• Disclaimer: This Vendor's Forum is a paid-for commercial area. Unlike the rest of diyAudio, the Vendor has complete control of what may or may not be posted in this forum. If you wish to discuss technical matters outside the bounds of what is permitted by the Vendor, please use the non-commercial areas of diyAudio to do so.

Edcor or Electra-Print for SSE Output Transformers (and what to ask for?)

So Tom, what "recipe" would you give Jack at Electra-Print if you were building the SSE?

And thanks for sharing that Lundahl link. They sure look interesting. Which transformer would you recommend from them?

It depends on which output tube you use. For the 300B I would recommend "15 W, 100 mA, 5 kΩ primary impedance, secondary taps for 4 Ω and 8 Ω, copper, for use with 300B". The Lundahl LL1623/120mA would be suitable for the 300B as well.

I have no experience with the EL34. I would go with whatever George recommends.

I seem to recall that you can configure the Lundahl do a lot of different impedances. I'm sure you can find a combination that works. Remember that tubes are not super picky about the primary impedance of the transformer, which is why Jack often recommends using a single 6 Ω secondary tap instead of two taps (4,8 Ω).

Tom
 
Last edited:
I thought I had settled on the Edcor CXSE25-5K for my output transformers on my "I have no idea what I'm doing" SSE build. But the lead time is outrageous, and I'd read elsewhere about successful SSE builds using Electra-Print transformers. His prices are higher, but his lead time is much shorter....What specs should I ask for from him? Has anyone else here used Electra-Print transformers? What specs did you ask him to build?

Another question. If I'm ordering from Electra-Print, do I need to specify anything about UL?

I have bought exactly one set of output transformers from Electra-Print. That was back in late 2003 or early 2004 before Tubelab was a company. A coworker named Albert P was gathering stuff to build a "Bugle 45" which was a popular SE amp for the 45 tube in that time period. He had ordered a pair of transformers from Electra-Print, but didn't have all the rest of the parts for his build, so he lent me the transformers. I swapped them into a 45 based amp that I had designed, and they were far superior to whatever I was using at that time. That amp would eventually become the TSE.

When Albert wanted his transformers back, I called Jack at Electra-Print and explained that Albert P had recently ordered a set of transformers and I wanted a set just like them. He said that they were a custom design but for $100 each I could get a set just like Albert's. I got the transformers, and still use them today in my TSE, the very first one ever built.

So I called Jack at Electra-Print, and explained that I would be building some more amps, and possibly selling parts kits, PC boards and other items related to my amps, how would someone buy a set of those custom transformers in the future. He told me to tell them to ask for the Albert P (using his full name) design. That's when things went very wrong.

Some potential customers emailed to explain that they were verbally abused by Jack who never heard of Albert P, or Tubelab, and that both should go away and my web site should be taken down. Some builders even posted some of the hate mail sent from Jack about me in this forum. This went on for a few years, so I removed all references to Albert, and those transformers. I still have a receipt from Electra-Print stashed in a box somewhere (I have moved twice since then) that lists a pair of Albert Pxxxx design transformers.

I do not know why this happened, and I have heard similar stories, some stating poor record keeping, and others relating to the two Jacks. It is possible that Jack's father (Jack Sr.) was the man on the phone taking orders when Albert and I got our transformers.

Finest Chokes, Power, and Output Transformers

Anybody try one of the Transcendar SE OPTs? I ordered a pair of 8k PP OPTs and got them quickly. They were reasonably priced. I haven't built anything with them yet, so I can't say how they perform. But they do seem well made, etc.

What do you guys think about these Transcendar options? The Transcendar with the specs closest to the Edcor CXSE25 would be their 20 Watt. It seems to have everything I want: 5K with 40% UL Tap to 4, 8 & 16 ohms. Max DC Bias Current 140 mA. Primary DC Resistance 215 ohms. Primary Inductance: 20 H @ 120Hz.
Very favorable frequency response of 20z to 75 kHz.

They have lower wattage options too, with the same basic configuration.

Correct me if I'm wrong, but that Transcendar transformer seems like it would be perfect for me, right? Like, I don't know what speakers I would use, so having the 3 taps would let me switch speakers as often as I like. And it has a UL tap, which means I could install that optional UL/Triode switch, right? (I don't even know what that does, but hey... I could have it!)

