Eva said:
UCD is little newer than this, it's just the superior concept, but not because it's self oscillating, they both are that, rather because of the stable post filter feedback that many examples of self oscillating amps lack. There aren't any known derivatives worth the title other than everyone plugging their own copies, where most lacked the vision in preserving the qualities that made it what it is.
I'd commend IcePower for at least having a fairly complete datasheet which doesn't hide these aspects of its performance, if people took the time to read it.
The graph is more the equivalent of a somewhat falsly imposed SOA by the filter's snubber's resistor that better designs don't even need. With real music, in real loads, at typical levels and even high levels for short duration, the limiting should rarely ever if at all come into play.
The protection does not shut down but rather limits the input signal, and I doubt you'd be able to tell when it's active with an amp like this short of a visual indicator.
Such a penny pinched commercial implementation is never a good sign of a healthy amplifier though. As soon as a manufacturer starts relying on the "music power" argument, it starts to stink in terms of ultimacy, and becomes merely just adequate at best. Or at least I like to think so, but when you see the junk people actually listen to and mistake for high quality sound it becomes a moot point. See tripath in the included graphs below. IcePower is a semi respectable turnkey commercial brick, not the ultimate in high end by far.
While the use of such a bandaid snubber isn't in itself detrimental to the sound, the deeper issue is the very need of it being a screaming indicator of truly detrimental to quality design issues. Pre filter or as in this case mixed mode feedback notoriously suffers a lack of load immunity and poor group delay, effects which audibly detract from accuracy in a big way.
While less than accurate the load peaking can be somewhat euphonic though, leading to comments for other similarly "high tech" synthesizers as "this amp plays music!!", rather than reproducing it. Others still will claim that they all sound the same provided they're all equally implemented ( poorly! ).
Speaking of which, otto88, wrapping the internals with ERS paper is an audiophool method of implementation that isn't going to save a flawed concept or an ignorant implementation- nor could it help a good amplifier in any way. Save the money and ignore such examples of ignorance, for their only redeeming quality is that the increased heat will kill them off sooner than later.
In terms of generalizing comments about all class d behavior, it would again be useful to see some actual measurements. Even without a grasp of the language you can easily make sense of the graphs.
Note that while IcePower falls short of ideal it is surprisingly respectable compared to others like Tripath that are simply laughable. However the load dependancy shown, while slight compared to most others, hints at a gross group delay that you'd have to look elsewhere to see, perhaps even in the datasheet.
http://www.hypex.nl/docs/classeD_393_lores.pdf
http://www.hypex.nl/docs/classeD_394_lores.pdf
Note how UCD performs with respect to a well behaved linear amp.
If you prefer euphonic assault of noise rather than accurately reproduced music then I guess the choice is open to interpretation but if you seek real, repeatable, dependable accuracy it's a rare and clear choice. It may be more involved than plugging in a few wires on an anemic commercial turnkey brick, but not by much, and the information required to do it right is easily found.
It's also worth noting that the use of UCD modules is fully supported by the manufacturer, unlike IcePower, where should something go wrong you'll be left to your own devices entirely.
That said, for the price YFW is dumping these for, I suppose you could do worse, but expect to get little more than you paid for.
If these perform better than the "laughable" Tripath as Berns says, then I should be pleased with my purchase. 
The main thing that attracted me to these amps is the integrated power supply. I have many many other class-d amp modules I'm not using because I have no motivation to buy/build power supplies for them.
The main thing that attracted me to these amps is the integrated power supply. I have many many other class-d amp modules I'm not using because I have no motivation to buy/build power supplies for them.
otto88 said:
Equivalent? I sure hope not. Seriously though they do offer completed very high quality unregulated power supplies and a soon to be released SMPS that will deliver where these things fall flat. What's a few extra wires? It falls to your needs, expectations and budget, but do your research for certain.
I'd like to point out some confusion with TNT's commentary here. He seems to be the very proud owner of the 1000ASP version. He first quoted from its datasheet which stated how it features input limiting circuitry as protection for the discussed frequency dependent thermal issue.
Later stating:
"As I understand it, you never experiance a "roll off" as in experianced reduced level of high freq. energy but rather, the amp shut down really. Something that never happend me despite of neighbour war levels."
His amplifier version never would shutdown from this as the ASP versions offer input limiting as protection against it. While ASC versions don't offer such limiting and do simply shut down, and that you will surely notice. There's a difference in cost between the two by several orders of magnitude X2. You do get what you pay for, and you can't in good faith comment on the robustness of a 200ASC through the eyes of a 1000ASP, one is weak and the other handicapped.
I find greater issue in lack of thermal mass in general.
"Note that long-term high power levels may be limited by other
safety circuits before the HF long-term power limit is reached."
"Thermal Protection
The ICEpower1000ASP is equipped with two thermal protection circuits. The first monitors the temperature of
the power supply and attenuates the output voltage if the temperature exceeds the limit. The other protection
circuit monitors the amplifier temperature and shuts down the amplifier if the temperature becomes too high.
Both protection circuits are self-resetting once the temperature has dropped to an acceptable level."
PT Continuous output power8) without
thermal shutdown.
Thermal stab. @ Ta = 25 OC.
4Ù, no external heatsink. - 85 - W
PT Continuous output power8) without
thermal shutdown.
Thermal stab. @ Ta = 50 OC.
4Ù, no external heatsink.- 40 - W
That's in free air.. for the 1000ASP. Slap it in a "very tigth shielded and closed box" and watch it ride the limiting all its life. Sorry to say it but I don't think I'd consider TNT's described implementation successful.
