Nuts and Bolts

# This is the original web page

There is practically no information or documentation on the Kent 700- and 800-series guitars (or any Kents, for that matter). I have seen a few questions online regarding the electrical values of some parts because they are so old that the printing on them is no longer legible, or the wiring may have been modified.

I hope to get some sort of documentation up here regarding the functions of the switches. I'm not very good at figuring out how a guitar is wired by looking, so if anybody has sketched the wiring out on any of these guitars, I'd really appreciate getting a copy. I am guessing that the wiring will be pretty similar on all of them. Since I hope to get other models in these two series', I'll be able to describe and compare them.

Stay tuned...

Common Details - 800 Series

It appears that all of the 800-series guitars are made pretty much the same, only differing in the features that make each model unique within the series. However, there can still be small differences. For instance, I have seen photos of Kent 820s with three different vibrato tailpieces and one non-vibrato tailpiece. In fact, I would say that the 820s have the most variants.

Body Layout

body On the hollow body guitars all controls are placed below the strings, as you look down from the playing position. At the end of the guitar body is a the tailpiece which may be fixed or designed as a vibrato. The vibrato seems to be far more common except on the basses and probably the 12-strings. Like most vibratos, if you use them, they probably won't pull the strings back to exact pitch. Guitarists all have their own way of dealing with that.

Close to the tilted neck-position pickup is a black slide switch and a way to select the pickups you want to use. The bass does not have the slide-switch. The three-position lever switch appears on the two-pickup models, which are most common, and allows the player to select either the neck pickup, the bridge pickup, or both together.

The slide switch is a rhythm/lead selector. There is a .002μfd ceramic disk capacitor that is supposed to bleed some of the higher frequencies to ground when the rhythm position is selected. I prefer to call it a "Hi/Lo switch".

This type of slide switch is extremely common on Japanese electric guitars of that era, as is the faux tortise shell material used for pickguards and control covers.

Most, all the 820s I've seen, anyway, of the tortise shell panels consist of a thin veneer, perhaps a photo, glued to a metal plate. So pickguards and control covers are very unlikely to break and the metal covers provide a little bit of RF shielding.

There are tone and volume knobs for each pickup. On the 800-series violin-shaped guitars; and all the 700s; the switches and controls are mounted to the control covers. One can simply remove the small wood screws along the edges of the cover and lift it up to get access to the electronics of the guitar. On the rest of the 800-series guitars the knobs are attached to pots that are mounted directly to the guitar body. To replace the pots and/or the capacitors attached to them will require the removal of the 10-mm nut holding them to the guitar body and pushing the shaft down through the mounting hole. The F-holes and the openings where the pickups are mounted are probably large enough to allow one to slip a few fingers into the body and pull the pots clear so that they can be worked on. Small hands will help. Otherwise standard hollowbody guitar repair techniques will be required, such as tying a string to a pot shaft before pushing it through so you can pull it back up when finished.

The solid-body 700-series guitars have a single plate covering about two-thirds of the guitar top with all controls mounted to it. It should be easy to put shielding in the control cavities of the 700s if they aren't already shielded. These guitars have a pair of rocker-switches above the pickups, one for each pickup instead of the three-way switch on the 800s. There is still a Hi/Lo slide switch.

Most, but not all, Kents from these two series feature different knobs for the volume and control pots. The two types of knobs are fairly common, considering how long ago they were made. I'm still looking for the right replacement for one on my 834 and 833 bass. All the 700 and 800-series instruments have a volume and tone control for each pickup, which must make things pretty crowded on the four-pickup Kent 742.

The Bridge

On the six-string guitars, the typical bridge consists of a grooved barrel-shaped saddle for each string. The saddles almost look like they are threaded, but they really aren't. Each saddle is on a screw so that the effective length of each string can be tweaked to ensure that they remain correctly tuned as you move up the neck. The term "intonation" refers to the ability of a guitar to play in tune at all positions of the neck.

The grooved saddles on these guitars also allow the player to move the string back and forth so that it is centered over its pole pieces on the pickups and will hold it in place. The grooves are wider under the bass strings and narrower under the treble strings.

