Optimal supply design for UCD and Zappulse modules

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#161
Hi,

Those look very nice.

What kind of relays are you using for the soft start?

Also, with your new design in the works, would it be possible to relocate that one connector so it's not stuck in the middle of a bank of caps? It really looks ackward there.

Good to hear from ya again, I knew you were around 🙂

Thanks
 
#163
Hi all! 😉

classd4sure,

relays are Schrack RT114024 24V and it can swith 12A/250V!
With this footprint it is possible to use a lot of kind of relay.

ewildgoose,
Here is the new PSU release with multiple cap's footprint and snubber: http://mattioli.free.fr/UCD180-PWR_rev1.0.pdf

I'm going to check my first PSU design when receive my UCD.
If this design work well, some PCB will be available. (the new release of course).

A new PSU design will be available very soon, the same as this new release but with 8 caps on board.
🙂
 
#164
Hmm, interesting circuit. Do you have a sec to talk me through it?

Basically, why isn't it symmetric?

8 rectifiers is presumably to drop the current requirements? Are you doing this because you are using something exotic here?

I'm assuming that R1 and R2 are there to prevent current hogging from one of the bridges?

Also, do you actually have a star earth here?

Seems to me that this latest board would not really be suitable for a dual mono supply (if I loaded it with 4 caps)? I'm kind of curious why you didn't design your board to be dual mono, since it seems to be half way there already?

Looks very interesting anyway. Keen to hear how it works out when you get your modules!
 
#165
Not being the designer....

- It looks symetric to me (at least the schematic)
- I assume he wants to use 2 of these for dual mono
- why 8 rectifiers? (quote from Zero distortion website)

This has several benefits: 1) it effectively isolates the transformer from the audio electronics and is bettered only by full voltage regulation, 2) it makes the plus and minus sides independent of each other, which theoretically allows for better reproduction of asymmetrical signals, 3) it reduces power supply output impedance, and 4) it doubles the current capability of the power supply, allowing for better transient reproduction and faster charging of specified and bigger electrolytic capacitors. In effect, it makes the power supply stiffer.
 
#166
Let me start by saying that my electronics knowhow is fairly low, but looking at the schematic and the two connections that are used to supply two modules: the circuit as viewed from each connection does not appear to be symmetric to my eye?

Also, if used in a dual mono, the center point of the second set of caps is not wired to the center point of the first set of caps, so is this going to satisfy a star earth arrangement if 4 caps were loaded and it was used to power one module?

Thanks for your comments on the other points. I still don't quite see why 8 rectifiers works as well as it does, but I will follow up on the site you recommended and see if I can't educate myself!

Thanks for your thoughts
 
#168
ewildgoose said:
Let me start by saying that my electronics knowhow is fairly low, but looking at the schematic and the two connections that are used to supply two modules: the circuit as viewed from each connection does not appear to be symmetric to my eye?
Click to expand...

Looks pretty symmetrical to me. I guess you could be caught out because the first set of caps has bleeder resistors, but if you look to the right of the bleeder resistors the next two lines of components are duplicated further along the schematic.

ewildgoose said:
Also, if used in a dual mono, the center point of the second set of caps is not wired to the center point of the first set of caps, so is this going to satisfy a star earth arrangement if 4 caps were loaded and it was used to power one module?
Click to expand...

This is probably another area where you can get caught out thinking it's not symmetrical. If you look just to the right of the second set of caps you can see an earth symbol. This point is shared with the earth symbol in the same position on the first set of caps, which is connected to the centre point, so a star earth is present -- or at least a groundplane is.

ewildgoose said:
Thanks for your comments on the other points. I still don't quite see why 8 rectifiers works as well as it does, but I will follow up on the site you recommended and see if I can't educate myself!

Thanks for your thoughts
Click to expand...

I do not agree with all the points listed as to why twin rectifiers on separate secondaries is better. In fact points 1 and 3 are not strictly 100% true -- in those areas claimed the performance is not really better than a single bridge and centre tapped tx, but point 4 is definitely untrue and misleading.

I personally use the twin bridge/separate secondaries implementation in my own PSUs. This is because you get proper independent rails (as per point 2), you get a better implementation of a true star earth, and you can load the transformer core slightly better and thus get a little more out of it for the same temp rise (although nothing like twice the current). All cf to single bridge and centre tapped tranformer of course. I don't waste my time with anything less than fullwave rectification.
 
