Optimal transformer for UCD700

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#61
Peter: Very cool that you got the UcD parts!

In order to save time, I think I may go the 800VA 60-60 Avel transformer (Parts Express Y236905) and then two smaller transformers for the other voltages. The "three transformers per mono block" plan of attack.

Would Parts Express numbers Y236651 (18V+18V) and Y236103 (15V+15V) be cutting it too close? Those values are at the rated UcD700 power supply maximums.

Or, go with a Y236103 (15V+15V) and then a Y236102 (12V+12V) which both are 1V under the nominal ratings?

I do not need ALL the power from these amps for my main tower speakers so if I lose a bit of output wattage, that's A-OK with me. The towers are 250Wrms into 8ohms. And, my eardrums are probably 120Wrms, heh.

I do intend to have a line-interactive (or true on-line "AC-DC-AC" if I can afford it) UPS supplying the power to both mono amps. So, the input voltage should remain constant....

Thanks and be sure to let us know how the project build is going! Any photos yet? 😉
Joe
 
#62
jdgonko said:
Peter: Very cool that you got the UcD parts!

In order to save time, I think I may go the 800VA 60-60 Avel transformer (Parts Express Y236905) and then two smaller transformers for the other voltages. The "three transformers per mono block" plan of attack.

Would Parts Express numbers Y236651 (18V+18V) and Y236103 (15V+15V) be cutting it too close? Those values are at the rated UcD700 power supply maximums.

Or, go with a Y236103 (15V+15V) and then a Y236102 (12V+12V) which both are 1V under the nominal ratings?

I do not need ALL the power from these amps for my main tower speakers so if I lose a bit of output wattage, that's A-OK with me. The towers are 250Wrms into 8ohms. And, my eardrums are probably 120Wrms, heh.

I do intend to have a line-interactive (or true on-line "AC-DC-AC" if I can afford it) UPS supplying the power to both mono amps. So, the input voltage should remain constant....

Thanks and be sure to let us know how the project build is going! Any photos yet? 😉
Joe
Click to expand...


I am planning on enclosures that may just be a bit too crowded for three transformers, so I'll wait until I know more about Kevin's custom torids. I did some parts searching in case I should go with dedicated transformers, and for those I have these listed:

Avel Y236959 - 60-60 - 800VA and $70 each

Plitron 117052201 60-60 1000VA $112.80 each

For the 12-0-12 V and the 15-0 supplies, the Avel 30VA Y236102 and Y236103 for $24.72 should be ok. remember - the rectifier will turn these AC voltages into something like 16.9-0-16.9 and 21.1-0 volts - which then are brought back down by the supply regulators to be a consistent +/-12V and 15V. You just don't want to be too high (overheat the regulator) or too low (below min input voltage for the regulator to do its thing). These should work just fine.


I like these transformers better because they are enclosed (and cheaper):

http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=317264&Row=28525&Site=US

http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=317264&Row=28526&Site=US

And they are cheaper - they are PCB mount, but you can probably do that without a PCB if you think outside the box.

they are only 60x60x37.5mm and possibly could fit into the chassis I am considering. It's an option.


Compared to your setup, my speakers are factory "rated" at 150W/4 ohms each, but it is a well known fact that having 10x that output will pay off in better sound even at low levels. It's not a matter of how far you can turn the dial before your ears fail, but how effortless the amp can handle what you do listen to. It's all about big reserves. I've gone through enough amp ugrades to know that I don't want to do this again anytime soon, which is why I skipped the 400s and went with the big boys.

Peter


by the way - all I know about UPSs is that they put out dirty AC - almost a square wave. Not sure what type you are talking about, but I'd never plug an audio component into those $800 APC units I have here. Doesn't mean that there aren't UPSs that don't do that, but they probably cost far more than what you should spend on cleaning up your power. Run a dedicated circuit to each amp and then check if you still need conditioning.
 
