After comparing tripath and UCD.
The tripath has a nice transparent sound with a bit metal coloration. I accentuates detail.
I hear a little hum with a 10K volume control.Probably I have to use a linear voltage control to suppress that.
After a while I am back at the UCD amp more natural then the tripath in the long run.
Conclusion:
If price is an issue defenedly tripath, midhigh detail tripath.
Natural sound UCD without outstanding points perhaps good sound stage UCD is the better performer because I automatically switched back to it because I like the overall sound more.
I also did a compare with the Yaqin mc10l. The UCD had a bigger more transparent sound stage soundsbetter.
The tripath has a nice transparent sound with a bit metal coloration. I accentuates detail.
I hear a little hum with a 10K volume control.Probably I have to use a linear voltage control to suppress that.
After a while I am back at the UCD amp more natural then the tripath in the long run.
Conclusion:
If price is an issue defenedly tripath, midhigh detail tripath.
Natural sound UCD without outstanding points perhaps good sound stage UCD is the better performer because I automatically switched back to it because I like the overall sound more.
I also did a compare with the Yaqin mc10l. The UCD had a bigger more transparent sound stage soundsbetter.
Just finished up my 5.1 surround sound amp. It's messy, but it sounds great and it's sturdy.
The complement:
(2) Meanwell 48 volt 350 watt SMPS
(4) Hypex UcD400ST front left, front right, center, sub
(2) Hypex UcD180ST rear left, rear right
Yeah it looks like Vegas, especially with the fan. The fan is on a speed control near the slowest setting and is essentially inaudible, but the little bit of air movement makes a lot of difference. The amp runs without the fan but gets hotter than I would care for it to.
This thing shakes my house and it weighs less than 10 lbs!
The complement:
(2) Meanwell 48 volt 350 watt SMPS
(4) Hypex UcD400ST front left, front right, center, sub
(2) Hypex UcD180ST rear left, rear right
Yeah it looks like Vegas, especially with the fan. The fan is on a speed control near the slowest setting and is essentially inaudible, but the little bit of air movement makes a lot of difference. The amp runs without the fan but gets hotter than I would care for it to.
This thing shakes my house and it weighs less than 10 lbs!
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An externally hosted image should be here but it was not working when we last tested it.
Actually it makes more sense to stand this amp up - less desk space.
I was afraid the SMPS would be under powered, but not even close - the fan has yet to come on (in the SMPS that is). It will wake the neighbors and not even get hot.
The UcD400ST sounds about the same as the 180ST to me. The 400ST has better specs but I don't here it. Both modules sound fantasitic to my ears. I hear no coloration - just a wide open, clear, faithful reproduction of the source.
I was afraid the SMPS would be under powered, but not even close - the fan has yet to come on (in the SMPS that is). It will wake the neighbors and not even get hot.
The UcD400ST sounds about the same as the 180ST to me. The 400ST has better specs but I don't here it. Both modules sound fantasitic to my ears. I hear no coloration - just a wide open, clear, faithful reproduction of the source.
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.
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Thanks, Helmuth, that is a useful comparison and good to know. Pretty happy with my hifimediy T2 but keep getting pulled toward the Bruno Putzey stuff...
I have no experience with anything other than the Hypex modules, but I've read the papers that Putzeys wrote and as an EE I can appreciate the points he makes (although not all of them - some of it goes beyond my knowledge to be able to understand it yet - over my head at this point).
He's pretty passionate about post filter feedback, he doesn't like toroidal output inductors, and he believes the self-oscillating class D with feedback is superior to clocked amps among other things. He makes a valid argument for not posting IMD specs, and maintains that in listening tests that the "universal class D" sounds the best. I've heard a lot of amps, and this one sounds GOOD. The only fault I can find is a very small amount of hiss, but it's not audible at more than about a foot from the speaker (at which distance the volume would split your eardrums so it's really a non-issue).
I like the compact design of the modules. All you need is a thick aluminum case to heat sink them, and that eliminates the need for a heat sink with fins directly attached to the modules. I was able to cram 6 modules and 2 SMPS in one small aluminum Hammond chassis (see above). I couldn't do that with some other designs. The fan isn't needed, but with it barely turning the case stays cool/slightly warm to the touch, even right where the modules bolt to the chassis with the amp literally shaking the house. Without the fan the modules get hot.
