A New Wave of Class D Integrated Amplifiers

alfa100

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I was offered Devialet Pro 440 For a few days home audition. Waited 24 hours for cable to settle ,selected a broad range of my favorite music , having had good night’s sleep followed by breakfast i proceeded to play the Devialet. CONCLUSION : I preferred my MSB Analog DAC , Aurender and Pass Labs Xa100.8 combination over The Devialet Pro 440, Roon Nucleus and NAS Hard Drive. . There was absolutely no comparison. On lower frequencies Devialet had no visceral slam and the Wilson Sasha can SLAM even better without SAM. Mids on the Devialet had no body . Tops were thin on the Devialet. As I turned the volume up on the Devialet , certain frequencies became louder ; mid bass upper mids and tops. Hurt my ears. could not hear air between instruments , transparency or the emotive aspects of music. Devialet felt compressed . The Devialet was set up to its best by Devialet dealer and everything was exactly the same in my room. The MSB/Pass Labs /Aurender combo sounded natural , real , normal. Solid bass with visceral slam , organic mids and painless clean clear upper frequencies. Based on proud Devialet owners I really wanted the Devialet to sound better. They take less space ,use less electricity, and way less cables. I liked Roon for its meta data and organising material from multiple sources in one screen. Also had I sold my kit and bought the Devialet brand new I would have spare cash . But try as hard as I could tuning bass . Treble , balance , SAM , equalizer etc I could not enjoy the sounds it produced. Maybe the DAC in the Devialet could not compete with MSB. Maybe the Devialet amplifier section could not compete with my Pass Labs Xa 100.8 mono blocks. The Devialet Pro 440 is also a pair of mono blocks. This friends is MY honest review .
 
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alfa100

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Kal,
Of course, you would want to review it. It is in the price range of the components you use. However, this does not give anyone enough information to really know what is going on. Why don't all the review magazines send all components to most all reviewers? Rather than the usual review in every magazine that says......"this is the best thing at its price point and also 2-3 times its price".......and then you re read the review and realize that the reviewer has NONE of its latest competition and is comparing it to something years old. I must of read this a hundred times. If these magazines would really want to SERVE people then they would get maybe 5-10 of the latest and greatest thing in a particular price range and send them around to 5 different reviewers and then post the results. This would give the public a really good idea of how they all sound versus each other so we could make informed purchases. The magazines (all of them) are in business to make money. There are so many products at every price point. How can people know what to purchase? It is all the blind leading the blind. If a magazine did what I suggest then you could actually know something.......AND...the magazine would probably go out of business.....since all magazines are based on revenue from advertising. For instance, if they did a shoot out of the 10 most coveted preamps 10-40K then the losers of the shoot out would never advertise again. What if they did a shoot out of cables and Audioquest did not come out anywhere near on top.....do you think they would continue to advertise? What if B&W was way down the list in a big speaker test?

When I first got into this game in the late 70s we did not need the magazines and there was no internet. Within a 4 mile radius my audio buddies owned pretty much ALL the best stuff in the world.....maggies, Quads, Dayton Wrights, KLH 9s, triamped JBL monster system, custom tri amped wild system, etc. All the best preamps, power amps, cartridges, head amps, tone arms and turntables. You see, there were not more than a hand full of "worlds best" stuff back then. Two of my friends were within a couple of blocks from me and we would even walk over to each others house with the latest cartridge or preamp and A/B directly. We all KNEW what was going on. Of course, we were all very ignorant of all the things we know today. We had no idea that cables made such a difference, that footers and shelves made a difference, that fuses made a difference, that getting your cables off the floor made a difference, that damping heatsinks on a transistor amp makes a difference, that AC line conditioning and dedicated lines make a difference, that room treatments, resistors, solder, wire, capacitors, jacks, etc...etc, into infinity makes a difference.