#63
I used Visio to do a rackmount enclosure layout of internal size 16" by 30" and the three transformers, softstart modules, and UcD boards seem to fit nicely with room to spare. I'll post it in PDF format soon (I don't have Visio or Acrobat on this laptop PC here). It could even be shortened to 24" in depth. And, yep, it still is a full dual-mono amp in one enclosure.

I believe the Avel part number you mentioned, Y236959 is a 1000VA model, right?

Those Digikey available transformers (Amveco I think) are smaller and I've incorporated them into the layout. I looked at the manufacturer's spec sheets for them and wiring them up doesn't seem all that difficult.

I too know that having a lot of spare wattage helps a lot. 😉 Classical music, with its extreme dynamic range, can tax amps at times.

And, some UPS's do put out pretty bad power but the non-line-interactive ones do claim to put out a pure sine wave (not a close-to version or even square). TrippLite has a SmartOnline series (not the SmartPro series) that claims to be very good with pure sine wave output and is rackmountable. A bit pricey but may be worth the investment.
Joe
 
#64
pburke said:


For the 12-0-12 V and the 15-0 supplies, the Avel 30VA Y236102 and Y236103 for $24.72 should be ok. remember - the rectifier will turn these AC voltages into something like 16.9-0-16.9 and 21.1-0 volts - which then are brought back down by the supply regulators to be a consistent +/-12V and 15V. You just don't want to be too high (overheat the regulator) or too low (below min input voltage for the regulator to do its thing). These should work just fine.


I like these transformers better because they are enclosed (and cheaper):

http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=317264&Row=28525&Site=US

http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=317264&Row=28526&Site=US

And they are cheaper - they are PCB mount, but you can probably do that without a PCB if you think outside the box.

they are only 60x60x37.5mm and possibly could fit into the chassis I am considering. It's an option.

Click to expand...

I'm getting "Your dataset has expired" when I click on the above links. Would you mind giving a description of the transformers you're thinking of so we can look them up on Digikey.
 
#66
jdgonko said:
I used Visio to do a rackmount enclosure layout of internal size 16" by 30" and the three transformers, softstart modules, and UcD boards seem to fit nicely with room to spare. I'll post it in PDF format soon (I don't have Visio or Acrobat on this laptop PC here). It could even be shortened to 24" in depth. And, yep, it still is a full dual-mono amp in one enclosure.

I believe the Avel part number you mentioned, Y236959 is a 1000VA model, right?

Those Digikey available transformers (Amveco I think) are smaller and I've incorporated them into the layout. I looked at the manufacturer's spec sheets for them and wiring them up doesn't seem all that difficult.

I too know that having a lot of spare wattage helps a lot. 😉 Classical music, with its extreme dynamic range, can tax amps at times.

And, some UPS's do put out pretty bad power but the non-line-interactive ones do claim to put out a pure sine wave (not a close-to version or even square). TrippLite has a SmartOnline series (not the SmartPro series) that claims to be very good with pure sine wave output and is rackmountable. A bit pricey but may be worth the investment.
Joe
Click to expand...

at Partsexpress, the largest Avel 60V transfomer is 800VA: http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=122-720

I really don't see why you would run anything through a UPS. If you have bad power, get a decent line conditioner - that's all you really need (good ones cost more than your whole amp project).

regarding enclosures - I'm building real monoblocks, and they'll be much smaller than what you have in mind. I prfer my speaker cables to be as short as possible, so we're on very different paths here. I found some nice cases that may cost me a bundle, but they do look very sharp and are about the right size for what I am building. Just waiting for the final word on transformer size from Kevin.

Peter
 
#68
I've submitted the quotes. With it being near the holiday and CES everything takes a little longer than normal.