The case isn't thick enough to conduct the heat away fast enough to stay cool, but it didn't shut down nor was it hot enough to burn, just uncomfortable to the touch. I'm putting a small, silent fan in the case just to move the smallest amount of air. If I get the energy I may install some thick aluminum bars in the case to conduct the heat and nix the fan. If I had to do it again I'd use a slightly larger and thicker case and mount the modules further apart from one another.
I cranked it up last night and it brought the wife out of the opposite end of the house it was so loud. Even she thought it sounded good when I put on something she liked, although she wasn't impressed by the fact it was all coming from a box weighing less than 10 lbs. I guess you have to build amps to really appreciate that part, especially 8 watt/channel 60 lb. tube amps. She was more concerned with the price, to which my response was "it's free, I'll just sell one of my tube amps". I think she bought it.
About hiss: are you sure its not really from your source? I noticed that there was slightly more hiss with UcD's than with my old amps (ICEpower), but it was all due to a little bit too much gain in the UcD's, amplifying the noise from my source so it was audible at half a meter from the speaker. I cured it by lowering the analog levels at the input.
Try shorting the input and check if there is still audible hiss in the speakers.
Try shorting the input and check if there is still audible hiss in the speakers.
Yeah, it's there with the inputs shorted, but it's sooooo low in level, and only on the tweeter, that I shouldn't have even mentioned it.
The noise in my sources swamps the hiss of the UcD. You're right, with the source connected and something playing, the noise floor goes so far above the hiss of the UcD that the tiny bit of hiss of the UcD is negligible.
Yes, simple "level matching" by adding a voltage divider at the amp-input is good practice to get the most out of a chain, though quite often overlooked.
Adjusting the sensitivity of the amp - directly at its input - exactly to the max level the pre-amp or active XO is capable to deliver distortion free not only lowers overall noise to its minimum but also keeps pick up of garbage along the signal interconnect at lowest possible levels.
Michael
Just some observation on hiss. I have two UcD180 monoblocks on B&W802's. I hear absolutely no hum and no hiss, even with my ear directly on the speaker. This holds for open input, shorted input or inputs connected to the preamp with a 3m cable. There is also absolutely no turn-on or turn-off thump.
I have added an input sensitivity switch, really just a resistor divider, to optionally lower the input sensitivity by 12 dB. What I said above holds irrespective of the switch position. I'm using the switch sometimes when listening at low volume.
The single most rewarding mod I have found is to fully DC couple the amp by bypassing the coupling caps. If you do this, you must be sure that your source is completely DC-free. Don't do this if you have a tube preamp, unless you are dead sure that the turn-on transient is fully supressed by a reliable output muting relay.
I have added an input sensitivity switch, really just a resistor divider, to optionally lower the input sensitivity by 12 dB. What I said above holds irrespective of the switch position. I'm using the switch sometimes when listening at low volume.
The single most rewarding mod I have found is to fully DC couple the amp by bypassing the coupling caps. If you do this, you must be sure that your source is completely DC-free. Don't do this if you have a tube preamp, unless you are dead sure that the turn-on transient is fully supressed by a reliable output muting relay.
You guys have some great advice. Thanks.
I retract what I said about the hiss. I made a bad assumption about the source being dead - suffice to say that with the inputs simply disconnected from the source, the hiss goes away. Now I'm blown away! The noise level is imperceptable even with my ear on the speaker tweeter. It's gone - completely! Wow.
I agree now that there is a need for an input attenuator in this case. The source I'm using is balanced with a pro level +22dBu output, way more than needed to drive the Hypex modules to full power, and running them at less than full output increases the noise.
Time to install some (precision) resistors to attenuate the input and the hiss. To be fair, the source has less hiss than just about any CD I've ever heard, and isn't audible beyond about a foot at the most, but the hiss is NOT coming from the Hypex module. Sorry about that Hypex - my error and your awesome modules. I look forward all day to coming home and cranking up Beethoven or Rush on my new 5.1 surround amp.
One thing that I noticed in an article about the Hypex written by Putzeys, is that the gain of the modules is arbitrary and can be changed by replacing one resistor on the board. Using a resistive divider on the input is definitely easier, but an even better (if more difficult) solution might be to change the resistor in the op-amp circuit to decrease the gain. But no way I'm pulling those modules out now and replacing six SMD resistors. They don't make a magnifying glass big enough.
