Me and My Big Mouth
Donal Henahan once said, "The
human brain can soften as a result of incessant listening to music with an intent to
commit prose." Well, I'm the poster boy for that particular premise. You'd think I'd
know better than to make promises about what I'm going to listen to, but nooooooooo,
I just rush on in there. My rash commitment to describe my experiences tube-rolling the Musical Fidelity X-Can V3 headphone
amplifier is a perfect case in point.
First, some background. Tube rolling is the practice
of changing the sound of a tube-driven circuit by changing the type and/or brand of tubes
employed. Why does this make a difference? A number of tube models are roughly equivalent
to one another -- in fact, back before the transistor, almost every audio hobbyist had a
tube-equivalency manual that told him which tubes could be substituted for others. Some
differences (such as in the tubes’ gains) were significant, and others were subtle,
but substituting one tube for its near equivalent could change a component’s sound.
But back then, tube rolling wasn't necessarily about
modifying the sound of audio gear -- it was a survival mechanism that allowed consumers to
make do with the tubes in stock at their local radio shop -- if the shop didn't have the
model you needed, you could generally substitute one that would work.
In the mid-1970s, when high-quality tube gear began to
reappear in high-end audio, some audiophiles began substituting tubes to make tonal
changes in their components. Many discovered the joys of substituting near equivalents,
while others found differences in various NOS models. (NOS stands for new old stock,
aka unused vintage tubes.) Audiophiles debated the tonal differences between, say, JAN
(joint Army/Navy) Philips 6922s and the same tube produced by Telefunken.
Some audiophiles were distressed by the whole concept.
Already wary of tube gear because tubes wear out, now they had to cope with
differences between tubes that were supposedly built to the same spec? It all made
life too uncertain for these folks, who preferred the stability and assurance of
solid-state.
I went in the opposite direction. I began to collect
vintage tubes at swap meets and jumble sales, and I never met a tube that didn't make a
difference in my heavily modified Audio Research SP-6C preamplifier. I couldn't understand
audiophiles who were "too lazy" to go the extra mile for better sound. In fact,
I was obnoxious about it.
But things changed. Solid-state designs got better and tube
designs became more stable. "Solid-state" no longer meant "cold and
clinical" sound, and tubes no longer guaranteed sound that was "too warm and
colored." The two camps moved closer together.
Another change was that, while early audiophile tube
circuits weren't greatly different from those of the 1950s, things began to change as we
entered the '90s. Tube designs were just as likely to use resistance-ladder volume
controls or solid-state power supplies as were the latest transistor models -- and
circuits became less reliant on the output tubes for their sound. Simple circuits seem to
derive the biggest differences in tone from tube rolling; the more modern circuits
differed a lot less from tube to tube.
Audiophiles differed in how they felt about this. I
welcomed the reliability of the newer circuits, and enjoyed what I perceived as freedom
from doubt. I was no longer obsessed with the notion that I might find the one
"magic" tube that would change everything -- and that would spoil me before
finally becoming unavailable once and for all. Other audiophiles felt that audio had lost
another piece of its soul. They viewed people like me the way I had viewed people like me
when I had the tube-rolling bug -- as simply not getting it.
So, when I reviewed the Musical Fidelity X-Can V3, I
thought it was a grand opportunity to dip my toes back into the world of tube rolling and
see if I was, in fact, missing out on one of audio's true pleasures. That was fine -- but
then I had to open my big mouth and say that I would report on it in a timely manner. As
anyone who relies on me for the timely delivery of copy will attest, that was Mistake
No.1.
If you want to make God laugh, tell Him your plans. No
sooner had I committed to writing about tube rolling than I began having health problems
that made that type of critical listening extremely difficult -- almost impossible. Then
there was another little problem, one that Musical Fidelity's Antony Michaelson had warned
me about. "Provided the tube is roughly the right gain group, roughly the right
current group, it should work," he told me. "If it doesn't, you haven't designed
your circuit properly. I think things should be consistent and predictable."
So when I substituted JAN Philips 6922s and Sovtek 6H23s
for the stock tubes in the X-Can V3, I didn't hear major differences. I felt the Philips
had a warmer, lusher sound. If pressed, I would admit to preferring those tubes to either
of the others -- as long as you didn’t ask me to identify any of them blind.
That doesn't mean there weren't differences among the three
tube sets that you might find significant. All it means is that I didn't
care enough about the minor (as I perceived them) differences to invest much emotion in
them. After all, a pair of 6922s is relatively cheap, and they're easy to replace -- and
tinkering is one of the great pleasures of audio.
But I simply couldn't work up enough enthusiasm to make the
small differences I heard seem meaningful. Maybe I’m lazy -- or perhaps Michaelson
did precisely what he’d set out to do when he "went back to first principles in
designing the V3."
I'm happy either way -- and if you'd prefer to play around
with tube rolling, you should do that, too. That's the great thing about hi-fi. It isn't
brain surgery -- being happy is good enough.
...Wes Phillips
wes@onhifi.com
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