• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Electra-Print still in business?

Well yeah - I concede that he knew his stuff, but, but I had to practically fight him to get the transformers made for my experimental headphone amp (which sadly didn't work so well due to compensation issues). I'm going to one of these days plunk those transformers on the bench and characterize them to see what I got for my money.

There are very few transformers made for vacuum tube headphone amp duty. Transcendar made one model that worked well for me - I have two pairs of them and one wound special with no gap for a parafeed headphone amp.
Both Van der Veen https://mennovanderveen.nl/index.php/nl/producten/other and Thermionic Labs https://www.thermioniclab.com/en/headphone-transformers/ make dedicated headphone transformers. Van der Veen has a sterling reputation, not sure about Thermionic Labs. TL also says they can do custom builds as well.
 
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A stock unit from Thermionic Labs has the output impedance tap I need for the job, which is interfacing between a triode with Rp of 920 ohms, driving a headphone of about 35 ohms impedance. I believe Monolith is based in Belgium.

Yep, just checked - Belgium it is...
 
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Thank God for Ecor and Hammond: affordable, measure well and sound great for low $$, Edcore being especially affordable. Lots of people on the forum despise them and at the same time do not have the data to support their opinion. Strange.
 
Thank God for Ecor and Hammond: affordable, measure well and sound great for low $$, Edcore being especially affordable. Lots of people on the forum despise them and at the same time do not have the data to support their opinion. Strange.
The cheap Edcor open frame XSE models do not measure well. They really are guitar use only and roll off big time at 100hz. The GXSE, especially the 15W version do perform well. I just tested these in a video, the cheap model is junk for HiFi use.
 
The cheap Edcor open frame XSE models do not measure well. They really are guitar use only and roll off big time at 100hz. The GXSE, especially the 15W version do perform well. I just tested these in a video, the cheap model is junk for HiFi use.
That's not what I see. Expecting them to pass 15 watts at 20 Hz will result in some serious saturation which sounds quite nasty. Run them in the 5 watt and under range and they do quite well. I spent several hours last night cranking an UNSET based SE amp running 6AV5 TV sweep tubes through a very old pair of XSE15's into my Yamaha NS-10M Studio monitors which are in the 12 to 20 ohm range below 100Hz. These things ROCK! The results were reported in post #583 here:

https://www.diyaudio.com/community/threads/unset-beta-board-build.376124/page-30#post-7741108

Since the setup was still on the bench, I measured the 3db roll off points at 2.5 watts of output. They are 18Hz and 56 KHz.
 

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I’ve gotten some really nice SET outputs from Hayboer. The ones that I get have no UL tap but I’m sure they will make those too. I run my KT150 SET amps with them and am very pleased. Ive used them in four amps so far and everyone that I sold them to is very pleased. They will do them to your spec for primary with dual outputs for four and eight ohms. No affiliation, just happy!
 
That's not what I see. Expecting them to pass 15 watts at 20 Hz will result in some serious saturation which sounds quite nasty. Run them in the 5 watt and under range and they do quite well.
I plugged one into a Musical paradise MP301 (after doing some circuit mods) and this is the results I saw, over 10db down at 20hz with a XSE15 compared to 1db down at 20hz for a GXSE15. Maybe the older versions were different? This was a current production model.