In the pass I have worked with people on class D technology at very low frequencies (below 30Hz). At that time I never thought it could get good to the point to get good enough for audio use. Now it seems actually becomming very popular, probably due to the size/power ratio and size/sound quality ratio.
I'm opening this thread to inspire people to post their own experience listening to class D amps and how they conmpare against well known quality products or kits not using Class D technology.
Not having heard any class D stuff before, I talked with a friend that had a slim amp that runs cool at over 100W/ channel that sounded quite good. I will be going back to see what brand and model it is.
If you want to post in this thread, please observe the following:
1. You personally own or have unlimited access to both Class D and linear amps.
2. You can audibly hear the difference of absolute polarity on your system.
3. You ocasionally listen to live unamplified music and are familiar with how live intruments sound without amplification.
4. You have some knowledge about micing techniques and how it effects the recorded sound.
5. No personall attacks on the comparison methods other people use, but exchange of ideas is encouraged. (I have seen too many threads start out good, but turn into attack and defend thread)
I'm opening this thread to inspire people to post their own experience listening to class D amps and how they conmpare against well known quality products or kits not using Class D technology.
Not having heard any class D stuff before, I talked with a friend that had a slim amp that runs cool at over 100W/ channel that sounded quite good. I will be going back to see what brand and model it is.
If you want to post in this thread, please observe the following:
1. You personally own or have unlimited access to both Class D and linear amps.
2. You can audibly hear the difference of absolute polarity on your system.
3. You ocasionally listen to live unamplified music and are familiar with how live intruments sound without amplification.
4. You have some knowledge about micing techniques and how it effects the recorded sound.
5. No personall attacks on the comparison methods other people use, but exchange of ideas is encouraged. (I have seen too many threads start out good, but turn into attack and defend thread)
To kick this thread off.
My first experience with Class D technology was listening to a class D USB dongle rated at 1W. The speaker that I used at the time was not very accurate, but the sound was pleasing, and there was no harsh sound I was expecting. After commenting that the bass seemed to be a bit lacking probably due to the little thin wired output coils, the next version that came out seemed to have eliminated the coils or resorted to SMD coils. But the bass was improved.
My second experience, not positive whether it was a class D or not even though this friend mentioned it to be a class D but was not sure either. This amp, supposedly made in Germany, also sounded smooth with good resolution probably around $2000 USD.
These two experiences lead me to become interested in Class D amps.
My first experience with Class D technology was listening to a class D USB dongle rated at 1W. The speaker that I used at the time was not very accurate, but the sound was pleasing, and there was no harsh sound I was expecting. After commenting that the bass seemed to be a bit lacking probably due to the little thin wired output coils, the next version that came out seemed to have eliminated the coils or resorted to SMD coils. But the bass was improved.
My second experience, not positive whether it was a class D or not even though this friend mentioned it to be a class D but was not sure either. This amp, supposedly made in Germany, also sounded smooth with good resolution probably around $2000 USD.
These two experiences lead me to become interested in Class D amps.
Re: Class D Kits Compare well agaisnt traditional linear amps?
That's a pretty discriminating statement, and I would bet that most of the people (including myself) who visit the class d forum would not be able to post based on that...
Regardless, I have made my own amps based on Tripath's TA2021B chip and Monolithic Power's MP7720 chip. Both are class d designs but the MP7720 is a self oscillating design while the Tripath is an oscillator based design. I started threads on both of them if need more info (the TA2021B amp was dubbed the Ref-T and the MP7720 amp was dubbed D10.1).
Both amps I've made sounded better than the Sony, Onkyo, and Yamaha receivers I had previously listened to. Both amps also had much less power, and I don't need much because my speakers are sensitive and I listen nearfield.
A number of people also have kits of the D10.1 and will hopefully post listening impressions once they get them built.
A question for you soongsc - are you talking about any class d kit or module or are you looking for ones with a specific topology or output power level?
soongsc said:
That's a pretty discriminating statement, and I would bet that most of the people (including myself) who visit the class d forum would not be able to post based on that...
