List of PWM Amplifiers. - Page 7

There are things that I like about both ICEpower and Hypex. For the most part, I view them as interchangeable. The main factor being the intended application.

The load dependent nature of the ICEpower is the main drawback, and it is not the same for all 3 power versions. The 1000 being the most load dependent. As they were originally intended for powered loudspeaker system, it may not be fair to call it a design shortcoming. It is frustrating that a module capable of delivering 1000 W would turn out to be less than optimum for low-Z, low-efficiency speakers. However, in fairness, I believe it was intended mainly for woofers and sub0woofers, and not full-range speakers that are a difficult load to drive. (The stand-alone version is only rated to 6 kHz; that ought to be a good clue.)

I think both ICEpower and Hypex are an excellent choice for HT systems. For high-end 2-channel systems..............system matching becomes more critical, as the customer has different expectation levels. Whether they are realistic or not.......that is a subject best left to audiophile forums.

Where my input is usually received in a less than welcome manner.

20+ years of dealing with neurotic audiophiles has a way of wearing on your nerves. Even for someone like me who has audiophile leanings. We would like to concentrate more on the HT market, but our roots run deep in conventional 2-channel systems. Change is not easy, especially for a bunch of cranky old engineers.

Pat

Audiophiles are a weird crowd indeed - I'd see myself more like a hifi-nut, not audiophile.

My dream was to buy N804 speakers, because I really like the way they sound. and finally I did buy them after a long long wait...

Now you can choose for yourself if these speakers are "high-end" or not, that depends on your wallet I guess ( ), but for me they are amazing sounding, and surely at the top of what I'd spend on speakers.

Problem was that I couldn't afford good amplification right away, I had to make do with my AVR, which had trouble to drive the N804's (not because the amp doesn't "sound" good, but pure electrical, N804's impendance is tricky)

I was happy to hear them on bryston, rotels, and other usual suspects but couldn't afford these.

Enter a DIY forum somewhere, where they are raving about Diy UCD amps - couldn't resist and dropped the cash, thinking I could use those amps for a second system I have here with old Philips speakers that can handle a lot of power.

Built it, tested it, sounds wonderful with the Philips... Couldn't resist trying them on the 804s... Never looked back, to my ears the speakers were alive just like in the shops where they are demo'ed with the above usual suspects.

Now why is UCD so good? I believe it's the feedback system - the load is included in the feedback and that way optimizes itself to whatever you connect to it (given enough clean power to work with) - other class-d designs have linearity changes due to the load connected - not the UCD's.

Secondary, these UcD's have a "linear" distortion, meaning the distortion isn't higher at high frequencies, like in a regular class AB. The result is very clean highs, even on speakers that are told to be very tiring & forward in the highs, like my N804's.

Couldn't be happier, really... everyone should at least take a listen

Of course, this might just be a my-kid-is-cuter-than-yours placebo effect...

Value for money it's a no-brainer! and meanwhile... "audiophiles" are laughing because I run the precious B&W gems with "dirty class-d" power...

the feedback scheme in the ucd doesn't really "optimize" for the load, it just makes the load less of a factor for the output.

99.99% of the amps out on the market today has that 'featuer'.

TLF, you mean 99.99% of the amps out there include the speaker in the feedback loop?

Interesting.....I have read of people driving Apogees(ie. difficult load) with ICEpower and having great results.

99.99% of the amps out there incorporate speakers in its feedback loops in a fashion identical to that of the UcD.

hopefully it clarifies a bit more.

Have a look at these units:
www.coldamp.com
They have 400W @ 4 ohms modules, plus switching power supplies, which makes perfect sense to rid yourself of bulky and heavy linear ones...

UCD Feedback gives cleaner highs, like class AB amps? Did I read that right? I am an owner of ICE powered amps that are driving 1 ohm speakers. The highs cannot get any more pristine.

I did not say that you can not drive Apogees with ICEpower. The poster above is a good example that shows you can.

I did say that the ASP1000 is not a good choice, in spite of its power capabilities.

Remind me some day to measure the 500W ICEpower with a 1 ohm load. We only have data on the 1000W version into low-Z loads.

Pat

Pat, do you have any data on the UcD700 into 2ohms?

ar-t, you know who I am. I agree that the ICE1000 is not the best choice. I think you would agree best results can be had using the 500A.

Muralman, imho the UCD's outperform most regular class AB amps I've heard, except for the more expensive ones.

For what it's worth, listening experience is much easier on the ears using the UCD400's as external amps on a denon 4306 then using the internal 4306 amps.

I do of course realize that this Denon receiver isn't up there with for example Rotel 1080 or better.

Didn't do ABX or anything - a good indicator isn't sound quality per se, but listening fatigue - the internal amps were fatiguing my ears a lot quicker than where I am now.

I tend to go up on the volume more easily as well, but this might have nothing to do with class AB vs D - it's just that the UCD amp I've built has more capacitance and way more VA on the transformer than the Denon has!

There is one important thing owners of Class D amps come to realize, if they are lucky. That is, garbage in, garbage out applies like never before. Class D amps have very little character of their own. Being ruthlessly transparent is a double edged sword. More of the signal gets through unscathed, but at the same time, all that capacitance in connectors you hear about also broadcast an Alkaseltzer fizz. More damaging seemingly OK front ends are spotlighted like the lame ducks they are. Conventional amps give these bad characters a soft landing, so they are hardly noticed.

