Meet the Ripper
Identification
The Choke
Wiring
Finishing Up
Meet the Ripper
I don't play bass [...yet!], but for a while I had been thinking of picking up a bass just for shits and giggles, so when
an anonymous copy of a Gibson Ripper bass showed up on eBay, I was interested. Interested not only because
it would allow me to try playing bass, but also because Rippers were significantly different from the usual Fender
J and P basses in that their wiring included in and out of phase and series/parallel switching as well as a choke
to modify the tone, all controlled by a rotary varitone switch. The bass looked like a rather faithful copy of a
Gibson Ripper except that the controls included four pots (Rippers had three) and two small toggle switches
(Rippers had none) presumably instead of a rotary switch. It also had a broken tortoiseshell pickguard,
a pot with the shaft snapped off, and was missing three knobs, and so I envisioned replacing the
pickguard with a proper black one and replacing the controls and wiring with those found in
real Rippers. All in all I thought it would be a fun project, and so I bought it.
Here is the Ripper copy as it arrived; it looks pretty good from a distance. Before taking it apart, I plugged
it in and tested the controls. One pot (the only one that had a knob on it) controlled the volume, and the
other three pots and the switches seemed to have no effect whatsoever on the volume or tone produced.
The bass also buzzed like crazy, not electrical hum type buzz, but vibrating parts type buzz.
This is a close-up of the headstock. There is no name at the top and no evidence that I can see that there was
one that was painted over, but I will investigate more later. The truss rod cover with its three screws sets the
bass apart from a real Ripper, which would have only two screws, and the cover faintly says "CUSTOM"
where a real Ripper would say "THE RIPPER". In addition, the nut is missing and has been replaced
with a block of wood crudely notched with a knife of some sort.
The body has a Ripper-correct three-point bridge, but all four saddles were missing and had been replaced with steel cylinders and wooden
dowels, none of which could be fixed in any particular position that would permit accurate adjustment of intonation. Adjacent to the bridge,
there are holes and discoloration from a missing bridge cover. The pickguard has holes in all the Ripper-correct places, but the jack was
moved and extra holes drilled for a pot and two switches. Although it isn't visible in this photo there is a light spray of sparkling gold
paint over the lower part of the body from the neck to the broken end of the pickguard. The spray paint does not extend under the
pickguard and so it would seem that at some point someone painted part of the previous pickguard gold and oversprayed onto
the body. The neck is bolted on where a real Ripper would have a set neck, and the neck plate says only "Made in Japan".
I removed the pickguard to examine the wiring, and was pleased to discover that the pickups are DiMarzios.
Note, however, that they are not Gibson-style humbuckers in that they have four pole pieces for each coil
and the coils are oriented vertically around each set of four pole pieces rather than horizontally on either
side of a single set of pole pieces. Unfortunately, when I put a VOM to the leads of the pickup coils, one
coil in one of the pickups was dead, and so I will either have to find another pickup or rewind the dead
coil. Given that I was already planning to wind a choke, I think I'll try rewinding the dead coil. If it
works, the DiMarzio pickups should be great, and they are a whole lot cheaper than buying a
set of Ripper-correct replacement pickups from Seymour Duncan for $199 each.
Here is the wiring. Neither of the toggle switches was connected, but what is really amazing is that the pickups do not
seem to be correctly wired. In DiMarzio humbuckers the red and black wires are from the north coil and the green
and white wires are from the south coil. Thus to wire up the pickups as humbuckers the black and white wires
should be connected to one another, the red should go to hot, and the green should go to ground. The arrows
in the picture above point to the green and white wires from the south coil that are not connected to anything.
Instead the black and red wires are connected to the pots and so only the north coils were connected to the
wiring. The cool thing is that if I want to I will be able to split the coils with a push-pull pot in addition to
setting up in and out of phase and serial/parallel switching with the rotary switch.
Identification
Careful examination has shown that the bass was a very faithful copy of a Gibson Ripper. It has the open book headstock,
the neck volute, the body shape of a 1975 or later Ripper, the body made of two slabs of alder? meeting at the mid-line in
the front and backed by another three pieces of alder?, the three-point bridge, the through body string routing, and seems
to have originally had body mounted pickups. In fact the only things that are not Ripper-correct are the bolt-on neck, the
truss rod cover, and the pickguard and electronics, though I doubt that they were original.
