How does it work?

Mainly, I receive headphones to work on them. I do not supply them.
The primary reason for this is that people send me all sorts of ‘unicorn’ vintage Sennheisers that they want me to work on.
Are there sonic differences between vintage and modern? Yes. So this is how it usually works.
The secondary reason is that people like how a certain stock pair they have sounds, and want them upgraded by me. Because, each pair sounds different, no matter how good Senn matching is. (And I can tell you their matching is really top notch.)
Sometimes I am able to source pairs locally, and some people have opted for this option.
This is not a set thing, so this is conducted in a case by case basis.
A long time ago, I used to supply pairs myself because I wanted to be able to offer a single consistent sonic profiles. But this has now proven impossible because of some changes to how Senn operates (especially how parts are much harder to source now).
When you send, you can choose to send the headphones without the headband (to save shipping cost), in which case read here.
With the HD800 you have to send the whole thing. I have to modify the headband too.
Also please read the FAQ and other sections of the site to fully calibrate your expectations.
Don’t complain to me if you expected a HD650 sound out of a HD600 or something like that, or vice versa. You’ve been warned.
My job is to help these headphones be at their best, in different styles and presentations. I can influence them to become a certain way, but I don’t alter their character and so their final sound depends a lot on how they were stock.
As a friend put it to me: “JAR- We turn horses into unicorns, but not into different animals!”
Best ways to make me angry and not reply:
1) I won’t reply to you if you ask “is the headphone included”.
2) Stop asking if these are kits. Believe me I wish they were as simple as that. Every process is unique because each of these headphones sound different at stock, despite how good Senn matching is. Otherwise I would be making a killing selling these as kits like candy, huh? Why go through the trouble having people send their pairs to me?
3) If you plan to bug me or push me to finish your pair faster, let’s not talk. Don’t email me. I don’t want to spend my time for you and I don’t want your money. These sort of people are the number one reason for my stress.