High end audio is so different from most other hobbies.....in that it is almost totally subjective. Each man is on his own....to tune his system any way he prefers. There is no racetrack that "proves" the absolute superiority of any component. Measurements for the most part mean very little compared to listening tests. In drag racing....everyone knows what is going on. There are no guessing games. This is why all dragsters in the big classes all look the same and almost all run the same. Everything is known.....you have horsepower, drag, traction, gearing, weight and the driver. That is all there is. And you can measure the best car with a stop watch. Nothing like this in high end audio. Every single thing you do to a system changes the sound and most of the changes cannot be measured. However, if you are smart and do a lot of research then you can find components at every price range that are really good. However, you really need to have the ability to listen to these things before you buy or buy used so you can easily move the unwanted component. Most of my audio buddies read, read and read more and ask questions before even trying something. They look for people who seem to have real knowledge and are tweaky.....not just fan boys. If you are diligent and committed you can make seriously great sound at any price point. But most reviews posted in magazines and by people on line are just one mans opinion based on his knowledge and ability to source other competitors products (both qualities usually seriously lacking). How many people would buy all the preamps (or whatever) they think might be great and A/B them (burning each one in for 500 hours....each one using the best fuse and on the best footers tuned to it and best power cord for it, etc.)? If you did this, you would REALLY know something. You could then sell all the losers and be happy till next year when a new version of your thing comes out....he he.

What a crazy game high end audio is!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Happiness is living in this moment......being aware of the infinite love and joy that exists in this and every moment. High end audio is a game of TRYing to find the best component that gives you a temporary rush and then you get bored and want something new.....he he....like anything material in life....it is in time.....and time makes rust. The heart never rusts. The soul never rusts. We are eternal joy. Can you feel it? Send blessings to everyone you meet.....when you give love you feel love. Hug the world.....Hug your self. We are incredibly beautiful....and deserving....way beyond what your mind could every imagine...........
My thoughts exactly. Thank you for taking the time to share your experience.
 

alfa100

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Hello Kal. I quote from your review “
Conclusion
The only clear conclusion is that the M33's Purifi technology is fully competitive that used in more expensive, separate power amps. Class-D without any ifs or buts. “. Am I missing something because I do not understand this sentence ?
 

DaveC

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Kal Rubinson

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ands. You're missing ands. ;)
Ha! That's possible. It is also possible that I meant only "ifs or buts" and, for some obscure reason, intentionally excluded an "and." ;)
OTOH, now that I look carefully, there really is a word missing: "The only clear conclusion is that the M33's Purifi technology is fully competitive with that used in more expensive, separate power amps. Class-D without any ifs or buts. “
 

Hear Here

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Ha! That's possible. It is also possible that I meant only "ifs or buts" and, for some obscure reason, intentionally excluded an "and." ;)
OTOH, now that I look carefully, there really is a word missing: "The only clear conclusion is that the M33's Purifi technology is fully competitive with that used in more expensive, separate power amps. Class-D without any ifs or buts. “
I had pretty much decised on changing my NAD M32 for the new M33 and Kal's review has prompted me to place an order. It should be with me next week as stocks have (at last) arrived in Europe.

Kal - Impressions on suitability with Avantgarde Duo XD horn speakers? Nominal 18 ohms, and 107dB. Far too powerful of course, but that's not a valid reason for not buying.

The Duo XDs have their own DSP abilities but no means of measuring frequency response curve so difficult knowing where to start. I'm thinking that Dirac in the M33 (using a good calibrated mic) will show this curve and I may be able to use the Duo's DSP to make all necessary adjustements. I'd prefer not use Dirac except for measurement purposes as my experience with room correction (when engaged) is that it often leads to some of the life being lost from the music. Peter
 
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Kal Rubinson

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Kal - Impressions on suitability with Avantgarde Duo XD horn speakers? Nominal 18 ohms, and 107dB. Far too powerful of course, but that's not a valid reason for not buying.
I have no impressions but acknowledge the issue you raise. In this case, SNR and gain are more significant than power, of course.

The Duo XDs have their own DSP abilities but no means of measuring frequency response curve so difficult knowing where to start. I'm thinking that Dirac in the M33 (using a good calibrated mic) will show this curve and I may be able to use the Duo's DSP to make all necessary adjustements. I'd prefer not use Dirac except for measurement purposes as my experience with room correction (when engaged) is that it often leads to some of the life being lost from the music.
Interesting idea. I am sure that you can make useful adjustments but doubt that you can "make all necessary adjustments." What tools exist in the XD's DSP? If you just want a measurement tool and EQ calculation, you can run REW on any laptop/PC with a $100 mic and get this done.
 

wil

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The XD software has a 10 band eq below 500 Hz. It's a pretty powerful tool.
 

