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Comparing the Fender AVRI, Mastery & Descendant vibratos!
My first experience with a Jazzmaster was one more than likely shared with many other guitarist's first experiences with Leo's late 50s Offset design. Reaching to grab a what was simply a poorly set-up Classic Player JM off a high street guitar shop's hanger. Due to this, which at the time I didn't realise could be resolved with a simple set-up, left me feeling pretty let down by the guitar I'd seen so many players I admired playing. Unfortunately I was of an age where I didn't really respect how important a good set-up was to a guitar, so set them aside in my mind for years as a result. Rather foolishly of course. Looking back this does perhaps explain why sadly, so many guitarists disregarded Jazzmasters (Jaguars of course fall into this association too) as inferior playing instruments. Good set-up is key to getting the most out of them, and in more recent years we have seen such a resurgence for the offset with so much more information out there on how to get the best out of them.

I've discussed this before, so I won't go into too much detail, but over the years there has been a fantastic amount of information available to get the best from their standard set-up, as well as hardware designs that can improve upon the original items too. As let's face it, the Jazzmaster was designed with more delicate jazz playing in mind where perhaps 12 gauge wound G flat wound strings were the norm. Although it didn't take off as intended as a Jazz instrument, their popularity with surf music in the following years kept them in production until the 70s. Then the 80s & 90s these guitars eventually became associated with experimental music, indie rock and harder playing styles and as a result, there was a gap in the market for hardware developments that would allow those players to further improve the Jazzmaster to suit this shift. There were some quick fixes of course, buzz stops and bridge swaps but it's great to see some great designs emerging that capture what is great about the original design and merely taking it further. 

Comparing Fender AVRI, Mastery and Descendant Vibratos

When I got my hands on a Descendant Vibrato unit back in April/May of 2020 after watching the development they shared on their instagram account before the product was released, I was really looking forward to sitting it side by side with it's fellow vibrato designs to see how much they all differ, or how similar they are for that matter too. I've finally had chance to do this alongside perhaps the two most popular units on the market. I personally chose to compare it to these for their equal quality to the Descendant and their popularity within the community. So I decided to show it alongside the Fender 'AVRI' USA replacement which is the most traditional design as well as the brilliant Mastery Vibrato which has dominated the aftermarket for offset vibratos since it's release. 

It's pretty difficult for me to convey the 'feel' of each vibrato, and I imagine there will be a plethora of YouTubers sharing how they work and sound in videos soon enough. We all also may have preferences on set-up or tension spring adjustment too, so I'll simply do my best here needless to say, to share the details about each unit, three vibratos I greatly admire. I'll try to share some nice photos and useful measurements to show the differences between each unit to perhaps help you if you too are interested in how they compare. This isn't as much a review, as just a comparison of my findings, all three are great units I would happily recommend so this is more of a chance to see the three side by side.

The Fender AVRI vibrato unit.
I bought this replacement unit new from Fender in around 2017, as an upgrade over the standard (and rather flimsy) unit that came fitted to my Squier VM Jazzmaster from the factory. Sadly, the Squier unit definitely didn't do the guitar any favours, it sounded rattly, the arm wobbled in the collet and easily fell out if you leaned even slightly forward and the playbility was pretty lackluster. Maybe I was particularly unlucky with it, but it had to be replaced that's for certain! Choosing a replacement for me at the time revolved around sourcing a Fender branded item, with either the Mexican made item used on Classic Player models for example which I believe had a threaded arm, or the USA 'AVRI' item.

The AVRI was actually a little easier to source at the time as I could find the product number from Fender and get a new item trouble free, whereas I couldn't seem to source the MIM version without hoping for a used one to crop up for sale. After some research though, the AVRI seemed the better choice anyway so this is what I opted for and bought one new for around £100 at the time (which didn't come with an arm, Fender supply and sell these as a separate item). From the info I could find online, it apparently featured higher grade metal for the baseplate (after all, it is an anchor point for the strings so better resonance) than the MIM and it certainly felt pretty weighty to back that up (305g) which was a lot more substantial than the Squier item I removed from the VMJM that's for sure. 

