I'm not joking, no dibs, no "calling it", nothing. In the unlikely event that I were to decide to part with it some day I deal with that then. It would be horrifically expensive compared to the Menace, that's all I know at this point.
It help a little more to know what about the 900s that you liked, what you didn't like, what sort of equipment you'll be using them with, what sort of music you like, etc, etc, etc.
You've given us so little to work with that you're not going to get much in the way of help.
Bought a few tubes for the MenaceTC.
Translation - 17 307A's, 10 KenRad, 7 Sylvania, average price of $9/each. Not all are guaranteed to work but crikey, at that price I just don't care. All I really wanted was one pair for testing (I have 3 NOS sets) and buying in bulk turned out to be cheaper than a single pair. Given DanC's love of the AD1 maybe I'll smash a couple 307As, just cause I can?
I can get you a couple bucks off anything Neotech (just about) and I wouldn't bother with anything heavy awg for this, isn't the power just for the bias? If you want to try 3x 18ga of the Neotech stuff I have some.
Dave,
I may have a length of bulk wire left over from god knows what and if not I can probably help you out anyway, just shoot me PM with the desired length.
LFF,
Honestly your cheapest trouble-shooting will be to simply order a new cable direct from Sennheiser. If you go to the parts section of the sennheiser usa website you can search by headphone and you'll pretty quickly find what you are looking for. And for whatever reason the 650 cable is half the price of the 600 so I'd recommend getting that.
If you find it's not the cable and is in fact the contacts inside the headphone I'm sure we can find someone around here willing to take a look at hard wiring them for you.
Feel free to PM me if you have any other questions.