I followed the above procedure using a pair
of Kevin's Private Reserve Russian tubes.
These were the high quality 6H23 "EB" version at $25 apiece.
The improvement over the stock JAN/Philips tubes was significant: Bass response
became very deep, the shrill highs were tamed, and the soundstage was widened
to an additional degree. "In your face" became "around your face", and the highs no longer
drilled my eardrums. This was a welcome change.
On the negative side, midrange instruments and vocals dropped into the background. These frequencies were noticeably quieter
than the rest of the spectrum, creating an uneven soundstage. The only solution was to crank the volume to extract
more detail.
Overall, the 6H23-EB was an improvement over the JAN/Philips stock tubes with
most types of music. Anything to get those shrill highs under control is fine with me.
Next, I rolled in a matched pair of Sovtek 6922's obtained from Uncle Ned of
Triode Electronics. The Sovteks
were moderately priced at $12 each.
Again, the upgrade was an improvement over the stock tubes. The bass octaves didn't
extend as far as the Russian 6H23's, but it was still clean and tight.
Midrange and treble frequencies were nicely detailed although I detected a touch
of "grain" at the higher frequencies.
The Sovtek 6922's reminded me of an inexpensive solid state amp, providing a neutral,
"dry" experience. They weren't my favorite set of tubes, but I'd certainly take them over the
stock JAN/Philips ones.
The last tubes I tried were JJ Electronic E88CC's, also ordered from Uncle Ned.
Immediately I knew I had a winner. Compared with the Russian 6H23-EB and the Sovtek 6922,
the JJ provided the best of both worlds. Vocals were impressively
evocative. The high frequencies were liquid and lush, free from any grainy characteristics.
Even the bass was deep and taut, extending almost as far as the thunderous 6H23-EB.
The JJ was the best of the four. It's also a bargain at a mere $11 each. Upgrading
the X-Cans amp with a pair of JJ's provides a typically awesome tube experience,
providing liquid, lush midranges that wash over you with realistic emotion.
Of the few tube factories that remain, JJ Electronic continues to produce a quality product.
I really like their E88CC tube, and hope they continue to improve
it.
There you have it... easy as pie. All you need are a couple of tools and a cheap pair of tubes.
A big thanks to Dusty Chalk of the www.head-fi.org forums who provided the
original inspiration.
Higher levels of performance can be attained by rolling
vintage Amperex, Mullard, Telefunken, and other classic NOS (New Old Stock) tubes into the X-Can.
Finding these gems can be difficult and expensive due to their rarity. If you want to make
more improvements to your X-Can, you must check out
Mike's page.
His instructions will help you take it to the limit.
Click here to see additional images of the interior circuit boards.
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