The
BLUESBREAKER:
Revisited
and components, plastic tube sockets, and
rewiring of the chassis to original specifications. These additions will make the
electronics of the amplifier more authentic,
but will not noticeably improve the sound.
These additions also significantly increase
the cost and add more time to the project.
The steps I have outlined above will reproduce the amplifier tone as heard on the live
cuts of Clapton with the Bluesbreakers, as
a CAD drawing of the Series II dimensions and features. I was very pleased with
the results I received a few weeks later. I
removed the chassis and speakers from
my Marshall reissue and reinstalled them
in the new cabinet. Even though the new
cabinet included pre-drilled holes and T-nuts for the speakers, it still took some
time to make this switch. While switching
cabinets, be careful to ensure the speaker
and amplifier connections are right.
cabinet incorporated the deeper 10. 5”
thickness, as can be found in the original
Model 1962 Series II.
Step 2: The Electronics
Before digging into the guts of the
Bluesbreaker, a word of caution: this phase
deals with potentially dangerous electrical voltages and it is highly recommended
that only a trained and competent amplifier
The new cabinet is over 2” bigger than the reissue cabinet, resulting in a fuller sound
well as the “Beano” record. In fact, after
making these changes, your Bluesbreaker
will no longer be a mere reissue – it will
sound like the real thing!
Step 1: A Bigger Cabinet
There are now several competent amplifier cabinet makers building exact replicas
of the Model 1962 Series I and II cabinets.
Be sure these makers use the required
multi-ply Baltic birch plywood, correct black
tolex covering, vintage gold veining and
the surrounding white piping. It is also wise
to have them confirm the correct cabinet
dimensions, as the Series I and II are two
completely different cabinets. To save some
money, you could use the Marshall logo,
casters and other hardware from your existing reissue. Two excellent cabinet makers
available on the internet are Vibroworld.com
and Swansoncabinets.com.
For the first phase, I ordered a new cabinet from a cabinet maker on the internet
– to ensure accuracy, I supplied them with
For testing, I used a Gibson Les Paul
Heritage 80 model. After re-checking the
chassis and cabinet connections, I turned
on the amplifier, and let it warm up. I started at low volumes and progressively turned
up the volume to 10, all while keeping
the other settings such as presence, bass,
middle and treble at 10. Upon hearing the
first chords, I was immediately struck by a
new “openness.” The amplifier seemed to
breathe and had a new, airy sound to it – it
did not sound as tight as the smaller reissue cabinet. With 30 percent more space
in the cabinet than the reissue, the trebles
seemed revived and the amp now had an
“airy” bottom-end. Comparative testing
with another stock Bluesbreaker reissue
verified the tonal improvements.
An interesting side note; in 1997,
Marshall produced a limited edition white
Bluesbreaker called the “Limited Edition
1997.” It was basically was the same
amplifier as the 1989 reissue, with one
important difference: the limited edition’s
repair person or skilled electrician perform
these tasks.
This phase involves swapping out the reissue
transformer, changing the 6L6 vacuum tubes
to KT66s, and replacing the filter capacitors.
The Transformer and Tubes
There are now some good vintage transformer manufacturers around, so one has
a choice in the matter. Since the original
Model 1962 used a Radiospares (RS Deluxe)
transformer, the objective here is to get
one like it. When I did my conversion, I purchased a Mercury Magnetics model O45RS-
L-8-M ( mercurymagnetics.com).
When it comes to power tubes, the only one
to use here is the revered KT66. There are
however, a few brand options available. One
could either purchase a matched set (two
are needed) of original GECs, or purchase a
pair from companies offering reissue KT66s.
The European and American tubes manufactured in the 1950s and 60s (new old stock)
