UcD400 Q & A

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#421
UcD400AD monos complete

Hi again. I just made it before New Year's Eve so they could get a good break-in that night ;-)

This is my first electronics DIY project, so any kind of constructive criticism is welcome.

The cases are from http://www.thlaudio.com/ and even though Taiwan is far away it was a trouble-free pleasure to deal with them.

About the sound: It difficult for me to evaluate in absolute terms, but at first the UcDs seemed very tizzy in the upper end with the treble sort of detached from the rest of the soundscape -- at least compared to my Plinius SA-100. That signature fortunately went away after leaving the UcDs playing for a couple of hours.

Now, after playing for a couple of days, the sound it good, very straight-forward with clear mids and firm bass -- and the top end is now integrating with the rest as it is supposed to. The top end is maybe not quite as smooth and easy on the ears compared to the Plinius running in class A mode, but then again, the Plinius has a dark/warm signature to it where the UcDs come across as more neutral. When playing loud it is easy to hear that the UcDs are more powerful. I think I prefer the mids of the UcDs over the slightly recessed mids of the Plinius. With the UcD, voices (both in music and in movies) are easier to understand than with the other amp.
 

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#425
matjans said:
hansen, may i ask how much the shipping charges for those enclosures were?

I'm thinking of buying an enclosure from them but i can't really get a good estimate on the shipping charges...
Click to expand...

I dont remember the exact price, but the price of the enclosures wasn't scary at all, and iirc the shipping price was quite fair too. Did you try to send THL Audio an email and ask for price and shipping options?
 
#427
Thermal issues with UcD400

Good morning.
I am in my way to build a ClassD amplifier (you can see that in the forum 🙂, but I am also interested on UcD modules specifications.

I would like the designers to put the thermal requirements of the UcD400 module in a nutshell:

Is the "T"shapped block enough to operate the modules at full power with music without attaching it to the case? If not, what is the estimated power range (I know it is difficult!) you can get only with the module alone? (mounted in a chassis with natural convection and slotted top cover, for example)

How can one know if the module is operating safely (thermally speaking)? For example, if I attach a temp. sensor in the T block just at the side of one of the Mosfets, what is the maximum temperature I should allow the modules to run?

I suppose the usual way to use them is to attach the T block to the side or bottom of the enclosure, does this give a suitable safety margin to operate a couple or four modules in typical applications?

Thanks for your clarifications!
 
#429
Thanks, Jan Peter.

I have read that, but still have some doubs: for example, it doesn't say nothing about the T shaped heatsink's thermal resistance:

If you measure temperature just at the mosfet, and calculate the dissipated power that cause a 75º increase in the junction, they are safe up to 100 degs at the heatsink, and if that occurs at a slightly higher than the rated power, the rating is ok.
But it is strange to me (I am not an expert in thermal calculations, to be sincere) that the heatsink's thermal resistance is not included in any calculation, so that doesn't answer my question about the module ability to "survive alone" at full power.

Another thing: your calculations are based only on conduction losses, while at the frequencies we are talking about, switching losses should be added, as they can be even higher than conduction losses.

Could you clarify this a bit, please?

Thanks!
 
#430
Pierre,

The thermal resistance of an aluminium pieces with a size of 8x25mm and length of 22mm is VERY little.

The total efficiency of the amplifier is 93% included the losses in the coil. So at an outputpower of 200W you have to dissipate 15W, not such a problem I guess.

I do not the exact value of the switching losses, but we use a very advanced power fet what has very low internall capacitive values so the switching are also not that high. In the Ucd400 we use the Fairchild FDP42AN15A0.

Regards,

Jan-Peter
 
#431
Plain stupid

That's me.

I switched + and - putting together my second (two channel) amp (the first was three channel).

So they are (at least partly) toast.

I hope the guys at Hypex can fix it....

Frans

PS
The three channel amp still performs great.
 
#434
Jan,

We have done some interesting improvements on the UcD400. I had planned to put the UcD400 in production before Christmas unfortenatly our subcontractor had to move this to beginning this year:bawling: :smash:

We are now planning to have the modules available in about 3 weeks.

To all customers:
Very sorry for the delay!!!!!!

Regards,

Jan-Peter
 
#440
Ok here we go for the improvements list of the UcD400 new version;

-- new high current outputcoil.
- maximum outputcurrent will go to +/-20A piek.
- 2 ohm load will be no problem, even with an 1 ohm Thd stays below <0.05%
- new shortcircuitprotection, the same as the UcD180 a true current limiter.
- incresed overvoltage protection to 68VDC.
- connection will be with fastons just as the UcD180.
- very low EMI, even better as the UcD180.
- input electrolytic capacitors.
- slightly improved THD performance.

We will have them on stock around 10th of februari.

I hoped our PCB assembler could start with the production BEFORE Christmas last year. Unfortenatly they cound't and I miscalculated that the guys were having also a winterstop for 2 weeks :smash:

Very sorry for the delay, and thanks to everybody for your patience :angel:

Regards,

Jan-Peter
 
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