Optimal supply design for UCD and Zappulse modules

[ghemink]

Hi Gertjan,

It doesn't use any type of switching, it just makes a small capacitance "appear" like a much bigger capacitance (X the gain of the transistor).

This has the effect of significantly reducing the ripple, just like a 100 000uF cap might. However, unlike a 100 000uF cap, it just can't store the same level of energy, and will readily sag more under load, further reducing power.

The reason it sags and is also so efficient is because it isn't regulating anything at all, and has less reserve.

If you think you have a hum problem or poor psrr it might be an interesting option to play with, but you have to be aware of what you're giving up, a nice stiff supply that can really deliver on demand, which is why unregulated raw DC supplies are good, and why they're still so commonly used in high end audio.

Maybe if you never plan on turning it up at all, it would be just the thing.

As far as the price of them goes, well, they closely match or slightly exceed the cost of the class-d modules themselves, and for what? I'm not really impressed with that. Although as far as what it is, it seems decent.

Also, the shut down feature is said to operate 5ms after triggered, that'll never protect anything at that speed, it seems like a useless feature to me.

Best Regards,
Chris

Thanks for all the replies.

The current limitation can be easily increased, see the reply in the UcD180 thread, so that is no issue.

I think 5ms shutdown is really fast, I don't think a relay opens that fast, does it?

However, I get the picture, it is a capacitor multiplier, which is still not a bad thing to use in combination with big caps as it will further reduce the riple, even when the supply goes down, less riple is never a bad thing I would say. And lower output impedance is also a nice to have.

So I may give it a shot.

Thanks and best regards

Gertjan

 

[richie00boy]

I think 5ms is fast enough. I'm trying to remember whether a good relay driven optimally was 5-7ms in opening, or closing. I know Doug Self wrote about this in his protection articles in Electronics World.

 

[classd4sure]

I've just seen a "high speed relay" at 20ms... I stand corrected.

 

[Yves Smolders]

If anyone still cares...

This is a good solution to build an easy soft-start:

http://www.nteinc.com/relay_web/R34.html

This is essentially a delay-on relay. You apply juice to it, the delay waits (0.1s to 10s) and then switches on.

Add a couple of heavy duty resistors and you're go

A question: is "Input" the voltage needed to switch the relay? Sorry for the silly question....

Yves

 

[richie00boy]

Very neat and interesting product. I think it's just the job, but seems to be only available in 120 volt version.

 

[fram]

Hi all!

I'm going to order PCB for my new PSU design.
If someone are interrested about PCB's, just let me know! (ewildgoose ?)

Price would be 23 euros/Pcb excluding shipping cost. (could be less expensive if a lot of people are interrested)
PCB is a double layer with metal holes, 2 solder masks and one silkscreen.

Here is my email: mattioli@nerim.fr

 

[hiwi3]

PSU PCBs

I'd be in for two, shipped to North America.

Here is my email: williamcarter@mindspring.com

Hi all!

I'm going to order PCB for my new PSU design.
If someone are interrested about PCB's, just let me know! (ewildgoose ?)

Price would be 23 euros/Pcb excluding shipping cost. (could be less expensive if a lot of people are interrested)
PCB is a double layer with metal holes, 2 solder masks and one silkscreen.

Here is my email: mattioli@nerim.fr

 

[ewildgoose]

Yeah, I would be up for a pair. I will reply directly (just wanted to show interest on the list).

Thanks for doing this

Ed W

 

[ghemink]

I've just seen a "high speed relay" at 20ms... I stand corrected.

The relay can be fast, but you need time to detect DC at the output of the amp. Probably it takes several 100ms before DC is detected since you don't want to trigger the DC protection on say a 20Hz signal at full output power.

Gertjan

 

[wytco0]

Fram, Interested in 2 and possibly 4, have also sent email.

 

[Tetman]

jensen four pole capacitors

Has anybody experience with the Jensen four pole capacitors.
I want to make a state of the art psu for my ucd180.
I'm also looking for the 10.000 63v 154 BC, these are hard to get.

