UcD400 Q & A

[SSassen]

Yves,

Is it possible to "eyeball" the VA rating based on the size of this thing?

No, not really, you can get an impression from experience, but there's too many variables, such as:

- Type of Fe used in the core
- Number of primary and secondary windings
- Diameter of wire used on windings
- Core type, H-core, N-core, O-core, etc.

Suffice to say that the power rating on the back of the device is a good indication. Never make the mistake of just adding output wattage of an amp and then concluding that that's the rating of the transformer.

Best regards,

Sander Sassen
http://www.hardwareanalysis.com

 

[Jan-Peter]

Originally posted by Mattjans

i'm not really worried about an asymmetric psu voltage during operation or at manual shutdown of the modules (unplug...).

JP, what will happen if 1 rail fuse breaks while the psu keeps running, ie either V- or V+ gets disconnected?

Nothing happens when you disconnect one of the power voltage even with playing music. The UcD module stops with working.

Jan-Peter

 

[Yves Smolders]

We worry too much... Hypex modules got it *all* covered

 

[matjans]

prima!

 

[Leeuwarden]

There's one thing they haven't covered: there are not enough units! I'm still waiting
Thank god it's only hobby and it doesn't matter.
(I had to wait 4 weeks for my new Apple computers. Thats work so that does matter )

I also found out that my local electronics supplier has to wait two weeks for my Amplimo 300VA 42V transformers. Doesn't matter either, it's just a hobby...


Heee, thats nice! Just recieved a mail from my Apple supplier: he just got my new computers!

 

[BOB LEWIS]

Jan-Peter,
What would happen if one fuse blew if the regulated part of the module was driven by a separate supply?

Curious,
Bob Lewis

 

[Jan-Peter]

Bob,

I don't exactly understand your question. Can you explain it more in detail?

Regards,

Jan-Peter

 

[BOB LEWIS]

Jan-Peter,
If the voltage dropping resistors which feed the regulators are fed from a separate set of capacitors would this affect the shutdown of the module in the event of one of the fuses blowing?

Bob Lewis

 

[Jan-Peter]

Bob,

This is a modification on the PCB and we can never guarantuee a good working in this way!

To come back to your question --> I don't think it will damage the module.

Actually we have never tested this because in a normal testsetup this can't happen.

Regards,

Jan-Peter

 

[BOB LEWIS]

Jan-Peter,
Thankyou for reply.

Regards,
Bob Lewis

 

[lorklorkii]

UdC phase vs frequency

Hello, all-

This is actually a question for Jan-Peter, but it seemed more appropriate to post so all can see the answer than just to email him. Of course, if someone else has the info, or I missed a post containing it, please just let me know.

My questions is what the phase of the UcD output is versus frequency (and, if I can get it, applied load). The ICEPower datasheets give this, and it doesn't look too good to me, so I am looking at the UcD (400) for my DIY... but can't find the info on the Hypex website (nor an email contact there), so I don't know if it's better.

Thanks for any info!

 

[lawbadman]

Hi,

Has anyone tried any of these UCD amps with any magnepan speakers, particularly the MMGs?
I want to know because I have the MMGs and plan to buy the UCD or the Zappulse, I just cant make up my mind as to which one to buy.

Thanks
Lawrence

 

[Yves Smolders]

Haven't hear of anyone that did.

What are those speakers...? 3 ohms, 2 ohms...?

Due to current limiting these might not be the best amps for your speakers.

They are stable at low ohm values but current limiting will limit the watts... The Ucd400's are not 800W at 2 ohms... unfortunatly

I've read bad things about capacitative (sp?) loads on class D units (ICEpower) - maybe this is a question for Jan-Peter or Bruno

EDIT: They are 4 ohm speakers - that should get you the full 400W when built right!

 

[Ouroboros]

I did a quick trial using my early-type UCD400s (mounted as replacements for the two amps in a Quad 405) into my MG2.5r speakers. No problems at all. I used to have a pair of SMGb speakers and they were a much more difficult load (when being driven from an Arcam 9P which was happy with the 2.5rs but not the SMGs).

I haven't tried the UCDs into capacitive loads (not that the Maggies are particularly capacitive) but a home-made current-mode self-oscillating class-D amp that I designed (similar to a Mueta but using a current-transformer to sense the inductor current), can tolerate enormous capacitive loads.

 

[mac]

I'm driving two large 8 ohm woofers wired in parallel (with an effective impedance of 3 ohms) off my UcD400. The module has no trouble with this configuration.

As far as driving capacitive loads, I've had my UcD180's connected to my speakers using unterminated Polk Corba Cable. IME the amps are unconditionally stable into this highly capacitive load.

 

[Bgt]

Jan Peter, I just received your amps, really pretty little blocs.
Is it possible to put 2 fuses(+ and-) between the supply lines and the capacitor bank or does this give/bring a risc of destroying the amps?
I am just so amazed about the size of these amps.

 

[Jan-Peter]

Is possible to use a fuse in the power lines. We have tested by the UcD400 removing one of the powerlines. The amplifier stops directly with working.

But I can advise you to use a DC-protection in the case one of the fet's go down

This week we have finally finnished our webshop, so next week there will be time to finnish our powersupply with a DC-protection!

Enjoy the modules! (wait till you have listen to them ;-))

Regards,

Jan-Peter

 

[Bgt]

Thanx JP, I always use a fast switching DC protection. Would not dare to do without! The Driades are too expensive!

 

[Franklin]

Just as additional info; the Maggies are a pure resistive loads for amps. I owned the 0.5 SE (European version).

Happy listening.

 

[wytco0]

JP, do you have any more information about your power supply? Any idea when it will be available?

Regards