@JeffKall, you're welcome!
Okay, so I have a couple of ORS builds that are nearly identical with 797 capsules, but one has a 3u GZT 87 transformer and the other has the $18 Aliexpress T-13 in it, and the one with the Ali transformer sounds closer to my 87. But, what stuck out, even when the one with the 3u in it had a different capsule was what I thought was a slight notch right about where the upper mids meet the high end. Changing the capsule didn't change the notch so I tried a couple of tests.
First was a 1k tone, fed from my phone, recorded in my booth.
(ORS 87 with GZT-87 transformer (797 Capsule))
(ORS 87 with $18 AliExpress T-13 transformer (797 Capsule))
Notice how the Ali T-13 seems to go right up to 20k.
Then, WHITE NOISE test.
3u GZT-87
Ali T-13
And there's the notch at 6k that I had thought I had heard.
Nearly identical builds in same HL-77 bodies, with 2n38a9's from the same batch of FETs I bought from Small Dog years ago.
Now, I'm not ruling out that it may not be the transformer, but since that notch was there with the previous capsule (3u K87), the transformer is my best guess.
And despite my initial disdain for the Ali T-13, I have definitely changed my mind about it given the results I've gotten from my two separate builds with them.
EDIT: Additional thought. I have 6 fully functional ORS 87 builds. I only have one with the GZT transformer and it's the only one that has that 6k notch in the sound.
Okay, so I have a couple of ORS builds that are nearly identical with 797 capsules, but one has a 3u GZT 87 transformer and the other has the $18 Aliexpress T-13 in it, and the one with the Ali transformer sounds closer to my 87. But, what stuck out, even when the one with the 3u in it had a different capsule was what I thought was a slight notch right about where the upper mids meet the high end. Changing the capsule didn't change the notch so I tried a couple of tests.
First was a 1k tone, fed from my phone, recorded in my booth.
(ORS 87 with GZT-87 transformer (797 Capsule))
(ORS 87 with $18 AliExpress T-13 transformer (797 Capsule))
Notice how the Ali T-13 seems to go right up to 20k.
Then, WHITE NOISE test.
3u GZT-87
Ali T-13
And there's the notch at 6k that I had thought I had heard.
Nearly identical builds in same HL-77 bodies, with 2n38a9's from the same batch of FETs I bought from Small Dog years ago.
Now, I'm not ruling out that it may not be the transformer, but since that notch was there with the previous capsule (3u K87), the transformer is my best guess.
And despite my initial disdain for the Ali T-13, I have definitely changed my mind about it given the results I've gotten from my two separate builds with them.
EDIT: Additional thought. I have 6 fully functional ORS 87 builds. I only have one with the GZT transformer and it's the only one that has that 6k notch in the sound.
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