I can do a custom power transformer, but quite frankly Jack at ElectraPrint would be a better choice. This is primarily because we, just like Jack, are somewhat capacity limited, since we have on going OEM mfg business we MUST see to.
If there is any question about design specs, to meet a CE 6500 safety standard, I would be happy to discuss any issues with Jack. I am not intending to suggest the fully fused version, but the "professional" version. Same thing without fuses.
Beyond that I don't intend to step on any toes and apologize in advance, nor have I contributed enough to the Forum to allow a commercial message to live for very long, so enough said.
Bud
If there is any question about design specs, to meet a CE 6500 safety standard, I would be happy to discuss any issues with Jack. I am not intending to suggest the fully fused version, but the "professional" version. Same thing without fuses.
Beyond that I don't intend to step on any toes and apologize in advance, nor have I contributed enough to the Forum to allow a commercial message to live for very long, so enough said.
Bud
Very interesting read on the other thread related to OPT transformers. Thanks Bud and others for the input. (will have to read it many more times to glean only a small portion of what was said). I too would be interested in a group buy provided that there isn't much compromise on the LF characteristics.
I would even be interested if it went to level two or even three.
Eli,
Why did you have to post that regarding 10H and the big caps. Now I have pulled them back off of the shelf. (I don't want to hijack this thread from its original design however)
I would even be interested if it went to level two or even three.
Eli,
Why did you have to post that regarding 10H and the big caps. Now I have pulled them back off of the shelf. (I don't want to hijack this thread from its original design however)
Antek 2T-350 based power supply
Well, I've been modeling the antek 2T-350 based power supply and I cannot get a B+ above 445V, even with the lowest R Hammond choke that I can spec (Hammond 193P)
I used the same currents as the existing Edcor based supply: KT88's=150ma, 12AT7=6ma, EF86=3ma
Inputting transformer parameters off of the datasheet gives a source impedance for the transformer of 54.6 ohms, which is limiting the B+.
I used an offload V of 353V, secondary R=72R/2 (parallel connection), primary V=120V, primary R=4.3R/2 (parallel connection), which yields a 54.6R transformer impedance.
Any ideas?
EDIT: I just modeled the Antek AN-4T360 and it would meet the requirements no problem. ripple V=150mv.
Well, I've been modeling the antek 2T-350 based power supply and I cannot get a B+ above 445V, even with the lowest R Hammond choke that I can spec (Hammond 193P)
I used the same currents as the existing Edcor based supply: KT88's=150ma, 12AT7=6ma, EF86=3ma
Inputting transformer parameters off of the datasheet gives a source impedance for the transformer of 54.6 ohms, which is limiting the B+.
I used an offload V of 353V, secondary R=72R/2 (parallel connection), primary V=120V, primary R=4.3R/2 (parallel connection), which yields a 54.6R transformer impedance.
Any ideas?
EDIT: I just modeled the Antek AN-4T360 and it would meet the requirements no problem. ripple V=150mv.
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Taj: One other thing.....it looks like R1 in the existing supply needs to be 470R instead of 220R. (the R between the 465V and 460V taps) to get the 5V drop.
Just curious, would that AN-4T360 handle a stereo amp? I.E. one channel per secondary winding? Seems like it might, intuitively.
..Todd
BW,
Would you kindly retry the 2T350 sim with the 350 V. windings paralleled and a "6.3" V. boost. Regulation effects will increase the effect of the boost winding, hence the quotation marks.
Given its 400 VA rating, the 4T360 could power a stereoblock. Hmmm, a 3 chassis setup employing the 4T360 is a possibility. Each of the 360 V. windings would be bridge rectified to energize a power amp chassis.
Would you kindly retry the 2T350 sim with the 350 V. windings paralleled and a "6.3" V. boost. Regulation effects will increase the effect of the boost winding, hence the quotation marks.
Given its 400 VA rating, the 4T360 could power a stereoblock. Hmmm, a 3 chassis setup employing the 4T360 is a possibility. Each of the 360 V. windings would be bridge rectified to energize a power amp chassis.
Then you run into that nasty business of transporting the HT between chassis.
..Todd
I think he just means to connect one 6.3v winding in series with the paralleled 350v windings for a total of 356.3 (boosted) volts.
..Todd
That's correct. However, the boost will be more than 6.3 V. Those filament windings are rated for Amperes. The B+ rail draw is a few tenths of an A. Regulation effects will raise the boost, perhaps over 7 V. Use 357 V. in the sim. BTW, another consideration is that modern line voltage is usually 120 V. or slightly higher. AnTek's data sheet assumes 115 V. on the primary side. Yes, it's nickels and dimes, but they add up to enough (IMO).
