Upgrading the tubes in the X-CANS amp may not be as simple as rolling the Earmax Pro, but any 6th grader could nevertheless do it with ease. Don't worry... it's a snap.
The X-CANS tube swap from the Jan/Philips tubes to Upscale's "Private Reserve" Russian 6H23's is a mixed bag. The good, the bad, and the ugly are all present. I let them burn-in for eight hours before writing this review. I do not believe further burn-in is likely to make any major differences... and I'm not going to wait and see, so there!
The typical upper-end shrillness is gone.
Bass response is deeper.
*Some* instruments seem to have a bit more "air".
The midrange is more subdued with a definite flatness that is not at all pleasurable. The murk-factor has actually been upped a notch. This is bad, indeed.
I bought the X-CANS amp for $150... a nice deal for the money. However, after adding $25 each for the two Russian 6922's the price/performance curve is shot considering that the tubes are still not the right ones for the job. The Russian 6922's would be better served in another amplifier. They do look very nice and have a superb bias match... so perhaps more testing is in order on other equipment.
I think I'm reaching the limit of "X-CANS technology". I suspect that even if I popped in a pair of vintage Amperexes the X-CANS may not be capable of delivering the full potential of the tubes, but I could be wrong. I'm not going to hunt them down, though.
The stock tubes are going back in! I'm not giving up my midrange detail, no sir. The bass can wait.
I'll be putting the Russian 6922's on eBay soon. In the meantime, I'll be picking up a matched pair of Tesla's and Sovtek's just for the hell of it. Call me curious.
Further results to come. Many others have taken this journey before me. Tube Avenue is a well-worn path.
P.S. Shame on you, Jude. Now what does the second line on my X-CANS upgrade page tell you?