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Old 13th January 2005, 04:18 PM   #1
WE91 is offline WE91  Norway
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Question Output trafo for WE-91 L'Audiophile amp?

I am new to this forum, and a little new to building tube-amps.

I have chosen to build a WE-91 L'Audiophile (WE310A/300B SE - amp.). I have collected quite a few parts for it allready including the WE 310A's. Originally I see that Jean Hiraga (I have the greatest respect for this man, knowing his other amplifier projects very well; 8W Le Monstre, Le 20W classe A, Lectron JH50 ...) - reccomend using a Partridge or a Tango (?) U 808 for this project. It's been a long time since this project was realized in L'Audiophile, and quite a lot has happened concerning trafos to be had that is of exeptional quality.

I have been searching the web a lot, trying to find not only manufacturers of good trafos, but most importantly, people/DIY'ers, magazines etc. that has made tests of different trafos in their SE 300B amps. - Wich one gives the best subjective listening results?

I have found the trafos I'm about to list to be very exiting in many respects, - but also often mentioned to be real good performers no matter what other trafos you compare them with, - and even giving extremely good value per $ ... (or £ or € ...):
- Sowther
- Tribute
- Electra Print
- Lundahl
- Bertolucci
They're not mentioned in any particular priority here (the Jap. trafo makes isn't in here, because I more often than not see that those I have mentioned perform better or equal at a lower cost).

I'm going to use two sets of "300B" output tubes; TJ Meshplate (gold pin) and VAIC AV 300 XL REF.TSE. These are a little different so to utilize them best I'm going to make the amplifier switchable for different settings of +B (500V/100mA and 420V/80mA - or ..)

Finally, - THE QUESTION:
Knowing that this is a WE-91 L'Audiophile design, with it's sonic character and using the output-tubes described, - what output trafo do you, learned DIY colleagues, reccomend me to use???
(Have any of you buildt this amp.?).

I'm looking forward to your answers to this (rather long) question.
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Old 13th January 2005, 06:34 PM   #2
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Quote:
- Sowther
- Tribute
- Electra Print
- Lundahl
- Bertolucci
I reckon you would make a fine amp with any of those (I have to admit I have never heard a 300b amp with any of those ...just goes to show how little I really know).

But if I was you I would also factor in the price, location and time to delivery as well.

I've seen a lot of posts saying that Tribute is the best....

But you would have to wait a year or so before they are delivered!!!

With the Lundahl (c-core)you nowadays have an amorphous version (in stock so to speak) which makes them a rather good choice in terms of price and "deliverability"...The reason why I mention that is because I seem to get the idea that core material and type are vital or at least one of the most important factors...and in that sense...it is often said that amorphous and permalloy (nickel/cobalt) are best sounding...and C-cores are preferable over EI cores for SE amps. (blanket statement)

Your location is also a pretty important point since shipping can really add to your price. If you are in the states...Lundahl/Electraprint are the best options. Since the others will have to come from Tribute (Netherlands) Sowter (UK) Bertolucci (Italy), Lundahl is from Sweden (since they bossed Norway around in the past..I won't get them if I was you .

Since Lundahl are probably the only ones that have an importer in Norway..they would be a pretty good choice.


Another one to consider would be AE-Europe also from the Netherlands.
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Old 13th January 2005, 08:23 PM   #3
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Hi,

The OPT specced for that project was especially made for "La Maison..." by Parmeko (Partridge Transformer Company) in the U.K.

If I'm not mistaken the reference was TK4519.

Back then it was very expensive but well worth it.
I've heard the amp on several occasions when visiting Mr. Hiraga and his colleagues in France and I must say it's still among the best SE amps I ever heard.

Maybe the shop in Paris still has some of those OPTs?

If not the Tribute (amorphous core) and Lundahl are certainly worth looking in to.

P.S. The WE91 has been discussed before on this forum. Have you done a search?

Cheers,
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Old 13th January 2005, 09:41 PM   #4
Jaap is offline Jaap  Netherlands
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Default do not forget

the plitron/amplimo toroids ! Menno van der Veen does know his job. Those round heavy bombs are outstanding transformers.
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Old 14th January 2005, 10:13 AM   #5
WE91 is offline WE91  Norway
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Thank you very much, all of you who have replied!

I see there has been several threads before on the WE91 amp., but this being such a popular design, I guess my conscience can be "clean" for posting one more. (When finding these earlier threads on WE91, I found very much interesting stuff, - so thank you fdegrove!). It was very interesting to learn that you've heard the WE91 L'Audiophile, fdegrove (and met mr. Hiraga - a sort of Guru for me). - I have read a lot about the WE91's, but not heard any. I guess my confidence in Jean Hiraga's designs is just so great that I'll follow him blindly
- But I almost mean it. I do know his 8W, 20W and JH50 designs!

