" Not one mention of the output filter that has to address the switching noise of the switching frequency, which is the Achilles Heel with present day switching frequencies."
George,
I understand the importance of having a good well matched passive filter in class D amps to remove the ultra high switching frequencies from the signal path after their Pulse Width Modulation job has been completed. I agree that this is a critical component in the process since this is where your theory states these switching frequencies can affect the audible range if not completely filtered out.
Perhaps I just got lucky and only bought class D amps with exceptionally good passive filters. If they weren’t so good, maybe I could catch a trace of the switching frequencies affecting the audible range that you mention so often. Thank you, George, I think you just might have solved the mystery of the missing sonic artifacts/anomalies in my, and likely boatloads of others’, class D amps. No wonder nobody believes your theory; All the evidence is being filtered out effectively just as designed.
Please tell me the class D amp brands and models of class D amps you were able to detect some audible artifacts from. We can compare all the specific filters operating flawlessly in our class D amps to the specific filters obviously working so poorly in the class D amps you listened to that inspired your infamous and discredited theory.
Thanks again for your help,
Tim |
Yes, and they are the industries top designers, nothing will change until that dreaded switching frequency is taken up much higher. So then the output filter can do it’s job properly without any effects down into the audio band.
Technics is leading the way with the SE-R1 with twice as high switching frequency, but it’s not mainstream yet, and really should be even higher, one can only hope.
Cheers George
It’s not just the switching frequency, but a combination of that..and some other potent problems. Some things can be done to fix it and I have my ideas on how to tackle these critical ’other’ problems. The solutions are all valid on paper, but the real world may say different. I have successfully dealt with these problems in other arenas of design, so the knowledge should be transferable. We shall see. That, is, if I ever manage to get to the point where I can spend time fooling with these Class D problems again. Too busy cranking cables out the door right now. I tried to do it on my own re existing modules (retrofit), but (un)said company wanted no part of it, unless it is in their domain - so I declined. |
I have a pioneer sc68 which has class D amplifier. I have it hooked to KET 205/2. The sound is just beautiful. Just clean sound with details about all the different instruments in the music. Steve Wonder ribbon in the sky feels like he is singing in the living room :)
Also I am not sure what warm up period of 1000 hours mean.. It does not make any sense to me as I read these posts. The speakers need warm up period because they are mechanically moving parts that need to settle or get flexible. If electronics change behavior that much with time.. that's scary to me from a Computer engineer perspective. |
The 1000 hours is urban legend with no basis in science or audible difference to a golden ear. |
sfseay
The 1000 hours is urban legend with no basis in science or audible difference to a golden ear.
msalha
Also I am not sure what warm up period of 1000 hours mean.. It does not make any sense to me as I read these posts. The speakers need warm up period because they are mechanically moving parts that need to settle or get flexible. If electronics change behavior that much with time.. that's scary to me from a Computer engineer perspective.
+1 sfseay and msalha, this is just a lot of Class-D paranoia rubbish, it’s said just to calm owners down that don’t like it from the get go, to eventually take it on the chin and live with it. Cheers George |
yes, the 1000 hrs is a total red herring. I’m embarrassed to hear it being uttered.
If, in your familiar home environment....you don’t hear some fundamental qualities that you like, and enjoy (IE, emotionally!! not cerebrally!! vital point!!), then it is simply not working.
Music is about your balls, your butt, your body, your heart, your breath of life.
not your brain.
You can analyze all you want, but it must get your butt swinging.
Otherwise it should go in the trashcan.
Seriously.
It’s about the endorphins. For with them on the fly and in-situ, you actually experience positive neural growth and change. You become more intelligent and become a better listener, a more accomplished listener with greater aural discernment skills. Every listening session you get really mentally/physically ’high’ on, you literally become more capable, and more intelligent.
Mo’ wired for mo’ better. The brain is plastic and the body’s ’positive engagement function’ (endorphin highs, pleasure, enjoyment, etc) is literally what enables the plasticity ----- to become something new.
If the sound does not move you, then get rid of it. Yesterday.
|
teo audio,
I haven’t heard the affects of music described like that before but I liked it.
Well said!
Thank you,
Tim |
All, the aforementioned "red hering" suggestion that upwards of 1000 hours and sometimes more might be required to break in a class D amp, or for what it matters, a class A/B amp, SS or tubed linestage, or CDP comes from me.
Over the years I have broken in a number of pieces. They all eventually stabilized with break-in times largely hovering around the 1K hours mark with some exceptions. Many of them created eventually thir own special kind of magic. Some did not at all, no matter my persistance. Shown below are only the ones which in time delivered real music:
Aragon 4004 (A/B) approx 1K hours Rowland M312 (D) approx 1K hours Bel Canto REF1000 Mk.2 (D) Approx 1K hours Bel Canto REF500 (D) approx 1K hours Rowland M625 (A/B) approx 1K hours Rowland M725 (D) approx 1K hours Rowland M925 (D) More than 1500 hours Merrill Veritas (D) approx 1100 hours Merrill (Teranis (D) approx 600 hours ARC LS2B (linestage hybrid) approx 1K hours ARC REF3 (Linestage tube) approx 1K hours Rowland Capri (linestage SS) (approx 1100 hours Rowland Criterion (linestage SS) approx 1100 hours Rowland Power Storage Unit approx 200 hours Rowland Aeris DAC greater than 1500 hours Esoteric X-01 (CDp SS) approx 1K hours Esoteric K-01 (SS CDp) approx 1200 hours GamuT CD-3 (CDp) approx 800 hours
As for warm up from power-on time for a well broken-in piece, I experienced it to vary from about one hour to about one day.
I claim no particular scientific knowledge. I purely rely empirically on my own old ears, which I have used one way or another for listening, studying, and occasionally performing music for some 60 odd years.
Doubtless, other equipment might behave differently. Besides, you might not experience the same long break-in curve as I did. If your quest for sonic nirvana is on a steeper curve, more power to you.... But if you find that after a couple hundred hours of installing a new piece nirvana has not yet reached you, you may want to wait a bit before succumbing once again to Upgraditis Furiosa.... Patience can be Golden!
G.
|
@guidocorona
Great post, thank you. I completely agree with your observations. I have yet to purchase a piece of gear, be it cables, DACs, amps or speakers that didn't take 500-1000 hrs to break-in completely.
Moving anything in my system also guarantees another three to seven days of settling-in. In light of that my gear tends to have more dust underneath it than most.:-)
Cheers,
Scott |
I kind of doubt anyone can actually track the sound of something breaking in, even though break in is probably real, since there are too many variables, e.g., weather, time of day, day of week, many others. In addition, any audiophile who’s going to keep track of the sound and determine when exactly a given component or cable or speaker has completely broken in will most likely be breaking in more than one thing at a time and will be adding tweaks all the while.
In addition, if I can be so bold, unless a purpose built break-in device is employed the chances are slim to zero that the component is question EVER breaks in completely. The music signal doesn’t cut it. There’s just not enough time to do everything that should be done without being slowed down to a snail’s pace by having to sit on one’s thumbs for 200 hours or 600 hours or whatever while something breaks in. Give me a break! |
guidocoronaSo you are saying you have spent over 19,000 hours burning in and doing interval listening to all the above amps while discerning audible changes at regular intervals? LOL...I don't believe everything I hear, and especially everything that is posted on audiophile forums by self-professed golden ear types. |
Good points @sfseay and Geoffkait....
No, I have not sat on my thumbs for thousands of hours, but yes, I typically assess the sound periodically on a number of CDs, particularly on a test CD containing several key tracks that I compiled in 2005. Yep, still use the same one for consistency, amongst other ones.
I also have developed an automated spreadsheet tracker that I have used for a decade or so to track and annotate progress.
When possible, I drive a music signal or FM instation hash through the system whenever I am not listening to music... Yes, this means also night time.... If not FM radio is available.... Like in my current setup, I play music at low level or a break-in CD containing hash.
If the weather is stormy, I disconnect the entire system from the AC mains.
I am sure that time of day, weather, AC mains load all play a part on any particular data point.... However, if the long term trend looks like a stockastic curve pointing upwards, I venture to guess that things are moving in the right direction.
And you guys are correct..... Do not trust me nor anyelse's ears, no matter their particular metallurgy.... Golden, Silver, Tin, Transuranic, leadden, or otherwise.... Use your own ears as much as you can, and well... Yes... Trust them... It's your musical taste that counts, not mine. If you do not, you will turn into a paper audiophile.
G. |
geoffkait,
I kind of doubt anyone can actually track the sound of something breaking in, even though break in is probably real, since there are too many variables, e.g., weather, time of day, day of week, many others. In addition, any audiophile who’s going to keep track of the sound and determine when exactly a given component or cable or speaker has completely broken in will most likely be breaking in more than one thing at a time and will be adding tweaks all the while.
In addition, if I can be so bold, unless a purpose built break-in device is employed the chances are slim to zero that the component is question EVER breaks in completely. The music signal doesn’t cut it. There’s just not enough time to do everything that should be done without being slowed down to a snail’s pace by having to sit on one’s thumbs for 200 hours or 600 hours or whatever while something breaks in. Give me a break!