That's absolutely right. Dynamics are effortless. Combined with decent speakers it's a blessing and a curse!

Piano & womens voices are absolutely fantastic to hear on my system, if the recording is ok.

However there's a bad trend towards "hot mastering" or the "loudness race" you hear about. It used to be only for pop music, but it's made its way to all styles of music.

I've got a CD here called "My name is Larry", a new artist with an amazing voice. She does the light jazz genre a la Katie Melua.

The CD is unbearable. Everything is mixed into the top 5db of the CD range. Try to imagine what a piano sounds like if the dying reverbs are as loud as the attacks, and you hear the compressor pumping away with each strike of a note. The recording is *killed* - heard the voice clip here & there... mind you, the voice, not the odd bassdrum clipping...

It's amazing these days, if you pick a late 80's album and start playing it, you need to turn up the volume quite a bit... the dynamics you're getting are very rewarding however!

just where did you get all the above? Amazing, isn't it?

Yvez, I hear you! A listener flew 400 miles to hear my system. Everything was stellar with my own discs, until the fellow put on, "A bad disc." We had to turn the volume way up just to simulate some form of dynamics similar to what we had been listening to. The strain was audible.

tlf, When I moved from a well known top flight solid state amp to my present class D amps, I kept the same wires. Everything sounded better, after all.

I learned. First to go were the power cords. A TacT owner nearby brought over some shielded cords, and the change was real. Next, out went the speaker wires. Exotics like ceramic, magnet wire, and helical, formally I thought of as perhaps quacky, proved to be the real deal.

You have some good points. If not matched properly, Class D can sound awful. And I believe that leads to a lot of the negative impressions that people who have not heard them are convinced are gospel truth.

As for the -500 being the best........

Depends.

I prefer the -250. It is a bit smoother, and does not interact with the load as much as the -500. The -500 has more "oomph", and if you have speakers like my friend above does, then it is the only choice of the 3. I remain convinced that he has a synergistic effect in his system, where the anomalies of the amps and the speakers cancel each other out.

My system uses Maggies (the ones without the ribbons), and as a result, it gives more of a "tube-like" sound. Our customer base is heavily weighted towards Maggie owners, but most have ribbon tweeter versions. They seem to blend well with all types of planar speakers.

Cone driver speakers..............requires some tweaking to get it right. They are not "plug and play" on those speakers. One of our beta testers has WATT/Puppies, and they can be brutally revealing. I did mange to convince him to ditch his horrible sounding MIT speaker cables. Muddy, exaggerated bass, and rolled-off highs. (I hope Dave Wilson isn't reading this, as he remains convinced MIT is the only way to go. Yuk.)

The reason I brought them up is that you can really hear differences in soundstaging on them. Very subtle differences in frequency response can make major changes to imaging. Anything from wider than the room, to putting the singer right in your face. I prefer the former, most customers the latter, and the beta tester can not decide which he likes. Actually, he likes both, and wants both. We made a special version that allows him to switch between the two, and have plans to make it a standard feature.

The results have been mixed. Some love it, others think it is the dumbest thing we have ever done. Others think they like the idea, but are unconvinced we picked the right settings.

As for capacitance.........

A lot of users report that high-capacitance speaker cables suck all the life out of the sound. That observation seems to hold true regardless of what brand/topology of Class D amp.

As for the UcD700........

We have looked at any yet. Based on our tests with the -180 and -400, I would not expect any difference in FR based on load Z.

Pat

Agreed. No class D amp is a sure bet plopped down into a system. I knew I could make it work. Some people are lucky, and have a system that is compatible. Others want to dismiss the new technology out of hand, and are most pleased if they can make it fail. Certainly, using MIT is a proven way to assure failure.

but you never used fully conditioned digital electrons did you? if you did, you would have thrown away anything you have bought. it is amazing how those little things can change the sound stage.

Yes, we experiment with conditioners too. They are not the fixall they are made out to be. Some are current limiting. Others lasso high frequencies. All the others I mention do very special jobs, and do make a big difference, conditioner in line or not.

This is a digital/class-d amp thread people, not an esoteric audio equipment thread...

Yves, our collective point is, digital/class D amps need carefully chosen components to not sound dull and lifeless.

If we were talking about tubes or solid state, I doubt the same system concerns would be shown.

the H2O Sig, when properly equipped, and with it's stable mate preamp, the Fire, Rocks big time!!!!!!!!!!!!!!!

"Yves, our collective point is, digital/class D amps need carefully chosen components to not sound dull and lifeless."

This is a digital/class-d amp thread people, not an esoteric audio equipment thread.

my experience with electron conditioners is that a) you have to make sure that they work on digital electrons; b) the correct spins make absolutely a huge difference. I have found 2.5 positive left spins help rendition of sound stage for classical music, but suck for rap; and 1.75 right spins, positive or negative, tend to be great for easy listening.

Of course, you will have to mate them with the right power cords, moon phase of the day and menopause cycles of the neighbor to your left.

magnet wire is exotic?

I think so. You have to admit, The use of naked magnet wire goes against the grain of a couple decades cable design theory. There is lots of room for .

I'm getting off this thread before someone starts to put stones on top of his class-d amp...