and to ground on the volume pot, and a
resistor soldered across two legs on the
other side, with one of those two legs
then being run to the R1 resistor on the
circuit board and the other to ground. We
decided to initially solder everything to
the switch, ending up with what looked
like a spider from the future.
Once we began soldering the leads
from the switch and components to the
intended spots on the circuit board was
when we encountered our first problem.
Since we found ourselves with a misplaced multimeter during the review, we
figured what the hell, let’s just eyeball
the solder joints and go for it. So once
we had everything wired in – before drilling the hole for the switch – we decided
to plug in and get some signal, as per
Bruce’s instructions. We were immediately greeted with faint, microphonic
feedback that increased as we rolled
the volume up. Also, as the notes began
to decay, they would fart out, with the
notes ending abruptly, like an old fuzz
tone, except it didn’t sound at all cool,
just damned annoying.
We tried resoldering all of the connections; the problems remained. We tried
swapping out the Valve Junior’s 12AX7
www.premierguitar.com 122 PREMIERGUITAR OCTOBER 2007
for a known good one; the flatulence and
feedback continued. We made sure the
power tube was seated properly; still it
persisted. I can still hear it. At this point
we were officially stymied, so off to our
favorite local shop it went. The verdict? A
bad volume pot. If you didn’t see that one
coming, don’t worry – we didn’t either.
But it does raise a good point: you may
want to live with the amp for a while
before doing any mods to give any like
problems a chance to pop-up. It’s a lot
easier to swap the amp out for a new one
at your local guitar store than solder in a
new pot. We would like to give big ups to
Ronny Boles and Bill Nix at Somewhere
in Iowa Guitars for being kind enough to
track down the problem for us.
Once that was out of the way, we decided to drill the hole for the switch in the
chassis and finish things up. Bruce offers
up advice for placement, suggesting placing it between the volume knob and input
jack. Figuring he knows what’s best, we
did as instructed and wrapped things up,
placing the chassis back in the box. He
also included a nice water transfer decal,
to indicate whether the switch is in the
“Low,” “Mo’,” or “Whoa!” positions.
“So, how does the mod sound?” I can
hear you asking. Amazing, I’m happy to
reply. Remember the earlier part about
calling in some help to chase down the
feedback? Ronny and Bill have been
in the vintage guitar business almost
since its inception, and, between the
two of them, have plenty of sweet old
amps floating around. What they don’t
own currently, they did at one time. The
BitMo mod made their collective jaws
drop. We plugged it a 4X12 cabinet, and
it sounded incredible. The Valve Junior
was plenty impressive before the mod,
but the three-way Voicing/Gain mod
turned it into something you could easily
rock at gigs.
In position one, or “Low,” the mod is
supposed to give the Junior more of a
blackface tone, adding a bright cap to the
circuit and offering up the most headroom of the three positions. We botched
this position because we used instructions from June, when Epi was still shipping the green PC board (revision twos),
but the amp we purchased in August
had a black, or revision three, PC board.
Speaking with Bruce indicated that this
would work, but would sacrifice some
clean headroom, due to Epiphone moving
things around from one board revision to
the next, and Bruce’s need to counter –