PT Continuous output power4) without
thermal shutdown. 0 - 8kHz5)
Thermal stab. @ Ta = 25 OC. - 40 - W
PT Continuous output power4) without
thermal shutdown. 0 - 8kHz5)
Thermal stab. @ Ta = 50 OC. - 25 - W
That's for the 200ASC.
Goes to show you the level of cheap we're talking about here, engineered to the final penny, geared towards PMPO.
The ASPs backside is screwed to the box via heatsink grease so in fact, the whole box is the heatsink and the box istelf is just bearly varm to the touch. 85 watts continous power - ... do you use your amps like that - your judgment may be blurred trying to hear through your tinitus. 
I wish You could hear my system
/
re: "200ASC through the eyes of a 1000ASP" - absolutley, my statements are only valid for 1000SAP !
... do you use your amps like that - your judgment may be blurred trying to hear through your tinitus. I wish You could hear my system
/
re: "200ASC through the eyes of a 1000ASP" - absolutley, my statements are only valid for 1000SAP !
I've used the ICEpower125ASX2 module, nice product.
In fact, I even have a commercial product based on it.
It's an "all in one board", the SMPS is on the same PCB. Just move a jumper to go from low voltage mains (100-150V) to high voltage mains (180-250).
It's a nice sounding amp, very tight and and powerful in the bass. Not as euphonic as the Tripath stuff, more neutral. Great bandwidth too.
B&O seem to have done a good job with the output filtering, it's pretty clean.
Of course I made a few tweaks, mostly to the input circuit, but it's OK stock.
In fact, I even have a commercial product based on it.
It's an "all in one board", the SMPS is on the same PCB. Just move a jumper to go from low voltage mains (100-150V) to high voltage mains (180-250).
It's a nice sounding amp, very tight and and powerful in the bass. Not as euphonic as the Tripath stuff, more neutral. Great bandwidth too.
B&O seem to have done a good job with the output filtering, it's pretty clean.
Of course I made a few tweaks, mostly to the input circuit, but it's OK stock.
As far I get , 92.4 db/ 1 meter should be ok with 200asc ? Bought one , cause it looks like a deal, so I can spend more $$$ tweaking the factory JBL crossover hehe. Then... how about preamp/signal conditioning? For now I want to build something like opamp attenuator with resistive element in feedback loop.
i ve been dissecting that asc200 Audio Precision plot, distortion is rising with frequency, 6khz curve is quite scary, so i sense biamping coming this way ... (runs even until 1khz tho, looks quite good infact )
FYI , innard pictures:
http://www.6moons.com/audioreviews/bcdtrio/trio.html
the atenuator looks to be standard integrated, let me know if you see more tidbits .
I want to build withg this chip,
http://www.profusionplc.com/pro/gex/pcatdtl0?ipartno=MAS6116
either with 5534+jfet input , or the new linear tech opamps.
FYI , innard pictures:
http://www.6moons.com/audioreviews/bcdtrio/trio.html
the atenuator looks to be standard integrated, let me know if you see more tidbits .
I want to build withg this chip,
http://www.profusionplc.com/pro/gex/pcatdtl0?ipartno=MAS6116
either with 5534+jfet input , or the new linear tech opamps.
I've been playing with the 200ASC modules from YFW and I have to say I'm pleased with my purchase (and glad I got them before the price jumped to $199).
They sound as good as my junk test speakers will allow them sound. And no, the highs are not missing or rolled-off like some have suggested.
They may only be ~40W amplifiers, but that is perfectly fine with my neighbors. If I played them even close to clipping I would probably have someone banging on my front door.
I replaced the 50v 560uF supply cap with a Panasonic FC 63v 820uF. I also added two additional 63v 820uF caps across the J2 PS header.
They sound as good as my junk test speakers will allow them sound. And no, the highs are not missing or rolled-off like some have suggested.
They may only be ~40W amplifiers, but that is perfectly fine with my neighbors. If I played them even close to clipping I would probably have someone banging on my front door.
I replaced the 50v 560uF supply cap with a Panasonic FC 63v 820uF. I also added two additional 63v 820uF caps across the J2 PS header.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Anoymous1 - how do these sound compared with the Tripath TA3020 from the DCP-501? Pano indicated his comments (ASC200 vs typical Tripath) earlier.
I have my last DCP-501 still in the box (all modded, but back in the original chassis as new), and have four of the ASC200 to experiment with.
I had a new Bel Canto S300, which has this same ASC200 module, but sold it. It was OK, I preferred my UCD400 over the ASC200, but at this price...
I have my last DCP-501 still in the box (all modded, but back in the original chassis as new), and have four of the ASC200 to experiment with.
I had a new Bel Canto S300, which has this same ASC200 module, but sold it. It was OK, I preferred my UCD400 over the ASC200, but at this price...
Well with all the time, effort, and money I've put into various amps/modules in the last few years I still do not own a decent set of speakers. I have some very crude test speakers thrown together, but they aren't good enough to make a very fair comparison between different amps.
The bass seems solid and the highs are there, but I'm not particularly picky. The amp has to have a fairly obvious fault for me to even notice.
I have quite a few amps I would really like to test against each other on some good speakers, but the way I'm going I don't think I will ever own a pair.
I have a set of Heil AMTs that have been waiting well over a year for me to decide what to pair them with.
EDIT: Oops, I noticed I said I put the extra supply caps across the J2 header in my previous post; I meant J1.
The bass seems solid and the highs are there, but I'm not particularly picky. The amp has to have a fairly obvious fault for me to even notice.
I have quite a few amps I would really like to test against each other on some good speakers, but the way I'm going I don't think I will ever own a pair.
I have a set of Heil AMTs that have been waiting well over a year for me to decide what to pair them with.
EDIT: Oops, I noticed I said I put the extra supply caps across the J2 header in my previous post; I meant J1.
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