[bryman79]

Paul, Josh, and All,

Thought it was time to officially say hello.  I've been lurking for some time, and hope to assemble my first Felicia here soon... as soon as I can acquire some transformers from BGMicro, that is.

For the benefit of myself and anyone else who is visually-dependent, I'd like to post what I understand to be the current configuration.




First, I'd like to confirm what I've discussed with others as to the caps.  I have sourced the following:
C1 = 18uF 400VDC Jantzen CrossCap (Parts Express: 027-938)
C2, C5 = 0.47uF 400VDC Jantzen CrossCap (Parts Express: 027-906)
C3, C6 = 0.1uF 400VDC Jantzen CrossCap (Parts Express: 027-900)
Any problems with this list?

Second, I was wondering if someone can comment on the fuses.  Assuming I stick with fuses (vs. breakers), I'm assuming F2 and F3 can be 1 Amp fast-blo?  What value/type should I use for F1?

Third, I've heard that breakers may yield sonic benefits over the fuses.  Is this true?  It would be nice not to have to replace fuses...

Fourth, I've been looking for a combined switch/plug receptacle and have been unsuccessful thus far.  My plan is to incorporate 4-6 Felicias into one box, with each going to a single receptacle with a dual-pole switch on each receptacle (I don't want to have to unplug each unpowered unit).  The closest thing I've been able to find are these white, 2-plug Australian units, which are apparently quite common over there (and have lights on the switches to boot):



Has anyone in the USA come across something similar?

Many thanks,
Bryan

-----
EDIT: Made changes suggested by JoshK
EDIT: Made changes suggested by Occam

[JoshK]

Welcome!

The schematic you show is correct, with the exception that you need to tie the output ground to the ground of the recepticles.  If you don't do this you are "floating" which isn't wanted in this case (we did compare the impact of floating versus grounded).  So all you need to do is make sure you tie the ground of the recepticle to the output ground in a star formation.  

The caps you show are correct but you can just as well use a 18uf Jantzen in lieu of the 20uf Solen.  It may be preferrable but I don't know if anyone has compared those two.  Oh, and I see you repeated the large value after the second secondary (C4) which you don't want.  There is no C4 in our config.  

Fuse values I am not sure of, 1amp sounds right but I can't recall if it were slo-blo or fast-blo.  So I don't remember the F1 either.  Someone else will have to chime in on that one.   I do like to use breakers but they are not always as easy to find inexpensively as fuses, which is why fuses are often used.  Breakers are slo-blo though and reset themselves upon cooling back down.  If you want to be extra safe you can install ground fault interrupts too.

[Gordy]

Hi Bryman79,

Excellent first post, welcome again!

The 1a fast blow fuses have handled all the source units I have tried, 3 tube preamps, 2 vintage tuners and a Denon 2900 universal... and a Teac L700P!!! Don't forget to mass load your chassis/box  

[bryman79]

Josh,

Okay, I made the changes you suggested in my initial post.  I figured this would be the easiest way so that I don't confuse myself and others down the line with several schematics.

Regarding grounds, both the transformers' center taps and the receptacle grounds get earthed, right?

Any suggestions on sources for switched receptacles?

Thanks again,
Bryan

[Occam]

Bryman,


Welcome to Audocirles. Its nice to see someone who actually knows how to use Micro-cap. Do you give lessons? I'm incredibly inept with it.

A couple of comments. As Josh says, the ground should be hooked up to the mains ground, which via the ground symbol is obviously your intent. And Gordy's fuse values seem to work quite well for the specific transformer currently recommended. I do wish they'd lay in an adequate supply.
The center tap of the input transformer's secondary does not need to be hooked up to ground, as it doesn't serve an electrical purpose. (I suppose one could hook up Y caps between the 2 legs of the secondaries conneciting to ground, but I've not explored that). As the secondaries are running at about 14vac, the 250vdc rating of the Solen is not a concern, but I do prefer, subjectively, the 18uf Jantzen, and I'd try the 22uf Jantzen if PE would ever get them in stock. I actually prefer the Jantzens to Auricaps in these roles, but will comment that adding a .01 600vdc Auricap accross either or both cap banks is a worthwhile improvement. But it does sort of defeat the cheap SOB ideal.

My last point is actually of greater concern. The output fuses should be prior to the the accross the line, output bypass caps. The 400vdc rated Jantzens , I believe should be rated at about 250VAC, but regardless, they are not X2 rated. In the event that these output caps should fail in a shorted mode, the output fuses should blow prior to their bursting into flames. Any capacitor that is not X2 rated and is subject to mains voltages, should (must) be fused. This also applies to the famous (infamous) 'Auricap tweak' as there is absolutely no reason why it should be wired accross an inlet rather that after the fusing.

