Blackface amps vs.
There is a lot of talk about modding
a silverface amp to blackface specs. Click
on the link to read more about it.
Fender made some "blackface" amps in
the early 80's that aren't really "blackface". These amps have master volumes
and sometimes channel switching which were NEVER features of vintage blackface
amps. If you have one of these, then they are either the late silverface
models with different cosmetics, or the hotrodded ones designed by Paul
Rivera (ie the 1x12 or 2x10 Concert, Super Champ, etc). There are also
some solid state amps that look "blackface". Beware of someone trying to
sell these to you as a "blackface" amp. They are decent amps, but not really
what is generally known as "blackface"!
My dates throughout will be a little vague,
but are a good starting point. Fender started producing blackface AA763
amps in August '63 I believe. AA763 was the first circuit that Fender used
and didn't last long. Soon after the circuit became the famous one, the
AB763. The AB763 had some minor but important updates. Amps such as the
Pro Reverb (AA or AB165, came out in late '64) and the Vibrolux Reverb
(AA864, came out in late '64) are identical to AB763 circuits and are still
considered the "good" ones. Blackface amps had a brighter, tighter, and
more "scooped" sound than the brown amps that came before. Leo was trying
to go for a cleaner and more "hi fi" sound. Hi fi may be misleading, because
Leo still had his ear to the ground and did what musicians wanted for sound
it seemed. Leo sold Fender in 1964, and the new company, Fender Musical
Instruments (owned by CBS) took over on January 1, 1965. Amps made before
this time all had "Fender Electric Instrument Co." (FEI) on the front panel,
or some variation of that. Then the "Fender Musical Instruments" (FMI)
panels started to get phased in. FEI panels can still be found as late
as mid '65. But
if your amp says FMI, it is a '65 or newer for sure,
and was made by CBS. Quality in the blackface amps stayed consistent
and good up till the end as far as I have seen. Silverface amps started
coming out in mid '67 and lasted until about '81 when they switched back
to "blackface" cosmetics for a very short period of time (these amps don't
look or sound like the old ones). Silverface amps outlasted blackface amps
by far, they were in production for more than twice the time blackface
amps were. I also have a notion that silverface amps were produced in much
greater quantities per year than blackface up to the last few years
of production of silverface amps.
There were some changes that the amps went
through that were almost universally not well received. I'll outline some
of them here.
Speakers: Blackface amps generally
have better speakers than silverface. FMI blackface amps usually have a
better chance of having a Jensen speaker(s) in them than the FEI's in my
experience. Other speakers that came commonly in blackface amps were CTS's
(most commonly in Super Reverbs, but my '63 Pro has one) and Oxfords, which
came in just about everything else. But when the silverface years came
around, Oxfords, Utahs, and later Rolas were the stock stuff usually. Fender
offered JBL's as a factory upgrade. They are fairly rare in blackface amps.
I believe that a lot of the Vibroverbs from '64 came with them. I think
a few blackface Twin Reverbs came with them and maybe even a few Super
Reverbs. I've heard of one Vibrolux Reverb that came with them. Sometimes
you can find blackface and silverface amps with JBL's, but they are rare
comparatively. Super Reverbs with JBL's are a rare treat. I'm not sure
if I prefer their sound to Jensens (I had a SF SR with JBL's), but it's
a cool sound. Silverface Twins came with them much more commonly. Speakers
in silverface amps were pretty much all dismal sounding except for the
JBL's. Any decent speaker you can put in a silverface amp will almost certainly
sound better than what came stock. Blackface amps with Jensen speakers
are my favorite sounding for sure. My favorite blackface amp of all time
is a '64 Super Reverb that came stock with Jensen C10R's that belongs to
Lead dress: In the silverface years
by about mid '69 to '70, Fender went completely to plastic sheathed wire.
It kind of looks messy when compared to cloth covered wire. The way the
wires were laid out (lead dress) was certainly messier than the older amps.
When you start getting into the late '70's, it gets pretty ridiculous compared
to blackface. Does this affect tone? It could. Putting a blackface chassis
and a silverface chassis next to each other is striking. Blackface amps
were wired with far more care and precision.
Circuits: Almost immediately after
the amps went to silverface cosmetics, FMI started making changes to the
circuits. These changes were not welcome at all. Some amps got big resistors
on the cathodes. These amps were operating in cathode and fixed bias mode
at the same time. They did not sound as good as the earlier amps. This
configuration only lasted about 6 months to a year I think. Fender took
the cathode resistors out, but still modified the phase inverter, bias
supply (balance instead of level) and reverb circuit. They also went to
5U4GB rectifier tubes, which either sag more or sound mushy depending on
the way you hear it. I'm not a fan of 5U4GB's. Most amps had caps on the
grids of the power tubes. Usually a .002 or 1200pf going from pin 5 to
pin 8 on the tube socket (grid to cathode-ground). These were installed
to suppress oscillation at "higher" frequencies than what you need for
guitar. This turned out to be not true. These caps rob the amp of some
high end detail. One other change that I particularly don't like is the
change to a .01 coupling cap to the phase inverter. The started doing this
in the early '70's I believe. This makes the bass response flabby to my
ear. A note on AB763 and silverface amps: If your tube chart says AB763
but you have a silverface amp, don't automatically assume it's the blackface
circuit. There is a better chance than not that you have a silverface circuit
in your amp. There is no way to tell if you have a blackface circuit
by looking at the amp from the outside. The only way to tell is to open
it up. However, if you own a silverface amp produced in '67 or early '68,
then the chance of it being AB763 is very good. I still recommend opening
the amp to find out though. I have heard of a way to tell cosmetically
if you have an AB763 amp, but I've never witnessed this and I won't try
to explain it until I see it with my own eyes.
