Hi Darren
Details of all the caps and mods I tried can be found here
http://bottlehead.com/smf/index.php?topic=6924.0
The Mundorfs were 2.7uf I picked them up in a promotion for virtually the same price as the 1,5uf elsewhere. Mainly because I remembered reading a few post on the bhf which suggested going a little higher in uf value wouldn't hurt if using speakers with the Sex which I do also.
The Jupiter HT Bees Wax Papers are 3,3uf only really because I had a bargain via ebay.
I carried out I think most of the mods to my Sex after following Marks's (mcandmar's) rambling thread and he kindly helped with some guidance whilst I was undertaking them. I have been very pleased with the results particularly liking the effect adding the two chokes and the flexibility offered by the attenuator I used.
As the good Doc mentions its important to keep in mind the headphones used as this can have quiet a bearing on choice and end signature.
I will start by saying coming from a hot-rodded Crack using Beyerdynamic T1's the Sex while better in so many areas I found it a bit lean or cool and toppy treble wise in comparison. Having spent a lot of time with the Crack and having it nicely dialled in with mods and preferred tubes for the T1's which I was my go to headphone at the time.
My main aim for doing the Sex mods and trying some different capacitors was to try and gain a bit more fullness and magic in the midrange for the T1 that I missed from the Crack and that I knew the T1 could deliver. The combination of mods and capacitors being the reasoning behind why I initially tried the Ampohms as they had a good reputation of delivering nice density of tone which was what I was after followed later by the Mundorfs SIO which easily delivered on this objective and I enjoyed the combination immensely.
I really had not thought to much about experimenting further until I spotted a sigle 3.3uf along with two 0.1uf Jupiter HT's listed on ebay I didn't expect to win them and was really surprise I was the only bidder and snagged them for just £9!
While what the Mundorf SIO brought to the table was excellent with the T1's I was always conscious the Mundorfs SIO had a brightness to them and I used the Mundorf 2.7uf SIO in combination with the Ampohm 0.1uf paper in wax aluminium foils as interstage caps as this dialled them back just a fraction and kept them from crossing the line into sibilant territory with my T1's.
The Jupiters on the other hand have never felt bright and give just as much detail but in a more cohesive and even handed way compared to the Mundorfs.
I have since moved to the Sennheiser HD800 and found them to be less finicky than the T1 and sound even more glorious. From reading reviews I had imagined the HD800 was going to be more finicky than the T1's with even more of a hot treble and was a little surprised and relieved when I found this not to be the case.