Regardless, I have made my own amps based on Tripath's TA2021B chip and Monolithic Power's MP7720 chip. Both are class d designs but the MP7720 is a self oscillating design while the Tripath is an oscillator based design. I started threads on both of them if need more info (the TA2021B amp was dubbed the Ref-T and the MP7720 amp was dubbed D10.1).
Both amps I've made sounded better than the Sony, Onkyo, and Yamaha receivers I had previously listened to. Both amps also had much less power, and I don't need much because my speakers are sensitive and I listen nearfield.
A number of people also have kits of the D10.1 and will hopefully post listening impressions once they get them built.
A question for you soongsc - are you talking about any class d kit or module or are you looking for ones with a specific topology or output power level?
Re: Re: Class D Kits Compare well agaisnt traditional linear amps?
I just wanted to get a feeling on Class D regardless of topology. To understand really how good they are. When different people talk about how good something is, technically, it's best to know what kind of reference they are comparing to, the observations are intended to understand just that and nothing more. Of course, the better linear amps people compare with, the more valuable the information is.
Lots of people just go though general impressions and not specific to a specific CD and the quality they notice. In my future listenings, I will post specific CD's and specific notice in detail such as the instruments, image, space impression, absolute polarity difference in sound. We already have too much in the meda that just post vague impressions just so that they can get advertisement, I certainly hope forums like this one does not become only and advertising place, but a place where people can know more detail about sound and products good or weak points.
Right now my own reference is a Hafler XL-280 made from a kit. While not expesive, it's performance is still hard to beat in terms of fidelity. It has served as a great reference when teaking speaker drivers because each time there is an improvement in the driver, the amp does reveal correctly the expected change in fidelity. I also have other not small brand name products, but since they have not established a reputation over time, it is not realy good to use as reference.
You have mentioned the Sony, Onkyo, and Yamaha, these are well known brands and many people are familiar with the type of sound they produce. Thanks for posting.
BWRX said:
I just wanted to get a feeling on Class D regardless of topology. To understand really how good they are. When different people talk about how good something is, technically, it's best to know what kind of reference they are comparing to, the observations are intended to understand just that and nothing more. Of course, the better linear amps people compare with, the more valuable the information is.
Lots of people just go though general impressions and not specific to a specific CD and the quality they notice. In my future listenings, I will post specific CD's and specific notice in detail such as the instruments, image, space impression, absolute polarity difference in sound. We already have too much in the meda that just post vague impressions just so that they can get advertisement, I certainly hope forums like this one does not become only and advertising place, but a place where people can know more detail about sound and products good or weak points.
Right now my own reference is a Hafler XL-280 made from a kit. While not expesive, it's performance is still hard to beat in terms of fidelity. It has served as a great reference when teaking speaker drivers because each time there is an improvement in the driver, the amp does reveal correctly the expected change in fidelity. I also have other not small brand name products, but since they have not established a reputation over time, it is not realy good to use as reference.
You have mentioned the Sony, Onkyo, and Yamaha, these are well known brands and many people are familiar with the type of sound they produce. Thanks for posting.
Here you can find interesting and valuable opinion on UcD classD modules:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=74511
post 9
I have listened the same system. Very very good.
Regards,
beppe
http://www.diyaudio.com/forums/showthread.php?s=&threadid=74511
post 9
I have listened the same system. Very very good.
Regards,
beppe
I have had many different solid state amplifiers over the years, some you may have heard of, some not, Audiolab, Rotel, Musical Fidelity Class A transistor amp, Valve amplifiers with EL84's etc etc.
I have modded several S.I amps with the Tripath 2024 and I have a Tripath 2020 based amp. I do not know in what they are "better" than the other amps I have owned or if they are just "different". However to my ears they do a lot of things right and the things they don't do right, I don't notice.
When I first heard an un-modded S.I i thought there was something unique about the sound that I liked.
I listen to a modded S.I all the time now. Sound quality is a very subjective matter and not everbody likes the sound. £ for£ or $ for $ I don't think much comes close in sound quality, but maybe I have cloth ears ?!
I have modded several S.I amps with the Tripath 2024 and I have a Tripath 2020 based amp. I do not know in what they are "better" than the other amps I have owned or if they are just "different". However to my ears they do a lot of things right and the things they don't do right, I don't notice.
