Have you actually tried a decent transformer box (not an srd-6 or srd-7)? I owned a kgsshv carbon and tbh, the transformer box + amp was every bit as good, if not a little better.

Its 3M micropore tape.

To my ears, it largely fixes the wonky sound signature of the stock SR-003, so it sounds much more "normal" vis-a-vis the rest of my headphones. The effect is similar to stuffing cotton into the CES-A1 cups, but unlike that mod, you don't need to own the CES-A1.

This sounds pretty good

Well, different headphones need different pads. Deep ear cavities are ok (makes the sound more V-like), but wide cavities seem to tilt the sound upwards.

I have brainwavz pads that look a bit like that, and my experience is that they suck. Pads that work for me tend to have smaller ear cavities, I think that helps to make the 007 work with smaller amps.

Where did you get these pads?

I had a KGSSHV Carbon and Sowter 4342 + Pioneer M22 together at one point, and i think the former wasn't really better in any obvious way. In fact, the direct drive amp felt slightly dry by comparison.

Yes, but I'm cheap, and SR009 pads are expensive. The CD3000 sheepskin pads I got can be found on Aliexpress for roughly $20 with delivery, and I find that they make the SR007 sound much more natural and lively. Attaching the pads is a little awkward though, as you need to use double-sided tape...

Pad roll :D "Senn-esque" pads https://cdn.discordapp.com/attachments/911256019139694592/1175329426377019442/IMG_20231118_145902.jpg?ex=656ad5d3&is=655860d3&hm=112d6f4712f442cdad1692f4ca75ef6f934935086891a188efea3e40b2c384db& "CD3000" pads (from China)...

Haha, they aren't vintage per se (O2 mk1), just doing a pad rolling experiment. I was using stock pads without the spring and cloth filter (to make the sound less dark), but there was an irritating treble peak somewhere and an annoying lack of oomph. Switching to these "Senn-like" pads took care...

Meanwhile...

Nope, haven't tried anything that really comes close to the KSE in terms of transparency, including the Elysian Annihilator.

Maybe the Sony MV1. Between my own headphones, I think the MS-Pro is the most "complementary", but I went through a lot of pad rolling to get the sound where I want it to be. My favourite headphones/IEM for "loud" listening is actually the KSE1500 driven by the Stax SRM-1mk2, with Fiio FD7...

No, it's the same driver size, the only difference is the bias (internal spacings). I didn't find it too different from the normal bias mk3 tbh, but my mk3 was in mint condition, which may have helped.

Has anyone tried Radius Deep Mount tips on the FD7? Curious about those, but they are a bit pricey.

Try putting on a pair of rubber gloves.

Changing the depth of the screws under the pads will significantly change the frequency response. Going by the measurement on your set (no meaningful response by 30hz and a fairly large treble hump), it looks like the screws are waaaay loose. (It has been hypothesized that "bass light" R10s...

If you aren't entirely averse to physically tuning the headphones, try tightening the screws under the pads.

The balanced ear tips that come with the FD7 and FDX seem to be a bit different (one is black, one is white). Is there a way to buy the balanced ear tips that come with the FDX? (white colored balanced ear tips)

Just wondering, could you try swapping the pads?

Putting up my Alessandro MS-Pro for sale (not entirely sure which version it is), will provide 3 different pads, which you can use to tune the sound to your liking :) If paying via Paypal, you will need to add 7% to cover the currency conversion cost and paypal fees.

The mods do look pretty interesting. I took a more brute force approach by just getting 1:50 transformers from Sowter that were originally made for electrostatic speakers :D

Transformer boxes aren't necessarily bad, its just that the SRD-7 series isn't particularly good. The other concern is safety, since you can easily "overpower" an electrostat with a power amp + transformer combo.