PAD Rev A vs. Rev B

Could anyone tell me the difference between Purist Audio Design Colossus (or others) cables Rev A and Rev B? I emailed the company but still haven't received a response.
The Rev 2 disc does the job in 1/3 of the time. It has been a while since I looked, so I may be off by a bit. I like it quite a bit, but it is a lot of money to spend for a burn in disc. Some people like the XLO quite a bit and it is much less expensive.
Forgive me, I should have been even more specific. I'm looking for the difference in the Colossus speaker cable.

Thanks again -
I am so sorry, I responded to the title. I never read the thread.

My Bad!

I believe the mix of metals in the wire were changed from A to B. The B is certainly better, but not the gain that occurred when the original Colossus was upgraded to Rev A.

The revisions continue to refine tonal balance as well as tightening up the bass frequencies. The latest Colossus has terrific bass impact, but without the excessive bloom the first version had.
I did ask this question to PAD sometime ago about their cables and what they replied was that apart from no difference in the looks, the Rev A was more hifi sounding while the Rev B was more musical and correct sounding! Apart from this, the Rev B is more extended than the Rev A especially in the upper regions and to a certain extent the lower regions! As such, if you have both side by side, you might feel that the Rev B is slightly more brighter while the Rev A slightly more warmer sounding but actually it is just revealing more! I've compared both the Colossus ic's and I find both give the details but I slightly prefer the Rev A as I find it a bit more warmer! Hope this helps!
The Rev.B is a big sonic improvement over the old Rev.A.