Like the rest of the instrument, the hardware used on the Dan Armstrong acrylic guitars and basses was the best
available. Even by today's standards, some forty years later, the hardware and appointments can only be equalled
and not really much improved upon.
The instruments were trimmed with a wood grain patterned Formica® scratchplate that also matched the veneer used
on the headstock. According to Matt Umanov the prototype was trimmed with rosewood until Dan started using Formica.
When asked Matt replied "Best I can recall, Danny went out and bought some Formica, I suppose they found something
similar, if not identical, for production."
Earlier models (right) have Formica that is smooth to the touch, while on later models (left) the Formica has a
texture to it.
Dan explains "our supplier, Rohm & Haas, switched over and began to produce a more textured look on the wood
grained Formica veneer." It is unknown for certain when the change occured, but based on serial numbers, the best
guess is that it happened toward the end of 1969, thus making the earlier 69 models a little more desirable to
As seen at left, two latter day, textured style Formica scratchplates for Dan Armstrong instruments. The scratchplate
on the left depicts the design used for the bass, though earlier models (D2000A and earlier) had no hole drilled for a
selector switch as they did not yet employ one.
The scratchplate for the guitar can be seen on the right, and is virtually identical, with the only exception of it
curving around the backside of the pickup a tad. When placed one on top the other, everything else lines up, even the
small mounting screws that attach the scratchplates to the guitar body.
There is, however, a marked difference in the placement of the mounting holes between a smooth, glossy surface
scratchplate and a textured scratchplate. The textured scratchplates were wider by a small margin. As a result, and
as can be seen at left, installing a textured type scratchplate onto an older guitar body that originally had a smooth,
glossy scratchplate quickly reveals that the mounting holes on the guitar body do not line up. Seen here, the textured
scratchplate mounting holes lie a fraction of an inch outside the original mounting holes. It's unknown for certain
why this change occured, but it is not recommened to alter the body of the guitar in this fashion. Although it cannot
be seen from the front side it will neverless, devalue the instrument.
As seen at left, the mounting screws used to secure the scratchplate to the acrylic body are phillips headed, chrome
plated screws that are self tapping and feature tapered heads in order for the screws to fit virtually flush with the
scratchplate surroundings. These same screws were used to mount the truss rod cover to the headstock.
The wood grained Formica scratchplate is adorned with the words Dan Armstrong · Ampeg
etched into it with white lettering.
Over the years players have sometimes had problems as they sometimes tend to step on their patch cord which in turn
pulled on the plug that went into the jack on the scratchplate. Since the force being applied was more downward
and not outward, the jack did not unplug, instead it cracked the scratchplate in and around the jack.
In todays world of wireless connections patch cords are almost non-existent but time was when using a patch cord was
the only way. Many players felt that the scratchplate material on the Dan Armstrong instruments were just too brittle
as a result.
In all fairness, it's worth mentioning that many Les Paul® jack plates are broken each year as well, and usually
replaced with metal ones. In the past, and as can be seen above left, guitar players would often times install a large
washer under the input jack's nut to solve this problem, though for cosmetic reasons, it is suggested to put
the washer on the underside of the Formica. Alternatively, one can always get a replacement pickguard from places like
The volume & tone potentiometers, as well as a 3-way selector type switch and input jack are all mounted, and wired in
underneath the scratchplate. Being an experienced guitar repairman, Dan made it so that his instruments would be easy
to service. By simply removing the scratchplate screws, one can slide the scratchplate out from underneath the strings,
flip it over, and begin repairs.
As fate would have it, Dan originally had no plans for a selector switch in his guitars. Bill Richardson goes on to
say "Dan said that after the prototype was made and shown to Ampeg they simply said 'nobody will buy a guitar
without a switch' - to which Dan replied...Guys, it's only a one pickup guitar with a single-coil pickup."
But Ampeg was adamant, and Bill continues stating "needless to say he was told to put a toggle switch in the
guitar ...and eventually the bass too. The bass one makes sense to me but the guitar one is a bit needless. If ya
think about how cool, funtional and downright modern the rest of his pickups, pot values and tone cap choice was
design wise in 1969, a switch to turn the tone to zero kinda reaked of afterthought to me. Basically, Ampeg got their
way and wrote about it in their marketing blurb."
Since Dan was forced to install a switch he figured it may as well do something, and put his best foot forward in
wiring it so that he could make the most out of a one pickup instrument. Even then, as early as 1970 Dan made
alterations to the wiring which made the switch on these instruments perform better, or at least differently then
before. Many articles covering these instruments since have greatly emphasized the fact that the earliest model
Dan Armstrongs were wired somewhat differently than the later models causing a wave of excitement and, unfortunately,
for many, a great deal of confusion.
It all officially began on March 8, 1971 when Ampeg released Product Bulletin #17 Procedures For Updating Armstrong
Guitars And Basses. This document, signed by Pete 'Buddy' Toscano and Roger Cox gave detailed instructions on
how one could bring older Dan Armstrong instruments up to date, stating "In an effort to improve the tonal response
from the Armstrong Instruments, several changes were made in their respective control assemblies."
We should all be aware of the significance of the above date, as some 6 months or so later saw the end of the original
production run of the Dan Armstrong instruments, and it's worth pointing out that the models produced in and around
this time were already updated with the changes that this document depicts. In a nutshell, the document describes in
detail, and in laymen's language, how one can change capacitors out with ones of different values, as well as relocate
a few wires in the control cavities of a Dan Armstrong guitar or bass.