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Hear Here

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Interesting idea. I am sure that you can make useful adjustments but doubt that you can "make all necessary adjustments." What tools exist in the XD's DSP? If you just want a measurement tool and EQ calculation, you can run REW on any laptop/PC with a $100 mic and get this done.

Thanks Kal. THe XD's DSP is pretty amazing. You need to connect a PC to both speakers via USB and you can adjust the straight line representing frequencies below about 500Hz just about however you wish.

To start, pick your preferred crossover type - 10 to choose from - Butterworth 24dB being default but others from Linkwitz and Bessel - at each end of the bass driver's range. Then adjust XO frequencies at each end. Then there are 10 adjustable points along the rest of the bass line that can be raised or lowered by up to 15dB each with an adjustable Q for how steep the rise and fall at those frequencies is. And those are just the few adjustments I've discovered so far and there are more still, some marked as "leave these to the experts". All too bloodly complicated for me!

The trouble is, this starts with effectively a straight line (curving down at top and bottom) because there are no "actual" listening position measurements. I've not yet even found out if a mic-measured response line can be substituted for the default theoretical line. However the XD software appears to be capable of just about every concievable adjustment to the bass response of these speakers, so if Dirac indicates where adhjustments are needed, I feel sure they can be made with XD. Peter
 

Hear Here

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The XD software has a 10 band eq below 500 Hz. It's a pretty powerful tool.
Thanks Wil - you've shown something I've just spent half an hour trying to describe in words! I hope Kal sees what XD can do. Maybe he should look at reviewing an Avantgarde XD speaker - we've not seen an AG reviewed for years. In fact I bought my original Unos as a direct result of Robert Deutsch's excellent review from about 2000.
 

Kal Rubinson

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The XD software has a 10 band eq below 500 Hz. It's a pretty powerful tool.
Perhaps two decades ago, one might have considered this powerful. In today's context, I would not label it more than effective. ;)
Thanks Kal. THe XD's DSP is pretty amazing. You need to connect a PC to both speakers via USB and you can adjust the straight line representing frequencies below about 500Hz just about however you wish................... ............................However the XD software appears to be capable of just about every concievable adjustment to the bass response of these speakers, so if Dirac indicates where adhjustments are needed, I feel sure they can be made with XD.
Dirac will only give you a continuous curve, not individual values, although you can move the cursor along each line and manually read the coordinates incrementally and try to adjust the XD curve for each speaker to match.

I still think that, unless you have reasons to want the M33 for its other capabilities (and there are many), just getting REW and a miniDSP Umik-1 would be more effective. You can do measurements with its internal tones and have it generate a set of filters/corrections for direct entry into the XDs.
 

Hear Here

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Perhaps two decades ago, one might have considered this powerful. In today's context, I would not label it more than effective. ;)

Dirac will only give you a continuous curve, not individual values, although you can move the cursor along each line and manually read the coordinates incrementally and try to adjust the XD curve for each speaker to match.

I still think that, unless you have reasons to want the M33 for its other capabilities (and there are many), just getting REW and a miniDSP Umik-1 would be more effective. You can do measurements with its internal tones and have it generate a set of filters/corrections for direct entry into the XDs.
Thanks Kal. That does seem to be a simple and inexpensive option, though I'm still getting the M33!

I already have a USB mic (though I don't know where I could finds its calibration table) that came with Martin Logan's PBK kit and there'll be another mic with the M33, but I guess the miniDSP Umik-1 ia a better one. I'll take a look at the REW software - I presume it's simple to use on a Windows PC.
 

Kal Rubinson

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I already have a USB mic (though I don't know where I could finds its calibration table) that came with Martin Logan's PBK kit and there'll be another mic with the M33, but I guess the miniDSP Umik-1 ia a better one.
It's not necessarily better than either but you can download the calibration data (use the 90deg option).
I'll take a look at the REW software - I presume it's simple to use on a Windows PC.
Not quite as easy as the PBK but more powerful.
 
