[audiowize]

  I've heard that all 6DN7's are the same so there's no advantage of tube rolling at all on the S.E.X. Is this true?

There are black and gray plate triodes for each of the big and little halves, so there are:
 
big triode black, small triode black
big triode gray, small triode gray
big triode gray, small triode black
big triode black, small triode gray
 
There are also series/parallel heater arrangements, though you'd be hard pressed to hear a difference there.
 
There are also coin based 6DN7's that are built a little differently.

 

[Loquah]

  I've heard that all 6DN7's are the same so there's no advantage of tube rolling at all on the S.E.X. Is this true?

 
I have heard that and my limited experiences confirm it. I've tried 3 pairs of different 6DN7s with no noticeable change.

 

[tdogzthmn]

Got my CS4 board installed this evening, only took about 4 hours from opening the box to sitting here with music playing sweetly through my headphones.  Already sounds stronger than before and hopefully the improvements will continue as it gets more play time.

 

[Loquah]

  Got my CS4 board installed this evening, only took about 4 hours from opening the box to sitting here with music playing sweetly through my headphones.  Already sounds stronger than before and hopefully the improvements will continue as it gets more play time.

 
I didn't really notice significant burn-in effects with the C4S, but I wasn't really listening for it. All I know is it made the sound significantly better!

 

[tdogzthmn]

I would say sharper and more present would be good descriptions for the changes I noticed immediately from the install. 

 

[Loquah]

Yes. That matches my experience too.
 
I feel like the sound became slightly smoother / cleaner sounding too - silky even

 

[jamc]

So I can run the HE-500's off the SEX speaker taps- need resistors?
I have them now on a Bifrost/Asgard combo and don't like the sound- 11 o'clock is loud enough and the bass is great but the rest seems bright, tinny, just not full enjoyable sound. Ran them for 4 days straight when new to break them in. It may just be me and failing hearing but I a hoping to get some warmer, fuller sound going tubey. I am going to try the Emotiva mini-x on speaker taps to see if more power helps.

 

[audiowize]

You won't need resistors on the SEX/HE-500.  You can also plug them into the headphone jack instead of the binding posts.

 

[SilverTrumpet999]

  You won't need resistors on the SEX/HE-500.  You can also plug them into the headphone jack instead of the binding posts.

 
This is 100% true. There is no need to source power from the speaker binding posts on the S.E.X. to power any headphone. The switching headphone jack routes the exact same signal to the binding posts - without additional resistors in the path - when nothing is connected to it. Some earlier versions of the S.E.X. did have resistors in the headphone jack path (cutting out about 10 dB of gain and raising the output impedance), but at some point prior to the 2.1 revision these were eliminated. It was a good change.
 
I know there's this myth that all orthodynamics need to be powered from the speaker taps, but unless that's your best cable - save yourself the trouble here. All else equal, the only difference is that the headphone jack has roughly a foot less cabling in the S.E.X. Also, the HE-500 sings when powered by the S.E.X. (and this combo has silly amounts of headroom).

 

[Loquah]

The Mainline plate has returned from the anodiser and the colour is great!!
 

 
Unfortunately there is a blemish on one edge and this was on the 3rd attempt to get it perfect apparently. There's only so many rounds of anodising that a sheet can take so I'll have to live with the mark (which is pretty minor), but I'm going to try to mask it with a pin-stripe (aka "The Mainline" 

)
 

 

[bigfatpaulie]

Very cool!

 

[JamieMcC]

Very nice I like the pin-stripe idea that would look super, some of the old school style pin striping styles are very classy.

 

[Dopaminer]

Pin stripe or racing stripe? 
 

 

[JamieMcC]

Looks great on the blue background but how about that red one it would be real kick ass on the Crack with power tube coming up through the eye.
 

 
 

 

[olegausany]

I don't have HE-500 but have HD800. I bought them in for sale forum here with Q-Audio French Silk cable with 1/4" jack. I also have S.E.X. which I bought at the recent PA meet and adapter cable which allows you to connect headphones to speaker taps was included but it has 4 pin XLR. I also had Moon Audio Blue Dragon cable for HD650 with 1/4" jack which I had difficulty selling with either headphones or by itself. So I ended up sending it back to Moon Audio and the removed HD650 connectors and put 4 pin mini-XLRs instead as my Q-Audio uses. They also cut short piece of cable with the 1/4" jack. Than they attached 4 pin XLR to the main cable so that I can connect it to speakers taps and put appropriate 4 pin XLR to the short cable so that it became 4 pin XLR to 1/4" adapter. After I received the cable back I first tried it with headphones jack and then with speakers taps and I can clearly hear smoother treble and better details retrieval when connected to speakers taps. I thought I know Daft Punk's Random Access Memory album well enough but I was mistaken because I now can hear things I never heard neither with HD700 with Moon Audio Silver Dragon cable with 1/4" jack nor with Q-Audio cable