Comparing Fender AVRI, Mastery and Descendant Vibratos

The traditional design certainly looks great though, the vintage Fender script type along with the PAT number stamped in particular at the centre of the plate keeping the spirit of the originals alive. Importantly too for vintage fans, the sliding lock button (the only unit of these three compared today to feature that). It's finished in a shiny chrome plating which looks great for a more vintage correct aesthetic if your guitar would look better with that in mind. 

Comparing Fender AVRI, Mastery and Descendant Vibratos

Upon first use though, I noticed was that the arm collet wasn't totally dissimilar to the original Squier unit that I personally disliked. This one was perhaps a little tighter than that though to give it it's due, but still just required a forceful push of the arm into the collet to keep it somewhat in place. Even then it seemed to work it's way loose after a few uses. I wasn't a huge fan of this, after all it was one of the reasons I wanted to remove the Squier unit in the first place, but in my research I had seen Staytrem here in the UK produced their own collect and arm replacement which very easily solved this issue.

Comparing Fender AVRI, Mastery and Descendant Vibratos

So I ordered one of those (around £35 I think at the time), very easily installed it ( a 13mm spanner and the collet is swapped) and was incredibly happy to have an arm that stays in place without falling out! If you can still source one of these (Staytrem have greatly reduced production in recent years and I believe have restricted orders to UK only) I would highly recommend it as a worthwhile mod to the AVRI unit. The design of the collet was essentially similar to the original aesthetically and without being told it was any different, you wouldn't really know visually so retains a traditional look. The Staytrem arm essentially has a small notch, which when pushed into the collet sits within a shaped sleeve inside that keeps it locked in place. The arm isn't super stiff, but it doesn't swing around freely, I always felt it worked really well. The Mastery unit adopts a similar design too, but more on that when I discuss that item. 

Comparing Fender AVRI, Mastery and Descendant Vibratos

As mentioned earlier, this is the only design to feature the sliding 'lock' system as per the original Fender units. For some players, this is a must have, but I must admit, I personally never found my self ultilising it in practice. I would however highly recommend taking the time to read the fantastic guides out there online on how to properly set it up, I did and aside from allowing the trem-lock to work correctly, also aids in correctly setting the spring tension too, so worth your attention either way.
If you really like the lock system, the other units compared today don't feature it so the AVRI might be your only choice in that regard. But, what does it do and why would I need it you ask? Well, when you break a string on a JM, the unit looses some string tension and knocks the guitar out of tune (usually sharp). This sliding 'trem-lock' button is essentially a mechanical tension 'memory' so to speak, when correctly set-up, if you break a string, you can depress the arm and slide the button over which in turn returns the unit back to the same tension helping you carry on in tune as you were before you broke the string. You are no longer able to pull the vibrato arm upwards, but you can still carry on using it downwards so maintain similar use until you have chance to replace the broken string and soldier on. As I say, I never found myself using it and I don't recall ever breaking a string whilst playing (mostly as I used Gabriel Tenorio 'long twist' strings with my JM which helps with breakages on these guitars) but it sure is an interesting aspect to the original unit design, another classic Leo idea! 

Comparing Fender AVRI, Mastery and Descendant Vibratos

Speaking of string breakages,  there is one noticeable complaint by JM players, and that is strings breaking at the ball end, or becoming loose near the ball end of the string. This happens mainly due to the pivot plate mounting screw heads being located near the anchor point for the ball end of the string. When you look at a string, you'll see the little twist that keeps the ball end in place, well more often than not, the end of that twist sits right by where those large mounting screw heads are and depending on your guitar's set up, they can rub the screw head over time and work the string twists loose. I personally never came across the problem, again, this may be because I predominantly use Gabriel Tenorio's specially designed 'long twist' strings to help reduce the risk of it happened (another great and very simple 'mod' by the way!) but it is a common problem and complaint for many other JM players in the community. Some of which have found neat ways to resolve it too, such as adding a blob of solder to the string's ball end twist to further secure it, or a mod popularised by Michael Adams is to unscrew those mounting screws and thread them in from underneath which I've shown in the photo below as an example. Easy fixes for this issue but as I say, I didn't encounter string breakages at the ball end like others have, but it's worth noting due to it's commonly discussed issue JM players have.

