UCD180 questions

[IVX]

Hi all,
I hope that tube buffer for UcD would be great. I'll try to check this out soon.

[IVX]

BTW, simple discrete opamp from here http://www.diyaudio.com/forums/attac...amp=1081722163 have ~0.03% THD at 2kohm load@4Vp-p output@gain=4, just by adding a current mirror ([bc857+bc857+220ohm+220ohm]=cost is nothing), THD will be less then 3 times (0.008%@20-20000hz flat).

[Jan-Peter]

IVX,

Intersting!!

Who is making the schematic complete and creates a SMD PCB????

Or starts a new thread, I will offer to make the PCB design, I will put the gerberfiles for free to everybody on the Internet.

Regards,

Jan-Peter

[stef1777]

Small PCB please. I don't have any space left in my boxes.

[classd4sure]

Originally posted by Jan-Peter
IVX,

Intersting!!

Who is making the schematic complete and creates a SMD PCB????

Or starts a new thread, I will offer to make the PCB design, I will put the gerberfiles for free to everybody on the Internet.

Regards,

Jan-Peter

Impressive! Nice offer, very admirable indeed.

Koldby was right on too, that is the exact thread I had in mind, I guess I didn't read far enough into it for it to seem familiar at the time.

Thanks Koldby for that other link too, I had it saved for some rainy day reading but then I lost my hard drive. Another thing I'd missed is where they said this discrete amp works in class A..

What I didn't miss was Peranders questioning the need for an output buffer stage, and that the design as it currently stands is for loads >5K. Have we got work to do on this?

Regards

[maxlorenz]

At last, I got all the parts an I built my amp

I'm the living proof that anyone can build an UCD based amp

Of course, I have some dignity left not to show picture's of it yet , after those "chef d'oeuvres" that were posted recently in both threads.

Preamp is mi excellent DIY transformer based volume control(Stevens&Billington's TX 102 MK III-copper). I made an unbal to bal adaptor cable. I built first a stereo amp with: Ampslab's Inrush Current Limiter (works OK and is cheap!); Piltron 300VA (35-0-35 VAC); common bridge rectifier; cheap 4700uF*2 PS Ecaps. I got a healthy 47.6V DC.

I only had the time to listen a couple of CDs (Bossa Nova and Bartok's string quartets) and I'm amazed about how soft and effortless the amp sounds! Also the frequency extension is great, specially the bass, though I listened through monitor speakers. Someone asked for a comparison with class A amps long ago. Well, my main amps are Monarchy Audio's SE100 delux class A amps (mosfet) and of course I will compare them. First impressions: UCDamp has the coherence and "continuity"of my class A amp, notably in voices. I'm amazed that bass seams deeper and fuller considering 9400 uF versus 120000 uF of PS capacitance!
I got a little buzz that I plan to eliminate soon.

I will add two more channels next. I hope my TX can cope with the burden: it didn't even got warm after the listening.

Now, has someone a pair of Epcos Sikorel caps to sell??

Thanks to Jan-Peter and Bruno for such nice products!

Mauricio

[pa]

Hi, thanks for the comparison with the class A, it's the only type of amp wich could be better on quality, i'have 3 ucd modules at home, but i'm wating some 10000uF low esr philips 114 series fro the initial test... :-)
35v isn't it to much ? i was thinking 32v was a maximum value...

[OA51]

Some pics of my finnished UcD180's

3 cabinets for UcD180's


Inside...


Back side...


Module, ferrite on the speaker wire


Caps...


Class-D Softstart utilized with a digital timer relay...


If the pic's are to big just tell me and I can change them to links instead...

This one has better Caps than the erlier one I made... I haven't checked yet if I can detect any sonic difference...

Regards

Stefan

[maxlorenz]

See what I meant? How could I ever post picks of my "Flintstone amp" after your gorgeous amp appeared

Congratulations! I hope mine can look half as good as yours.

BTW, it seams I found some good parts seller here...they have BHC, RIFA and Epcos caps! at good price. "rs-export.com"

Pa:
My TX is rated at 230VAC but my actual AC is 220V, minus 0.7V from rectifier and ... voilá! +/-47.6VDC.

I will repeat comparison with my SS class A amps but with everything else equal, to be fair.

Mauricio

[classd4sure]

Hi Stefan,

Do you teach robotics or something?

I don't mean to find fault with perfection, that is excellent work, but I would be concerned with those PSU wires eventually being cut or even simply worn by the metal. Perhaps consider some nice rubber grommets to prevent this from ever occuring.

They sure are nice!