When I first heard an un-modded S.I i thought there was something unique about the sound that I liked.
I listen to a modded S.I all the time now. Sound quality is a very subjective matter and not everbody likes the sound. £ for£ or $ for $ I don't think much comes close in sound quality, but maybe I have cloth ears ?!
You're trying to extract too fine a resolution from a very subjective experience.
Only a professional reviewer would go to such an extent to convince, but look at the spew they put forth.
The fact is so many people find _the better D amps_ to be good enough to do away with whatever they had before can be used a weighting factor that it has in fact arrived, but that's not to ever imply they all have attained such performance.
You want to compare regardless of topology? If that's all you go by, class D will be in the stoneage for you for a looooooooong time, because there aren't that many out there that belong in the upper class. You could likely count them on one hand, after which all the others will drag them down and class a/b would still rule the roost. Look at car audio for instance, where D technology is at least a decade behind and still really for sub use only.
I think if you really want to get a feel for class D, you just have to try it, even if it means building your own from scratch.
there are new high end car amps that are using full range class D designs so hopefully, things will change.
Not to be argumentative, but could you name a few? Last time that came up it wasn't the case at all, and I honestly don't follow car audio equipment at all.
Thanks
Thanks
I can't remember the car amps but I've seen several manufacturers are starting to use icepower technology in full range amps.
haven't checked how many models using the technology each manufacturer are making though.
haven't checked how many models using the technology each manufacturer are making though.
I have some experience in comparing the different amp topologies.
1st system:
PC source lossless files oversampled on the PC to 88.2Khz, EMU 1820M using SPDIF
DIY NOS DAC dual TDA1541A
MOSFET 80W DIY amp (15 years old, minimalist ETI design)
Dunlavy SCIV-A tower speakers
Dedicated AV room with sound treatment
In this system I have swapped out the MOSFET amp with tweaked UCD400s, re-using the power supply.
The MOSFET system sounds sluggish & mushy by comparison, with the UCD beating it hands down, providing more 'air' (clean), wider soundstage and firmer bass. This is one of the best sounding setups I have heard, the only complaint is its 'speed' / transient response could be better compared to the system below (possibly caused by the NOS DAC).
2nd System:
PC source lossless files with M-Audio Revolution using SPDIF and PC based digital room correction (frequency & time domain).
Panasonic XR45 receiver 80w (TI Equibit true digital amp)
Dunlavy Athena speakers
This system can produce wonderful dynamics (transient attack) that I have not been able to duplicate with the UCD setup. It has good soundstage but the bass could be a bit better (I suspect the XR45 power supply here). However the room is not ideal and is improved with DRC but cannot match the 1st system even with very similar speakers.
3rd System:
PC source lossless files with tweaked EMU0404 analog out
AMP6 Tripath TA2020 20w with DIY Jordan JXR6 full range above 100Hz near field
AMP1 Tripath TA2022 150w bridged with DIY Peerless 8" subwoofer below 100Hz
DIY Active crossover filter & DRC to produce a flat in-room response.
As the system on my main home PC I listen to it a couple of hours a day. This system produces a huge soundstage and does a great job in placing instruments inside the soundstage. The bass is firm and tight however the JXR6 lacks presence in the mid bass and would be better crossed over at say 300Hz (speaker fault not amp).
In summary:
A well implemented Class D system will give you better soundstage and a more controlled bass compared to an equivalent Class A/B system. Class D amps are very revealing and can be brutal (harsh) with poor sources. I have also noticed that the power supply quality is more important than in a class A/B setup. If done right a Class D amp will give you audiophile performance with plenty of watts, low price and less heat.
I dont understand what you mean by tell the difference between absolute polarity and why this matters when comparing amplifiers?
Regards,
Dean
1st system:
PC source lossless files oversampled on the PC to 88.2Khz, EMU 1820M using SPDIF
DIY NOS DAC dual TDA1541A
MOSFET 80W DIY amp (15 years old, minimalist ETI design)
Dunlavy SCIV-A tower speakers
Dedicated AV room with sound treatment
In this system I have swapped out the MOSFET amp with tweaked UCD400s, re-using the power supply.