The guitar was probably the easiest modification of all and applied to models with serial numbers below A2000D (which
would seem to suggest that the guitars were wired this newer way for some time already). In essence, one is to simply
remove the 500µµF and the .033µF capacitors and wire in a .01µF and a .02µF capacitor -
not just in their place, but in a different fashion. Lastly, a few wires get relocated as well as a few removed
altogether for a rerouting of the audio output signal and the update is complete. The end result is a 3-way selector
switch that would now only shift to change the tonal spectrum, leaving out any volume type boosting.
As seen above, a Dan Armstrong guitar scratchplate, complete with volume & tone potentiometers, 3-way selector switch,
input jack and capacitors. Notice the .022µF and the .01µF capacitor wired into the circuit depicting the
changes shown in Ampegs Product Bulletin #17 literature. This instrument, is wired as per that literature. However,
keen eyes may have already noticed the pot codes on the volume and tone potentiometers - 1377035 - which indicates the
35th week of 1970. The red paint markings on the solder joints are clearly visible, meaning they are untouched. All of
which would not only seem to suggest, but even prove, that although the Ampeg literature was dated March of 1971, that
the guitars models had been wired this way for some time already.
The original owners manual states that with the switch in the forward position (towards the headstock) defeats the
volume control, resulting in full volume which means that the volume control does not work except when it was turned
full off. The idea was to be helpful in allowing a preset rhythm or lead volume level. After the modification, the
switch in the forward position now offers the steepest reduction of high frequencies.
Also in the owners manual, it states that in the center position the tone and volume controls would function in their
normal way. After the modification, the switch in the center position bypasses the tone control completely, accentuating
high frequencies (suggesting that the older wiring scheme never really bypassed the tone control altogether).
Lastly, the manual states that with the switch in the back position (towards the rear of the guitar) will defeat the
tone control (notice how it said defeat the control - not to be confused with bypassing the control), resulting in a
full bass tone regardless of the tone control setting which would be useful if one wanted to get a front rhythm pickup
sound while at the flick of a switch be able to go to a bridge sounding pickup. After the modification, moving the
switch to the back, or rear position will yield a moderate reduction of highs.
photo courtesy of Jim Edwards
The bass guitar was slightly more involved, but not overly complicated. The first bass modification was for basses
below serial number D1000A. All that is required is to loosen the strings and remove the scratchplate, and
(if applicable) the chrome plated pickup plate that secures the pickup to the body as well. Lastly, one unscrews the
pickup from the body and once removed, to take notice a short lead wire protruding from the pickup and to simply
solder that wire to the nearest terminal lug on the pickup itself (this is usually the front & foremost, closest to
the neck lug as the pickup lies in its cavity as can be seen at left.
For those who didn't want to mess with such things, or for those just plain uncomfortable an alternative replacement
bass pickup was available with the short lead already wire soldered to the pickups terminal strip, as well as the
required capacitors to complete the job. The last step is to replace the .05µµF capacitor with a .1µF
capacitor. This modification will yield a more balanced response coming from the bass as earlier model basses were
notorious for having very bassy E & A strings, and trebly D & G strings.
The second bass modification was for basses with a serial number below D2000A and is a way to update the Dan Armstong
bass with a toggle switch. A drawing type template was included depicting where to drill a ½" hole in the
scratchplate for a double pole - single throw switch. Once this switch is mounted, wires get relocated and a .1µF
capacitor gets installed into the circuit and the .05µµF capacitor gets doubled.
The resulting switch functions are such that with the switch in position #1 forward (toward the neck) results in
the deepest possible tones from the instrument with bassy E & A strings - coupled with more trebly D & G strings
(or in other words, it will sound and behave just like the earliest models Dan Armstrong basses). With the switch in
position #2 back (towards the bridge) results in a balanced sound from the instrument (or in other words, the sound one
gets after one completes the first modification mentioned above). The switch, then, simply allows the player the choice
between the two, and when used in conjunction with the tone control, makes it handy by allowing ever greater control
over the sound of the bass.
The volume and tone potentiometers are made by CTS®
and for the guitar model, the volume pot has a value of 200K, while the tone knob is a 100K pot. The earliest guitar
models were equipped with a 500µµf & a .033µf capacitor while later models employed a larger green
capacitor that was made by Cornell Dubilier®
and is a .022 mfd 400vdc cap, while the disc cap is rated at .01 mfd and 600v. The 3-way selector switch was made by
Carling Technologies®. If one looks
closely the name 'Carling Und. Lab Inc.' is stamped on the bottom as is its 3A 125 VAC rating and is a Single Pole -
Double Throw switch.
The volume and tone potentiometers on the bass guitar are also made by CTS and both have a 200K value. The earlier
bass guitars were wired with a single .05µf capacitor while later models were wired with two .05µf
disc capacitors that have a 400 vdc rating while the third capacitor is a .01µf and has a 200
vdc rating. On the basses that employ a switch, those with a serial number of D2000A or higher feature a Carling
Technologies Double Pole - Single Throw switch. Both the guitar and bass models use a ¼"
Alternatively, to take a newer model Dan Armstrong guitar or bass, and wire it like an earlier model, all one needs to
do is reverse the wiring instructions given in The Ampeg March 8, 1971 Bulletin. This Bulletin, complete with
an early Dan Armstrong owners manual (which contains the wiring schematics of the 1969 model guitars and basses) are
available as a download at the
Unofficial Ampeg Page. It is
in the schematic section of that web site, and is a PDF type file.
Names and images are TMand © Dan Armstrong / Ampeg. All rights reserved.
All other names and images are TMand © of their respective owners. All rights reserved.