become a ’radio’ using the music you listened most recently. When the album/playlist is over, it will find other music that is similar (using your library, or if you are connected to Qobuz/Tidal?etc, a variety of similar songs from the entire available list via the web). I find myself listening for many hours as I go about my business, discovering new music/artists.

I just recently moved to New Orleans. Being much warmer than my previous address, I just ordered the Atma-sphere Class D. Going to put it up against my FirstWatt Sit -3 amp. Not a lot of extra heat from the FirstWatt, but it does add warmth in the summer.

Innuos Zen -> Exogal Comet -> Audio Hungary Quality APR 204 -> FirstWatt SIT-3 -> Rethym Saadhana

Should arrive early next month

The main reason AB exists is to reduce heat and power consumption, with some of the benefit of class A operation.

And the main reason D exists is to reduce heat and weight, while (hopefully) retaining some of the benefits of AB operation. But the gold standard sonically remains A. Where heat/weight is not a consideration (eg., preamps) class A is the norm.

If you take an amp like the LSA Voyager......you can make it sound way more liquid and musical and detailed by changing parts and eliminating parts......and this CANNOT be measured. The amp will measure exactly as it does stock. The amount of measured distortion or the types of measured distortion are just one indicators of sound.....not sole indicators. You can send me 5 pairs of Atmasphere amps and I will mod each one differently and you will hear them as all different sounding and they will all still measure like stock......this is the truth. To think we can measure everything we hear is simply NOT TRUE. Can you tell me how an interconnect SOUNDS via measurement?.......NO, YOU cannot....because all cables measure basically the same (minor amounts of capacitance and inductance differences). Even Belden make a line of audiophile cables called Iconoclast.....made by a very scientific kind of guy.......but they have three levels of cables.....basic copper, OFC copper and PCOCC copper......EVERYONE agrees that the PCOCC copper one sounds best.....yet the cables are all made the same except for the wire purity........and they measure the same. Same with everything in an amp......you cannot measure the filter caps on the output of a class d output stage but every brand will sound different and also if you put the outside foil to ground (it will sound better.....and still measure the same). This game is infinite.

@atmasphere :

In addition, the distortion of the output section isn't made in the same way that it is in a class A or AB design. The result can be that the distortion the class D amp generates can be far more benign to the ear. 

Very interesting statement; would you please elaborate on this? What kind of distortion does a class-A's output section produce that the class-D is less vulnerable to?

But the gold standard sonically remains A. Where heat/weight is not a consideration (eg., preamps) class A is the norm.

This statement is false. What is the 'gold standard' is a benign distortion product, one that allows the amplifier to be smooth, fast and detailed all at the same time. That may or may not be a class A amplifier; any amplifier is easy to mess up if feedback is poorly applied and this is often the case.

Very interesting statement; would you please elaborate on this? What kind of distortion does a class-A's output section produce that the class-D is less vulnerable to?

I cannot speak for all class D amplifiers; in our class D amp, the two sources of distortion are the encoding scheme and the use of deadtime (to prevent the output section from overheating due to finite turn-on and turn-off times of the output devices; if both are on at the same time you get 'shoot-through current' which can heat them up quite rapidly to eventually fail) in the output section. In our circuit, these non-linearities produce lower ordered harmonics rather than higher orders. Because the lower orders are benign and innocuous to the human ear, the result is a smoother sounding amp that sounds a lot like a tube amplifier- the distortion signature is really similar.

A class A amplifier, because its output section is not perfectly linear, will generate not just the lower orders but the higher orders as well. The class A operation is used to put the output device or devices in the most linear operating region, but that isn't the same as saying its actually linear and no class A output section is, so it generates distortion.

Again:

The ear is keenly sensitive to the higher orders since it uses them to sense sound pressure. This is why an amp with THD of 0.01% can still sound harsh, if the higher orders are not masked by lower ordered harmonics. The assigns tonality to all forms of distortion and higher ordered harmonics are sensed as harshness and brightness. 

I currently have and use a Parasound A21+ amp and became intrigued with the idea of these new Class D amps. So without even hearing one I purchased the NAD M23 amp. Should be in within a couple of weeks and I cannot wait to compare the two. 

For those interested, here's a video I made with Alberto Guerra explaining what is different about his amps:

I pulled the trigger for Starkrimson monoblocks with optional Gan power supply and 3 ft short speaker cables.

TAS_Product_Of_The_Year_2021.pdf

The above review by Dick Olsher is informative.

It will be nice if Leo can ship it tomorrow.

By the way one gentleman with Atma D will visit my house with his amp sometime next week

Then I will have chance to compare  Starkrimson monoblocks with Atma D.

Thomas

@shkong78, thanks for the support.

@shkong78 looking forward to your input re Starkrimson, and Starkrimson vs Atmasphere (expecting Ralph's to sound better given price differential). 

@orchardaudio are you considering a PCM digital-in amp along the lines of Peachtree GAN1? This looks appealing for multiway active speakers

@lewinskih01 I have that, see here:

https://orchardaudio.com/product/starkrimson_streamer_ultra/

@orchardaudio 

Thanks for the quick reply. While the product you linked does indeed have digital input like the GAN1, I believe these are very different concepts. Yours seems to require an internal DAC - effectively a DAC+amp in one box - while the GAN1 is a different concept altogether. 

@lewinskih01, you are correct its a compeltely different concept but the functionality of both is the same.

its a compeltely different concept but the functionality of both is the same.

@orchardaudio If you ask me your amp has the greater functionality...