I have an old audio book, The Gramophone Handbook, by Percy Wilson, published in 1957. Wilson was an elderly man when he wrote the book and his involvement in reproduced music went way back.
He mentions that back in the late 20's when when both electrical recording and gramophones were first introduced many enthusiasts steadfastly, and loudly, refused to contemplate the new system. How could an electrical system of recording and reproduction possibly be better than their beloved 'acoustical' method of sound box, tone arm and horns?
Some folk do not like change!
I have a UCD700HG amp with HG power supply. Initially I thought it sounded great. Lot's of control, mature sound with vice grip. Can go loud without a strain. After comparing it to my almost 20 year old Hiraga Le classe A 20W amp I had serious second thoughts. The Hiraga has lots and lots more decay on every note it plays. There is a lot more low level information at the end of each note while the UCD amp seem to cut off before the note ends. This is what makes the sound much more "airy" and much more enjoyable to listen to. I also have a pair of Trends TA10 amps wich are pretty terrible in this department at a point that they are almost unlistenable for me. I have heard other Tripath amps do the same things so I gave up on Tripath in general. The UCD700 is moved to the woofers in my active system where it does a pretty good job. My old NAD2200PE wich I used before on the woofers had more slam than the UCD's but the UCD's just never run out of steam and while more polite it integrates better in the system.
Comparing a 700W D amp with an 20W A amp is apples and banana. Like comparing a vintage sports car with a family van. UCD 700 would drive a PA top speaker quite efficiently while a class A amp is always nice and handy when it comes to heating your home during wintertime. Completely different application. I don t believe that the UCD does cut off notes. UCD maybe has slightly higher noise level so the note reaches "footroom threshold" earlier, when driven at only a few watts.
For what it's worth, the 30 watt compact stereo UCD modules and the UCD 180 ST do exactly the same thing. The UCD 700 HG sounds better overall but the truncation of the notes is exactly the same on both. It's not about 700 Watt (350 watt actually) vs 20 Watt. So yes I think it's fair to compare and it's not apples vs oranges. And I don't see why a higher powered amp should be noisier at low levels then a low powered amp. If it's good designed it's dead quiet, even at micro levels.
You can actually hear a D-amp switching? What about the 0's and 1's of digital recordings?
I can remember back in the 70's when cassette decks with all their hiss, wow and flutter was hi-fi.
We have CD and DVD sound. What do you think the compression rate is on those?
So, what does it matter, most of the "Quality" or harmonics and headroom have been removed anyway!
Back in the 90's, Yamaha Electronics produced a CD player, along with Philips, that when an orchestral part of music that required more headroom was being played, the uProcessor flagged that information up and increased the analogue output by 2 or 3dB.
All gone.
So, what does it matter, most of the "Quality" or harmonics and headroom have been removed anyway!
Back in the 90's, Yamaha Electronics produced a CD player, along with Philips, that when an orchestral part of music that required more headroom was being played, the uProcessor flagged that information up and increased the analogue output by 2 or 3dB.
All gone.
I have several d-amps and they all sound very, very good to me.
Perhaps I am lucky to have been born without "golden ears".
Well, I am proud that my class D amps have evolved to be dead quite.
Still my class AB amps remain even more dead.
Considering a switching frequency of 400kHz and targeting a noise floor of -100db for 1-2kW amp, means controlling MosFets of the category 200V/100A/10mOhm with a precision in the range of some tens of pico seconds. Even worse, you not just need to control the switches, but you have to ensure that the switching transients do not disturb your fast comparator. Amazingly all this works.
...while achieving a -100db noise floor in class AB power amp is really trivial.
Fortunately zero noise is not necessary for high end.
In fact there are audio-biological studies, which indicate that a certain background noise lifts our subconscious attention and results in subjectively 'better' sound. ...sorry can't remember the link anymore.
Even with home brew equipment you can check multiple more important criterias for the sound quality of an amp and the usually shown noise+THD figures are just a starting point. IMHO the key for a good sounding amp is a well balanced combination of many diverse properties.
Unfortunately trends/hypes/promotion typically focus on one fashionate property. And this narrow focus is just the beginning of the misery, because most design engineers don't even get the mission to optimize this property, but a tight budget combined with an idiotically dictated time schedule.
Despite all numbers my tech soul is in trouble, because once and a while I subjectively notice differences in sound and do not find a correlation between sound and measurement
The Hiraga Class-A was famous for that. It seemed to not erase all that low level info. At first listen it would sound "polite". With further listening and comparisons you'll start to hear all sorts of ambient details and spacial cues that other amps miss entirely. It's addictive.
Tried a pair of UcD180HG with the corresponding powersupply on a pair of Final 300 ESL, it was clear that the UcD had a problem driving ESLs.
Certainly no air in the sound and low ambient information, a good tube or SS class A amp really excels here.
One problem could be the output filter, presenting a higher driving impedance to the load at high frequencies while ESLs have a low impedance there.
Certainly no air in the sound and low ambient information, a good tube or SS class A amp really excels here.
One problem could be the output filter, presenting a higher driving impedance to the load at high frequencies while ESLs have a low impedance there.
Not gone at all Jon, a simple expander plugin can undo some of the damage that my kind is forced to do to us.
Well, I am proud that my class D amps have evolved to be dead quite.
Still my class AB amps remain even more dead.
Considering a switching frequency of 400kHz and targeting a noise floor of -100db for 1-2kW amp, means controlling MosFets of the category 200V/100A/10mOhm with a precision in the range of some tens of pico seconds. Even worse, you not just need to control the switches, but you have to ensure that the switching transients do not disturb your fast comparator. Amazingly all this works.
...while achieving a -100db noise floor in class AB power amp is really trivial.
Fortunately zero noise is not necessary for high end.
In fact there are audio-biological studies, which indicate that a certain background noise lifts our subconscious attention and results in subjectively 'better' sound. ...sorry can't remember the link anymore.
Even with home brew equipment you can check multiple more important criterias for the sound quality of an amp and the usually shown noise+THD figures are just a starting point. IMHO the key for a good sounding amp is a well balanced combination of many diverse properties.
Unfortunately trends/hypes/promotion typically focus on one fashionate property. And this narrow focus is just the beginning of the misery, because most design engineers don't even get the mission to optimize this property, but a tight budget combined with an idiotically dictated time schedule.
Despite all numbers my tech soul is in trouble, because once and a while I subjectively notice differences in sound and do not find a correlation between sound and measurement
Lots of words, but the question remains: Can a Class D amp "truncate" musical notes? Y or N?
"Your question I would answer with Y.
But the question according head line would be:
Is it a typical property of class D amp to truncate notes ?
This question I would answer with N."
OK, so Class D can truncate notes, but this is not a typical "feature" of Class D acc Choco who has definitely more experience than me.
Just wonder why this issue seems to happen on UCD, which is quite a good class D implementation ? Would be interesting to compare to nCore...
But the question according head line would be:
Is it a typical property of class D amp to truncate notes ?
This question I would answer with N."
OK, so Class D can truncate notes, but this is not a typical "feature" of Class D acc Choco who has definitely more experience than me.
Just wonder why this issue seems to happen on UCD, which is quite a good class D implementation ? Would be interesting to compare to nCore...
What about the new TI class D amps, TPA3116D2, TPA3118D2, TPA3130D2, they supposedly have a switching freq. of up tp 1.2MHZ ?
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