Optimal transformer for UCD700

Status
Not open for further replies.
Jump to Latest
#41
classd4sure said:
Hi,

Didn't mean to imply necessary at all, just wanted to start the "were money no object" discussion. 😉
Click to expand...


money no object UCDs - yes. Let's start with the Blackgate N series 100V 2200uF capacitors for the power supply - $240 a pop. I did the math and for my 4 monoblocks, that's just about $18,000 for the caps. That's GOT to sound grand! 🙂

Let's run the whole thing of a large bank of SLA batteries - forget all that line noise and AC crap, rectifier noise, etc - batteries is where it's at! Hey - saves you those pesky transformers!

Peter
😉
 
#42
serengetiplains said:
Greg, yes, every possible improvement comes down to a question of "how much" and whether the improvement is worth the extra time and expense. I suggest that one reason the 700 sounds better than previous UcD versions is that it uses separate power supplies, including separate transformer windings, for the low voltage supplies. "Separation" would be the key contributor to the betterment if that analysis is correct. Dual mono works on the same principle, suggesting, further, that any separation possible is better. Jan-Peter's recommendation implies this, don't you think?
Click to expand...

You're talking about a couple of very different issues of separation here. One issue is channel separation which is the major reason to do monoblocks.

The other issue is separating out the low voltage power supply for the opamp from the high voltage power supply, the goal being to provide more stable, lower noise power for the opamp. My understanding is that the UCD amplifier modules currently use a combination of resistors and zeners off of the high voltage lines to power the opamp. The UCD power supplies have a regulated voltage supply built in for the opamps which when fed by the appropriate voltage, should provide a more stable, lower noise supply and hopefully improve the sound. I don't see how separate transformers would be better than separate windings in accomplishing this.
🙂
 
#43
GregD said:

My understanding is that the UCD amplifier modules currently use a combination of resistors and zeners off of the high voltage lines to power the opamp. The UCD power supplies have a regulated voltage supply built in for the opamps which when fed by the appropriate voltage, should provide a more stable, lower noise supply and hopefully improve the sound. I don't see how separate transformers would be better than separate windings in accomplishing this.
🙂
Click to expand...



the 180 and 400 modules use the zeners, the 700s are fed by regulators on the UCD700 supply, which is what these extra windings or separate transformers are needed for. You could apply this as a tweak to the 400s, as I read somewhere in that endless 400 thread, but you'd have to disable a few parts on the UCD modules.

I agree with your about these extra windings not being a major issue. The load on them is constant, and it's very low (20VA supposedly does the job).


Peter
 
#44
Peter: Do you mean Parts Express part number Avel Y236905 800VA 60V+60V? The link you posted brought me to part number Avel Y236903 which is a 40V+40V. Also, it looks like there is an Avel Y236959 that is 1000VA and 60V+60V. Too much?

I greatly appreciate all the discussion on this topic. I've figured that the dual mono UcD700 based amp would be around $1,500 (not including taxes/shipping). And, if it performs as well as it claims to, it should be the last amp I'll ever need. I don't get into surround sound...just give me two kickin' towers and one or two very accurate subs.

I would easily do the three transformer per channel option if it did provide for a better end-result signal (i.e. less EMI). The debate seems to be equally weighted for and against doing so. I don't have to consider a "spousal acceptance factor" (aka SAF) into the equation here (haha) so if the amp case is even larger, due to three transformers, that's fine with me.😉

I can now say that I know how transformers work and constructed with their windings/cores from the research I've done, heh. I'm still 1% knowledge and 99% motivation about power amps though.:bawling:
 
#45
jdgonko said:
Peter: Do you mean Parts Express part number Avel Y236905 800VA 60V+60V? The link you posted brought me to part number Avel Y236903 which is a 40V+40V. Also, it looks like there is an Avel Y236959 that is 1000VA and 60V+60V. Too much?

I greatly appreciate all the discussion on this topic. I've figured that the dual mono UcD700 based amp would be around $1,500 (not including taxes/shipping). And, if it performs as well as it claims to, it should be the last amp I'll ever need. I don't get into surround sound...just give me two kickin' towers and one or two very accurate subs.

