When did you get involved with the
design of the 5150 III?
Pretty much at the beginning. When
we were first approached by Ed to do
this, Fender had taken a tack of trying
to provide existing platforms that we
felt were close to what he was looking
for. It wasn’t necessarily the path he
wanted to take. He’s always chasing
his tone. It’s very evolutionary, and he
always wants to go to the next step.
After discussing with him and realizing
what he was looking for, we had
some good starting points.
It’s a three-channel amplifier. For
a lot of his career he has been a
one-channel guy. Did you start with
a core tone, and then branch off to
cleaner and dirtier from that?
We did start off with some basic
tones that were akin to what he had
been doing in the past. But he gave
us a lot of freedom on the first channel.
He said, “You guys know what
you do as far as a clean tone—you guys come up with it.” But we
also knew he wasn’t looking for something super sparkly clean—
which is why Channel 1 does clean up very nicely, but it can get
down and dirty if you adjust it properly. We knew that Channel 2
had to be a killer crunch tone—something that was very articulate,
but had the girth underneath to really grab you. Channel 3 has been
the channel that evolved the most. Ed is somebody who looks for
a lot of sustain, and that’s something he’s still driving us to perfect.
So Channel 3 has become more chaotic and over-the-top from
where we started on the early production models.
Channel 1 has a surprising amount of sustain for a clean channel.
It’s how we designed the gain stages to interact. There’s a heck
of a lot more gain that can be had in that channel—especially on
the pre side of the gain control. You can roll that off, and get it nice
and clean, but if you really want to dig into it, you can get that sustain
characteristic—though not the buzz-saw type of tone you can
get with Channel 2. He was pretty happy with Channel 1 from the
beginning, and it was like, “Yep—move on to the next channel.”
One thing that always comes up in the discussion of this amp’s
design are the transformers.
The transformers are a huge key to the amp. Ed was very specific
about certain companies to use, and certain materials to use.
This is still something we talk about as we evolve into the next generations of amplifiers. With the power transformer,
it was a matter of getting the design
right in terms of what the voltages were going
to be, and how it was going to react when you
dug into it. On the surface, it’s a design you
can find in a lot of tube amps. It’s fairly linear
supply. One of the keys, though, is we didn’t
put a choke in there. Instead, we use a highwattage
resistor, which also changes the character.
It allows the power supply to breathe, it
allows it to sag, and it also allows it to come
back up in a more natural way. It doesn’t make
the amp as stiff.
There’s a lot of iron in the output transformer,
but Ed felt really strongly about that.
For the type of tones he’s getting, a lot of it is
defined in the preamp, of course, but there’s a
particular feel to the amplifier that the power
amp provides, and we wanted it to sustain,
but also compress nicely. It also keeps the harmonic
content you developed in the preamp,
and doesn’t degrade it in any way. Those were
the basic tenets to move forward on.
What about the tube complement? Was it
always 12AX7s in the front, and 6L6s in the
back, or did you experiment with different
They were always 6L6s. EL34s were discussed
at one time, but we started out with the
6L6s, and they felt good to him, so there was
no reason to stray. The preamp side is completely 12AX7. What
did change from the production model and the current amps were
the different flavors and different manufacturers of tubes. Some
of it was due to getting a higher quality tube. We always looked at
this amp like it was a Ferrari—a high-performance machine. So we
experimented to see what were the best quality tubes we could get
in there—what would make this amp perform at a different level
than any other amp.
As this design was coming together, you guys performed a “crash
test,” where he turned everything up all the way, put the guitar
in front of it, and let it feed back for a month. Is this a recommended
thing from a design standpoint?
It was definitely not something we would normally do. Ed felt
very strongly that this was a way to exercise the amp and tubes to
see if everything would hang on and survive. He didn’t even know
me yet, and he came up to me and said, “Hey, make sure that nobody
messes with that sound test. I’m performing this crash test that’s
really going to prove the reliability of the amp.”
So far, we’ve been talking about the 100-watt model. What can
you tell us about the new 50-watt version?
It’s a three-channel amp with a clean-but-kind-of-dirty Channel
1, a nice crunchy Channel 2, and an over-the-top lead channel
on Channel 3.
The first two channels
share EQ on the
50-watt. What are the
challenges to making
We did have to change
some of the voicings, but
we tried to hold true to
the voicings we had done
on the 100-watt. Channel
3 was translated straight
from the 100-watt to the
50-watt, because that channel
is very important for
Ed, so we wanted to maintain
that. The 50-watt has
the same tube complement—
though two 6L6s
instead of four—and it’s
completely 12AX7 across
the preamp, effects loop,
and phase inverter.
Is the footswitch the
same design for the 50-
watt as the 100?
No. We did change the
circuit topology where
we felt we could improve
upon the design, but still
keep the same channel
Ed loves on the 100-watt.
The 100-watt uses a 7-pin
DIN cable, but our view
was, “Wouldn’t it be better
to use a regular two-conductor
1/4" cable that you
can get anywhere?” So
that’s what we did. Based
on feedback from other
artists who were using
the 100-watt model, we
also added a MIDI In to
switching via external controllers,
such as a Voodoo
Lab Ground Control or a
Boss multieffects pedal.