Most, if not all, of these grooved-saddle bridges were equipped with a mute consisting of a strip of rubber glued to a small metal shelf attached to a spring-loaded lever. The lever allows the guitarist to flip the mute up into contact with the strings. Kent literature of that period refers to the mute as the "thumb controlled damper". The resulting sound is kind of plinky with no ringing after picking. It is often heard in surf music of the 1960's. A player can achieve a similar sound by resting his picking hand on the strings near the bridge while playing. I refer to the bridge with the grooved saddles and mute as the Standard Mutable Bridge.

The rubber damper on the mute is frequently missing on the old guitars, so if you engage the mute, you will get the metal shelf against the strings and it sounds terrible.

There are some problems with this type of bridge. The muting lever can, and probably will, get in the way of the player's picking hand, causing it to engage when not wanted. So the player may have to modify his/her playing style. For me, it's a bigger problem with the 820-type body than with the violin-shaped 830-type, probably because the 820-type body is wider. It is probably less of a problem with the 700-series solidbodies as well, since the bodies are smaller. Most of the photos I have seen of 700s with the mute have the mute on the treble side of the bridge.

The lever is rivetted on, so if you're concerned with keeping the guitar all original, you won't be able to remove it.

bridge done right

The bridge has studs that just slip into a pair holes on the guitar top. It's an easy matter to just remove the bridge and turn it around so that the lever is on the other side. It may be less in the way there. But that puts the mute on the back side of the bridge where it will be ineffective. Moreover, the saddles become reversed. The saddle with the narrow grooves is under the fat-E string and it doesn't take much to pick that string right off the saddle and make it sound bad. You can remove all the saddles and put them back in reverse order. Then you will have to re-adjust intonation, and the mute is still on the wrong side of the bridge. I've seen photos of a couple of Kents with the lever on the bottom, the saddles correctly placed, and the mute in the right spot in front of the bridge. I don't know how many there really were.

The photo on the right shows a bridge with the damper on the bottom, hopefully out of the way of the player's hands. The saddles are correct with the wider grooves under the fat E string, and the damper is on the correct side of the bridge. It's on a Kent 834.

On many of the hollow-body Kents, there is a nicely-shaped piece of rosewood between the bridge and the body. This is common on archtop guitars. This may place the strings pretty high, away from the pickups. In the case of my 823, they are also at an angle, making them further away from the middle and bridge pickups. My 834 doesn't have that piece of rosewood so it doesn't have that problem.

Note that a tune-o-matic type bridge made to fit a Gibson will fit a Kent 800-series guitar without modification. However, due to the number of mysteries and "curveballs" seen within this series (and probably every series of Japanese Guitars), measure between the mounting posts and make sure they match before you buy a replacement bridge. Often this type of bridge comes without grooves cut in the saddles for each string. Cutting grooves in the saddles is similar to cutting slots in the nut at the other end of the string. If you don't have the tools, expertise, or confidence to do this, take it to a competent luthier. It shouldn't cost very much.

The vibrato tailpiece found on most of these guitars can also hold the strings rather high, although it may not cause any problems. The strings may not make solid contact with a lowered bridge. There are fixed "trapeze" bridge that wrap around the end of the guitar body that may be direct replacements.

The model 820 seems to be the most "serious" of the series. It was available with either the standard Kent vibrato tailpiece, a Bigsby tailpiece, or something very much like a Bigsby. Some came with a fixed tailpiece, but not nearly as many. The Bigsby-equipped guitars came with a bridge very similar to Gibson's Tune-o-matic, and there may have been variations in that respect, also. My 820 came with a fixed tailpiece and a Tune-o-matic style bridge made by Gotoh.

Tale of Three Tailpieces
standard bigsby sorta bigsby
Standard Bigsby Sorta-bigsby

The pickup toggle switch on the two-pickup models is in a location that may require the player to make an adjustment to the way he plays. That would not be a great an adjustment as working around the mute lever, but the two together may be a problem.


The electronics on most passive guitars (the ones you don't have to put a battery in) usually consist of pickups, switches, potentiameters (pots), and wire. For the most part, the 700 and 800-series Kents all use the same parts with the exception of pickup switches. Pickups on the bass guitars only have four slugs.

