True
restoration in the purest sense would be to replace all materials in this
Wollensak vintage tape recorder project with originals, or the closest available
facsimile. In this sense, my work with the Wollensak 5750 is more of a rebuild,
as I used currently available materials to get the machine into proper working
order. This page discusses the Wollensak reel to reel tape recorder speaker
wings, what they were, what they are now and how I did the rebuild.
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Machine Cabinet -->
How
this:
became
this!
The
Speaker Problem:
When
I received my vintage tape recorder from the seller at E-Bay, I was surprised
to find that the "wing" speakers for the Wollensak 5750 reel to reel tape
recorder were in pieces.
I
checked them carefully and found that the glue had given way on all the cabinet
joints. But the quality of the cabinet making was such that this was easily
repaired.
The
speakers have 45 degree mitered joints (as can be seen in the photo above,
look at the top right corner). To support the miter joint, they used a spline
which is exposed on the ends running the entire length of the joint (not
evident in the photo - see image.) Additionally, the cabinets have small
support blocks on the inside to strengthen the joints and the glue gave out
on these as well. However, they supported this construction with special
staples, and these were in tact, making a guide for the reconstruction -
to know which piece matched with which other piece.
The
speaker grill cloth was old, stained and rotting in places, so it had to
be replaced. (See top "before" photo). It was held to the speaker
grill boards with contact cement, and that had given way, making it easy
to remove.
Each
speaker cabinet contains an inset RCA jack for connection to the tape recorder
through an audio patch cord. The hinges are not directly wired, as they are
in some vintage tape recorders to make the need for an external connection
unnecessary - unless the speakers are to be placed at a distance from the
machine. With the Wollensak 5750 tape recorder, the RCA audio cables are
always required to power the speakers.
The
blocks holding the inset RCA jacks were also glued, and these gave out and
needed new glue. Again, special staples acted as a guide for placement.
The
Speaker Solution
My
success with the reconstruction of the speaker wings was due largely to modern
glue and the training I received in cabinetry when I was an apprentice pipe
organ builder where I learned wood joinery. I simply scraped the old
glue off the splines and blocks (which came off very easily) applied carpenter's
yellow glue (available at ACE Hardware stores), then
fit the pieces together using the staple holes as a guide
and clamped them up. Wollensak had been careful to align the grain of the
wooden parts so that even when glued, expansion and contraction would not
try to pull the joints apart. When the glue had set, the speaker cabinets
were whole again and solid.
The
speaker hinge pins (coated to look like bronze) were really dirty and "stuck".
I cleaned them with plain soap and water (to protect the coating) and then
applied silicone lubricant to make them slide properly. It was obvious from
examining the insides of the vintage tape recorder that it had been subjected
to some degree of air pollution, as all the metal parts had some amount of
pitting.
I
carefully removed the old grill cloth from the speaker grill boards and recovered
them with something a bit unique. Rather than search for matching cloth in
fabric stores (which could have taken a lot of time, if it was even possible
to find a match), I chose to replace the cloth with a very durable and practical
substitute - rubberized shelf lining material.
I
found it at ACE Hardware in the right color (taupe). The product is called
"Wonder Liner." It is a rubberized cloth that is very tear resistant
(it comes with a 10 year warranty!) I have used "Wonder Liner" in
my kitchen for 12 years with no deterioration at all, so I knew this was
a durable and lasting material -- and the rubber feel is very "modern".
The most important thing about speaker grill cloth is that it be of an open
enough weave to allow sound to pass through with little or no sonic defect.
The "weave" in Wonder Liner makes this quite possible. And it is
pleasant to use and reasonably priced. One 6 foot roll (at $3.99) did the
trick for all FOUR speaker grills - yes, there are four of them, not two.
More on that below...
Characteristics:
- Speaker
type - 6 inch GP (general purpose), permanent magnet
- Paper cone
1-way (no woofer-tweeter combination)
- Shallow depth
(2-1/4 inches)
- 8
ohms
- Unrated
Wattage (powered by 3 watt amplifier)
The Wollensak
5750 wing speakers are actually quite simple. Each enclosure (cabinet) contains
a shallow 6-inch paper cone general purpose speaker that was common at the
time of manufacture. These used small permanent magnets (cobalt and selenium
magnets would be in use today, but not then.) While the sound from these
speakers is a bit "hollow",
replacement with modern speakers is a challenge.