The Electra-Print transformers that I have are very good. I have not used anything from them since 2004 or so. Sometime later, maybe 2006, I am building 300B based TSE's and selling them occasionally, so I need transformers. I see some fairly low priced "300B OPT" transformers on Ebay, so I buy a pair. They worked very good, and were well liked at an impromptu transformer shootout I organized many years ago. I get in touch with the seller to find out that he had designed them for a high end 300B amp which had been on the market for a few years before the amp company folded. He had about 15 transformers left, so I bought them all, and stuck them in 300B TSE's, and SSE's of several flavors. That OPT maker is now known as Transcendar, and the transformers I had are nearly identical to the vertical version of the current 15 watt transformer. Since they were made for a 300B there is no UL tap, and mine have no 16 ohm tap, just 4 and 8.

The 20 watt Transcendar transformers you mention would be a good choice.

The UL tap offers an option to get nearly the power of a pentode with nearly the sound quality of a triode. Some people love it, some hate it, I find that it works well with some speakers and some music. The only way to find out is to try it, but you can't do that if your transformers don't have the tap.
 
Well, I've just heard back from Transcendar. They're not taking orders. Shame, because that seemed to be my last hope for a decent multi-tap transformer.
Based on George's description of the various Electra-Print "kerfuffles", and based on the issues I've already had in communicating clearly with Electra-Print, AND based on reports of shoddy workmanship, I'm not feeling very confident about ordering with him.

I have an inquiry out with Lundahl, but I'm anticipating they will simply be too expensive.

So it seems the remaining option of any quality would be the Edcor CXSE25-5K, with a single 6 ohm tap. Not ideal, especially in terms of timing, but probably the best I can get.
 
There's always Hammond. Mouser has four in stock ready to ship.
 

Attachments

  • hammond.png
    hammond.png
    17.7 KB · Views: 214
Dont give up. Ask the forum, maybe someone has a pair of transformers that would fit your purposes....


Waiting to get the right trafos will be worth it. They are the most important part of a Tube Amp.

Never give up! Never surrender!
I'll get something good in the end, even if I have to wait. Is there a WTB area of this forum?

There's always Hammond. Mouser has four in stock ready to ship.

That's an easy option to be sure, but I read on the Tubelab site that the Hammond transformers tend to roll off the high end. If it weren't for that, I'd be all over 'em! I have a Hammond power transformer, so there'd be a nice consistency to the build.
 
I can't find any supporting documentation, but I remember reading somewhere in this forum that Hammond had updated their designs within the last few years.

I'm only thirty six now and my hearing doesn't go much past 15 kHz anyways. I work in a lot of noisy industrial environments and ALWAYS wear PROPERLY INSTALLED hearing protection, but I think I damaged some of my hearing in my early twenty's when I used to fix a lot of guitar amps.
 
I can't find any supporting documentation, but I remember reading somewhere in this forum that Hammond had updated their designs within the last few years.

I'm only thirty six now and my hearing doesn't go much past 15 kHz anyways. I work in a lot of noisy industrial environments and ALWAYS wear PROPERLY INSTALLED hearing protection, but I think I damaged some of my hearing in my early twenty's when I used to fix a lot of guitar amps.

I read on the tubelab site that the Hammond transformers George tested were the SE series, and now they have the updated to the SE-A series.

I'm 33, and luckily my hearing is very good. I can definitely hear up to 20kHz, possibly a bit higher as I'm very sensitive to HF sounds. Would I be able to hear pure tones above 20kHz? Almost certainly. Would I notice any difference when listening to music if my amp didn't extend much beyond 20kHz? Probably not.

At this point, I'm considering a perhaps radical option... I could order the Hammonds now, AND order the Edcors now. I could use the Hammonds to get my amp built, and swap out the Edcors in a few months when they arrive. Then sell the Hammonds on eBay, or just use them for another project down the line. The big Hammonds and the big Edcors have more or less the same mounting footprint, so swapping would be very easy. Especially since the leads are just hooked up to the PCB with screw-type terminal blocks.

Hmm....
 
Last edited:
I'm really curious what you find with Octave electronics. The transformer on the left in their picture has "James" on it but the others appear to say Jain Shin (or something like that). I did encounter a place on ebay that claimed they had lots of other James transformers available once. I'd love to have a pair of JS-6123H transformers.

I've almost bought Lundhal ones but the connection options shown on their spec sheet confuse me a bit and the info overlaps between the PP and the SE versions. I haven't been able to get a reply from K&K audio but Lundhal did reply directly to inquiries.

I think with the lockdowns everyone that had ever thought of building a tube amp decided to build one and the transformers got hard to find.

