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

So, I think the Toroidy transformer I would need is too expensive with shipping and all.
I've contacted Electra-Print Jack one more time, to correct my mistake of telling him I had a EL84 tube when in fact I had an EL34 tube. I'll give him a chance to get back to me.
If he can offer something appropriate for a reasonable price, he's still a potential option (bad attitude aside).

If not, I'll go for the Edcor CXSE25, and just practice the virtue of patience while I wait for it to arrive.
 
Jack just got back to me. He "took his blood pressure medication" so his language and demeanor were more civilized. He suggests a 50-60mA transformer for the EL34, $188 for 4 and 8 ohm taps, or $150 for a single 6 ohm tap.

If I'm going to take the 6 ohm route, I think I'm still leaning toward the Edcor CXSE25, because it would save me $100.
 
Besides the higher price, there's a couple things nagging me about transformers from Electra-Print Jack.
First, it's the frequency response. I've got no real way to know what kind of response to expect from his transformers. I tend to get/build speakers with good bass extension, and I can personally hear frequencies up to around 19kHz, so I want to be sure that my amp is capable of sending those frequencies to my speakers with some level of certainty.
With the Edcor transformers, that's more assured since they advertise a frequency response of 20Hz to 20kHz. With Jack's transformers, who can say?
Secondly is the matter of power. All the other transformers that have been recommended for this build, with the EL34 tubes, have 100mA or higher current. The Edcor CXSE25 specs show 200mA. Jack wants to sell me a transformer with "50-60mA". I'm not sure how to interpret that. Seems like skimping on power, but what do I know?

His pricing isn't terrible. Basically boils down to $150 for Jack, or $100 for Edcor. I like the notion of ordering from Jack, because his lead time is only 10 days from time of payment. But by the same token, the Hammond 1628SEA would be here in mere days if I order it from Mouser, it's basically the same price as Jack, and at least it has a spec sheet with it, so I know what to expect; they also advertise a 20Hz to 20kHz range like the Edcors, so there's that advantage also.

It's funny, even as my options continue to narrow down, this decision is no easier to make.
 
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It is a difficult choice. I have Heyboer OEM power transformers for some of my projects, but the lion share of my audio transformers are from Monolith Magnetics in Belgium and Lundahl. I have a marked preference for amorphous cored transformers - the only surviving pair of non-amorphous cored audio transformers in my system (in this case outputs) is a pair of custom designed transformers Jack Elliano built for me more than a decade ago that do duty in my GM70 amplifiers - which these days reproduce the range from about 25Hz - 700Hz in my tri-amped DHT SE based system. (These amps ran full range for about 8 years until I went all active to six channels of DHT SE amplification almost 3 years ago.)

I think EP and Onetics (closed at this point AFAIK) were the best audio transformer winders in the U.S.

The Edcors are a great deal, but I still believe the EP transformers will be more than a bit better. If they are not I will be very happy to take them off your hands. :)
 
It is a difficult choice. I have Heyboer OEM power transformers for some of my projects, but the lion share of my audio transformers are from Monolith Magnetics in Belgium and Lundahl. I have a marked preference for amorphous cored transformers - the only surviving pair of non-amorphous cored audio transformers in my system (in this case outputs) is a pair of custom designed transformers Jack Elliano built for me more than a decade ago that do duty in my GM70 amplifiers - which these days reproduce the range from about 25Hz - 700Hz in my tri-amped DHT SE based system. (These amps ran full range for about 8 years until I went all active to six channels of DHT SE amplification almost 3 years ago.)

I think EP and Onetics (closed at this point AFAIK) were the best audio transformer winders in the U.S.

The Edcors are a great deal, but I still believe the EP transformers will be more than a bit better. If they are not I will be very happy to take them off your hands. :)

I asked Jack what he thinks the FQ response will be like, and what the estimated wattage is. Perhaps I'm just poking the bear. But his response will dictate my decision.

Is it weird that I kinda want to try the Hammond 1628SEA over the Edcors, just because they're black, and will match the rest of my build? There also doesn't seem to be a lot of feedback on this forum about the SEA which allegedly fixed the high frequency issues with the SE transformers, so I could be, like, a guinea pig.
 
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In the end it's all good. You'll learn as you go. There are a lot more options for output transformers than when I got started in this hobby more than 4.5 decades ago.