 

[blaaberg]

Hey,

Try a look here for BC caps:
http://www.schuro.de/preisl-bc154.htm

Venlig hilsen Jan Jensen

 

[Duck-Twacy]

I think series 154 is not made anymore by BC Comp (Phiips, Vishay?). Probably Schuro has a large stock.

 

[vroum90]

hello,

what about the BC 114 ?

(On the datasheet the 114 is better than the 154 )

 

[maxlorenz]

capacitor ratings:

I'm searching for parts for my UcD400 monoblock amps.
I wanted Epcos Sikorel 15000uF/100V caps but I didn't find a source.

I next focus on BHC Aerovox ASL30 series. If all gets well done my PS will have a DC of 60.8VDC. The BHC manual says that 63V caps can handle lots of picks of 72.5V (more than UcD's overvoltage protection) being "industrial, Long Life" caps.
Would it be safe to go for the 63V caps?

Thanks

 

[Hans L]

I heve made an intresting experience....

I have made 1 UcD400 and 3 UcD180 stereo amps...

one of the UcD180 is equipped with 2 Rifa PEH200 22000µf 63V caps fed from a700 VA trafo via 2 rectifier bridges...

the other two UcD180 has the same trafo but 4 rectifier bridges feeding 2*15000µf 63V BHC ALP20A153DF063 per UcD module...
http://194.205.122.12/servlet/AdminBHC?purpose=spec&partNo=ALP20A153DF063

There is a big sonic differance between them... the one with BHC caps sound much better!
Tighter bass, clearer, more open mids and great high's without "sssss-sounds"...
...
I will replace the Rifa PEH 200 in the first UcD180 as soon as possible...

Hi Stefan,

did you get around to testing the different between the RIFA and the BHC, all else being equal?

Thanks,
Hans.

 

[maxlorenz]

Has anyone compared Epcos Sikorel against BHC's??

I know my BHC ALS40 (22000uF) sound very good.

 

[blaaberg]

Hey,

The same experience do we have on the danish list.
RIFA is not a god cap with Zappulse. When change it, the modul sound a lot better and more tight.

Venlig hilsen Jan Jensen

 

[maxlorenz]

Thread resurrection:

I thought about resurrect this interesting thread. It has some good info that passed overlooked to my eyes.

After my initial success with my UCD180 I had bad HF noise with my UCD400 monoblocks, wich led me to ask our nice big brothers here at the wonderful forums.

Eminent EE's don't agree about the best PS wiring scheme for UCD. The picture is what I tried last night: PS is floating, or I least think so, with only T-piece bolts attaching to chassis. I added tween rectifiers (no snubers). My fear of lack of VDC symetry was absurd: perfect symetry, even without grounding. I have common type 35A diode bridges on one monoblock and Ixiz, 68A, on the other.
Wiring/solder are still burning-in but I find this is the least noisy wiring that I tried so far.
I still use copper plate for PS caps ground because of mechanical reason and easiness of wiring.

An externally hosted image should be here but it was not working when we last tested it.

[/URL][/IMG]

I will next add a Power filter, "technical balanced power", wich is represented on the next drawing. Now it is serving the secondary UCD180 based system . All I can say is "enhanced clarity". I'll report back when burn-in proceeds.
Also I will try XLR's Pin 1 lifted from chassis,

[URL=http://imageshack.us][IMG][URL=http://imageshack.us]

Please refer to:
[url]http://www.equitech.com/articles/articles.html[/url]
For technical explanation about iso-Tx.

Any comments, regading snubbers, wiring or other topics are welcome
Regards
Mauricio :)

 

[maxlorenz]

C'mon guys,
will nobody criticize my wiring nor my, in my view, indispensable power filter?

Equi=tech ask big money for its transformers, though you can buy or wire one for much less.
This "technical balanced power" is said to allow even addition of Y caps, from secondaries to ground, without noise contamination of gound, against wich Bruno also warned us.

Just see post #26 from Jan Didden, wich states the extreme PS dependency of UCD, to achieve superior sound.

Regards
Mauricio