class D amp project coming along!

[Cowanrg]

well, i have my prototype class d amps built and running! im listening to them to see how i like them and if they are a good match for my system.

they are build off of the UCD400 modules from Hypex. so far, they sound great.

[ThomasW]

Looking good Rob ..... :T

Nice to see you've got a manly power supply ....

[Cowanrg]

these chumps are recommending like 330va or 500va transformers for this amp.

screw that, i dumped in a 1.7KVA transformer for each mono 8O

i dont mess around. they are actually sounding REALLY good. im not like one of those "OMG class D is the future!" guys yet, bit its impressive what this little module can do.

[Cowanrg]

btw thomas...

i havent gotten my BG's yet, it seems they are heavily backordered (supposed to arrive next week maybe), but the Tympani's are still for sale

[cinema bob]

very cool, have you been taking pics along the way to help all us wannabes out? ;D

[Cowanrg]

ive been taking some pics. there really isnt much to it. i could walk you guys through it. its pretty basic amp building 101 stuff.

if you have questions, shoot.

[mikec]

these chumps are recommending like 330va or 500va transformers for this amp.

Guess that makes me one of them.

Image not available

[mikec]

ive been taking some pics. there really isnt much to it. i could walk you guys through it. its pretty basic amp building 101 stuff.

Didn't seem like it the other night when I was helping you with your grounding problem. :W

[cinema bob]

i just downloaded the manual for the ucd400, i'm amazed i think that even i could put together a couple of nice monoblocks. besides the power supplies are there any tips or special parts that you used or recommend?

I doubt that i will ever build one of these but its really cool knowing i could (i think).

[Cowanrg]

mikec,

it is basic amp building 101, but i never took that course, so im not so good at it its not hard, but it still takes some knowledge, and im still learning. BUT, i think just about anyone with some patience and common sense could put these together. but, the grounding is a bit different than what im used to though.

[TacoD]

If you follow the connection diagram of Hypex, you get with almost no effort, a nice amplifier. I have build Hypex ucd180 for a friend.

[RobP]

How much was the cost of building your amplifier?

[mikec]

If you follow the connection diagram of Hypex, you get with almost no effort, a nice amplifier. I have build Hypex ucd180 for a friend.

I agree. My build was 100% trouble-free.

How much was the cost of building your amplifier?

Cost can be as little as $495 if you build the diycable 2-channel kit which uses all hypex parts. If you source the components yourself you can save even more. I didn't cut corners on my build but I didn't go with stupid-crazy parts either. 6-channels of UcD180/400 amplification cost me about $1600.

[eros28]

MikeC

Would you be able to disclose where someone could 'source out' these various components. I'm interested in building a two monos amps (either the 180 or 400 don't know yet) to go into one enclosure. Any info, is greatly apprecitated.

I'm in Vancouver, BC and can do the drive to DiyCable but if I can save a few dollars by getting them locally or elsewhere then I'm game.

[mikec]

MikeC

Would you be able to disclose where someone could 'source out' these various components. I'm interested in building a two monos amps (either the 180 or 400 don't know yet) to go into one enclosure. Any info, is greatly apprecitated.

I'm in Vancouver, BC and can do the drive to DiyCable but if I can save a few dollars by getting them locally or elsewhere then I'm game.

You can save a few bucks by ordering direct from Hypex, but IMO it's not worth it. OTOH, you can save some $$$ on the power supply components and chassis. PM me and I'll give you the scoop. Cheers, Mike

[DeanP]

Cowanrg,

How does this amp compare to your Rotel amp in sound?

[Cowanrg]

alright, here is the post many of you have been waiting for...

(this is a copy and paste from my post from diyaudio.com, so if im referring to a previous post or something, its not on THIS thread, but another one. if you have questions, just ask)

a showdown between goold old class AB versus new school class D. and by this i mean a comparison between passively bi-amped rotel b-1070's and a pair of mono UCD400's. the rotels are roughly 185 watts into 4 ohms per channel. i passively biamped with them, so i was getting around 370 theoretical watts per speaker with them. so, the wattage was very close between these two. i used the same cables and everything. the only variance was the amplifier. look back a couple pages in this thread to see the entire system.

im not going to bore you with which tracks i used, etc. if you really want to know, you can email me. but, its nothing special. in my opinion, you can use anything, as long as you are familiar with it and have critically listened to it before. i ran both amps full range and turned off my subs for this test. my subs do way too much to have them left on. plus, the levels of these amps were slightly different, so i would have had to recalibrate the subs each time i switched. so i just ran each amp full range and didnt use a crossover point in my processor.

now, it took me so long to get results to all of you because the amplifiers sounded very similar. i dont think i could do a blind test and tell which one was which. i could hear differences for sure, but im not sure if i could do it blindly, but maybe. the main differences between the two were soundstaging, bass, detail and overall "listenability".