- I "had some WE 310A's lying about", - and did some searching for some more, - and found some, - so I guess I'm "set" for this project. If any other should want to have some of these tubes, let me know and I can point you in the right direction.
Does anyone know of how to get in touch with "Le Maison L'Audiophile" in Paris nowadays? (to hear if tey've got any Partridges left).

If I do not find any Partridges or the "Maison ...", I can always ask Parmeko if they'll make two for me, - or I'll just go for the Lundahl amorphous core (or Tribute as my last choice because of delivery time); - thank you for your thoughts Bas Horneman!
I'll do some searching to find out more concerning the plitron/amplimo toroids, Jaap.

Again thank you very much!
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Old 14th January 2005, 12:48 PM   #6
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Hi,

La Maison De L'Audiophile:

14, rue de Belfort
75011 PARIS
Tél : 01 43 79 12 68
Fax : 01 43 79 26 31

The OPT should be 2K3 to 2K5 Zprim, Zsec 8 Ohm

The correct Partridge reference is TH 4663 but I very much doubt Parmeko wants to do just a pair of them.

I still have some 310As with ceramic sockets and topcaps to go with them.
Send me a PM should you be interested.

The WE274B is electrically identical to the 5U4G if I'm not mistaken.
I hear the NOS US ones are getting scarce, so it may be wise to stock up on those.

Cheers,
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Old 15th January 2005, 05:08 AM   #7
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Default Partridge transformers

The Partridge transformers are available from a shop in the UK called The Emporium.

The model number is different but I was told they are the same spec as the ones made for L'Audiophile (I can't verify this). They can be wired for 2.3k or 3.5k primary and 4, 8 or 16 secondary. They are also quite big.

The company which makes them is Tranformers and Rectifiers Ltd.. They bought the rights to the Partridge name and designs some years ago. Although they mainly make power transformers they will make audio transformers to the original Partridge specs to special order.

I've compared these Partridge OPTs to Lundahl 1663s in my amp using 45 and 2A3 valves (but not 300Bs). I didn't hear much difference.

I'm attaching a photo of the Partidge alongside the Lundahl.

Cheers.
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Old 16th January 2005, 02:41 PM   #8
jlsem is offline jlsem  United States
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Quote:
The WE274B is electrically identical to the 5U4G if I'm not mistaken.
It's more like a 5R4G in terms of voltage drop, however. In any case, use a 5U4G and make the usual adjustments.

John
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Old 16th January 2005, 03:32 PM   #9
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i have used both the lundahls and the electraprints in various applications (never this exact circuit).

both are excellent. i personally prefer c-cores if available, but jack elliano's EI electraprint trannies are extremely good and well worth the price....as are the lundahls.

i am trying some James transformers in a 300b right now...but not finished yet.

all things considered...Lundahl
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Old 17th January 2005, 11:32 AM   #10
WE91 is offline WE91  Norway
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Again, thanks for all the input and answers ...

I'm down to these OPT's now:
1. - Partridge TH 4663 (expensive at The Emporium)
2. - AE amorphous C-core
3. - Lundahl amorhous (C-core)
4. - Tribute amorphous (C-core)
- And the list shows my priorities ... These priorities are just a result of the feedback here, from other DIY'ers, general impressions of the products and the service of the producers, the originality (Partridge) and delivery times (Tribute).

The first thing for me now is to get in touch with La Maison De L'Audiophile and get a price quote for the Partridge OPTs there (if they got'em). If the price still is in the 500£ vincinity, I guess I'll drop them, - especially since reading zeitkino's comparison of Partridge and Lundahl.

For powersupply I'm going to go down a rather different and controversial path ...
I'm going to use regulated DC supply for the filaments to both input and driver and, since I've heard what the latest and best of the switch-mode supplies can deliver, - and since a friend of mine is a professional electronic designer specializing in such supplies, I'm going to use a design from him for the HT supplies ... This is very controversial, I know, - but in real tests these newer supplies have a noise-spectrum so high in the frequency register, that it's "no biggie" to filter it away and, actually get a completely clean power-source. This results in a vast improvement in clarity, detail and "blackness of background" - this is when compared to a few years old switchmode supplies and regular unregulated supplies with high storage capacity. It resembles the results from battery-powersupplies. Unfortunately you can not ask me questions about the design detail of this supply, and I can't tell you much more about it either because it isn't designed yet, - and the designer isn't me. I will come back to this, though, - when it IS designed and tried out in the WE-91 L'Audiophile.

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