I forgot to add, I am getting a very low volume midrange "thump" (without the thump) on power up/down. There's no bass and no treble in something that sounds in between a click and a thump, and it's very low in volume but clearly audible. However, I have the enable control lines directly tied to ground so the amp modules are set to power up as fast as possible. Maybe that's the reason.
Does your amp use the control lines to delay turn on of the modules until they become ready, or are the control lines tied to ground? I may do the right thing and put a switch on the amp and the enable wires. I turn it on and off by unplugging it from the wall, but with an idle dissipation of only a light bulb I'm not that concerned. I'm used to four KT88s and associated 60 lbs. of iron and high voltage parts burning hundreds of watts at idle. These class D modules are a dream for a guy in Vegas where it will reach 115 this summer.
I'm hearing in great detail all of the flaws of my CD and wave and flac file collection. The noise of the Hypex modules is far below both the source (CD) as well as the D/A converter in my audio interface (although an attenuator will help in the latter case). The distortion seems non-existent - at least I don't hear any at high volumes on any sources I know are clean.
To put it simply the output of the amp sounds like it's simply a replica of the input. It has no "character". It amplifies, no more, no less. It's "transparent" in the sense that there is no acoustic "veil" in front of the instruments, there's no audible noise (even with your ear on the drivers!), and it responds to dynamics in a very "authoritative" way for lack of a better word. The soundstage is open and wide in the sense that these are mono-block modules, and although they share a PS in most designs, the PSRR is over 65dB, so unless you have a terrible power supply, the channel separation should be absolute (equal to the SNR).
I've heard a lot of amps, and I still need time to keep listening to these modules and go back and forth between my different amps to make sure of what I think I'm hearing. But if my first impressions are right these modules will replace most or all of my amps, at least eventually. Time and many hours of listening will tell. They sound great, that's for certain. Whether they can rival a $100,000 amplifier I will never know because I simply can't afford one. I know my ears are pretty good. I've been listening to mixes and picking out guitar, bass and drum parts to learn for over 35 years as well as doing digital multitrack recording since the Alesis ADAT (early 90s). I started with a Tascam PortaStudio 4 in the early 80s before that, and bounced tracks back and forth between two cassette decks while layering instruments before that (late 70's). The point is I'm used to listening "through" a mix to focus on individual instruments and I've heard a lot of amps over the years through the same set of monitors that I've owned and maintained for over 25 years (JBL 4410), and with these amp modules it's very easy to hear the individual instruments clearly, and my first impression after a couple of weeks with these is that they sound as good or better than any amp that I've ever hooked to my speakers.
I also like the Hypex design more and more the more I read of Putzeys papers. He makes a lot of good points against the "other guys" designs, but the other guys either don't refute his arguments or do so with arguments I don't buy as a EE. I still want to hear some of the competition though. What else is the chief engineer going to say about the competition?
Great report!
My experience with the Hypex "sound" (or lack thereof) is the same. I've been going back and forth between Hypex and ICEpower for the past month, and there is no doubt that Hypex is vastly better. I really can't see any better sounding alternative than Hypex when it comes to Class D!
I really have to put a voltage divider at the input of my Hypex amps, I still have too much level.... at least 10-15 dB too much I guess. I really wish Hypex could lower the gain of the UcD modules, or maybe offer an option to select high or low gain.
My experience with the Hypex "sound" (or lack thereof) is the same. I've been going back and forth between Hypex and ICEpower for the past month, and there is no doubt that Hypex is vastly better. I really can't see any better sounding alternative than Hypex when it comes to Class D!
I really have to put a voltage divider at the input of my Hypex amps, I still have too much level.... at least 10-15 dB too much I guess. I really wish Hypex could lower the gain of the UcD modules, or maybe offer an option to select high or low gain.
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I'm switching on/off directly at the mains power, i.e. at the primary side of the transformer. No standby.
I have clearly audible hiss on my 400ST modules, even with the input disconnected and the amp muted....
The amps are mounted close to the speakers, and wired as the manual says. No wires close to the powersupply, and no mains power or network anywhere near the amp or speakers.
This is a PSD2.400 plate amp, btw.
Any tips to where I should start looking?
The amps are mounted close to the speakers, and wired as the manual says. No wires close to the powersupply, and no mains power or network anywhere near the amp or speakers.
This is a PSD2.400 plate amp, btw.
Any tips to where I should start looking?
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