I would easily do the three transformer per channel option if it did provide for a better end-result signal (i.e. less EMI). The debate seems to be equally weighted for and against doing so. I don't have to consider a "spousal acceptance factor" (aka SAF) into the equation here (haha) so if the amp case is even larger, due to three transformers, that's fine with me.😉

I can now say that I know how transformers work and constructed with their windings/cores from the research I've done, heh. I'm still 1% knowledge and 99% motivation about power amps though.:bawling:
Click to expand...

I meant the 800VA 60-60 unit - I don't think they even sell a 1000VA with those secondaries (I know they make them, based on the data sheet, but it's not listed at PartsExpress). 800VA should be plenty for a ucd700 Monoblock

your estimate on price is about right - I think I'll be spending about $1600 on a pair, excluding shipping. I'm planning on using pretty high grade connectors and wiring, nice cases, and possibly pay a machine shop for proper machining of the holes in the front and back panel. Without all of that, you should be able to keep it around $1500 for the pair.

last amp you'll ever need? with the way this stuff is progressing, I think in a few years, these modules will be surpassed by another generation...

The three transformer option - there is nothing wrong with it if you have the space in the enclosure and don't mind doing it that way. I'm planning on some future upgrade to these voltage circuits with super regulators that may involve different transformers or even batteries for the +/-12V cicruit.

Peter
 
#46
Regulation of additional windings.

I have a question that I hope someone knows the answer to.

Would the additional low voltage windings on one big transformer have better regulation than with separate small transformers? Since your typical 800VA+ transformer has 3-5% regulation versus 12-15% for a typical 30VA transformer, separate windings on the big transformer would be better if they have the big transformers regulation.
 
#47
Re: Regulation of additional windings.

GregD said:
I have a question that I hope someone knows the answer to.

Would the additional low voltage windings on one big transformer have better regulation than with separate small transformers? Since your typical 800VA+ transformer has 3-5% regulation versus 12-15% for a typical 30VA transformer, separate windings on the big transformer would be better if they have the big transformers regulation.
Click to expand...


the regulation isn't done by the windings. There are "voltage regulators" on the UCD700 board that do this. To get better regulation, you have to build your own regulators. All the windings do is provide AC at the proper input level. Everything else is done by electronics either on the PSU board, or built to the same spec by you. Only the 60V secondaries do not get "regulated" by additional silicon beyond the rectification.

Peter
 
#48
Re: Re: Regulation of additional windings.

pburke said:



the regulation isn't done by the windings. There are "voltage regulators" on the UCD700 board that do this. To get better regulation, you have to build your own regulators. All the windings do is provide AC at the proper input level. Everything else is done by electronics either on the PSU board, or built to the same spec by you. Only the 60V secondaries do not get "regulated" by additional silicon beyond the rectification.

Peter
Click to expand...

I understand that, but it's not what I'm referring to. I'm talking about the regulation of the transformers themselves. If you look at the spec sheets for transformers, there's usually a regulation % specified. For instance, check Avel Lindberg's specs here.
http://www.avellindberg.com/transformers/y23_range_specs.htm

I would think that if the voltage coming into the regulators is more stable, the overall circuit should be a little more noise free.
 
#49
Re: Re: Re: Regulation of additional windings.

GregD said:




I would think that if the voltage coming into the regulators is more stable, the overall circuit should be a little more noise free.
Click to expand...


if you're talking about the 12 and 15 volt circuits, that would be completely irrelevant. Regarding noise in those circuits, it is much more important what happens after the rectifier diodes. As long as you stay above a minimum input voltage, the regulators will put out the voltage they are supposed to produce, no matter what the transformer tolerances are.

Peter
 
#50
I recently built a phonoclone, and one of the things that other people came across was a grounding issue after the regulators causing noise when an unregulated power supply was used to feed the onboard regulators. The problem wasn't observed by people using battery power supplies or that had preregulated the power going to the board. Of course, it's quite possible that UCD's board is designed in such a way that it's not an issue, but I think it's at least worth thinking about a little bit.

