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Wollensak 5750 Vintage Reel to Reel Tape Recorder Restoration
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How this:
became this!
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.
<-- To Restoration Introduction | To Machine Cabinet -->
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.
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