Comparing Fender AVRI, Mastery and Descendant Vibratos

The strings feed through from the rear of the unit and pull through to string up, and this for the most part is absolutely fine and quite normal for many types of tailpiece. But if you're a player who likes to keep your guitar looking it's very best, be cautious of pulling the string through and preventing and scratches to the body/finish, as there is potential for scratches from the string/ball end on the finish.
My AVRI unit was really nicely chrome plated, with no signs of sharp edges or knurls at the string holes, but if one did have a knurl there is a chance of damaging the wrapped strings as you drag them through the hole too. But this really is being anal here for the sake of detail, as I didn't encounter any issues with scratching my guitar (I'm pretty careful when stringing a guitar anyway) or damaging a string for that I could notice. There are countless guitar bridge/vibrato designs where you pull the string through a tailpiece, but again, I've seen it discussed so figured I'd highlight it as part of this units design and only one of the other units has an alternative method for this which again, I'll get onto in due course! 

Comparing Fender AVRI, Mastery and Descendant Vibratos

Overall in use, I really liked my AVRI vibrato when installed with the staytrem arm/collet. If felt great to use and had lovely tension in the arm, that great 'floaty' yet precise feel which makes this design so great. I came from predominantly playing strats growing up, so I was used to playing pretty firm feeling vibrato arms. Using a quality system like the AVRI really made me appreciate how much better this unit is in that regard, it's intuitive and rewarding providing the player with more control. You can certainly see why the surf guitarists in the late 50s and 60s quickly adopted these guitars as their own as it's so easy to recreate that sound with one of these in your hands! For around £100, this unit is great, it has it's niggles which the other units do improve upon, but it works well and I would happily recommend one if you're looking for a more vintage correct upgrade and can't source an original. 

The Mastery Vibrato unit
This design became an industry standard, with traditional Jazzmaster players, luthiers and boutique guitar designs alike all adopting it as a quality aftermarket take on the original vibrato design. There's good reason for that, it's incredibly well made, addresses a few of the niggles from the original design and looks pretty nice indeed too. This particular unit is the brushed finish, but they do offer them in more traditional chrome etc as well as some limited edition finishes for example too which I think helps for those looking for a vintage aesthetic or unique touches for a colour scheme. Visually, 'trem-lock' aside, it's very similar to the AVRI, placement of the spring tension adjustment screw and placement of the three pivot plate mounting screws. Only this time, Mastery of decided to use neat flush mount screws instead to completely remove the risk of string breakages due to the screw heads contacting the ball end twist of a string like the Fender design. So straight away, we're onto an improvement.

Comparing Fender AVRI, Mastery and Descendant Vibratos

The arm is the next improvement and adopts the similar method to the Staytrem arm mod on a Fender unit, where the arm has a little notch on the end and pushes into a locking collet (ball bearing on this design though which is perhaps a bit more hard wearing, a nice touch) to stay in place. It takes a fairly firm push to lock into place, and likewise to remove it, but it's no problem to do this and certainly secures the arm with zero concerns. The collet itself is a rather meaningful looking piece of simple engineering underneath the unit, a reassuring sign of this units quality construction. The collet is also the place where you can adjust your arms swing tension, so whether it swings freeley like the shoe-gaze style of playing where you can hold it at all times whilst strumming, or the much firmer Bigsby esq stiffness where there's no real arm swing, just a firm movement where it stays where you leave it. To do this, the unit has to be lifted off the body as access is only available at the back of the collet itself. Loosen the brass nut using an 11mm spanner (you can use pliers but if that nut is tight you may slip and cause damage, so better to use the correct tool), and adjust the flat head grub screw to your tastes and re tighten the brass nut. 