Here's a link to the thread.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=57398
And the most pertinent link.
http://www.diyaudio.com/forums/showthread.php?postid=746363#post746363
 
#51
Re: Re: Re: Re: Regulation of additional windings.

pburke said:

if you're talking about the 12 and 15 volt circuits, that would be completely irrelevant. Regarding noise in those circuits, it is much more important what happens after the rectifier diodes. As long as you stay above a minimum input voltage, the regulators will put out the voltage they are supposed to produce, no matter what the transformer tolerances are.

Peter
Click to expand...


I disagree. There's no question the purity of what precedes regulators affects post-regulator purity---easily measureable and easily audible.
 
#53
GregD said:
I recently built a phonoclone, and one of the things that other people came across was a grounding issue after the regulators causing noise when an unregulated power supply was used to feed the onboard regulators. The problem wasn't observed by people using battery power supplies or that had preregulated the power going to the board. Of course, it's quite possible that UCD's board is designed in such a way that it's not an issue, but I think it's at least worth thinking about a little bit.

Here's a link to the thread.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=57398
And the most pertinent link.
http://www.diyaudio.com/forums/showthread.php?postid=746363#post746363
Click to expand...


if you're that paranoid about your torroid messing with the regulation, I would recommend to use pre-regulation and a second regulator. The thing is, you can get quite caught up in all this and spend a lot of cash on boutique parts, but sometimes you never hear any difference. Since nobody has built a UCD700 here yet, it's up to you to go and experiment. Let us know. My modules are still somewhere on a boat in the Atlantic, dodging icebergs...

Remember - the UCD400 and UCD180 get by with a zener diode to do the same job. Nobody stops you from calling Plitron and ordering a few custom shielded audio series torroid for each secondary, except maybe your bank 🙂

thing is - you can always get those additional transformers or even complete custom super-regulated power supplies (got the bookmarks - just holler), but why not build a baseline first and then decide if you want to spend the extra cash? I'm all for boutique parts if they make a difference at a reasonable price (reason in that arena is defined differently by each audio nutcase), but you'll only know that if you build it the cheap way first.

Peter
 
#54
pburke said:



if you're that paranoid about your torroid messing with the regulation, I would recommend to use pre-regulation and a second regulator. The thing is, you can get quite caught up in all this and spend a lot of cash on boutique parts, but sometimes you never hear any difference. Since nobody has built a UCD700 here yet, it's up to you to go and experiment. Let us know. My modules are still somewhere on a boat in the Atlantic, dodging icebergs...

Remember - the UCD400 and UCD180 get by with a zener diode to do the same job. Nobody stops you from calling Plitron and ordering a few custom shielded audio series torroid for each secondary, except maybe your bank 🙂

thing is - you can always get those additional transformers or even complete custom super-regulated power supplies (got the bookmarks - just holler), but why not build a baseline first and then decide if you want to spend the extra cash? I'm all for boutique parts if they make a difference at a reasonable price (reason in that arena is defined differently by each audio nutcase), but you'll only know that if you build it the cheap way first.

Peter
Click to expand...

I think you kind of missed the main point of my question. Basically what I'm wondering is whether or not the end result would be better with separate windings on a single transformer or separate transformers for each voltage. If the superior regulation of a bigger transformer applies to the ancillary windings, then I think a single large transformer would be preferable to separate transformers. Plus, I think it will actually end up being cheaper than buying separate transformers for each voltage.

So --- save money and better sound. 🙂
 
#55
GregD said:


I think you kind of missed the main point of my question. Basically what I'm wondering is whether or not the end result would be better with separate windings on a single transformer or separate transformers for each voltage. If the superior regulation of a bigger transformer applies to the ancillary windings, then I think a single large transformer would be preferable to separate transformers. Plus, I think it will actually end up being cheaper than buying separate transformers for each voltage.

So --- save money and better sound. 🙂
Click to expand...


Ah, but it is "load" regulation. An 800VA varying with load could be something like 5% regulation/variance. Say you use a 20 or 50VA xformer for the input stage, you could probably run both your input stages off it and never draw more than an amp, so even though it has a regulation factor of something like 15%, you're really only loading it down 1/50th ... I'd guess it would then vary 1/50'th of that 15%?, which is what 0.3% variance?

Additionally it could not be modulated load, which is really what you're after. My numbers may be wrong but I think there's no doubt seperate transformers is best, baring the extra expense.