The off load voltage data from Antek is 353V@120V. That's what I used as the transformer input parameters for PSUD, so I'm assuming that the line voltage nickels dimes are already collected. Using 353V+7V=360V gets the B+ to 456V, about 10V shy of the target.
Does series connecting the 6.3 winding reduce the secondary winding composite R? That would probably put this over the top if it reduced it a bit.
The latest sim is using a big-honkin' Hammond 193 enclosed series 5H/26R choke for minimal drop across the choke, so that will burn up additional $$ savings when comparing it to the Edcor/Hammond 159T solution. Of course this solution has twice the henries.
Does series connecting the 6.3 winding reduce the secondary winding composite R? That would probably put this over the top if it reduced it a bit.
The latest sim is using a big-honkin' Hammond 193 enclosed series 5H/26R choke for minimal drop across the choke, so that will burn up additional $$ savings when comparing it to the Edcor/Hammond 159T solution. Of course this solution has twice the henries.
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Me too, but I can't organize it.
The difficulty with a transformer group buy is the high dollar figures and expensive shipping options involved. For example, if PayPal were used to pay the organizer, an 8% processing fee would need to be added because the organizer would have to pay another 4% to PayPal to pay Bud. It would be cumbersome to say the least.
If Bud were willing to work with the group-buy organizer to collect payments directly, then drop-ship the transformers, it would probably be do-able, but a pain in the butt for Bud.
I also think we're getting a bit ahead of ourselves. This design should be built, tested and tweaked before everyone runs off to the hardware store to buy the wrong model hardware. 😉
..Todd
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BW,
Let's approach this from a different perspective. I'm specifically thinking of SGregory and his separate filament trafo concept.
The exact voltage of the remaining filament winding is not critical, if it's used to energize a voltage multiplier. So, instead of boosting the rectifier winding, boost the primary and allow step up effects to take hold. The turns ratio for 115 V. and 350 V. is 1:3. While it's not exact, figure on 370 VRMS into the rectifier. Using Jim McShane's 1.3X RMS rule of thumb yields 481 V. Even with filter losses, that should be adequate.
Let's approach this from a different perspective. I'm specifically thinking of SGregory and his separate filament trafo concept.
The exact voltage of the remaining filament winding is not critical, if it's used to energize a voltage multiplier. So, instead of boosting the rectifier winding, boost the primary and allow step up effects to take hold. The turns ratio for 115 V. and 350 V. is 1:3. While it's not exact, figure on 370 VRMS into the rectifier. Using Jim McShane's 1.3X RMS rule of thumb yields 481 V. Even with filter losses, that should be adequate.
Henries are good.
As far as the PS is concerned, if the ANtek doesn't get it, then there is the possibility of custom Edcor , Electraprint or if you want torroidal a company called Victoria Magnetics in Atlanta GA.
The latter custom wound me some very nice 1.5KVa torroids for my aleph x. When I was at his shop, I for some reason remember him working on some high voltage ones. If anyone is interested can look him up and see if he is still around. They were very reasonable.
Boywonder, I have a XPWR033 which is an EDCOR 760VCT @200mA. The winding DCR to CT is 40.3Ohm. I can't see what value you are using in your sim maye that will help.
As far as the PS is concerned, if the ANtek doesn't get it, then there is the possibility of custom Edcor , Electraprint or if you want torroidal a company called Victoria Magnetics in Atlanta GA.
The latter custom wound me some very nice 1.5KVa torroids for my aleph x. When I was at his shop, I for some reason remember him working on some high voltage ones. If anyone is interested can look him up and see if he is still around. They were very reasonable.
Boywonder, I have a XPWR033 which is an EDCOR 760VCT @200mA. The winding DCR to CT is 40.3Ohm. I can't see what value you are using in your sim maye that will help.
Thanks! I'm using 31R for the Edcor sim (best guess). I'll adjust the sim for 40R. Do you happen to know the offload secondary voltage and the primary R? This would help dial-in the Edcor based supply a little better.
Ok Primary winding is 1.2R. I will wire it in once the table is clear and get the no load voltage.
The electric company is boosting the primary input (on your behalf) to 120v rather than 115v, so output (with the series winding) is about 370v before rectification, and 481 after.
[edit] Though I think this isn't what Eli was talking about.
..Todd
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