The electra-print stories are funny, I thought I had uniquely messed up in communicating with them. The first time I sent a link to the PP schematic for what I was going to build and got his recommendation for which transformer and ordered from there. He was very helpful and answered several questions. The next time I was getting ready to buy I was asking about the specs on his SE transformers and how that would affect the sound compared to what I currently had. I started it with a compliment on how good I thought the PP transformers I got from him sounded but somehow I think he thought I was questioning his design and that was the end of the communications. Oh, and the electra-print transformers I got absolutely stank for months. I sat them out in the sun for most of the summer hoping the varnish smell would go away and after about 4 months I was able to use them.

I had a pair of Transcendar ones that I didn't get around to using and sold a few months back to someone that was going to use them right away.

I nearly ordered a pair of sowter ones and at the last second came to my senses on the price.

I'm really happy with the edcor ones that I have but I have intermittent upgrade-itis and start wondering "how much better could it sound?"
 
Last edited:
I'm really curious what you find with Octave electronics. The transformer on the left in their picture has "James" on it but the others appear to say Jain Shin (or something like that). I did encounter a place on ebay that claimed they had lots of other James transformers available once. I'd love to have a pair of JS-6123H transformers.

I've almost bought Lundhal ones but the connection options shown on their spec sheet confuse me a bit and the info overlaps between the PP and the SE versions. I haven't been able to get a reply from K&K audio but Lundhal did reply directly to inquiries.

I think with the lockdowns everyone that had ever thought of building a tube amp decided to build one and the transformers got hard to find.

The electra-print stories are funny, I thought I had uniquely messed up in communicating with them. The first time I sent a link to the PP schematic for what I was going to build and got his recommendation for which transformer and ordered from there. He was very helpful and answered several questions. The next time I was getting ready to buy I was asking about the specs on his SE transformers and how that would affect the sound compared to what I currently had. I started it with a compliment on how good I thought the PP transformers I got from him sounded but somehow I think he thought I was questioning his design and that was the end of the communications. Oh, and the electra-print transformers I got absolutely stank for months. I sat them out in the sun for most of the summer hoping the varnish smell would go away and after about 4 months I was able to use them.

I had a pair of Transcendar ones that I didn't get around to using and sold a few months back to someone that was going to use them right away.

I nearly ordered a pair of sowter ones and at the last second came to my senses on the price.

I'm really happy with the edcor ones that I have but I have intermittent upgrade-itis and start wondering "how much better could it sound?"

Yeah, I'm gonna wait to hear back from Octave and Lundahl before I do anything else. Earlier today I was feeling really gung-ho, and thinking of buying those Hammonds. But the Hammonds and the Edcors have the same proposed frequency response, 20Hz to 20kHz, and I feel like there's still better options out there.

Especially where the James transformers are concerned. 15Hz to 70 kHz is an excellent spread. I'm hoping I hear back from them.
 
As usual i would suggest looking at the polish guys, Ogonowski and Toroidy. Im not affiliated but a happy customer. I see you are from the US so maybe the shipping would be expensive.

I'm really digging the look of those Toroidy transformers, and their TTG-EL84SE has exactly the specs I'm looking for. Thank you for bringing these to my attention! I'm going to email them for a US shipping quote immediately.
 
As usual i would suggest looking at the polish guys, Ogonowski and Toroidy. Im not affiliated but a happy customer. I see you are from the US so maybe the shipping would be expensive.

Personally, I would just throw money at Edcor. I had a pair of the CXSE-25 at one point. I seem to recall that they quoted 2-3 months' of lead time but shipped within six weeks. The transformers are pretty decent. They're certainly excellent value for the money.

+1 for Toroidy as well.

Tom

I'm now definitely hoping for Toroidy to pan out. They look awesome and the specs are just right.
Edcor is my ultimate backup plan. I've already got three transformers on order from them to build Pete Millett's "Jonokuchi" headphone amp. I placed the order a couple weeks ago, so I'm eager to see when they actually ship out.
 
I'm now definitely hoping for Toroidy to pan out.....

I've looked at those quite a bit too. I've heard mixed comments about toroidal for SE applications. First hand experience seems to be good but plenty of comments about how it shouldn't work too. Their prices are good, shipping isn't bad either and they reply to emails quickly.

....Especially where the James transformers are concerned. 15Hz to 70 kHz is an excellent spread. I'm hoping I hear back from them.

I'm the farthest thing from an expert but it also comes into play the curve of the frequency response.
If they go to 15hz but are already 5dB down at 20Hz then one that advertises to 20Hz and is a flat line from there to 20KHz seems better.

I was excited about this Tango transformer until it was pointed out that in my 5K application it wasn't particularly good.
 

Attachments

  • temp.jpg
    temp.jpg
    19 KB · Views: 181
Last edited: