Hotrodding the UCD modules

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#202
Jocko Homo said:
You can use your coupling transformer without adding anything, but...............

It may not like the load presented by the UcD module.

Jocko
Click to expand...

Indeed, however, fortunately, 1:1 trafos are usually pretty flexible. I asked the designer of the trafo if it'd be happy into such a load, he said yup. There's a shield on the secondary (as well as the overall mu metal can) so that'll keep any capacitance out of the picture. I'll try it in the near future, but who the hell knows if I'll notice an improvement given it's in a biamped system doing only up to 200Hz
 
#203
Since it is not full range, yeah, you probably won't hear the difference.

Most of those guys will tell you what R-C load it needs to flatten out the response. They may be off a little. (I know that I use a different load than advised.) But the UcD has some caps to make a LPF, and that might be too much.

Without knowing which one it is, I can't say for certain. I just know how the ones that I have tried react to it. There are ways around that minor problem.............

Jocko
 
#204
While I didn't implement the trafo input (cap coupled device before the amp makes it unnecessary, ATM) the UCD 180AD got it's caps bypassed tonight. Driving bass only, the improvement is obvious. It's just plain better, in every way. Big fuggin' rug lifted off the bassbins. Nasty electrolytics have no place near the signal path!!
 
#205
Well i tried taking the dc caps out of the circuit tonight.It did sound better untill the clicking sound set in.I guess i have to much dc offset like that.

I did not insert one 1.0uf 200v cap in line with the "+" pin and Mount the cap at the RCA jack..Wanted to see how bad my dc offset would be first.Anyway i have to order 1.

regards
jeff
 
#207
Yves Smolders said:
Off-topic, but fun to see where the UcD quality is going:

Stereophile august 2005 reviews Channel Islands Audio D-100 monoblocks. These are UcD180 based monoblocks @ $1599/pair

Haven't read the article yet, i'm curious about it! 😀
Click to expand...

Havent read it either but i found following comment from http://www.amusicdirect.com/products/detail.asp?cat=270&sku=ACIAD-100

"
“Channel Island’s nifty little D-100 amplifier is extremely well built-the fit and finish are superb. I kept having to remind myself that a pair of them costs less than $2000! A lot less! I really had to keep pinching myself as I auditioned them. In performance, the D-100s might be giants; the fact that they’re so small is just icing on the cake. I think I’ll keep a pair around as a reminder of just how good affordable high-end can be. You might want to do the same!”
– Wes Phillips, Stereophile, August 2005
"
 
#208
I have read it. Against the Coda S5, they fell short in a few departments, but not far short, by any means. And since coda knows their stuff and the s5 is significantly more expensive, one can assume that if Wes is being honest, these are pretty durned good amps. I'm liking mine more now that the coupling caps are jumpered out. A lot more.
 
#209
Guys, somebody try turning the bias pot on the UcD400? I do turning about 90 deg. and THD :=.005% at 80w/8ohm (160w are max power for my setup), instead .017% for standard position. But i think, that copper T-heatsink probably needed, for such tweaking.
 

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#210
IVX said:
Guys, somebody try turning the bias pot on the UcD400? I do turning about 90 deg. and THD :=.005% at 80w/8ohm (160w are max power for my setup), instead .017% for standard position. But i think, that copper T-heatsink probably needed, for such tweaking.
Click to expand...


Nice results, is your soundcard good enough to measure that 0.005%?

In fact I turned down the pots a bit on my modules since they got a bit too hot. I guess my heatsinking in the experimental setup is not good enough. They are used now as woofer amps and I don`t hear issues with increased distortion. Well woofers will distort easily a few percent, depending on level of course so probably UcD distortion is not limiting here.

Best regards

Gertjan
 
#212
Re Off-topic:

I can add a couple bits of data re the Channel Islands D-100.

The units tested by Stereophile unfortunatly had the current limiting set incorrectly--so the tested results reflect that.