The amplifier
only puts out 3 watts of power. The only type of replacement speaker that
could fit in the narrow enclosure (2-1/4 inches interior depth) would be
a speaker made for a car door. While there are many shallow car door speakers
available, ALL are rated at 4 ohms, which does NOT match the Wollensak tape
recorder amplifier's rated 8 ohm output. It IS possible to hook up a 4 ohm
speaker to an 8 ohm amp, but it causes the amp to "run hot" and
is not a safe procedure, especially in a Wollensak vintage tape recorder,
which has a reputation for running a hot amp. Notice the large amp cooling
opening in the back of the machine cabinet in the picture below. In addition,
modern car speakers are rated for high power audio amps, up to 200 watts
with minimum start up wattage ratings usually at 3 to 5 watts.
So I kept
the general purpose speakers, as they were undamaged and fully
functional. If I want a richer sound, I can simply plug the Wollensak's pre-amp
output jacks into my stereo system. I have tried this and the sound is
excellent, rich, and full - certainly matching that of a phonograph and even
my cassette deck - though not quite as impressive as a CD. One really nice
thing about the Wollensak 5750 tape recorder is the stereo imaging! It has
great separation and wonderful dimensional sound which comes though especially
well on the wing speakers. I was very impressed when I first heard it.
Each
speaker is electronically
connected to the main cabinet by an RCA male-male audio patch cord. Each
speaker has a female RCA jack deeply inset into the lower side, in such a
way that the speaker cabinet can be fully opened while hinged to the main
cabinet, as long as the audio patch cord is thin enough. This is managed
by little blocks inside the speaker cabinets that hold the female RCA jacks.
The back of
the reel to reel tape recorder has female RCA jacks fed by the amplifier.
At the right is a picture taken after my success at refinishing the the
wooden cabinets. Note the large brass escutcheon around the opening on the
speaker cabinet for the RCA audio patch cord. This is necessary so one can
grab the cable and disconnect it. A high end audio cable such as
"monster cable" could not be effectively used with this machine,
but then, given the audio specifications, such cable would be pointless and
do nothing to improve sound quality.
Each
speaker mounts to the main cabinet with a pair of "slip hinges".
Note in the photo how the hinges are stained a coppery-bronze color. The
main cabinet has "male" hinges with upright pins and a "boss" to
prevent removal of the female part of the hinge except when
the hinge is almost fully open - a slot cut in the female hinge allows this
release. Each
speaker cabinet has "mating" female
hinges which slide down onto the "male" hinge pins located on the
main cabinet.
View the little
animated gif to the right to understand how this works. To remove a
speaker wing from the main cabinet, one swings it almost fully open and lifts
the speaker wing up off the cabinet hinge pins. However, removing the speakers
from the main cabinet isn't necessary for good stereo separation. The width
of the main cabinet places the speakers at a fine distance for impressive
stereo imaging.
The
speaker cabinets are designed so that the Wollensak tape recorder can actually
play while the speakers are "closed". This is because there are
front and back open speaker grills (made of particle board, not real wood.)
Sound is able
to emerge from the front and back of the speaker cabinet, a design that is
quite different from a "tuned"
port enclosure which has a sealed back. The picture at the right shows how
space is allowed for the tape recorder mechanism
to operate with the speakers closed. This picture shows the left
speaker closed. Note also the two oval head screws which allow the speaker
grills to be removed from the speaker cabinet frame. The opposite sides of
these grills fit into grooves cut in the cabinet frame itself.
Also seen
here is the locking catch for the large copper speaker closure "lift
latch"
(see top photo to view this latch). Originally, these were attached to the
speaker cabinets with rivets. They had to be removed to change the grill
cloth, which meant destroying the rivets. I replaced them with small wood
screws.
From
an audio point of view, this "play when closed" option actually
changes the effect of playback from stereo to mono, since when closed, the
speakers are so close together, stereo separation cannot be heard. The sound
is also muffled somewhat since it is coming from the back of the speaker
cones instead of being projected from the front (it actually projects sound
into the machine itself, but apparently does not interfere with operation.)
It is an interesting effect.
When recording
from a microphone, or listening to the machine with headphones it is not
possible to fully close the left speaker cabinet because the microphones
and headphones plug into 1/4-inch phone jacks located on the front of the
main cabinet, blocking the speaker closure.