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alfa100

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Ha! That's possible. It is also possible that I meant only "ifs or buts" and, for some obscure reason, intentionally excluded an "and." ;)
OTOH, now that I look carefully, there really is a word missing: "The only clear conclusion is that the M33's Purifi technology is fully competitive with that used in more expensive, separate power amps. Class-D without any ifs or buts. “
That’s better. I know the meaning of competitive
 

Mikem53

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If I ever downsize my stereo I am getting Class D amps. I am tired of having to run the AC to listen to music. I have to admit the Pass amps are nice in the winter.
I had a pair of Bel Canto Ref600 mono amps, same hypex modules used in their Black line. Never turned them off and they consumed 15W at idle. Unfortunately the low power consumption was it’s best attribute. I had a pair of Focal speakers with metal domes at the time that combo tried to kill me.. Every time I listened, and Once when I was bending down in front of the speaker, my ear came close enough to the Be tweeter and I grounded my static buildup through my ear to the tweeter. It was enough to kick the protective circuit of the Yggdrasil DAC and shut it down.. hurt like hell.. Was crazy.. now I have silk domes for safety reasons, lol and it stopped my ear bleeds.
I Love my inefficient, heavy Pass heater !! it hasn’t tried to kill me yet.. just my back a little, and winters coming again..
I got those BC amps from Joe Grado who just had them stacked up in his basement unused and unopened.
 

alfa100

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I had a pair of Bel Canto Ref600 mono amps, same hypex modules used in their Black line. Never turned them off and they consumed 15W at idle. Unfortunately the low power consumption was it’s best attribute. I had a pair of Focal speakers with metal domes at the time that combo tried to kill me.. Every time I listened, and Once when I was bending down in front of the speaker, my ear came close enough to the Be tweeter and I grounded my static buildup through my ear to the tweeter. It was enough to kick the protective circuit of the Yggdrasil DAC and shut it down.. hurt like hell.. Was crazy.. now I have silk domes for safety reasons, lol and it stopped my ear bleeds.
I Love my inefficient, heavy Pass heater !! it hasn’t tried to kill me yet.. just my back a little, and winters coming again..
I got those BC amps from Joe Grado who just had them stacked up in his basement unused and unopened.
Wow. Did not realize this . Hope it did not damage hearing in that ear. How wud you compare the sound made by Pass Labs to your Class D Amps ?
 

Mikem53

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My ear zap was a freak accident .. and I’m fine, thank you..
Those class D amps and the Focal combo was not for me, very hot On top, too intense on the highs. bass was powerful and tight.. but I found it mechanical sounding. Listening sessions were short and I found myself using my headphones and leaving the main system off.. It’s all gone now.. I never paired the Pass with the Focals.. I almost Always have used Tube amps in my systems.. I got the Pass on a home Trial as I wasn’t sure it would fit my needs.. It’s very transparent but it’s not sterile or clinical sounding. I’m using a quad of 6SN7’s in my preamp. This works well with the Pass sound and my Daedalus speakers.. So I’m liking the Pass very much! and I’m not dealing with 6C33’s shorting and cracked ceramic sockets anymore..
 

alfa100

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My ear zap was a freak accident .. and I’m fine, thank you..
Those class D amps and the Focal combo was not for me, very hot On top, too intense on the highs. bass was powerful and tight.. but I found it mechanical sounding. Listening sessions were short and I found myself using my headphones and leaving the main system off.. It’s all gone now.. I never paired the Pass with the Focals.. I almost Always have used Tube amps in my systems.. I got the Pass on a home Trial as I wasn’t sure it would fit my needs.. It’s very transparent but it’s not sterile or clinical sounding. I’m using a quad of 6SN7’s in my preamp. This works well with the Pass sound and my Daedalus speakers.. So I’m liking the Pass very much! and I’m not dealing with 6C33’s shorting and cracked ceramic sockets anymore..
Very similar to why I prefer Pass Labs to Class D.
 
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Hear Here

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It's not necessarily better than either but you can download the calibration data (use the 90deg option).
Not quite as easy as the PBK but more powerful.
Kal - If I use the REW software with a calibrated mic (either the one you suggest or the Drayton one that comes in ML's PBK kit), would you suggest that the mic is pointed towards the speakers or upwards towards the ceiling?

I ask because the Dirac instructions say point upwards, but my results were poor, probably as there's a pendant light above some measurment positions. This causes the left speaker to play louder when the filter is engaged. I hope you'll say it's usually best to point towards the space midway between the speakers. Thanks. Peter
 

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