Two good things however:
1) Wes Phillips found the sound of even a under-performing UcD based amp quite good.

2) The September Stereophile will publish revised tests showing at least the following: .027-.0285 THD
110w @ 8 ohms
200w @ 4 ohms
300w @ 2 ohms

I do not know if they re-measure any other parameters.
Stereophile's John Atkinson does the testing with an AP1 and his own filter set-up (not sure how much that might effect results).

Finally, the current D-100 amp, while still a '100w' amp, now uses the UcD400.
I own a pair, and can say the UcD, combined with an excellent implementation by CIAudio, has sonics that surpass any amp I've heard.

Congrats and thanks to BP and JP -- I have enjoyed reading these threads for the last year! Even if I understood little....

Mark
 
#213
Maybe the Channel Islands D-200 monoblocks can give some new ideas for additional modding.

Channel Island D-200

--------
Our new D-200 Class D Monoblock builds on the technology of our highly acclaimed D•100. The new higher voltage D-200 version incorporates independant power supplies for input and output sections, dual discrete diode bridges, and oversized filter capacitors to produce the power to drive the highly efficient amplifier section.
-----------

What about the part "independant power supplies for input and output sections"?

Any idea?

using_e
 
#215
Hi,

I'd imagine the modules already have "independant power supplies fo input and output sections" nothing new there at all.

The point of that is that for instance with the ucd700, having the option to easily swap to your own "high end" low noise tightly regulated low voltage supply for the front end is a great feature for the hardcore enthousiasts who may do that with it.

From what's been said about the D-200, for all we know it could still be using the standard independant supplies.

Regards,
Chris
 
#216
I tried posting that statement over at audiogon (D-100 Channel Islands = UcD180) and someone wasn't happy with me saying that...

Check the thread, superlatives for the UcD sound:

Audiogon Statement

Or read the quote here:

Impressions Channel Islands Audio D-100 monoblocks
guys:

1) You *are* correct about the D100, UcD class-d amps sound magnificent.

2) You *are* aware that the D100 is based on Hypex UcD180 modules, that can be bought for 100 euro's/piece ??? - just add power supply...

3) D-200 same story, based on UcD400 by Hypex.
07-26-05



Impressions Channel Islands Audio D-100 monoblocks
D-100 also now uses a custom version of UcD400 (not UcD180). D-100 and D-200 do not use standard "off the shelf" Hypex modules. These amplifiers have been engineered from the ground up with over a year of R&D. The UcD technology is great to design an amplifier around, but you can't toss a Hypex module and power supply in a box and have something equal to D-100/D-200.
Ci_audio 07-26-05



Impressions Channel Islands Audio D-100 monoblocks
@Ci-Audio,

I'm not by any means implying that you use off the shelf Hypex modules, just pointing the people where to get a alike-sounding amplifier at a fraction of the cost.

No offense meant!
07-26-05



Impressions Channel Islands Audio D-100 monoblocks
No offense taken, just wanted to clarify the points of your post.

Yes, you can build a pair of Hypex mono's for about half our retail price (that's a big fraction)...this is true of any amplifier. You'd still have to buy chassis, switches, jacks, binding posts, etc., and build them and hope they work. With the standard Hypex parts (transformers, power supply boards, etc.), you'll get about 100w out of UcD400, but it still won't sound like a D-100.
Ci_audio 07-26-05
Click to expand...
 
#219
Friends,

A little adivice: "Do not poison our own water source..." If you hostilize or imply on other vendor forums that the UCD module that is sold for the DIY community is either the same, or better, or can be made better, you will give them ammo to force Jan-Peter and Bruno to reconsider not selling modules to the DIY community. Remember that this is a business for them, although they want to sell products to the DIY community and clearly like to support the community, selling to high-end audio makers is more profitable and very relevant for them. We do not need to hide anything, but let's keep a low profile wjhile outside of the DIY forum, ok?

Allan
 
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