The SEA may be a good output transformer, the SE definitely wasn't. I have very limited recent experience with EI type output transformers having moved to more modern designs based on amorphous C cores. I am contemplating learning how to wind my own. I need to build fixtures that will allow me to use my metal working lathe as a winding machine first..
 
The Tubelab SSE design you are building with EL34 tubes will run at a current of around 60-80mA based on what George has described in this thread and is consistent with what others who have built his design have posted. Mine is at 57mA and uses those One Electron transformers (that are newly out of stock at Antique Electronic Supply store). If you order from Jack at ElectraPrint, you won’t go wrong going with one at 80mA. I wouldn’t worry about other transformer specs showing 200mA, since you won’t be anywhere near that with this design.
 
Note that frequency response numbers are much like power ratings on OPT's the differences in how the transformers are tested make for far more differences than seen in the transformers themselves. Most transformers are tested with a signal generator at some low power level like 1 watt. They will test quite differently in an actual amplifier, and very different again in a different amplifier. My new UNSET design was created to get the most out of a less than stellar OPT. It does this by acting like that low impedance signal generator used in some OPT data sheets.


Is it weird that I kinda want to try the Hammond 1628SEA over the Edcors, just because they're black, and will match the rest of my build? There also doesn't seem to be a lot of feedback on this forum about the SEA which allegedly fixed the high frequency issues with the SE transformers, so I could be, like, a guinea pig.

I have a pair of each. They are however over 15 years old, so they may not be representative of what's being made and sold today.

Back when Edcor first started selling transformers direct to hobbyists I bought a pair of the big ones. They came in "pimp my ride" bright metallic blue which was quickly replaced by the baby blue color seen today.

I had ordered a pair of the new 1628SEA's from AES, but they shipped me the old 1628SE's instead. They also shipped some tubes in the same box, some of which were smashed. They said that I could return them but the shipping both ways would be at my expense. After some ugly email exchanges and a discussion on this forum, a compromise was reached. The gave me a discount on the correct 1628SEA's, some replacement tubes, and low cost shipping. I sold the 1628SE's.

The 1628SE's had a severe notch in the high frequency range resulting in as much as 10db of loss at 15 KHz. The 1628SEA's still have the notch, as do most large OPT's, but it is moved well above the audio range resulting in minimal HF losses at 20 KHz. These losses depend on the circuit and tube being used to drive the transformers.

I tested the Hammond and Edcors and a few others against each other back then. The 1628SEA's were pretty far down the list from the top in HF response, and in overall efficiency, consistently wasting about 10% more power than any other transformer tested. When it was time to pick one of the two pair of OPT's for my own amp build, I chose the Edcors, based both on the test data, and on listening tests. The amp was a 307A based TSE, and it saw a lot of use for several years until I canabalized it for parts, freeing up the Edcors for a new project. The Hammonds have never found their way into a complete amp in the 16 years that I have owned them. That will likely change soon.

Using a new amplifier circuit design, I recently tested the same pair of Hammond and Edcor transformers against each other again. The differences were much smaller except for the 10% Hammond power penalty. Note that I ran the tests at 10 watts, not the usual 1 watt or less.

This test can be seen in post #32 of this thread:

UNSET is coming?

The Hammonds can pass more power than the Edcors, and I now have the technology to squeeze nearly 40 watts per channel through them, so they will likely wind up in an UNSET based amp once the new boards get here.
 
They have never been my first choice, but again, a lot depends on what the amp will be used for.

Many years ago I brought a big box full of OPT's and an SSE board mounted on a piece of wood to a listening session with 6 people, some pricey speakers, turntables, and other goodies. What I got was 6 different opinions, with some obvious trends.

I don't remember the exact details and this was not a scientific ABX test, and there was also about a minute of silence between tests where I swapped out OPT's with clip leads. The listeners chose the music, The speakers were a pair of high efficiency 104 dB full range horns, and a pair of 90 something dB three ways, the amp was always the SSE with Electro Harmonix KT88's in it, and nobody but me knew which OPT was being tested, only its number.