The MOSFET system sounds sluggish & mushy by comparison, with the UCD beating it hands down, providing more 'air' (clean), wider soundstage and firmer bass. This is one of the best sounding setups I have heard, the only complaint is its 'speed' / transient response could be better compared to the system below (possibly caused by the NOS DAC).
2nd System:
PC source lossless files with M-Audio Revolution using SPDIF and PC based digital room correction (frequency & time domain).
Panasonic XR45 receiver 80w (TI Equibit true digital amp)
Dunlavy Athena speakers
This system can produce wonderful dynamics (transient attack) that I have not been able to duplicate with the UCD setup. It has good soundstage but the bass could be a bit better (I suspect the XR45 power supply here). However the room is not ideal and is improved with DRC but cannot match the 1st system even with very similar speakers.
3rd System:
PC source lossless files with tweaked EMU0404 analog out
AMP6 Tripath TA2020 20w with DIY Jordan JXR6 full range above 100Hz near field
AMP1 Tripath TA2022 150w bridged with DIY Peerless 8" subwoofer below 100Hz
DIY Active crossover filter & DRC to produce a flat in-room response.
As the system on my main home PC I listen to it a couple of hours a day. This system produces a huge soundstage and does a great job in placing instruments inside the soundstage. The bass is firm and tight however the JXR6 lacks presence in the mid bass and would be better crossed over at say 300Hz (speaker fault not amp).
In summary:
A well implemented Class D system will give you better soundstage and a more controlled bass compared to an equivalent Class A/B system. Class D amps are very revealing and can be brutal (harsh) with poor sources. I have also noticed that the power supply quality is more important than in a class A/B setup. If done right a Class D amp will give you audiophile performance with plenty of watts, low price and less heat.
I dont understand what you mean by tell the difference between absolute polarity and why this matters when comparing amplifiers?
Regards,
Dean
You could say it's a myth that he's bought into?
(that's going to start a war.... which other threads are already dedicated to)
I assume it has to do with the phase of the reproduced signal with respect to the original (inverted / non inverting)?
I have not tried it myself, but I can't see how the ear can tell the phase of a signal in the temporal domain where sound is cyclic, and if it can, what does the difference sound like?
Regards,
Dean
I have not tried it myself, but I can't see how the ear can tell the phase of a signal in the temporal domain where sound is cyclic, and if it can, what does the difference sound like?
Regards,
Dean
deandob said:
deandob said:
The absolute polarity issue is discussed in this thread, which probably would be a better place for discussion.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=69783
So hopefully we don't get into debate here. But is was just a finding during the process of improving a speaker driver in that the better the driver performed, the more obviouse difference between the absolute polarities.
I'm quite sure the JXr6 would be able to reveal such difference.
re: comparisons with suggestions ...
deandob:
" ... 1st system:
... Dedicated AV room with sound treatment ... In this system I have swapped out the MOSFET amp with tweaked UCD400s, re-using the power supply. The MOSFET system sounds sluggish & mushy by comparison ..."
One could only wonder how the MOSFET would have performed with a little tweak to that power supply. I have added 0.22 uF poly "snubbing" caps across the PS output power rails of MOSFET amps with considerable success = brightening these up nicely.
" ... 2nd System:
... Panasonic XR45 receiver 80w (TI Equibit true digital amp) ...
This system can produce wonderful dynamics (transient attack) that I have not been able to duplicate with the UCD setup. It has good soundstage but the bass could be a bit better (I suspect the XR45 power supply here). ... "
I too have a Pana under test (XR-70) and have noticed that after extended listening (bridged A/B stereo into power hungry mains), "fatigue" sets in ... possibly the PS rails become anemic (poorer response from the PS?) or general lack of brightness and punch possibly caused by warming in the PS components. I have not seen reports of this with the XR45, but have this in other Class-D amps ... possibly a comparison between the XR45 & XR70 would show similar PS designs, Panasonic using the '45's PS design for the '70 ... puzzled ??