There are usually a volume and tone pot for each pickup. Often the volume knobs are a different color from the tone knobs. The resistance value of the pots seems to be 500k. Nowadays it's commonly accepted that single-coil pickups should use 250k tone pots and humbuckers should use 500k. These are single-coils pickups but they are wound with more wire than modern single-coil pickups, so 500k seems to be alright. Pot values affect the tone of the guitar, so there is plenty of room to customize the sound. There is no absolute value needed for pots. The pot shafts are a little smaller than the 1/4 inch shafts on most American guitars, so be sure you get metric parts, unless you like needlessly enlarging holes.

The pickup selector on the hollow bodied guitars is a three-position toggle, except on the 823. The 823 has three mini-slide switches. They are white while the lead/rhythm switch is black. The solid-body guitars have white on-off rocker switches above the strings, one for each pickup.

The tone capacitor is usually .05mfd. Today's more common .047mfd parts are good replacements. Once again, you can experiment with cap values to get the sound you want. Guitar pickups put out a miniscule amount of voltage, so just get the smallest physical size cap you can find. No sense in trying cram a big-ass 10000V capacitor into a guitar. The hi/lo switch has a .002 mfd cap on it. The most common replacement today is .0022 mfd. You can experiment with that value, too, but I don't think it'll make much difference.

All the switches can get "tired" after 50 years and may require cleaning and/or some creative bending of the contacts. I'm pretty sure there are suitable replacements available, but you have to do some searching. It may be difficult to find a match with the same shaped plastic slider part as the original. Any information I find on the sourcing of parts will appear on this page.


pickup The pickups are single coil units mounted to the body on faux tortise shell/metal mounts. They have white plastic covers with the name "Kent" written in black script on each one. There is an adjusting slug on the pickup beneath each string so that you can balance the loudness of individual strings. The pickups are completely enclosed in plastic and have a brass or copper plate on the bottom.

The pickups have been described by some as "weak". They really aren't. If DC resistance is any indication of how hot a pickup is, (which I don't believe in) these would be pretty hot pickups. Adjusting the height of the pickups may help. There are single screws on either side of each pickup to adjust the pickup height. The screw passes through a threaded hole in the base plate and there is a spring between the base plate and the mount. I get great sound from my 820 and 823 with the pickups adjusted so that the slugs are about 1/8 inch from the bottoms of the strings. You don't want to use the slugs for pickup height adjustment. Use the screws on either side of the pickup. After each adjustment, retune and check the distance. Adjusting string distance from the frets is a combination of neck adjustments and bridge height screws. Intonation is also adjusted at the bridge. Often when intonation is adjusted, the neck needs readjusting. You go back and forth until you get it the way you want it. It doesn't take all that long.

kent 833 wiringI have no trouble driving my tube amp into distortion with my guitars, so the pickups can't be too weak.

Another attention to detail: All the wiring in the guitars is done with shielded cable with the shield part grounded. Note the photo at left. It's the pots and output jack of a Kent 833 bass. All the wiring is shielded except for the brown wire. That's a ground wire. The other end is probably connected to one of the bridge posts or something that makes contact with the strings. There are a lot of little touches like this with these guitars. That being said, all four of my 800-series guitars have fairly strong single-coil buzz.

The Neck

tuners The tuners on the headstock are fully-enclosed chromed steel and seem to be pretty well made. The guitars that I have stay in tune as well as any mid- to upper-end modern guitar. There is a nice looking mother of pearl design in the center of the peg head.

tuner graphic It should come as no surprise that occasionally one of these old tuners will fail. I had a bad tuner on my 740 when I got it. The knob would turn but the winding post would not. I opened up the tuner expecting to find gear teeth missing or worn out. I didin't find anything wrong until I removed the black screw holding the round gear. That gear sits atop the winding shaft and is keyed by having two flat sides on the shaft and the hole through the center of the gear. The hole was worn out and didn't engage the shaft any longer. That happens when steel meets brass. I had some tuners left over from a cigar box guitar build, so I removed the round gear from one of the tuners and replaced the one that was worn. Not only was it a perfect fit but it tuned exceptionally easy. You don't have to replace the whole tuner. I plan to repair the ones that are hardest to turn, maybe all of them. The tuners I used were an economy set from There are probably cheaper sources for these. There are quite a few listed on Ebay. Most have great photos but no exact specs for that gear. Since they're all made in Asia, the cheap ones, anyway, I would expect the gears to all be the same... possibly all from the same factory.