If you make the changes to your schematic in your gallery, may I 'appropriate' it for the Felicia 'sticky'? It does seem time for an update.

[bryman79]

Paul,

How we lookin' now?

I'm a noob at Micro-cap, but I will see what I can do.  Email me as to what changes you'd like to make, and I will see if I can make it look right.  Based upon your sticky, you appear to be more adept than I...

Thanks,
Bryan

[Occam]

Byman - tis looking very fine indeed. Some last niggling comments -
1. extend the 'ground' line to the left of the 'earthing' symbol, terminating where the line and the neutral lines end, to make clearer that the origin of the 'earth' is the mains input

2. In parentheses add '(60 VAC)' at the output by the 'Hot' and similarly add '(antiphase 60 VAC) by the output's 'Neutral'

and with your permission I'll
-add and identify a 'Moderator's Note' to your schematic post, saying that the follow on posts reflect suggested updates to your schematic in that post, so folks can understand what transpired

and I'll also copy your schematic and put it in the sticky thread, with an acknowlegement and reflect the current preferences in components

Many thanks,
Paul

[Occam]

Bryman - tis looking very fine indeed. Some last niggling comments -
1. extend the 'ground' line to the left of the 'earthing' symbol, terminating where the line and the neutral lines end, to make clearer that the origin of the 'earth' is the mains input

2. Add '(60 VAC)' at the output by the 'Hot' and similarly add '(antiphase 60 VAC)' by the output's 'Neutral'

and with your permission I'll
-add and identify a 'Moderator's Note' to your schematic post, saying that the follow on posts reflect suggested updates to your schematic in that post, so folks can understand what transpired

-and I'll also copy your schematic and put it in the sticky thread, with an acknowlegement and reflect the current preferences in components

[EDIT - The Felicia 'sticky' page has been updated to reflect these changes
http://www.audiocircle.com/index.php?topic=18441
and within a few minutes the first posts of this constuctor's thread will also be udated.]

Thanks again,
Paul

[bryman79]

Paul,

Do whatever you wish with the schematic.  Don't mind the nagging details... I dish them out regularly, so I should be able to take them.  

I put a "-" instead of "antiphase" because it fit better, but I can change this if you want.  Just let me know.

Regards,
Bryan

[JoshK]

Bryan,
Good job on the schematic and thanks for your help on that.  It does clear things up for those who haven't followed along with every update.   It reads very clear now!

Josh

[Christopher Witmer]

With some of the transformers I'm planning to use (in pairs, a la Felicia), I notice that the electrostatic shield (ESS) is on the secondary side; however, because I will be balancing by means of the dual pair of primary side wires, the ESS ends up being oriented "wrong": it is not on the downstream, equipment side (balanced side) of the rig. Rather, it faces toward the center of the rig.

Is this going to make any difference? Is there a "best" way to use the ESS in this sort of a configuration?

BTW, some of my nicest transformers have a pair of ESS -- one on each side -- so with those it is a moot issue.

Thanks!

Christopher Witmer
Tokyo

[Occam]

Christopher,

I'm unsure of this, so take it with the required grain of salt. One has to draw the shield on one or the other side of the symbol for the core (unless you draw it on both sides), but in reality, it is merely a symbolic representation of the shield between the primary and secondary. The core in the schematic representation is simply 'in the way', and it may be that by convention, its typically shown on the secondary side. This is somewhat straightforward with regards to a shield in a toroidal or overwound EI core transformer. In the case r-core or m-core transformers, where the primary and secondary are not overwound over each other, the shielding might totally encompass one or the other winding, in which case the shielding would be associated, and drawn with the particular winding(s) it encompasses.

FWIW,
Paul

[Christopher Witmer]

I found several units of an interesting transformer available used. It is a variant of the "WB transformer" that I purchased earlier. (http://www.ttfmr.com/trans-e.html) These latest units are 100V, 2kVA input, and 24V x two 42A taps out. (In other words, 84A output total at 24V.) The secondary coils are bifilar wound, so it seems it could do a good job for balancing. Obviously, unless the input voltage is more than doubled, there is no way 24V + 24V output is going to be usable!

Here is my question: is the only way to use this as a balanced xformer to input 208V on the input side and so that both the secondary outputs are boosted to around 50V each? (I'm refering to the situation Japan where 100V is standard.) I am wondering how much I would have to derate the transformer to do this . . . I know resistance increases with the voltage so I think heat might be more of a problem, although these WB transformers are incredibly cool in operation to begin with.