 
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There is little information available to identify the maker. Repeated examination of the headstock has convinced me that the black paint is original,
there are no traces of a name or badge below the paint, and there are no traces of a name or badge that might have been on top of the paint. There
are no marks whatsoever in the neck pocket. The neck plate (upper left) says "Made in Japan". The maple neck is made of three pieces with the
middle piece rotated relative to the other two, which suggests that it might have been made by Matsumoku. Other than that, the two pieces of
information that might be useful for identification are the truss rod cover (lower left) that reads "CUSTOM", and the pattern of routings in the
body (middle). Note the two small holes in the pickup routs that were presumably for mounting Ripper-style pickups, whereas the deep
holes on either end of the pickup routs (right) are not original and were presumably drilled by whomever installed the DiMarzios.
If anyone can provide information as to the make, please let me know at cbennett@fhsu.edu.
Here are photos of a Shaftesbury Ripper copy recently offered on eBay UK. It looks pretty close to my copy
and shares its tuners, 3 piece neck, tortoiseshell pickguard, and seems to have similar control and pickup
routing, but differs in that the 'CUSTOM' lettered on the truss rod cover is larger and bolder, the neck is
set with the strap button on the body rather than the base of the neck, and the strings are not routed
through the body. It also lacks pickguard shielding, and so a Ripper-correct choke is visible
between the volume and tone pots (third photo from left). So, this one is close but no cigar.
Rippers used a choke to cut midrange frequencies. Here is the wiring diagram
showing the choke (Part #70-442) and its cap controlled by a 250K pot.
The Ripper's choke was the same one that was found in Series 2 EB3's, but the diagrams of the
choke differ: the Ripper's diagram (left) shows a single coil whereas the EB3's diagram (right)
shows two coils with the bottom wires of the coils connected. Based on comparisons with
photos of the choke (below) and comments I saw on a discussion group, the illustration
on the EB3 schematic is more accurate, and the choke consisted of two identical coils
connected to one another by their white wires, perhaps to reduce hum.
Here is a photo of a 1978 Ripper's wiring [stolen from www.gibsonbass.com] showing the choke.
Here is a closeup of the choke with its bracket (left), and of the end of the pickup from the same photo (right). Note that the color
of the windings on the choke is identical to that of the pickup. So the choke was presumably wound with ~42 gauge pickup wire.
Here is a photo of the internals of of an EB4 pickup [also stolen from www.gibsonbass.com]. Note the similarity of the spools
and their black and white wires to the spools and wiring of the Ripper choke. My guess is that they are the same spools, the
only difference being that those of the pickup have a magnetic core and are wound full whereas the choke's coils have
a non-magnetized steel core and are not wound as full.
Based on the close-up photo above plus the assumption that the internal diameter of the jack tube is 0.25" and the diameter of the pots
is 0.90", I came up with the above diagram and the following measurements for the choke. The bolt (light gray) has a diameter of 3/16
inch and a length (A) of 1.75" and a matching nut and washer (dark gray). The choke is bolted to a mounting bracket (blue). There are
two spools (yellow) that have a length (B) of 0.682" and a diameter (E) of 0.597". The width (C) of the windings (orange) is 0.588",
and so the thickness of the sides of the spool (D) is 0.047". The outer diameter of the windings (F) is 0.48", and assuming
that the thickness of the core of the spool (G) is the same as the ends, the thickness of the windings (H) is 0.1"; however
that assumption may be unwarranted and the windings may be up to ~0.14" thick.
Homemade polyethylene spools. The width for the windings is 0.64", 9% wider than the
originals because of materials available when I was making the spools, and the outer
diameter of the core is 0.31", 10% greater than the diameter of the original based
on the assumption of a 0.047" wall thickness.
To wind the choke coils I set up an electric drill on a makeshift stand, put a bolt through the spool, chucked it in the
drill, and spun it while feeding the wire under a slight tension and moving the feed side to side slowly to produce a
tight even coil. I found that after a slow start I could lock the drill on at maximum speed (1200 rpm) for about
six minutes (thus ~7200 turns) to fully wind a coil. Note that 42 ga. wire is incredibly fine and practically
invisible to mere mortal eyes. At right is a wound coil before taping.
The four coils had resistances ranging from 1.8 to 1.95 k ohms. Two coils were placed on a plain steel bolt,
the top wires of coils were connected and taped down, and the bottom wires were left free to connect to
the pickguard wiring. At right are the finished chokes, which measure 2.5 and 2.7 H, respectively.
Kenneth Trantham of FHSU Physics tells me that the resonant frequency of a 2.5 H choke is
~320 Hz, which suggests I am not too far off in my interpretation of the choke's design,
though I must note that I do not know the inductance of a real Ripper choke.
Wiring
I obtained a 5 position 3 pole rotary switch from Mouser and modified the original Ripper schematic (above) to
allow switching to the neck pickup alone at Position 5. When I modified the schematic I included coil splitting
with a push-pull pot, but when actually wiring up the pickguard I decided not to include it. Maybe later.
The Triumphant Finish
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