One feature of most of the 800-models is the presence of a "zero fret". This fret marks the end of the playable part of the string instead of the nut, as found on most other Kent guitars. See "The Zero-fret Puzzle" below. It's not something you'll never see anywhere else, but it is a little unusual. Not all the 800-series Kents have it.

neckThe scale length of the six-strings, at 25.25 inches, is close to the standard Fender scale of 25.5". Gibsons are usually around 24.75 inches.

The fretboard on most of them is a nice medium-brown rosewood with square and rectangular mother of pearl inlays. Every one of the inlays is a different size and/or shape. There is a "skunk stripe" of darker wood on the back of the neck.

The rosewood seems to be good quality with nice tight grain. It does not appear to be subject to drying out and splitting as is sometimes seen on vintage guitars. Maybe it has something to do with the quality of the wood available in the 1960's. There probably isn't much rosewood growing in Japan now, but there may have been rosewood forests available for harvesting then.

You'll read a lot of opinions regarding the upkeep of rosewood fretboards. Some people swear by certain oils to clean and treat fretboards, others say you shouldn't put anything on rosewood. There is a video on Youtube made by the C.F. Martin company where the tech suggests 3-in-1 Oil. He went on to use something else when demonstrating how to treat a rosewood fretboard. I haven't formed an opinion because all of my fretboards are in pretty good shape.

The frets on the sixes are typical vintage-thin but not so shallow that string bending would be too difficult if the neck is reasonably straight.

back Truss rod adjustment is made at the end of the neck where it attaches to the body. A 5mm hex wrench is required except on the basses, where 5.5mm is needed, and sometimes the end of the rod is far enough inside that the short portion of the standard bent hex wrench should clear the nearby pickup, meaning that you may not have to remove the neck to adjust the truss rod. But on most necks the adjustment is harder to reach with standard hex keys. Plan on removing the neck to make adjustments. Be careful not to force truss rod adjustments on vintage guitars (or any guitars, for that matter), the rod may be stuck from disuse. Loosen the strings before attempting any adjustments. If you can get the adjustment nut off, it would be a good idea to clean the threads at the top of the truss rod if you can, and inside the nut. A light application of a dry lubricant like powdered graphite or teflon on the inside of the nut may help keep the truss rod healthy. If possible, avoid any liquid lubricants like oil or WD-40. Those can attract dust and debris and may work their way into the wood, softening it and eventually cause problems with the finish; plus they dry out and get gummy. Sometimes you just need a liquid lubricant to free a stuck truss rod adjustment nut.

For some reason, some of the necks lack side markers, the little black dots (usually) that correspond with the positions of the fretboard markers. This could be an issue for some players, especially those who play standing up a lot. I just recently noticed that a couple of my Kents are missing those. I doubt that all guitars of a certain model would be like that but I don't have duplicate guitars of any model to compare.

The hollow-body guitars seem to react to changes in atmospheric conditions more than most modern guitars. Air temperature, humidity, and maybe even atmospheric pressure seem to affect them in one way or the other. I'll pick up a guitar that has been sitting overnight and all the strings may be sharp or flat in equal amounts. It can be severe enough to require a truss rod tweak. The best thing to do is tune it back to pitch and play it for awhile before assuming that the neck needs adjusting. Often the strings and/or neck will warm up and the problems will disappear. A few weeks ago I pulled out my recently-acquired Kent 823 for a recording and found that I had a few buzzing frets. The neck had lost its slight bow and flattened out enough to cause some buzz. Since I was busy with something else, I put it away for a couple of weeks. When I took it out to adjust the neck, it was fine. We had been under the influence of unusually high humidity when I took it out before. The relative humidity was somewhat lower when I took it out to tweak the neck.

It's a good idea to check your guitar's setup at each seasonal change point. The chipboard cases that most of these guitars came with offer no protection against atmospheric changes, especially after 50 years. It would help a lot to get a case that seals well and keep it humidified.

red The guitars were available in white, blonde, burgundy, yellow sunburst, and cherry-red. The most commonly seen colors today are the sunburst and blonde. The white, burgundy, and red ones are less common. The bodies and necks are bound in white (black on the white bodies) with additional binding on the body top to simulate four layers of binding. The back of the sunburst and blonde model is sunburst on both. The red bodies are red on the back. I'm assuming that the other two are the same color on the back as the front. Another interesting feature of these guitars is the striped body sides. There are two black stripes and a white one along the sides of the sunburst, white, and blonde guitars. The others are alternating white and body-color. The white stripe appears to be the same material as the binding.