I am also wondering if it might not be possible use a pair of these and have the balancing taking place in the "middle" of the pair: do a balanced wiring of one unit's secondaries and connect that to the secondaries of the other unit. So I would end up with something like the following:

Commercial mains 100V --> (100V : 24+24V balanced) --> (24+24V series : 100V) --> Clean 100V power to equipment.

Is something like that (or a variant) going to work, or is it nuts? If it would work, it seems to me that I could get by without any derating whatsoever, and I could get a low profile, low mechanical noise, low temperature 2kVA balanced power system for cheap. (These trannies are about $35 each used.)

If this latter method won't work, I am sure the method I mentioned first (increasing the input voltage from 100V to 208V) would work fine -- provided I don't overload the transformer. If this is the way to go, how do I know the proper amount to derate the transformer?

Thanks!

Christopher Witmer
Tokyo

P.S. If these trannies work out, I may be able to get my hands on a few with some regularitiy since they were taken out of Japanese pachinko parlors (pachinko is a cross between pinball and slot machine) that were being remodeled, and since pachinko is a more lucrative industry than even Japanese automobile manufacturing (!), vast numbers of pachinko parlors get remodeled with some regularity.

[Occam]

Christopher,

Please, don't even think about it. Generally, its not dangerous to run transformers at voltages BELOW their specified limits (while staying at the same current specification), but please don't even consider running them at higher voltages than specified, unless you have a death wish. Period.

The more I look at these highly efficient transformers-
http://www.ttfmr.com/trans-e.html
the more I'm unsure of their suitability for any audio related application. While they are very compact and have very low losses, They appear to be overwound, with a tremendous amount of capacitive coupling between primary and secondary, making them unsuitable for power supply applications in audio. The physical spacing between the windings might mittigate this, and if there is interwinding shielding that would allay my concerns, but without detailed specifications (I don't speak or read Japanese), I don't think they should even be considered. I apologize for not picking up on this previously.

Please stop buying transformers. You've bought more than sufficient transformer capacity and quality to accomplish your goals. Get Skype working and contact me.

Concerned,
Paul

[Christopher Witmer]

Thanks for the reply. Sorry for causing you worry there. I am aware that I alrready have enough good transformers to keep all the bad stuff out of my audio equipment; these and other recent acquisitions are to satisfy my curiosity about what different types of transformers can do. After I have satisfied my curiosity, I plan to keep what I can use and dispose of the rest.

Part of my initial interest in these "WB transformers" is that they are used inside various high-end audio components. They are used inside Japanese-made CSE balanceformers, which are intended for audio use. The CSE TX-2000, which has a list price of about US$2500, was chosen as 2004 "Product of the Year" by Hong Kong's Hi-Fi Review.

TEAC also uses them in several of its high-end "Esoteric" brand products. They are used inside the Esoteric A-70 monaural power amplifier (list price over US$7000), inside the Esoteric G-Os master clock generator (over US$10,000), inside the Esoteric P-01 and P-03 SACD transports (over US$20,000 and US$10,000 respectively)

There is also a more modestly priced balanceformer on the market, the Musica ibf110 (about US$350), that is based on the WB transformer.

Here is a pic of a pair of WB transformers as used in the Esoteric P-01:


While not every WB transformer is necessarily created equal in terms of quality, I think the above list shows that at the very least, WB transformers are capable of being put to good use in audio applications.

So, on your advice, I have put out of my mind any thought of trying to put 200V into a 100V transformer, regardless of the current.

That leaves the other possibility, of pairing identical transformers so two pairs of 24V secondaries face each other . . . is there any way that the benefits of balancing could be enjoyed by proper wiring of the secondaries as they face each other between two identical transformers?

Thanks for everything. I still can't get Skype running (I'll have to replace my motherboard for telephony) but I may be able to call you over the phone tomorrow if it is not inconvenient for you.

Christopher Witmer
Tokyo

[Basil]

Hello

I know that it`s sound mad, but I have ordered 10 of the EI-transformer PWR1164 from B.G.Micro., about 2 months ago,
but does anyone know when they got it in stock
and can deliverer it to us, there so badly would like to make balanced power?  

I had tried to email them, about when they will got them in stock, but haven`t got any answer.

Why it`s mad... Because it`s a lot cheaper for me to order 10 trannies at B.G.Micro, than buy some like these here in Denmark
and I really don`t understand why EI-trannies are so expensive here...

