[hpeter]

I know I am probably a majority of one on these boards preferring SET amps with Stax transformers over Stax direct amps, however, once in a while somebody asks about transformer upgrades for the standard Stax boxes.

I was going to get a Woo Wee. However, having heard Woo products, I was very uncertain of the transformer quality.

Instead, I tried a pair of the new manufacturer Z-565 Dyna OP's from Triode Electronics wired in reverse. I removed the standard stax transformers, and appended the Z-565 trannies to a breadboard for wiring. The Z-565 run about $210 delivered, less than the lundahl and James types often cited.

I have to admit, I was always pleased with the standard stax boxes, but these trannies are a significant, not minor, upgrades. High frequencies are much finer and better defined, soundstage about 20 percent larger, and bass much better defined with lots of internal detail. I have been using it with my fave 300b.

For DIY types who also like transformers, it is worth considering. It will probably also require a plexiglass shield to cover the bias circuit, which is exposed in this breadboard.

So far I have only been able to try it with standard low bias Lambdas, because the pro socket on my Spritzer mod SRD 7 box has not been working, but plan to get the 507's in action as soon as possible if I can get the pro socket working.

i think the lundahl is better quality than hammond, at least from symmetry point

 

[cjfrbw]

Still have my Frankenstein Stax 507/z565/normal bias and they are still the best headphones I have ever heard. Several times I have heard 009/Blue Hawaii, various 007 with 300b or Cavalli amps, Abyss etc at shows, and these strange 507 DIY still sound better to me, I don't know why. 009/Blue Hawaii too dry albeit detailed, 007s too soggy. Older Orpheus sounded great, but not as incisive. Dynamic models like Senn 800 a bit rough, even with tubes. I really liked the Abyss headphones, heard them five times, but they just don't quite have the speed/texture of the Stax 507 rig.

I am sure the Lundahl opts are better quality than the Z565 Dynas, but the Z565 sound quite excellent to the point I am not motivated to upgrade. However, I would probably encourage anybody to go for the best quality transformer they could afford.

I currently have been using the Frankenstein Stax 507/Z565/low bias with either Wavac SET or a 20 watt class A VFET Pass inspired amp. Best combo of tone, texture, space, detail, drive, bass etc. in a headphone to date that I have heard. It's probably why I am no longer that interested in headphones that much except to listen to them at shows etc. They are kind of magical in the way they hang the sound images in space, and manage to be revealing without losing tone, texture or body. I have a couple of sets of good dynamic headphones for casual listening in different locations, but the Stax 507 setup is the only one that challenges my high end speaker setup for general listening quality. I got a set of Sony MDR Z7 for casual listening, and I enjoy them, great headphones, but still eclipsed by Stax rig.

 

[Swann36]

Well almost 2 years on from the last post , I must thank all posters here for a fascinating topic thoroughly explored

 

[eskamobob1]

If uograding the stranformers for a transformer box like srd-7, how does one go about specking them? I'm assuming it's far more complicated than just picking the gain on a differential transformer? Anyone have any reading I can do on the topic? I currently use a woo wee that is far and away the best transformer I've heard (had it side by side with iesl, srd-7 mk2, and mjolnir srd-7) and am trying to figure out why it's so much better.