Most of these guitars came in cheap cases, although better cases were available at slightly higher cost. The cheap cases have not withstood the years very well. The measurements in the charts behind the links below should help you find a better case. Good luck on the violin-style bodies.

A Gator case sized for a Gibson ES-335 (model GWE-335 Economy Wood Case) seems to be just right for the 800-series 6-strings. I recently got one for my 820. It cost less than $100.00. It's a solid case that should protect the guitar from knocks and also changes in humidity. My 823 was sent to me in a case that was much longer than needed for the guitar. The model 822 bass should fit quite nicely. Unfortunately, I can't find anything on the case that would indicate the manufacturer or model. If I am ever able to score a model 822 bass, I will put it in this case and get another Gator for the 823.

While I was looking at the Gator case website, I found that the GWE-TBIRD-BASS case would be a pretty good fit for the 833 violin bass, size-wise, but the gator cases are not all foam, so cutting the opening to size probably won't work. Otherwise I'm planning to build cases for the two violin bodied axes.

A comparison of violin-body guitars
833 Bass834 6-string
833 body



to make

a space

833 body

To the guitars

My740Kent 740 My820Kent 820 Kent 823 Kent 834 Kent 833

The Zero-Fret Puzzle

updated July 2015

peg head Most Kent 700 and 800-series guitars employ a zero-fret.

In order for a guitar to play in-tune up and down the fingerboard the length of each string has to be precisely adjusted. The thickness of each string will affect the length to some degree. That is why changing to a different gauge set of strings will often require adjustments at the bridge. This is intonation adjustment.

Also, the slots in the nut that the strings pass through must be carefully cut and smoothed by hand, usually with precision files. The width, depth, and angle of the nut slot are critical. If the slots aren't right, the string may sound strangled, or the string may not return close to pitch after using the vibrato, or the string may make a little "plink" sound when tuning. Unless there is a zero-fret.

There may still be issues with strings returning to pitch or sounding funny or "plinking", but those issues are much easier to solve when there is a zero-fret.

Modern guitar manufacturers are using computer controls to accurately cut nuts, although guitars still often come from the factory needing work on the nut, for some reason.

Before computer-controlled machinery, guitar nuts had to be made by hand for each individual guitar. This work required skilled labor and time, adding to the cost of each neck. This, I'm sure, is one factor in the decision to use a zero-fret, but obviously not the only one.

With the use of a z-fret, the need for skilled labor and time is reduced. A machine with a cutter for each fret placed in exactly the right position was probably used to cut the slots for the frets, anyway, so the addition of one more fret would be a simple matter and make sense. If you look at a bunch of older guitars with z-frets you will notice that the distance between the nut and the z-fret will vary. Necks and/or fretboards were probably measured and cut to size by hand.

Kent 820s (maybe other 800s, too) came with and without zero-frets. Most of them have it. It's not known whether they started out without z-frets and then added it to save money or if some were made without for some other reason. Maybe it has something to do with workload and/or availability of skilled nut-cutters. Maybe custom jobs had hand-cut nuts that they added to the price.

Notice these two advertisements, presumably from the same time period. I have enlarged the headstock end of the neck in the photos. The one on the left has the standard Kent vibrato tailpiece and mute-able bridge. It has the zero-fret. The one on the right has the Bigsby tailpiece and tune-o-matic style bridge. It does not have a z-fret.

So maybe the Bigsby, tune-o-matic, and precision-cut nut make the one on the right "custom". Perhaps the manufacturer thought that anyone that bought a guitar would know that not having a z-fret meant the guitar was "better". That would be an incorrect assumption. The average guitar player would look at the zero-fret and think "Hmmm... I wonder why this one has that and that guitar over there doesn't." and get on with their playing.

And it doesn't necessarily make the guitar better.

Lately photos a couple of Kent 820s have come to light with a Bigsby and the standard muteable bridge. They have a zero-frets. It is important to note, however, that the Kent advertising literature of the time states that the muting bridge (referred to as a "thumb-controlled damper") was not available on Bigsby-equipped models. If it was just one I might consider the possibility that the Bigsby may have been an after-purchase addon, but not two. Be that as it may, I hadn't noticed that the first guitar I saw wasn't really "correct" for a Bigsby-equipped Kent 820 and I bid way too much for it. Luckily for me, there was someone else willing to bid more. It looks like they came that way from the factory, so they have to be considered "stock". If I ever bid on a Bigsby-equipped 820 again, it will be one like in the advertisement... standard bridge and no zero-fret.