Comparing Fender AVRI, Mastery and Descendant Vibratos

The pivot plate sits directly onto the top plate and the string through plate all essentially look identical to the original Fender design. The spring cup is brass, and the spring itself is actually a bit longer than the Fender item, measuring at 27.1mm compared to the Fender 24.45mm. Unfortunately, I don't know the spring rates, and don't have a way of measuring the rates, but Mastery have chosen a very nice feeling spring that has a great effect of the vibrato in use and feels very nice to use. I believe they spent quite some time testing numerous springs to find the perfect one, and the unit was developed alongside some prolific JM and Jaguar playing artists so it's safe to say, the spring chosen works very well and when adjust correctly really does feel superior to the standard Fender design.

Comparing Fender AVRI, Mastery and Descendant Vibratos

One very quick tip I have found from working on numerous guitars with Mastery Vibratos is simply just eyeballing that the pivot point is sat nice and straight as you pull the strings back up to tension. If it is sat off centre or not quite right, you can find odd vibration or unwanted metallic type sounds occurring. It's really not an issue, just the nature of the design and I imagine if you own one, it'll just be part of your re-string routine to check it's sat correctly when tuning up to pitch.

Comparing Fender AVRI, Mastery and Descendant Vibratos

The unit overall is superb and there is good reason why you see them on so many instruments, and relied upon by so many guitar makers. It's a solid design and very well made, quite weighty at 321g which is the heaviest of the three units compared here, so perhaps worth considering if you have a particularly weighty guitar already, but playing feel is superb and they look great. I haven't bought one personally, but have commissioned many instruments from the guitar makers I have represented over the years to use one on a build. I believe they are available online for around £200 new in the UK.

The Descendant Vibrato Unit.
The newest take on this style of vibrato to hit the market, courtesy of Chris Swope of Swope guitars. A man with a wealth of experience of working with offset guitars through his career in the industry, resulting in a product idea he has had in development for many years, finally bringing it to life in 2019. This is perhaps the most drastically different looking and designed unit out of any on the market for this style, it certainly stands out from the pack visually with it's counterparts featured today. It does perhaps posses a more 'modern' aesthetic, which might leave the players looking for vintage styles feeling a little uncertain, but I suppose the improvements on the design may outweigh the aesthetic.

Comparing Fender AVRI, Mastery and Descendant Vibratos

The first thing you'll notice visually is the grooves in the top plate. This is because a focal point behind this design is to aid string break angle over the bridge, another common discussion for Jazzmasters & Jaguars. So not only is this vibrato addressing some of the original unit's niggles, it's also helping with the bridge niggles too which it does very effectively I'll add. The grooves in the top plate are needed as the strings sit low within the unit itself, how deep depends on how you set it up with the supplied shims. This would ultimately depend on your intentions or existing set-up of your guitar.

Comparing Fender AVRI, Mastery and Descendant Vibratos

They come supplied with two shims fitted, shown here installed between the main top plate and the pivot plate (scroll up to the similar photo I included of the AVRI & Mastery plates to compare). Chris recommends going with two shims on initial install and going from there depending on your findings. This is a good way to approach it, but my personal experience and recommendations (if you'd rather fit it right first time than spend time adjusting it that is) from installing and adjusting it on my own Jazzmaster, is that if you have a particularly shallow neck break angle and your bridge sits fairly low into the bridge thimbles, then 1 shim may be the best. It will still provide improved break angle over the bridge, but will help prevent the strings from contacting those grooves as they pass up through the plate which can be an issue with a shallow string angle/bridge height. I tried setting up the unit on my own JM with a few different guitar set-ups in mind, and when I had a shallow neck angle, one shim in the unit seemed to be best for me, it functioned great and strings cleared the top plate comfortably. Whereas when I increased the neck angle, and raised the bridge in the thimbles to perhaps a more optimal JM set-up style anyway, it provided ample space between the string and top plate meaning two shims within the vibrato was perfect. Personally I felt this approach brought the best out of everything associated with that. I went from the standard AVRI, to the Descendant and noticed increased string sustain and resonance, and it also allowed me to drop a string gauge to 10s from my usual 11s in an effort to put the unit through the tests of it's claims of aiding string tension. I was impressed, I must say, the string tension felt great despite dropping a gauge. 

