UcD400 Q & A

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#501
Henrik,

I am sorry but my answer is no. The overvoltage protection works at 68VDC........:angel:

We recommend for the highest sonic performance a voltage between 50V and 63VDC.

On the other hand a low impedance of even 1 ohm is no problem for the UcD400. Actually in our testsetup we use 1 ohm to check if the amp delivers the maximum current of +/-20A piek. In the THD versus Power curve the THD stays nice below 0.05% 😉

Regards,

Jan-Peter
 
#502
Jan-Peter said:
Henrik,

I am sorry but my answer is no. The overvoltage protection works at 68VDC........:angel:

We recommend for the highest sonic performance a voltage between 50V and 63VDC.

On the other hand a low impedance of even 1 ohm is no problem for the UcD400. Actually in our testsetup we use 1 ohm to check if the amp delivers the maximum current of +/-20A piek. In the THD versus Power curve the THD stays nice below 0.05% 😉

Regards,

Jan-Peter
Click to expand...

How about a graph of that if you have the time? We haven't seen one yet for a 1 ohm load. Not that I don't believe you or anything it would just be neat to see.

Or whatever graphs you posted before for the UCD400 done on the new version would be neat too. You must have some kicking around?

Thanks
 
#504
pot recommendations

I'm planning to put the amp in a box together with a xls10 and two passive radiators each with a 100g extra weight. The only thing between the ucd400 and my amplifiers sub output will be some copper and a pot. What's a good value for that pot?
 

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#506
aawirth said:
Hi, is there an answer to the question Brian Lewis brought up earlier on the DC offset of the UCD400 and a way of getting rid of it???

Al
Click to expand...


Of the UcD180 modules that I have, the DC offset at the output is in the order of 20-30mV or so, measured it a while ago, so may not be exactly that, guess it will be similar for the UcD400. I don't know if that is too much for certain ribbon drivers? I don't think it is that easy to get even lower offset, using DC servo circuits?

Gertjan
 
#507
On the other hand a low impedance of even 1 ohm is no problem for the UcD400. Actually in our testsetup we use 1 ohm to check if the amp delivers the maximum current of +/-20A piek. In the THD versus Power curve the THD stays nice below 0.05%
Click to expand...

Amazing stuff. Is 20A peak, or can it be sustained for a while?

Just think about how much $$$ you have to drop on a class AB monoblock that is stable to 1 ohms and can deliver 20A....
 
#508
Yves Smolders said:


Amazing stuff. Is 20A peak, or can it be sustained for a while?

Just think about how much $$$ you have to drop on a class AB monoblock that is stable to 1 ohms and can deliver 20A....
Click to expand...


Hello Yves,

As far as I understand it, this 20A is where the protection starts to kick-in. It means you should be able to have 20A all the time, just if you ask for 21A, the protection circuit will prevent you from doing that 🙂

20A peak is very good since with a 4 Ohm load and say 56V peak voltage at the output (for 400W in 4 Ohm) the module "only" has to deliver a peak current of 14A, so at 3 Ohm you could get about 530Watt. If you bridge two modules (I plan to do that for my woofers, you can just get 800W at 4 Ohm. That should be enough to rock my house without actually having an earthquake 🙂. However, I have dipole woofers that can use some power.

Best regards

Gertjan
 
#509
20A peak is very good since with a 4 Ohm load and say 56V peak voltage at the output (for 400W in 4 Ohm) the module "only" has to deliver a peak current of 14A, so at 3 Ohm you could get about 530Watt
Click to expand...

Yeah,

That's why I asked... My speakers are 8 ohm but have nasty drops to 3.

If Ucd400's can pump 530W (ideally) into each channel continously at 3 ohms, that is just amazing... No surround receiver can do such a thing (except the new denon 5.... something, but that thing is a 5000$ beast) - a huge toroid and lots of caps will take care of the rest 😀

When I complete my amp i'm going to test it on a friends disco-setup 😉
 
#510
Originally posted by Bob Lewis;
Hi All,
Anyone any ideas about the best way to null the DCoffset on the UCD400AD modules as I intend to actively drive APOGEE ribbon speakers with these? The MRT ribbons are very sensitive to DC,suffering displacement in the magnet structure plus premature aging and stretching.
Click to expand...

The best idee is to add some DC at the input of the UcD400 after the coupling caps. Supose you have 20mV DC output, the gain is 20 times, when you ad -1mV at the input you will have zero output. Ofcourse you have to decouple this DC very good because it's connected to your input.

Regards,

Jan-Peter
 
#511
1ohm Scintillas?

The Scintilla will draw upwards of 40A at peaks that has been proven.
Will the UCD just cut at that point (ie distort)? A large power supply will not overcome a current limiter. What happens if current is not limited. is that modifiable? Willl they overheat?

I do know the ICE amps will drive these speakers and put out up to 45A without a problem and will not limit current.
I'm just a bit concerned because i'd rather not spend all this money if they are not quite right for these speakers.


Anyone have any experience with very low impedance loads?

Thanks
Torin
 
#513
Re: 1ohm Scintillas?

gruvytune said:
The Scintilla will draw upwards of 40A at peaks that has been proven.
Will the UCD just cut at that point (ie distort)? A large power supply will not overcome a current limiter. What happens if current is not limited. is that modifiable? Willl they overheat?

I do know the ICE amps will drive these speakers and put out up to 45A without a problem and will not limit current.
I'm just a bit concerned because i'd rather not spend all this money if they are not quite right for these speakers.


Anyone have any experience with very low impedance loads?

Thanks
Torin
Click to expand...

Is this with respect to IcePowers 1000W model or their 200/500 watt models?

Regards

EDIT:

I'll just answer my own question:

"Performance High-power amplifier with ASP1000. Has received an outstanding HIGHfidelity review.
Special Contain the best sonic tweak of the far more expensive eAR 1001 Ultra mono-blocks
Max. power output (truly RMS Watt) 1 x 1200W RMS into 4Ù,, 1 x 600W RMS into 8Ù
Internal wiring Hard-wired with OFC , internal AWG12 power cord and internal AWG12 speaker cables.
Power stage efficiency 83% including everything
Peak output current > 45A"

Hardly comparing apples with apples here now are we. I see their 500W model states output current >35A. The key words here could perhaps be "peak", what's the max that it can sustain? I'm not sure if that's a figure I'd be willing to bet on.

Regards

Edit#2:

The output devices of the UCD400, provided they haven't been changed, handle 35A continuous at 25 deg. C and 24A continuous at 100 deg. C. So a limit of 20 amps seems really good.

Perhaps the UcD700 will be more suitable for your needs.

Regards
 
#514
when is the UCD 700 due to be out.

i'm not convinced these wont do the job yet.

i listened to them last night with my KMA160s and they produced some very respectable sound level hardly straining the amps.

we shall see, first its time to fix the buzzing in the ribbons...
 
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