One trend was that the tiny "Fender Champ replacement" transformer universally sucked in all tests. The Tiny $29 Edcor XSE15-8-5K was well liked on the high efficiency speakers, and the 1628SEA was disliked on the same high efficiency speakers. Three of us were engineers at Motorola, and in a discussion about the results we came to the conclusion that our average listening level with those speakers was in the 100 milliwatt or less level, and most of that energy was lost in 12 pounds of transformer iron. The Champ transformer still sucked (worse) on the mid efficiency speakers, but the Hammond and the low buck Edcor wound up in "good enough to hear again" category on the mid efficiency speakers.

We had the Electra-Print's out of my TSE, a pair of One Electrons (don't remember the number) and the Transcendar 300B transformers. The big Edcors and Hammonds, the XSE15-8-5K and the champ transformer. All of these but the Champ, performed well on the mid efficiency speakers. I remember that two people picked the Electra prints as "best" and one called them the worst. The Transcendars beat the one Electrons and the big Edcors beat the Hammonds.

The results were different on the high efficiency speakers, where the physically larger transformers wound up near the bottom of the list.

My work / listening room/ recording studio was all crammed into a 10 X 10 foot room in Florida. I sat very close to my Yamaha NS10M Studio monitors, or my FH3's. My 2 WPC TSE had plenty of power in that room. Average power levels were below 1 watt, so the big Hammonds were just "too big." Smaller transformers just sounded better.

Now I am in a 2000 square foot basement. A 2 WPC amp is useless, and my current listening amp is a 20 WPC UNSET with the big Edcors in it. A 30 to 40 WPC amp based on those Hammonds would fit right in here.

If you have speakers with an efficiency of over 100dB you don't want the big Hammonds. If your speakers are in the mid 80's you might find them about right since you will be running the amp at full crank most of the time.
 
So, I think the Toroidy transformer I would need is too expensive with shipping and all.

You wanted the ones that are sealed into the stainless steel covers? Yes, they are significantly more expensive.

If you order on TME.com, then they are around $85 shipped. At that price, there are other options for beautifying them, and you can always be on the look out for an alternative while you are getting great sound from your amplifier.

I am constantly in awe of my SSE with Toroidys. Its one big flaw is that it is so good, it is hard to justify making more amplifiers ;-/
I am hoping my son will have space for it one day.
 
Quote, "I am constantly in awe of my SSE with Toroidys. Its one big flaw is that it is so good, it is hard to justify making more amplifiers ;-/
I am hoping my son will have space for it one day."

My toroidys are also in my SSE and I was also really pleasently surprised by them...

I had the 1628sea from hammond and my results were basically the same as Georges. They were simply too big and too inefficient. I cannot reccomend them for Hifi.

If I had to spend money on a new set of outputs I would be looking at Toroidy, Lundahl, or Sowter. In that order based on price vs. performance.

When I lived in the states I had a few pairs of Edcor as well. The were the budget champ, but dont forget, the outputs are the most important part of any tube amp and also have the most influence on the sound.

If you plan on keeping this amp for any amount of time buy the best trafos you can afford, and sit back and enjoy the amp!
 
They were simply too big and too inefficient. I cannot reccomend them for Hifi.

I would add that they are too big and inefficient for HiFi, unless you were using a significant portion of that capability. That's why I said that they would not be my first choice in a daily use amp that rarely sees more than a watt of output.

Most music has at least a 10 dB peak to average ratio. Well recorded (not super compressed to be loud) music is usually better than 20 dB. This means that the average power being produced by the amp is 10 to 20 dB less than the music peaks. A 10 watt amp turned up so the it is just touching clipping on the loud peaks will be averaging 100 milliwatts (20db) to 1 watt (10 dB).
 
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Myself I only used Toroidy transformers in Pete Millett's engineer amp, which is a push-pull design, so no direct experience with their Single-Ended OPTs. I have had excellent experience with their PP OPTs, and as well with 2 power-trannies I asked to build on specs for the Engineer Amp. Thomas who answered my requests was always nice and helpful... without medics I presume :)
 
I heard back from Toroidy, and shipping isn’t as bad as I thought it would be. It would work out a little cheaper than Electra-Print, actually. So they’re kinda back on the table, if they make one that would work for my application.
At this point though, I’m tempted to just go for the Edcors. This is my first amp build of this kind, and I’m finding it hard to justify spending $350+ on transformers for what is basically a gamble. I could get the large Edcors for a reasonable amount.