Yes, but IMO that is the overall package that wins, not the audio quality of class D...
Having tested a bunch of Class D and A/B amplifiers it is clear that A/B can be better, but also A LOT worse depending on implementation.
There is no reason why class D should not be taking over - it is the better overall solution. but on a single parameter -audio quality- it can be surpassed by a good A/B solution.
Unfortunately the test was done using blind testing, so results are not easy to document.
\\\Jens
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A good way to reduce overall distortion is to have an inner positive feedback loop to boost loop gain, then an outer negative feedback loop to reduce output stage distortion. Maybe not what you were thinking of?Hiten said:
Mr.Jacco do you want to yell on me to ? , please don`t ! 🙂
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- How I was biased on that great Mr.Gabor(Bella) thread ? , in that way that I busted some my old &crappy sounding Japanese VFA based SS PA amp ? , and wanting to convert that amp using original parts but now on Gabor new to me at that time CFA way ?
( - About Mr.Karsten(Atmasphere) OTL -GNFB-free tube amps I`m sure that soon or later hi will appear here with genuine measurements charts , since hi never hiding anything from DIY people , genuine schematics , knowledge , support of any kind ... , again Atmasphere charts can content only measurements hard facts which don`t hides anything ,but characteristic for which hi can only be very very Proud ! )
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Yes it does. Can't say how well conducted the blind tests were, but that was years ago and the sample pool too small to be of much use IMO.
Thanks. I get that to you it appears to be ideology. I've mentioned this before and I'll say it yet again. I want SS and feedback to work, plain and simple. What I find is so far the best sounding SS amps I've heard were all claimed to be zero feedback (First Watt, Ayre, and a really expensive one from Georgia whose name escapes me now). These amps were better than many tube amps I've heard.
I experience many of the same problems when applying feedback to tube amps BTW (and FWIW, not nearly so much when dealing with preamps). I do concede that my viewpoint is based on experience (I've serviced hundreds of amplifier designs over the years), and also based on a lot of customer feedback.
You might want to read 'Born to Run' by Christopher McDougall.
The last review in which this happened was in a French magazine if memory serves. Trust me, these days this problem is very much on the radar. Computer cards have improved quite a lot so this really should not be a problem now.
To the latter, ironically I prefer independent measurements, but mine is a small company and often I have my hands full just dealing with production. But I think its a good idea and will pursue it.
I don't agree with this at all! Its just not factual. Are you really saying that there is something about all tube amps that makes them sound dull?? As I mentioned earlier, I have heard SS amps that don't sound bright, but none of them employed feedback. IMO its not a tube or SS thing, its a feedback thing. Those of you that think I come to this topic with a tube perspective or agenda are simply mistaken. I just don't see feedback working: as I posted in one of my first posts on this thread, IMO its because it is so poorly applied in 99 44/100% of all cases.
To the latter: anyone who spends time in a recording studio behind the glass spends time dealing with heat! Class D is a boon on this account and should be no wonder that studios embrace it- good clean power with low heat and no worse than traditional SS for sound.
text in bold: I would be very interested to discover what you mean by controlled conditions!! For example if you look at the distortion spectra of almost any SET, you will see the 2nd order predominate, and that is the harmonic associated with warmth. FWIW, Sunn, a well-known instrument amplifier manufacturer, made a series of SS amps that were well-known for a 'warm' 'tube-like' sound back in the early 1970s. A look at the schematic told the story: zero feedback single-ended FET-based preamp section, single-ended voltage amplifier and driver circuit, converting to push-pull only at the output section via a driver transformer. Lots of 2nd harmonic... topology cannot be ignored in this conversation! I am very interested to see how controlled conditions will prevent the ear from translating the 2nd harmonic into warmth.
With regards to the initial comment, what I stated was that the most common complaint laid at the door of solid state is that it is bright. Now if a tube circuit and a SS circuit have the same bandwidth, what causes the brightness? By your comment our OTLs will sound dull, but they don't. And many of them have full power bandwidth within 1/2db to 300KHz...
Ralph, if you wish, I will be happy to do fully balanced measurements. I'm not that far away, so if you wish, you're welcome to bring a unit and make sure that I'm not doing anything unfair. We have a guest room if you want to stay overnight, and Jan will attest to the quality of the food and drink.
Some of my favorite transistors from the 80's.
Where do you suppose the second harmonic is coming from?
😎
Not really, yelling on the web lacks some intimidation appeal, for all you know I could be a skinny Wall-EE in real life.
It was just amusing to finally see Mr Didden throw a slipper (makes me less of a savage)
By your own words, you are ;
- mainly interested in tube amps
- not actively interested in contemporary SS design.
My first experience with class D in the previous century was total yuck, haven't taken it seriously for decades.
Fortunately I know fashionable folks who love to show off bobo hardware.
One example is a friend with €40k of beolab 5 in a surround setup for his 103'' plasma tv, still yuck imo.
A relative bought an appartment in A'dam a year ago and had it completely renovated for half a million, with a music server in the hallway closet, all the wiring and Hypex amps inside the walls, wall mounted loudspeakers in every room.
Not my idea of an audiophile dream, but better sounding than his previous active ICE powered B&O pillars
Overhere we had an Aitos OTL (more than enough negative feedback) cult, still do, on occasion I still bump into one.
You likely can't get them to listen to a UcD/nCore even if you brought it over to their home.
If you do not consider yourself predispositioned, why not go have a listen, doesn't have to be €70k, not even from JRDG.
Love to see what you get. I'll see if Ralph is still interested in a Chicago voyage.
I could also offer a balanced test in Ohio on freshly calibrated equipment, depending on where Ralph is geographically.
One really needs to have one person listening alone, and a computer selecting the DUTs and recording the preferences. Too many cues from other participants when several people are together. It makes it particularly tedious and protracted, which is one reason why almost no one does it.
The better part of the present discussion concerns how presented source material is handled at the business end of the chain.
The result cannot be any better than the source material, so is it pertinent to ask what is the current state of current analogue technology in the studio production and digital recording processes? I have been under the impression this involves some use of IC op amps. I am somewhat reminded of the use of compression in the days of the loudness wars.
Also what equipment/technology is used for monitoring purposes?
The result cannot be any better than the source material, so is it pertinent to ask what is the current state of current analogue technology in the studio production and digital recording processes? I have been under the impression this involves some use of IC op amps. I am somewhat reminded of the use of compression in the days of the loudness wars.
Also what equipment/technology is used for monitoring purposes?
I've not looked at the APs recently but the old ones did not support AES file 47 (you might say they had a sort of pin 1 problem). At any rate if you decide to check it out, of course neither output terminal can be allowed to be at ground and there really isn't any point of 4 ohm performance (half of the output power is dissipated by the output section itself) and quite a lot for 16 ohms.
The M-60 employs about 2 db of GNFB (our larger amps use none); make sure that a jumper pin is in place between pin 1 and 3 if you are driving it with the RCA input; without the jumper FB will be increased unless driven balanced.
Customers routinely express comments about various brands of 6SN7s used in the amp; we are using the garden variety of Chinese 6SN7 so the distortion can be affected by the driver tube setup. The DC Offset control can affect distortion; if the best setting is not the same as 0volts output it indicates that there is an imbalance in the power tubes which, when corrected, will produce lower distortion.
The amplifier distortion is not tailored in any particular way nor is any compensation employed. The line voltage should be 120VAC, measured at the IEC connection (we have found that a voltage drop across the power cord will affect the the amp).
UCD THD+N vs Frequency at 40KHz Bandwidth, plot is valid up to 15KHz.
Now can we stop this Class D can't do more than 6KHz bull or it hides snakes over 6K you need pre analyser AES17 (20K or 40K) filter to stop AP from overscaling not because Class D has killer snakes above 20KHz, besides you can't measure correctly nCore (0.00045 THD+N at 6W) with more than 20KHz Bandwidth, the analyser is 0.0004 THD+N at 80KHz and 0.0002 THD+N at 20KHz.
Now can we stop this Class D can't do more than 6KHz bull or it hides snakes over 6K you need pre analyser AES17 (20K or 40K) filter to stop AP from overscaling not because Class D has killer snakes above 20KHz, besides you can't measure correctly nCore (0.00045 THD+N at 6W) with more than 20KHz Bandwidth, the analyser is 0.0004 THD+N at 80KHz and 0.0002 THD+N at 20KHz.