Well spoken and so totally true.
Kenny.
|
I've owned an emerald physics 100.2SE for a couple of years now and harsh, thin, hashy, fatiguing are not words I'd ever use to describe it. Its been smooth, effortless, and detailed with two different pre amps and 3 different speakers. I have a nuprime dac10 now and would love to try an ST10 with it |
If classD=trash, than Audiogon should have curb alert section. |
If classD=trash, than Audiogon should have curb alert section.
That's Funny,I don't care who you are.
Kenny. |
In reading the commentary concerning @guidocorona and tracking break in I offer this. I recently bought a new Jeff Rowland Continuum S2. I hooked it up and it sounded really good immediately out the box...then it didn't sound as good as it did. Gulp. I read Guido's posts about Rowland's seemingly very long break in time. I followed his advice and ran the JRCS2 all day and all night. I listened to it at intervals in between. Guido accurately forecasted my qualitative listening experience. I just passed the 500 hour break in mark and the sound quality has improved markedly. The JRCS2 now sounds fuller, more detailed, pretty close to the Rowland amp sound I heard at AXPONA in the Joseph Audio/Rowland room. Granted that was a Daemon, with an obscene amount of power (1500W/channel) compared to the Continuum S2 (400W/channel), but Guido's experience, shared on this forum, matched my own regarding Rowland amps. Whatever he's doing and however he is doing it seems to provide valuable insight regarding Rowland amps in my experience. |
|
Hi George, it Seems that when I try to follow the links you just posted, I end up on an image instead of a regular page.... As my screen reading software cannot decipher images, may I ask you to post links to the actual pages, or to post the model of amp you are referring to? Al, past the 500 hours mark, performance trof should be relatively minor on the Rowland Continuum S2.... Gradually, sound will continue to open up for quite a spell.
Saluti, Guido
|
Hi Guido, George's picture is of a JR Model 102S. Looks like it is in Sydney.
Regards
Al |
Thank you Al, Rowland M102 is the most entry level class D amp that Rowland ever created. The model is almost 10 years old, and is today hardly representative of what can be done with class D and with SMPS. M102 has been discontinued a couple of years ago, and has been replaced by the M125, which sports a much newer ICEpower module, supports bridged mode operations via a toggle switch in the back of the chassis thus delivering 500W per chassis, and contains several other technical updates. According to all 3rd party reports I heard, M125 is an exceptional little amp... Far superior to the original M102. G. |
Jeff Rowland 102s power amp only version
Rowland:
"Model 102 stereo amplifier employ the ICEpower 200 AS power conversion module"
Cheers George. |
|
Hello all,
I have over 500 hrs on my S-500 and thought I might comment a little about it.I think it's a step up in Sound vs nc400 and ref600m,these are the 3 class d amps that I own and I have access to more through a local audio club where we lend and or borrow equipment or occasionally listen to each other's systems.
I have been using a bel canto pre3 with all the diff. amps just to make a even playing field,the pre 3 is a pure water no coloration preamp.
The S-500 is the best class d amp I have had in my system and it has the warmest most engaging midrange with very sweet nicely extended top end that has more air and separation with the individual instruments making the entire frequency range very coherent.The bass is equally as good maybe better than my other class d amps listed.
I borrowed a Nuprime st10 to try out and found it too be a very close match to the S-500,with the nod to the S-500 for the best overall sound especially the midrange.
Offcourse this is in my system with my ears and judging the musical presentation that I prefer.
The next test will be comparison with a modwright kwa100se that I have owned for a few years but I haven't used it in about 3 years,I have loaned it out to club members though.I know it's a very good amp but can it equal or beat the S-500,only time will tell.
So many very good choices out there nowadays,
Kenny.
|
|
George,
That is the one.
You probably would need 2 of them to pwr your big panels.
Best regards,
Kenny.
|
|
George,
I haven't found the price but they do look the same as the pascal x pro2.Built in universal switching pwr supply with 2 channels,500 into 4ohm.
I would like to see one and compare bit by bit to verify that they are the same,I really don't know much about them.
I will be getting a push pull class a Amp that uses NOS Sony Vfet's built similar to nelson's Sit 2 but has twice the pwr.I have owned or heard the majority of the first watt amps with the exception of both sit's and the F7 the newest one.Should be a very interesting comparison for me.
|
|
I see what appears to be contradictory statements about break in. But you are all basically correct based on my experience.