Changes/Updates
The speaker
cabinets were heavily scratched on top, had "dings" and nicks in
them and the finish was an extremely dark walnut. They were finished on ALL
sides, both inside and out, and from what I could see, the original finish
was meant to hide most of the wood grain, making them look almost painted.
The same was true of the machine cabinet.
With the speakers
and grills removed, leaving only the frame, I stripped all the old finish
off, exposing the raw wood. I discovered that not only was the cabinet construction
high quality (with mitered corners supported by splines, blocks, and staples)
but the wood itself was quite nice, a type of Tropical American or Philippine
Mahogany, almost as blonde as maple or pine, yet with a more pronounced grain
speckle and swirl pattern. It is a semi-hardwood with a pleasing light appearance.
The Wollensak
5750 is a vintage tape recorder and so had a vintage look. I knew that at
the time the Wollensak 5750 was made, the "walnut
look" was
popular (later replaced by the "teak look".)
After stripping
the all the cabinet woodwork (speakers and main cabinet) down to the raw
native wood, I gave it two coats of a latex American Walnut stain (Minwax)
followed by four coats of semi-gloss latex polyurethane (Minwax) and two
coats of Butcher's furniture wax. My success with this approach can be seen
in the photos.
The new finish allows
the natural beauty of the wood grain to show and "play" in
the light (sometimes called the "wood glow") without masking. You
can see this grain and glow in the photos on this page. While this finish
is not exactly true to the original vintage tape recorder as it must have
looked in 1967, it looks better to me, and is consistent with the walnut
color choice that was popular at the time.
Since the
vintage tape recorder ads for the Wollensak 5000 series positioned it as
fine furniture, and nothing says fine furniture like beautiful wood grain,
I feel my choice honors the goals of the original design. Below is an image
of the refinished full cabinet as seen from the above left (your right).
Move the cursor
over the image to see a view from the opposite side. Notice the red
audio speaker plug and cable for the right speaker. The small square piece
on the speaker grill front (lower right corner) is a plastic gold and silver
3M logo.
I also noticed
that there were no protective feet for the speaker cabinets, so that if they
were removed from the machine cabinet and placed on a table or shelf, they
would have no protection for the finish on the bottom.
I applied
four self-stick clear half round vinyl pads, 3/8-inch diameter, from ACE
Hardware, to the bottom of each speaker cabinet. These allow the speakers
to swing open
(the original rubber feet on the machine cabinet are larger) yet will protect
the bottom finish if the speakers are removed and placed on any other surface.
If you look closely at the large top image, you can just barely make out
the little half-round pads on the bottom of the speaker cabinets.
These pads
have an added benefit, that of support for the machine when closed. The speaker
cabinets are moderately heavy, and the Wollensak 5750 reel to reel tape recorder
when closed can easily be knocked and tip forward because of the change in
the center of gravity. The little pads prevent the machine from tipping very
far (no more than 1/4-inch) and damaging the finish on the bottom of the
speaker cabinets. In fact, if I place the Wollensak 5750 on a flat table
top and swing the speaker cabinets open 90 degrees, the machine does start
to tip over. The little vinyl pads under the speaker cabinets prevent the
tipping from being very pronounced, while the locking "boss" on
the hinges prevent the speaker cabinets from sliding up on the machine cabinet
hinge pins. The little vinyl pads, while a small and seemingly insignificant
change, have a very beneficial effect for the tape recorder.
These changes
make the Wollensak 5750 vintage tape recorder project less of a restoration
in the purist sense, as a purist would preserve the design problems for the
sake of absolute historical accuracy. This is why I call the project a restoration/rebuild.
Now it is
time to examine the main cabinet and the function of the Wollensak 5750,
it's controls, it's inputs and outputs and see what changes I made in the
restoration/rebuild.
<--
To Restoration Introduction | To
Machine Cabinet -->
Please
note that ClydeSight Productions DOES NOT rebuild or sell vintage
reel to reel tape recorders, nor can we help anyone involved in such a project.
The tape recorders shown in these pages are part of a personal collection
and are not for sale. We Do Not recommend
that unqualified or inexperienced persons attempt to restore vintage audio
equipment.
Visit
www.clydesight.com Master Site
Web site copyright ©ClydeSight
Productions - 2007