the UCD's pretty much won on all these categories. there was a couple things i liked better on the rotel, ill go into that later. my speakers are soundstage monsters to begin with, so this was actually a hard one. ususally, i get a massive soundstage no matter what i do. i could use a home theater in a box receiver from wal-mart and get a great soundstage. but, the soundstage was taller and wider with the UCD's. it was a little more laid back, but not by much. its not that it was necessarily "bigger", but it seemed more filled in. the UCD's gave more of an impression of a wall of sound. however it sounded like this with the rotels, just not as much.

the bass was almost identical. but, the UCD's had a little bit more of it. the rotel wasnt leaner, but it was a bit sloppier and was lacking mid-bass punch. you really had to turn it up a bit louder to get what you wanted out of the speakers in terms of bass. however, neither one was really fantastic. my speakers are very difficult to coax bass frequencies out of. but, on some tracks, i was overall pretty happy with the results full range. but, in NO case would i have not used my subs if i had the choice. but in general, if i had a speaker that WAS full range capable, i would probably use the UCD, it just seemed to have more to it, and a better quality.

one of the first things i noticed with these amps was there was a bit more pronounced detail that i hadnt noticed before. now, its not like i heard things id never heard before. my system has always been absurdly detailed (almost a bad thing). but the UCD's seemed to make things seem more natural without being flaws as much. when you could hear toe-tapping or coughing in the background before, it seemed more like it was meant to be there, rather than a flaw that they tried to cover up. i did notice things that i hadnt noticed before. but when i went back and used the rotel amp, i heard it there too, just not quite as apparent.

now here is the most vague of all the differences. the UCD's overall just sounded better to listen to. the rotels have a slight edge to them. this is partly due to the fact that the magnepan tweeter is a 20+ year old design on my speakers and naturally has a slight edge to it. on poor recordings, it comes out and is VERY apparent. the UCD's didnt necessarily alter the quality of the music, they just smoothed off the edge. i still had a shimmer on symbols that was realistic, it didnt compress anything, but it took off the edge. this was a nice and welcome improvement. i have a lot of bad cds (dont we all!) that are still great to listen to because its good music. but, i cant turn them up that much without hearing serious flaws. overall, the UCD's were just easier to listen to. plus, as i mentioned before with the soundstaging, there just seemed to be more of the sound filled in. the rotels sounded slightly leaner.

so, thats basically what i heard. however, i would take either amp without question. if i were in a store and they were the same price, i would simply choose based on appearances of the amp. i just wouldnt have a chance to A/B them like i did. i think in a store environment it would be impossible to hear any differences. maybe on a switcher it would be easier though.

overall, im not BLOWN AWAY by the UCD modules, but they dont sound any worse than my rotels, and on almost all fronts, they sound slightly better. i might try some better caps and a bit more complex power supply on the final versions to get every last bit of performance from them. but, all in all im pleased. in the past week or so that ive had these running, everything has just generally sounded good and i have been happy with my system. ive not heard my speakers sound better, and there weren't any tradeoffs with these amps either. i didnt have to give anything up. so, im in. they will get a case built for them and become my main amps.

so thats the review. its not as absolute as i would have liked it to be. but, im not disappointed at all. i didnt expect much from these (i just didnt know what to expect). in any event, for DIY, they are robust, relatively cheap, easy to put together, and small. plus, the heat issue is completely gone. i ran them on pathetic heatsinks and they got warm, sometimes hot, but never dangerously so. but, like i said, they are pathetically small.

[JoshK]

I have three stereo UcD 400 amps, so I have some basis for comparisons. I've gotten good dividends by going a little further than the basic PSU. Best PSU caps I have tried out so far aren't the most expensive ones, Nichicon KG Golds, from Michael Percy ~$7/ea (4,700uF) iirc. I use two per rail with dual mono designs.

I got some IXYS bridges, can't say they made a huge improvement but for $16 it was worth testing out. Bypassing the bridges with .022uf caps made a larger improvement, IMO. I also bypass the Nichicons with Jantzen .1uf and .01uf caps and then a snubber after that. Sounds a treat.

[Cowanrg]

hum. yeah, those caps are $8 each. i would need 4 of them per channel. and im planning on making these stereos too. i wonder if he would do a quantity discount on a bunch of them... it might be something to try, ive heard that nichicons are a great value and its hard to get a significantly better sound without spending 4x more money.

im not sure what i will do for a bridge rectifier. i might get some nice diodes or something, but im not sure yet. one of these days ill get downstairs and put the power supply on my scope and look at it with different configs, or listen to it. its just so tedious.

i do plan on using bypass caps across the rectifier, and it seems pretty universal that it makes a good improvement in the sound.