Teo says if something sounds bad, don't keep it. Well good, but when you find a product that does sound good, what do you do?... Break it in to get the most out of the component.
I agree with Geoff, that very low power, like in interconnects (2 to 6 volts) is not enough. A burn in devise is needed. Don't get too wild here like I've done in the past. Be safe and practical.
Finally, an important factor is time, mentioned by the person taking notes over several months. Also the FM noise is great for burning in tubes. It only takes a couple of hours of the noise along with some music for tubes in my experience.
So go with a burn in devise, a burn in CD, and music. This will drastically reduce the time needed for full burn in and stabilizing the sound.
Regarding Class D amps: I have heard very good ones, and some that sound like something is wrong somewhere. You just need to listen to a few of them to know. |
I just read this thread from the top and, as one who has only briefly heard a couple of Class D amps in hifi shops, one a Rotel, the other a Bel Canto, the sound wasn't anything remarkable or outstanding.
But the comment I want to make here is that, if I were considering which way to go if I were building a system from the ground up, and I did my due diligence by reading all of the above, the content of this thread would give me pause and would likely steer me away from considering Class D anything.
I'm not reading consistent sonic and utility praise for the format. Why is that? |
Hi @stevecham, for a different perspective on class D amp, you might want to read the following thread:
https://forum.audiogon.com/discussions/class-d-is-just-dandy
There is a rapidly growing number of music lovers are adopting class D amplification and are loving it. Having said that, not all class D amps are able to make wonderful music... But isn't this true of all amplifier topologies?!
Regards, G.
|
stevecham, You asked: "I'm not reading consistent sonic and utility praise for the format. Why is that?"
I can only speak for myself but I think many class D users will probably agree with my answer to your question. I don't specifically praise the sonics, or mention any of the usual terms used to describe the sonic characteristics of amplifiers in the past, in any of my posts on this thread or whenever I've attempted to convey the overall sound of my several class D amps for a very simple reason that is very obvious to anyone listening to a good class D amp in their system:
Good class D amps are extremely neutral, have no consistent sonic signature that is imparted onto the music and therefore there are no sonic qualities to criticize or praise.
Criticizing or praising the sounds one hears through a good class D amp is essentially just an evaluation of the music since there is nothing discernible that is added or subtracted from the original signal. In my experience, good class D amps behave just as many have consistently described how an ideal amp should behave; like 'a straight wire with gain'.
As to consistent utility praise for the format, I think you need to reread this thread and pay closer attention because the practical advantages of class D amps when compared to traditional amps has been well covered in this thread. I'll summarize the utility advantages of class D amps have over traditional amps, however, to save you the time:
Class D amps are much lighter, usually much smaller, are significantly more efficient, produce much less heat and generally are less expensive than traditional ss and tube amps. I also believe class D amps will be proven to cost less to maintain and operate while determined to be more reliable than traditional amps as data is accumulated and analyzed.
Tim
R
|
stevecham,
You asked:
"I'm not reading consistent sonic and utility praise for the format. Why is that?"
After rereading your post from 8-28-2017 at 1:00am, I now realize I may have misunderstood your exact question just prior to posting my reply on 9-19-2017 at 8:36am. I originally understood your question to be referring to why all posters on this thread, "that posted favorable experiences listening to class D amps", were not consistently reporting sonic and utility praise for the format. I currently understand your question to be referring to why all posters on this thread, "that posted either favorable or unfavorable experiences listening to class D amps", are not consistently reporting sonic and utility praise for the format.
In other words, I think your intended question was basically:
" Why do some posters on this thread report positive experiences, while some report negative experiences, listening to class D amps?" Please let me know if I'm incorrect.
IIn any case, this is a very interesting and insightful question that I believe gets to the very heart of the issue concerning why some really like the performance of class D amplification and others really do not. This difference of opinion is currently reflected in 2 diametrically opposed current forum threads:
This one titled "Class D= Trash" started by madavid0
versus
The opposing viewpoint titled "Class D is just Dandy!" started by erik_squires
This dichotomy of opinion on class D performance has also confounded me since I first learned of class D about 5 years ago and began reading Audiogon and other audio forum opinions on their performance.
I recall the opinions on class D from this time alternating between glowing reports and those that claimed the sound was "thin", "strident", "shrill in the high frequencies" and comments like "it just seems like something's missing". The only consensus of opinion I remember from about 5 yrs ago was that the bass performance, noise levels, distortion levels and detail levels were considered by almost all to be very good along with the obvious utility advantages of small size , low weight, low heat and relatively low cost. My perspective is that the conversation hasn't changed much over the past 5 years.