Comparing Fender AVRI, Mastery and Descendant Vibratos

This is actually the lightest unit of the three, weighing 270g (with both of the shims installed but I can't imagine the shims weigh very much to be honest), but still feels incredibly solid and features the exact same plate thickness as the mastery too at 1.85mm thick (AVRI is the thinnest even with the chrome plating at 1.5mm). Construction wise I would definitely liken it to the Mastery. It too has a brushed finish similar to the Mastery unit example I have to hand, which I personally like but do respect those looking for a more vintage correct aesthetic might be crying out for a chrome plated version. I do think though that if you have a relic or real 'well played' guitar, the Mastery or Descendant brushed finish would look pretty cool roughed up a little to suit the aging, but that's just me! The branding is also a little more subtle than Mastery or Fender, with a very finely etched Descendant logo behind the string anchor point as apposed to the comparative unit's deeply engraved logos (the mastery perhaps being the more subtle of the two though with their sleek logo instead of a big script)

Comparing Fender AVRI, Mastery and Descendant Vibratos

You'll also notice that the pivot plate mounting screws have moved, on the Descendant it has four instead of three, whether there is a definitive reason for those, I'm not sure, but again it resembles the Mastery unit here with flush mount screws only this time due to there being four screws, they actually sit between the strings rather than directly under them so it perhaps wouldn't matter even if they were raised screw heads.

Comparing Fender AVRI, Mastery and Descendant Vibratos

For the arm, it too features a locking system, but the Descendant has it's own take on that design with a very useful adjustment available to the arm too. Just below where the arm pushes into the collet, there is an adjustment grub screw and this serves as a way of adjusting how loose or tightly you want the arm to swing around once in place. The arm has a notch just like the Mastery, but it also has a flattened side, so once you have your arm swing tension perfectly adjusted to your tastes, you don't need to worry about reaching for the allen key again as you simply turn the arm to a specific position and lift the arm out of the collet with zero force, and do the same again to push it back in. This in use works really well I must add, and having some control over how much the arm swings is a useful function. If you like the arm to firmly stay in one position for you to reach as you please, then tighten the grub screw up and it stays put. All without having to remove the unit which is a great feature and very useful. Want it to swing completely loose but never fall out, then slacken it back. A simple detail which has clearly had some thought behind it to aid the player. 

Comparing Fender AVRI, Mastery and Descendant Vibratos

The strings mount differently too, mainly due to the string anchor plate sitting deep into the unit, you simply wouldn't be able to feed the string through the back of it as there isn't space to do so. Instead, you'll notice three grooves each with a central hole large enough to pop the ball end of the string through and slide over to it's respective string position. These means you don't have to feed the string from the back and pull it all the way through the unit, it's super simple but can be a bit fiddly if you're doing all of the strings in one go, I would probably recommend doing one at a time to keep the curse words to a minimum during stringing up (still a darned sight easier than stringing up a bigsby though that's for sure!). One thing this also means is that if you need to pop the strings off the guitar for any reason for maintenance work etc it's easy to do that without removing the unit or pulling the strings right the way back through. So although a matter of necessity, it does have it's advantages in use too. 

The spring, much like the other three, feels great in use and captures that same lovely floaty yet controlled feel of the other two units. Chris, as with mastery, spent some time finding the right spring to use, and he's picked one that feels very similar to me to the AVRI vintage esq feel. It's actually the longest spring of the three units, measuring 27.7mm but it doesn't foul a standard Jazzmaster vibrato body route. I have listed the total depth measurement for each unit below (measured from the top plate, to the bottom of the spring cup with the spring merely held captive) if that helps with any build planning though!