Component quality: The general
quality of components used in silverface amps seemed to go down. The coupling
caps on the circuit board went from blue Mallorys to the chocolate drop
looking ones. These caps are generally talked about with great disdain
by techs and tone mongers. I've recently done an A/B test with the chocolate
drop caps compared to Sprague Orange Drops. The Spragues are noticeably
nicer. The only way I can describe the difference is that the amp seemed
"numb" with the chocolate drops. Some blackface amps, such as the Champ,
did use these brown caps sometimes. The rectifier tube went from a GZ34
to a 5U4GB. The 5U4 is a cheaper to produce tube than the GZ34 and it sags
more. Some people like this. This is arguable, but transformer quality
seemed to suffer as well. Cabinets went to particle board instead of pine
(more on that below). I think the general image of the amps just went down
in the silverface years. Everything just got progressively a little worse.
Cabinets: Sometime in the mid '70's,
Fender went to particle board construction throughout the amp. The amps
were solid pine with a particle board baffle up to that point. There is
a lot of debate on what actually sounds better, but I'd have to believe
that there is something to the pine cabinets. Curiously, Fender did use
particle board for the speaker baffle from the beginning of blackface production.
All brown amps that I know of do have plywood baffles, and then they suddenly
switch to particle board in mid '63 for the blackface amps. It's curious
that the baffle was the only place that they used the particle board. Maybe
Leo tried a particle board cabinet but didn't like the sound? Fender went
to a velcroed on baffle that held the grill cloth sometime in the mid '70's.
This is actually a convenient way to do it, it makes it much easier to
change speakers. But, these grill cloth baffles have some rattling problems
in my experience.
Master volume/pull boost: Fender
put master volumes on amps starting in 1972. I believe the 100 watt amps
all got them this year. Then most of the rest of them got them by about
1975. The master volume is right before the phase inverter just like a
Marshall. The pull boost feature came in about 1975 as well. This feature
can be activated by pulling out on the master volume control. What it did
was take some of the signal routed to the reverb circuit and route it around
a series resistor to get more gain. The master volume and pull boost features
are pretty useless in reality.
It seems Fender was trying to make a
nod to the popularity of Marshalls, but these features they added did absolutely
nothing to make the amp sound like a Marshall, or even sound good!
I haven't met anyone that uses the master volume and pull boost on a Fender
to get distortion. Trying to get distortion this way sounds far worse than
any pedal, $10 pawnshop ones included. The good news is that these features
are easily defeated. The pull boost does nothing to the circuit when it's
not engaged. The master volume can be easily bypassed by adding a jumper
from the junction where it originates to the coupling cap to the phase
inverter and then removing the wires that go to the pot. The effect of
the master volume is like adding a 1 meg resistor to ground. Even when
you have the master volume all the way up, some of the signal is being
bled off to ground.
The late '70's early '80's changes:
Amps larger than the Vibrolux Reverb built from about '77 to about '81
when the last of the "silverface" type amps existed had some major changes
done to them. They got higher voltage and current power transformers, and
ultralinear output sections. The power supply is also beefed up. These
amps have no hope of ever sounding like their vintage brothers. The dead
giveaway on these is the wattage printed under the speaker jacks. If it
says 70 or 135 watts, then it's the later model. Amps that had the rectifier
tube such as the Super Reverb and Pro Reverb no longer had it at this time.
These amps are generally not very good sounding. I do like the 135 watt
models for certain things though. For instance, since they are very clean
sounding they do work good for country or steel playing. With some changes
to the circuit, they can sound good, but still not like the old ones. Amps
that are the 70 or 135 watt variety should be worth less, and is a bargaining
point if you really want one. If you play bass, then the Bassman 135 is
a bit of a better bass amp than the 100, but still grossly underpowered
if you want to fill a big room. For a more intimate gig, it may be just
the thing (after it's been gone over by a tech of course).
So, the final question: Are silverface
amps all that bad? No. They are Fenders, so they are still better than
most amps! I tend to hold them against some unfair competition, namely
the blackface amps because blackface is my favorite of all time. Silverface
amps were made by a company that didn't care as much about tone or quality,
so they are going to suffer for sure. Still, as long as you don't have
one of the later ultra linear models (70 or 135 watt), then your silverface
amp can be made to sound very good, about 95% of the way to blackface.
I'll go on record and say that the best Twin Reverb I ever heard was a
'70 that I converted to blackface. I had my own Quad Reverb, a '64 Twin
Reverb (blackface), '66 Twin Reverb (blackface) and the '70 (silverface)
all side by side plugged into my Quad speakers (4 16ohm Jensen C12N's).
The '70 was the best. Amazing, but true. Which is not to say that I think
the '70 Twin Reverb is the best of them, but that particular '70 Twin Reverb
was to my ears.
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