I can sympathize with your confusion since I recall being equally perplexed at the time about why there were such a differing opinions on class D performance. Also at this time about 5 yrs ago, my high powered class A/B Aragon 4004 MKII amp's power supply capacitors leaked and it went dead. I had to make a decision on whether to have the amp repaired for a quoted $1,800 or buy a new amp. This was a pain at the time but, in retrospect, I now consider this amp failure as very fortuitous.
I decided not to spend $1,800 to repair my nearly 15 year old amp and instead viewed it as an ideal time to audition a class D amp in my system and just determine for myself how well or poorly class D performed. I considered this option as low risk (as it remains today) since many class D amp sellers offered generous in home trial periods with 'no questions asked' full refunds if you were not completely satisfied. I wanted an amp that at least matched the power of my now deceased class A/B Aragon amp (400 watts @ 4 ohms) that was stable into low impedance loads to drive my fairly inefficient ( 86 dbs/1 watt) Magnepan 2.7QR spkrs that I know sound best with lots of power.
So I chose an SDS-440CS stereo amp from ClassD Audio that had numerous good reviews, a 4 week in-home trial period, was powerful ( 440watts @ 4 ohms) and very affordable ($630 5 years ago and still $630 today). This amp sounded very good right out of the box and I was thrilled with its performance. It outperformed my former Aragon amp in every area I cared about; power, dynamic range, quietness, imaging, distortion, accuracy and musicality. Oh yeah, it was also about 1/3rd the size and weight of my former amp, ran cool to the touch, consumed significantly less electricity and there were zero detectable EMI or RF interference issues in my system.
Needless to say, I kept this amp and it has now been operating faithfully in my system for over 3 years (currently driving my in-ceiling surround spkrs). I've subsequently purchased additional class D amps (a stereo Emerald Physics amp to drive my Magnepan CC3 center ch and a pair of D-Sonic M-600 monoblocks that currently drive my Magnepan 2.7QRs). All have performed equally well or better than my original ClassD Audio SDS-440CS amp and completely outperformed the very good class A/B amps they replaced. My combo HT and 2-CH music system is now completely class D amplified and I've been completely satisfied with the sound of my system for both for a few years now.
Now, this is just 1 person's honest opinion of the performance of good class D amps.
I would urge you, and any other readers of this thread considering class D amps in their systems, to not take my or anyone else's word for how good the better ones perform. Just audition one or more in your own system and discover for yourself how class D sounds to you.
I say this not only because it's the best method to determine how any component affects your system, but also because it seems as if class D may not be the best solution for everyone. I've been admittedly and repeatedly confounded by how class D has performed and been perceived to be so exceptionally good in my system while others claim to have issues with its perceived performance in their systems.
Is it possible that some individuals have an 'allergic' reaction to class D produced sound or are more sensitive to certain affects introduced by class D amplification? Can it be true, as georgehifi has adamantly and repeatedly claimed, that the Switching Frequencies currently used in most class D power amps (about 500 Khz) are too low and cause sonic anomalies in the audible range (about 20-20,000 Hz)?
I tend to doubt both theories because there is absolutely no scientific evidence I'm aware of to support either. However, if actually true, it would go a long way in explaining the rather wide spectrum of reactions thus far concerning class D performance.
I'm going to try and keep an open mind,
Tim |
Also at this time about 5 yrs ago, my high powered class A/B Aragon 4004 MKII amp's power supply capacitors leaked and it went dead. I had to make a decision on whether to have the amp repaired for a quoted $1,800 or buy a new amp.
I decided not to spend $1,800 to repair my nearly 15 year old amp and instead viewed it as an ideal time to audition a class D amp
It outperformed my former Aragon amp in every area I cared about; power, dynamic range, quietness, imaging, distortion, accuracy and musicality.
I'm going to try and keep an open mind,
Tim
Of course it did Tim, in case you don't know, your Aragon didn't die over night, leaky caps start to deteriorate the sound over many months even up to a year, so in actual fact you were comparing the sound of a very sick amp, to one that was healthy. The real comparison would have been to fix the Aragon amp then do the comparison. Cheers George |
Hi George,
You're probably right, my old Aragon likely died a slow death with its performance dropping so gradually I failed to notice it was ailing til it seized up.
However, I also noticed the exact same improvements when switching my decent quality and healthy class A/B center and surround channel amps for good quality class D amps.
I've also continued to leave my amps on 24/7 barring severe weather. I've noticed a significant ($30-40) reduction in my monthly electric bill ever since.
Good point, never the less.
Tim
|