" ... 3rd System:
...AMP6 Tripath TA2020 20w ... AMP1 Tripath TA2022 150w bridged with ... subwoofer
As the system on my main home PC I listen to it a couple of hours a day. ... huge soundstage ... great job in placing instruments inside the soundstage. The bass is firm and tight however ... (speaker fault not amp). ..."
" ...Summary: A well implemented Class D system will give you better soundstage and a more controlled bass compared to an equivalent Class A/B system. Class D amps are very revealing and can be brutal (harsh) with poor sources.
* I have also noticed that the power supply quality is more important than in a class A/B setup. *
... If done right a Class D amp will give you audiophile performance with plenty of watts, low price and less heat. ..."
Ditto to all that and then some. Perhaps the greatest area for improvement of Class-D amps could come from power supply tweaks, possible more or better use of more responsive catacitance on the power rails, located physically close to the last amplification stage, plus maybe Ferrite Beads and other humbucking technics located there as well.
As for over all efficiencies, no question Class-D has the potential to dominate the future of high tech audio amplification.
I would like to see comparable high technology power supplies to go with them, especially addressing the "audio fatigue" question. As this "fatigue" or loss of response sets in, the listening experience suffers, even at low levels. (I wish I could describe this better as a term like fatigue is not very scientific ... lack of response ? ... lossing "punch" ?? ... phase shifting over time ???)
😕
deandob:
" ... 1st system:
... Dedicated AV room with sound treatment ... In this system I have swapped out the MOSFET amp with tweaked UCD400s, re-using the power supply. The MOSFET system sounds sluggish & mushy by comparison ..."
One could only wonder how the MOSFET would have performed with a little tweak to that power supply. I have added 0.22 uF poly "snubbing" caps across the PS output power rails of MOSFET amps with considerable success = brightening these up nicely.
" ... 2nd System:
... Panasonic XR45 receiver 80w (TI Equibit true digital amp) ...
This system can produce wonderful dynamics (transient attack) that I have not been able to duplicate with the UCD setup. It has good soundstage but the bass could be a bit better (I suspect the XR45 power supply here). ... "
I too have a Pana under test (XR-70) and have noticed that after extended listening (bridged A/B stereo into power hungry mains), "fatigue" sets in ... possibly the PS rails become anemic (poorer response from the PS?) or general lack of brightness and punch possibly caused by warming in the PS components. I have not seen reports of this with the XR45, but have this in other Class-D amps ... possibly a comparison between the XR45 & XR70 would show similar PS designs, Panasonic using the '45's PS design for the '70 ... puzzled ??
" ... 3rd System:
...AMP6 Tripath TA2020 20w ... AMP1 Tripath TA2022 150w bridged with ... subwoofer
As the system on my main home PC I listen to it a couple of hours a day. ... huge soundstage ... great job in placing instruments inside the soundstage. The bass is firm and tight however ... (speaker fault not amp). ..."
" ...Summary: A well implemented Class D system will give you better soundstage and a more controlled bass compared to an equivalent Class A/B system. Class D amps are very revealing and can be brutal (harsh) with poor sources.
* I have also noticed that the power supply quality is more important than in a class A/B setup. *
... If done right a Class D amp will give you audiophile performance with plenty of watts, low price and less heat. ..."
Ditto to all that and then some. Perhaps the greatest area for improvement of Class-D amps could come from power supply tweaks, possible more or better use of more responsive catacitance on the power rails, located physically close to the last amplification stage, plus maybe Ferrite Beads and other humbucking technics located there as well.
As for over all efficiencies, no question Class-D has the potential to dominate the future of high tech audio amplification.
I would like to see comparable high technology power supplies to go with them, especially addressing the "audio fatigue" question. As this "fatigue" or loss of response sets in, the listening experience suffers, even at low levels. (I wish I could describe this better as a term like fatigue is not very scientific ... lack of response ? ... lossing "punch" ?? ... phase shifting over time ???)
😕
All I know is that having listened to some pretty expensive amps (Marantz, high end-Yamahas, and McIntosh), the T-amp is quite good in comparison.
It's also much cheaper, and works nicely with inexpensive Fullrange-based speakers.
It's also much cheaper, and works nicely with inexpensive Fullrange-based speakers.
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