If anyone has any questions here is the design parameters I've submitted for all the quotes:

Size: 6.7" x 3.0" approx
Finish: Polyester Tape
Weight: 16.5# approx
Primaries: 115V, 230V (US and EU) Frequency: 50/60 HZ
A) Voltage: 60V Amps: 6.5A RMS
B) Voltage: 60V Amps: 6.5A RMS
C) Voltage: 13-0-13 Center tapped Amps: 1ARMS
D) Voltage: 16V Amps: 1A RMS
E) Mounting: Resin-Filled Center (Clear Hole), rubber/foam insulating pad, stud and nut mounting hardware.
E) Primary-Secondary Copper Screen
F) Peripheral Goss Band
 
#69
Hello Kevin:

Please do let me know what you get back for quotes. The dimensions of that transformer, one each per channel, is better than using three for each channel! And, I've decided to wait until after the holidays to begin building mine. Not much else to do in Minnesota during the cold of winter, haha. Well, maybe ski.

Thanks!! 😀
Joe
 
#70
Could ya all take a look at this diagram I sketched?

Let me know if I'm WAY OFF or getting close to understanding how all this stuff works. 😉

Thanks!
Joe

attached file (gif format file)
 

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#71
jdgonko said:
Could ya all take a look at this diagram I sketched?

Let me know if I'm WAY OFF or getting close to understanding how all this stuff works. 😉

Thanks!
Joe

attached file (gif format file)
Click to expand...

Nice drawing. :up:

A few notes.

You should have 2 wires for each of the 60V windings going from the transformer to the power supply.

The soft start is rated at 1500VA. 60V x 6.5A x 2 = 780VA plus at most 90VA for the other windings giving 870VA total. 60V at 6.5A is roughly equivalent to 115V at 3.4A. The soft start should be more than adequate.

Definitely include a switch between the inlet and the softstart if for no other reason than safety when putting everything together.

With the softstart, you shouldn't need a slow blow fuse; a properly sized standard fuse should work well.
 
#72
That is a great drawing. A couple notes:

#1. Even though the softstart docs show the AC power ground going to the chassis Hypex suggest floating the AC power ground from the chassis. The only point that connects to the chassis is Pin number one on the XLR input. It should be firmly tied to ground at the XLR input.

#2. Use an IEC that holds the fuse. The Softstart documentation suggest you can use a fast blow type. I've not experimented with values yet.

#3. The Softstart can be shut down with a thermistor on the heatsink. Its a nice feature. I plan on ordering some and giving it a try for an extra level of safety.

Once I get all the parts I'll try to clarify all the assembly details and post them in an area for people to access easily. The Hypex Docs are good but we need a FAQ to cover all the little details.
 
#73
Ok... Latest update on the transformers:

First specs are the same as I have listed. I've chosen to use an extra copper shield between primary and secondaries. I've also chosen to have these built with an extra Goss shield around the transformer to limit the radiated field even more than in a standard toroid. Mounting will be with a resin filled center and thru bolt and a rubber pad under the transformer. That supplies the double insulation requirements. The resin filling cost a little more than the top/bottom plate used on something like the Avel transformers but it’s infinitely more secure. The transformers will shift during shipping with the cheaper mounting method. Not an issue for DIY but certainly an issue for us when building and shipping amplifiers.

I've spec'd the primary & larger secondary wires with 14AWG stranded leads. The smaller ones will be either 16AWG or 18AWG and they are all 10" long as the shorter ones included with many transformers are not long enough to reach where you need them to.

Prices are going to be higher than I initially planned (often the case). I'm going to order 50 units to start and prices for those willing to give me an up front order will be $85 per transformer. Lead-time is looking like this:

4-6 Weeks Lead Time Manf.
1-2 Weeks on the water
1 Week to clear customs

I'm getting a sample also before submitting the order. I don't know what the turn-around time will be on the sample. I'd plan on at the very minimum a 10 week turn-around for those who are interested.

After I have these in stock they are going to be $125 each. I'll put together a package with the UCD700 & UCD700PS also for those who are interested.
 
#74
Hello Kevin and Greg:

Thanks for the kudos on the drawing. I'm learning power amps from scratch and creating a drawing such as that one helps me to better understand how all the components work.

I have to give Visio most of the credit for the drawing! I love using that program. Been using it for almost every kind of block drawing since it first was available (i.e. long before Microsoft bought-out the company).