#169
Yves Smolders said:
Could anyone direct me to information on running UcD's on car battery power?

I believe I need a DC-DC solution for this, but can't find too much on it.

Anyone here running Hypex modules in your cars? 😀
Click to expand...

LC Audio has a SMPS module to convert 12V to split rails for this purpose. You could also build one given the information on the ESP site (look under power supply projects), but this is definitely not a beginners project. Not that I am implying you are a beginner or anything, just covering myself 🙂
 
#170
Ritchie00Boy:
It probably is a matter of interpretation so I guess benifit 4 should read: "it doubles the current capacity of the RECITFIER". Further down the page it explains that you can use smaller rectifiers because of this and therefore build your entire design more compact.

I also think benefit 1 helps preventing the high pitch tone that you can get when building 2 mono's


Ewildgoose:
Dual mono means: 2 transformers, 2 separate power supplies.
Sometimes the 2 power supplies ar eon one PCB board but they don't share any signal at all. So in this case you need 2 PCB's
 
#171
ericpeters said:
It probably is a matter of interpretation so I guess benifit 4 should read: "it doubles the current capacity of the RECITFIER". Further down the page it explains that you can use smaller rectifiers because of this and therefore build your entire design more compact.
Click to expand...

Again I must disagree 🙂 If a current is being pulled through any part of a circuit, that current will remain the same at all parts through the circuit. The requirement for the current capacity of the rectifier is identical in the case of the twin bridge/separate secondaries as with the single bridge/centre tapped transformer. What is reduced is the voltage requirement, as now each bridge only sees half the total rail voltage.

I am not getting at you as the website is not at all clear on this matter (IMO it is actually misleading by saying that you do not have to use bulky rectifiers any more) and it is easy to make the wrong assumption.
 
#173
Hi,

At the begining, this PSU was designed to drive two UCD180.

Caps C1, C2 (10000µF) and connector J2 will be used for "midwoofer UCD" and caps C3, C4 (6800µF) and connector J3 will be used for "tweeter UCD".

BTW, you can use this pcb for only one UCD 180 or only one UCD400. In this case, J2 is not used, only J3 used.

1) it effectively isolates the transformer from the audio electronics and is bettered only by full voltage regulation, 2) it makes the plus and minus sides independent of each other, which theoretically allows for better reproduction of asymmetrical signals, and 4) it doubles the current capability of the power supply, allowing for better transient reproduction and faster charging of specified and bigger electrolytic capacitors. In effect, it makes the power supply stiffer.
Click to expand...

this is right!🙂 (for me...)

This is probably another area where you can get caught out thinking it's not symmetrical. If you look just to the right of the second set of caps you can see an earth symbol. This point is shared with the earth symbol in the same position on the first set of caps, which is connected to the centre point, so a star earth is present -- or at least a groundplane is.
Click to expand...

Well, I add the possibility to connect heart with a screw at the corner of the pcb but add a pcb screw terminal at the center of the groud plane too (bottom side). I think having GND/heart point at the center of the PCB is better.

😉
 
#174
OK, well I for one would be interested in two of these modules, and the possibility of one/two more later - assuming the price is reasonable (as in I expect you to charge more than cost, but not too much). Given a choice I would prefer to buy everything bar the main caps + the board, but whatever is easiest for you.

Basically just registering an interest - don't feel any pressure to do anything about it!

Hope your amp works out well!
 
#175
Ericpeters:

quote: "I also think benefit 1 helps preventing the high pitch tone that you can get when building 2 mono's".

Yick! 😱 I didn't knew that (I don't know many things 🙂 )
Is it true? Appart this solution, How can I prevent it?

In fact I own monoblocks and sometimes I feel that they sound a bit on the light side. Now I plan to build UCD400 mono and I would hate to get them wrong.

Thanks
 
#180
I'm not sure if it would really have any affect anyway. I don't think it's a transformer or supply issue really, it's EMI related. Right? Switching noise of one module being induced into the other with a slight difference in frequency.

Also, while everybody is a fan of the dual rectifier approach let's not forget Bruno doesn't like it, having said it invites hum, he's been consistant in this viewpoint. I think I'd be forced to try it and find out for myself though, if it doesn't hum, why not keep it.

You're still apt to getting the whistle even with dual supplies, proper layout and distance are key to avoiding/reducing it.
 
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