Paladin79
Previously MOT: Cables For Less
The Crack with HD650's, HD6xx, DT880 will be a perfect match actually. I've heard the S3X drive Audeze's 3's with very very good results.
The S3X is very versatile in it's own right. In my personal situation, i have one driving my living room speakers right now. It delivers every bit of oomph i need for a good NYE party.
Since you'll reading this thread, the worst advice i could give you is to buy a Crack. As it will open up another pandora's box of tube rolling options..
So that would be my advice, with your line-up of headphones. What Crack does to those Senn's! I use HD800's with it a lot.
It's not designed for planars, so don't try them. They are much too hungry for the Crack and don't pair well with an OTL's output impedance (you'll need for negative feedback to get them going ).
The secret to Crack is it's super short signal path. No output transformers make for a lot less copper the signal needs to run trough.
The only capacitors in the signal path are the output capacitors and these contribute a lot to the sound signature.
And i'd recommend to get the speedball (CCS on the driver plate) installed. It just tops every cap coupled, resistor loaded similar OTL amp (like the darkvoice) for a "lower" price (on most occasions).
And for tube rolling. It's just as happy with 6SN7's as it is with 12AU7's. And if you think you've heard the best of 6SN7 there's 76, 6J5, 7193's etc and you'll have your mind blown by what this cute amp is capable off.
But, it has one downside, it can't roll E88CC's like the Vali 2.
O Schiit... what has just landed on my desk (with 5670 adapter to make things worse)...
I may have to check out the tubes you mentioned as the best of the 6sn7's, the 76 and 7193. 6J5's, 7A4's, and most 6sn7 variations, I have. I am in the process of building four identical OTL amps for blind testing 6sn7 equivalents and I want to be sure I do not leave any out. When all are completed a cage will over said tubes so any variation can be concealed for said tests. I am using 6080 power tubes just like the Crack only the native driver tube is a 6sn7 instead of 12AU7.