Kevin: Please do keep us apprised of the custom transformer build progress. I am interested in purchasing two of them and then working with all interested "UcD700 people" to make sure I properly wire them up, heh. January could be a very rocking month. 😉

Have a good one!
Joe
 
#76
Kevin Haskins said:
Ok... Latest update on the transformers:

First specs are the same as I have listed. I've chosen to use an extra copper shield between primary and secondaries. I've also chosen to have these built with an extra Goss shield around the transformer to limit the radiated field even more than in a standard toroid.
...
I'd plan on at the very minimum a 10 week turn-around for those who are interested.
Click to expand...

extra shielding is always good.

10 weeks - ok - but starting when? Have to wrap up a few projects by then.

I'll take four of these transformers - count me in and let me know how this works out. I may actually want a 2 channel UCD700 package on top of that (2x UCD 700AD and 2x UCD700 supply) since the shipping from the netherlands for my first two modules was rather expensive.

Peter
 
#77
Not really on-topic but is related to the UcD700 project we've all been discussing. Figured while we wait until Kevin hears back about the custom transformers, I'd ask about some other needed parts.

What would be the best XLR connectors (for balanced pro-signal input) and then speaker connectors (outputs, of course) to use on the enclosure/chassis?

I've never had to buy parts like those separately, heh.

Any awesome quality Neutrik model numbers to share? I did notice that some of Neutrik's XLR female 3-pin connectors do have the "pin-1 to ground" (which I believe I/we need). But there were a TON of different XLR connectors to choose from so I became a bit overwhelmed (translation -> confused). 😉

Thanks!
Joe
 
#78
jdgonko said:

What would be the best XLR connectors (for balanced pro-signal input) and then speaker connectors (outputs, of course) to use on the enclosure/chassis?

I've never had to buy parts like those separately, heh.

Any awesome quality Neutrik model numbers to share? I did notice that some of Neutrik's XLR female 3-pin connectors do have the "pin-1 to ground" (which I believe I/we need). But there were a TON of different XLR connectors to choose from so I became a bit overwhelmed (translation -> confused). 😉

Thanks!
Joe
Click to expand...

I bought some black chrome Neutriks from Mouser a few weeks ago. Don't plan on using balanced, since I don't have a balanced crossover, nor a balanced source. I'm just putting those parts into the enclosure in case I ever should have such devices. Meanwhile, I'm spending the money on some decent WBT Nextgen RCA jacks.

There are some big dollar XLR parts out there, but usually those are just the cables. Have not seen any Teflon dielectric chassis parts anywhere, so the Neutriks should be as good as any. I'll have them cryo treated before the build, together with all the other hookup parts and wires. Should be good enough for duds I don't plan to plug anything into.

That's the XLR chassis part I got:

http://www.mouser.com/index.cfm?han...ductid=252643&e_categoryid=44&e_pcodeid=56802


Peter
 
#79
I've always used the Neutrik XLRs. The black ones with the gold pins which I source from either Parts Express, Westlake or Tecnec depending on who I'm placing an order with. All the Neutrik parts are excellent quality and I don't know what you could do to improve upon them. The black ones I use have an external grounding pin so that you can either float them from the chassis or ground them at the point of entry as Hypex suggest.

I'm waiting to hear back on a turn-around time on the sample transformer. I'm pulling the trigger on the order as soon as I can confirm the specs of the sample. The company is the world's largest toroid manufacture so I'm sure they have the equipment and expertise to do it right. Murphy can always raise his head so its better to be patient and safe rather than hasty and sorry.
 
#80
Ok... after a long wait I finally have the sample transformer:

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


We are looking at eight weeks right now for production units. Those who are still interested please contact me via my email: info@diycable.com

I'm also doing a package with the UCD700AD & UCD700PS for those who are interested.

Final Details on the transformer:
*Dual 0-115V Primaries
*Dual 60V Secondaries 6.5A each.
*13-0-13V Center tap 1A
*0-16V 1A

*Copper foil shield between primaries and secondaries.
* Goss Shield to limit EMF
* Potted center with through hole
* Bolt, top plate, nut, rubber insulating pads for mounting hardware.
 
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