My Kent 820 has no vibrato tailpiece at all but it does have a Tune-O-Matic style bridge. Mine doesn't have a zero-fret. So the bridge may be a determining factor. Mine may also be a one-off anomoly. Maybe there is no determining factor at all. Who knows?

I have also seen a photo of a Kent 820 equipped with the standard Kent vibrato tailpiece and a non-muteable bridge. That guitar does not have a zero-fret. Can't explain it.

This discussion is not about the pros or cons of the zero fret, however. It's about figuring out how some Kent 800-series guitars came to have a zero-fret and some didn't. Most of the photos I have of the 700-series solid-bodies show no zero-frets, but there are a few.

But since, for some people, the zero-fret issue has become a holy war, let's throw a few necks into the fire and get it burning brighter.

If you look around the internet for a little while you will find "experts" who will give perfectly valid reasons why the zero-fret is superior while others will make it clear that it is not. This is similar to the the argument about which wood produces the best tone from a solid-body guitar, followed by the question "Does the type of wood even matter in a solid-body guitar?". And then the question is asked about a thin nitro-cellulose finish versus a thick poly finish and their effect on tone.

Those questions will never be definitively answered. Shut up and play yer guitar.

There are a few indisputable points to be borne in mind regarding the zero-fret question:

For the 2015 model year Gibson started equipping most of their guitars, except reissues, with a nut which incorporates a zero-fret. Naturally, you will see mostly negative comments about it on the internet, but they seem to be selling okay.

The Stewart-Macdonald company, supplier of guitar parts and repair tools sells a nut that incorporates a stainless-steel zero fret called the Zer0 Glide Nut. The idea, again, is to take the nut out of the vibration-path (a term I just made up) of the string. It claims that the fret takes on 93% of the load.

It could be argued that the zero fret transfers string vibration to the guitar better than the nut alone. Nuts have different transfer characteristics depend on whether they are made of metal, plastic, or bone and whether the strings can be locked down or not. Metal frets are sunken into the fretboard. Would a zero fret make a difference? It seems that it would. But there are so many factors affecting the sound of a guitar that whatever difference a z-fret might make would be difficult to discern.

My feeling is this: Most guitars are made predominately of wood, often a combination of different types of wood. Every piece of wood is slightly different, even if from the same tree. Therefore, every guitar has its own "personality", and I think the differences are greater among hollow and semi-hollow guitars. The environmental conditions that the ax has lived in during its life will also have an effect, further differentiating individual guitars. The trick is to find one that feels and sounds right to you. If you keep an open mind and play a bunch of axes, one of them will pick you.

Obviously, that method doesn't work when you're looking for a vintage guitar. You take what you can get and then try and work with its personality.

For me, z-fret makes no difference. I may have to take it into consideration when I have to make some adjustments, usually not. If the guitar is set up properly, any differences in playability or sound are too small to matter to me.

For another look at the zero-fret question plus a lot of great information on the Kent 820 and the other Kents that use the same body, take a look at

The Kent 700 and 800-series guitars represented a seriously improved series of Japanese guitars that were hurt by bad timing. They just didn't break well into a market that was beginning to pull back by the late '60's. Few standard guitars have completely shielded wiring and metal pickguards that don't look like metal cheap tin.

These guitars are approaching 50 years of age. Many players believe that older guitars sound better because the wood has been through many cycles of drying and dehumidifying, and if they've been played, so much the better. Vibrations are thought to loosen the wood fibers making the body resonate better than new wood. If you are of this school of thought, these guitars should be in their prime.

In my opinion, the six-stringed guitars suffered from "too much stuff" and maybe too many versions. The poorly-designed mute-able bridge may have been a big factor in the demise of this series of Kent guitars. I think that if they had sold basic models of each style and "value-added" versions with vibrato tailpieces and properly designed mute-able bridges, they could have become mainstream guitars instead of Japanese curiosities.

If a musician learns to work with the quirky design and can keep feedback under control, they should be great gigging guitars.