Comparing Fender AVRI, Mastery and Descendant Vibratos

I do think there is a little more to consider when installing and setting up a Descendant than the other two units discussed, perhaps with the exception of the Fender AVRI due to correctly setting up the 'trem-lock' button, but the results are worth it and I genuinely was amazed at the difference it made on my Jazzmaster after installing from the AVRI unit. So much so, I have decided to keep the Descendant on the guitar as a result. I think you'd be happy with any one of these units so I do really hope that this article touching on some of the details of each unit, good and bad, will help guide you in which you feel is suitable for your needs. 
The Descendant is an item I now proudly stock, and these are £220 so the most expensive of the three designs, but it also has more features so I suppose it's relative. 

To save filtering through the article to find any of the measurements I have mentioned, I have decided to list them below in case it helps too!

Comparing Fender AVRI, Mastery and Descendant Vibratos

One thing I would like to add is the length of the arms supplied with each unit. Unfortunately I couldn't cover this accurately as I don't actually own a Fender AVRI arm anymore due to using the Staytrem version with my AVRI unit instead. But from research and discussing it with other offset fans, it seems the Fender AVRI replacement arm is the longest of the three. The Staytrem arm I owned was a touch shorter than Mastery, but featured a much more prominent curve to it which some JM fans really like. Downside to that curve is it's overall length from initial bend is compromised and actually ends up shorter than the Descendant's. The Mastery and Descendant are relatively similar in regards to the bend in the arm, although the mastery does have an additional kink just before the arm tip which helps it curve a little closer to the player. The Descendant features the straightest curve, but it still reaches just below the neck pickup if that helps gauge it in real terms. 

Fender AVRI unit weight (without arm) - 305g
Mastery unit weight (without arm) - 321g
Descendant unit weight (without arm) - 270g (with both 'shims' installed)

Fender AVRI plate thickness - 1.5mm / .059"
Mastery plate thickness - 1.85mm / .0725"
Descendant plate thickness - 1.85mm / .0725"

Fender AVRI overall depth from top plate to lowest point with spring adjusted so it is just captive but at no tension - 32.46mm / 1.278"
Mastery overall depth from top plate to lowest point with spring adjusted so it is just captive but at no tension - 36.1mm / 1.4215"
Descendant overall depth from top plate to lowest point with spring adjusted so it is just captive but at no tension - 36.83mm / 1.451"

Fender AVRI Spring length - 24.45mm / 0.9625"
Mastery spring length - 27.1mm / 1.067"
Descendant spring length - 27.7mm / 1.09"

Staytrem replacement arm length from initial bend to end of plastic tip - 200mm
Mastery arm length from initial bend to end of plastic tip - 210mm
Descendant arm length from initial bend to end of plastic tip - 200mm
Fender AVRI replacement arm length (currently unknown as I don't have one to measure personally, but will update the article should I find the info out).

Comparing Fender AVRI, Mastery and Descendant Vibratos

I hope this look into each of my favourite vibrato designs helps with your own research and curiosity!


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Chris vE

Chris vE said:

Excellent comparison-thank you! I have a Descendant on the way, thanks to this review

James Gascoigne

James Gascoigne said:

Hi Chris!
Ah thank you very much. I’m glad you enjoyed it and found it useful. They’re honestly all great units each with their own merits. I hope the extra adjustability of the Descendant meets your requirements!


Philipp said:

Very instructive ! Can you tell how much lower the string are sitting compare to the others?

James Philip Gascoigne

James Philip Gascoigne said:

Hi Philipp,
Cheers! Glad it’s been useful. Yeah you can visibly see the strings sitting lower than the standard style units. The actual ball end of the string sits below the line of the top plate, compared with the traditional designs where they sit above so a visible difference for sure

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