Thanks for the Jantzen capacitors info, I will try them and bypass with some Jensen  paper in oil or Rifa PFE 225 polyester caps.

Regards Basil.

[bryman79]

I know that it`s sound mad, but I have ordered 10 of the EI-transformer PWR1164 from B.G.Micro., about 2 months ago,
but does anyone know when they got it in stock
and can deliverer it to us, there so badly would like to make balanced power?  

I had tried to email them, about when they will got them in stock, but haven`t got any answer.

Basil,

I'm in exactly the same situation.  It makes it hard to plan a project when you can't even obtain the main component.  But such is life...

To those who have recently obtained their transformers, any word from BG about when he expects more?

Thanks,
Bryan

[Occam]

Basil, Bryman, et al....

I understand your frustration.  Billy and Tammie at BGMicro are as anxious as you to obtain the transformers as you are. That is their bread and butter. But sadly, their source has higher priority, more profitable, orders to fufill. Nor will their source allow BG to send their own staff over to retreive them because of insurance concerns. They don't want any prepayments, and as soon as they're able to obtain the transformers, they will ship them. I'm in touch with BG on a weekly basis, and will update you as soon as I get new information.

I've searched for other sources of other equivalent transformers, have a few leads, and will apprise the board as new info, sources, are available.

Towards that end, I have found a source of very high quality 56va CE certified, split bobbin transformers. These would make excellent non-balanced conditioners, in pairs, for components that don't have grounded powercords, such as dvd players like the Samsung/Toshiba, or cable/satellite settop boxes , etc..... basically, 2 pronged components consuming less than 30-40 watts. For non-North American users, these could provide that same power capabilities, but with fully balanced power for 220-240VAC consuming units. These would be less expensive than the presently unobtainium 175va Signal transformers.
I've put BGMicro in touch with the wholesaler who has 400+ of these units. I have no, nor want any financial interest in this, and simply wish to facilitate the availability of appropriate components.

I am also in contact with another vendor who may have appropriate transformers, substantially more expensive than the 2 discussed above, but have to obtain units for evaluation.

Believe me, I too am frustrated over the difficulty in obtaining appropriate transformers for Felicia.

[Occam]

.....So, on your advice, I have put out of my mind any thought of trying to put 200V into a 100V transformer, regardless of the current.

That leaves the other possibility, of pairing identical transformers so two pairs of 24V secondaries face each other . . . is there any way that the benefits of balancing could be enjoyed by proper wiring of the secondaries as they face each other between two identical transformers?...

Chris - You're killing me dude. The only feasable approach is to take 2 transformers, hooking up the primaries in parallel, and wiring the 4 24v secondaries as as center-tapped 96v. As each transformer's secondary is wound bifilar, this means if you take one secondary from transformer A, and one from transformer B, in series, and make the other seconday from the leftovers, we have, by definition, an accurately balanced 96Vac supply. You've now got a 4KVA balanced transformer. Assuming its lightly loaded at 1KVA, the transformer's regulation,say 3%, will bring it up to 98Vac+. Close enough for government and audio work.

[Builder Brad]

Occam,

+ everyone elso who has given advice in the last couple of months.

I am getting near the end of my project to build  1 x AKSA GK 1R and four AKSA power amps, and have just tried out the basic Felicia balanced power supply on my Arcam @8 Cd player and my Pioneer DVI868 DVD Player ----wow!

I have use 2 x dual 120v primary/ dual 20v secondary 100va transformers from www.jprelec.co.uk/aps as sugested by Occam with just a single 630 volt audio grade polypropylene cap at 3.3uf between.

This is such a simple thing to rig up, not much more to it than wiring a couple of plugs, but what a difference!.

The only negative observation was a high frequency hum that was produced by one of the transformers when running the Pioneer DVD player – this is a high end unit and I suspect has a high power consumption.

As soon as I finish the AKSAs I intend to build 5-6 Felicias into a 3U rack mount case to run my Orion x-over PS, Arcam Cd player, Satellite receiver, Pioneer DVd player, Pioneer plasma media centre and GK 1R.

I will post voltage drop measurements ect. for each device if this would be useful information for other builders – just let me know

I really feel like this is a bit of a cheat because this involves so little time and there does seem to be a significant immediate improvement. I will definitely not be happy to leave things like this and will have to play around with additional filter caps on both the low voltage section and on the output, just to satisfy my curiosity and my no pain no gain mind set! This is just too easy. Does anyone have any suggestions on initial cap values, configurations ect that I should consider.

Brad