While the 700 has onboard regulators who's yet to say that doesn't consist of anything more than a zener/pass transistor/exact same circuit as on the previous models? No doubt it could benefit from a high end regulator as well.

The way it is does two things, most likely one being help push up the rated efficiency a little transformersbit, and the other at least forces one to use seperate supplies. I bet you could really do it on the cheap, swap a few values on the board and jump the inputs together and use a single transformer for it all, no doubt like some manufacturers will end up doing. Most likely they'll wait to have the SMPS handed to them on a platter, but that won't be available to us.

Regards,
Chris
 
#56
classd4sure said:



Ah, but it is "load" regulation. An 800VA varying with load could be something like 5% regulation/variance. Say you use a 20 or 50VA xformer for the input stage, you could probably run both your input stages off it and never draw more than an amp, so even though it has a regulation factor of something like 15%, you're really only loading it down 1/50th ... I'd guess it would then vary 1/50'th of that 15%?, which is what 0.3% variance?

Additionally it could not be modulated load, which is really what you're after. My numbers may be wrong but I think there's no doubt seperate transformers is best, baring the extra expense.

While the 700 has onboard regulators who's yet to say that doesn't consist of anything more than a zener/pass transistor/exact same circuit as on the previous models? No doubt it could benefit from a high end regulator as well.

The way it is does two things, most likely one being help push up the rated efficiency a little transformersbit, and the other at least forces one to use seperate supplies. I bet you could really do it on the cheap, swap a few values on the board and jump the inputs together and use a single transformer for it all, no doubt like some manufacturers will end up doing. Most likely they'll wait to have the SMPS handed to them on a platter, but that won't be available to us.

Regards,
Chris
Click to expand...

I'm actually more concerned about the extra space required for the extra transformers and the extra complexity of mounting and connecting multiple transformers than I am about the expense. I like to keep it simple for improved reliability if possible. I think that separate windings on one transformer will have virtually the same benefits as separate transformers.

I can't find it now, but I remember that Jan-Peter posted somewhere that the UCD700 power supply uses the LM7800 series regulators for the low voltage supply.

Edit: Found Jan-Peter's post. He was answering someone's question ....... 😉
http://www.diyaudio.com/forums/showthread.php?postid=780457#post780457
 
#57
GregD said:


I'm actually more concerned about the extra space required for the extra transformers and the extra complexity of mounting and connecting multiple transformers than I am about the expense. I like to keep it simple for improved reliability if possible. I think that separate windings on one transformer will have virtually the same benefits as separate transformers.

I can't find it now, but I remember that Jan-Peter posted somewhere that the UCD700 power supply uses the LM7800 series regulators for the low voltage supply.

Edit: Found Jan-Peter's post. He was answering someone's question ....... 😉
http://www.diyaudio.com/forums/showthread.php?postid=780457#post780457
Click to expand...

Heh heh....... :cannotbe:

For what it's worth I think you're right, I do think seperate xformers would have an edge, but very likely only at extreme power levels, and possibly not even enough of an edge to justify the extra real estate. I wouldn't be losing any sleep over using aux windings, it makes the most sense.

Besides, even if they would vary a few percent more under heavy loading, it's still less than the 10% mains variation, which you can't get away from with just a transformer anyway. So there's a chance the extra expense of it can't be justified?

Still don't think it hurt to have brought it up for discussion.

Regards,
Chris
 
#59
classd4sure said:

.

While the 700 has onboard regulators who's yet to say that doesn't consist of anything more than a zener/pass transistor/exact same circuit as on the previous models? No doubt it could benefit from a high end regulator as well.
Regards,
Chris
Click to expand...


the regulators are not on the board anymore. They are on the UCD Supply. Nothing fancy, but still nicer than a zener. I can post some high-rez shots tomorrow, since today, on a Sunday, my postman worked overtime to get me a package from the Netherlands 🙂

First impression: they package these things very well!

Peter

PS- separate transformers probably are better - I see no reason why they should be worse than a single one, but the difference in my eyes isn't going to be that big unless you're about to do what the thread title is all about - optimal.
 
#60
Status
Not open for further replies.
Top Bottom