carbon-composition resistors—although
they, too, provide a certain flavor of tone in
certain spots in these amps. I just don’t prefer them all the way through, because then
it loses high-end fidelity and doesn’t sound
like a Marshall.
But NOS parts are only part of the
puzzle. You have to know what to do with
them and which ones to select, and you
have to have a very finely tuned ear to do
this. It’s more than just whipping together
a recipe.
Is shelf life a concern with NOS parts?
I suppose any NOS part does have a shelf
life if you’re talking about a long enough
time frame. I won’t use old electrolytic
capacitors for obvious reasons—they dry
out. Also, depending on how the parts
were stored—and just because they’re old
parts in general, with different manufacturing processes than today—you can
get ones that are way off tolerance.
Sometimes that can be a good thing or a
bad thing.
Do you test all of your NOS parts?
I measure each part, and I sometimes
utilize components that do not measure what they actually are supposed
to. I have a large stash of vintage parts.
Sometimes certain part values measure
near spec, and others always measure
higher or lower. I’m not talking about
different-toleranced parts, but ones that
were supposed to have the same tolerance.
By having a large selection go through
my hands, I’ve been able to figure out
some things that someone with a smaller
quantity wouldn’t know. You can’t just
look at an amp’s insides and copy it,
because it will not sound the same.
There’s more than meets the eye.
Tell us about some of your builds.
My most recent amp is based on a 1966
Marshall JTM45/100. I went all out on
details, so it’s cosmetically and sonically like
the original. The back panel has the proper
gold font—even the misaligned “III” in
“MK III”—and the dot in the second “i”
in “Amplifier” is slightly oval, as per the
original amps. The gold knobs on the front
panel are old and nearly identical to vintage Marshalls. The circuit board is NOS
Paxolin, as per the originals. This does have
an effect on the sound. I used all NOS
original resistors found in amps from that
era. The coupling capacitors are original
Mullards with a date code of 1966.
I sourced as many original components as possible from all over the world.
I even managed to source original PVC
[polyvinyl-chloride-plastic-insulated]
stranded wire from a guy in England
who supplied Marshall with them in the
’60s. I also sourced the original pink wire
to the pots and the slightly thicker diameter pink wire for the pot jumpers and
input jacks, as per original amps of this
era—this wire is next to extinct and plays
a role in the vintage tone.
How so?
The old wire had a different molecular
structure, a different strand arrangement, and a different grade of PVC.
Also, the old Marshall carbon-film resistors I used are part of the tone of this
era. I find modern carbon-film resistors
much too bright for these amps, and
carbon-composition resistors lack too
much high-end fidelity.
