UcD400 Q & A

[Jan-Peter]

Gertjan,

You bring up a good point, perhaps we must put some glue on the pot to avoid the Class-D will go to Class-A .

No, the best THD curve, in the 5W, area is the middle adjustment

I am glad you enjoy the UcD180, with the UcD400 in your active setup you will have even more fun.......

Cheers,

Jan-Peter

[ghemink]

Originally posted by Jan-Peter
Gertjan,

You bring up a good point, perhaps we must put some glue on the pot to avoid the Class-D will go to Class-A .

No, the best THD curve, in the 5W, area is the middle adjustment

I am glad you enjoy the UcD180, with the UcD400 in your active setup you will have even more fun.......

Cheers,

Jan-Peter

Hi Jan-Peter,

If the middle setting gives the best result, it may indeed by wise to put some glue on the pot. Then real hard-core tweakers can still solder that pot out and put another one in, but then it is fully their responsibility if they screw things up.

Best regards

Gertjan

[peranders]

Jan-Peter, do you have a "meatier" datasheet than the non-existant

[nickywicky]

The T-shape aluminium is blue and need to be connected to an alumnium frontplate/mountingplate or whatsover. To change the colour to

Is steel (1.2mm say) good enough heat conductor to mount to ?

[UrSv]

Originally posted by peranders
Jan-Peter, do you have a "meatier" datasheet than the non-existant

It's on the web site.

[classd4sure]

Originally posted by Jan-Peter
Gertjan,

You bring up a good point, perhaps we must put some glue on the pot to avoid the Class-D will go to Class-A .

No, the best THD curve, in the 5W, area is the middle adjustment

I am glad you enjoy the UcD180, with the UcD400 in your active setup you will have even more fun.......

Cheers,

Jan-Peter

Hi, thanks for those graphs.

Yeah that's exactly why I asked if it was OK to drop some epoxy on it. If people see a pot the first thing they do is grab a screwdriver and give it a turn. Question is can the pot adjust the deadtime to a point that can be detrimental to the output stage or is just a "fine" tune adjustment that wouldn't really matter? If it's the second you can leave putting epoxy on up to the user, if not, you'll save yourself some money and hassle by gluing it at the factory.

Thanks

PS: Great job on the pictures, that's much better.

[classd4sure]

First thing I'd do with that pot is mark it to preserve the factory preset, provided it isn't already.

Other thought, you've all seen em, "if torn warranty void" stickers, that'd be ideal!

Saves Jan-Peter any hassles, and anyone so inclined can tear it off and tweak it to their liking without needing to order the correct replacement pot, less hassles all around.

[DSP_Geek]

Originally posted by Jan-Peter
Hi Guys,


There is an adjustment for the Idle current, we will adjust this for the best performance.
We use now an OPA2134 opamp and the inputimpedance is 100K, and no coupling caps anymore. (sorry for the mods guys)


www.hypex.nl

JP, would it be possible to retrofit the UcD400 modulator onto a 180?


Thanks,
Francois.

[nickywicky]

The UCD400 pdf says that the idle mode power dissipation
is <6w.
Is this when the /ON signal is not pulled to GND so it is turned
off. Or is it when /ON is pulled to GND but there is no signal ?

[classd4sure]

Hi,

I've been pricing some power transformers, 40V rms secondaries at 650, 750 and 1000 VA. I think for two modules off one transformer I'd want at least 650VA.

So my question is this:

I've found "low noise" transformers offered, they don't even say what is different about them, such as any screens, magnetic shielding, or otherwise.

What is different is they're triple the cost of a regular one.

What's the consensus on having such a "low noise" transformer. Is it a must have? Is it a joke? Is it worth the extra cost? Would you notice any difference at all?

Now what I found was just marketing hype, no specifications offered or anything, so I'll also ask, how important is any screen /shielding as well, and we'll consider that to be low noise for the purpose of this part of the discussion.

Thanks