A really common question I get asked when customers are looking to order a new pre-wired harness is whether or not they should order a treble bleed mod too as for some this is a mod/spec that they may not have knowingly experienced yet. I offer most harnesses the choice of one included, or not, and there's good reason for that rather than fitting them as standard. That is of course, personal preferences! As we all know, tone is like, totally subjective, man...
So how would you decide if the treble bleed mod is for you or not? Also, how do you choose which type?! This is particularly relevant if you haven't played a guitar with one installed before. It's important to quickly add here that with your volume pot on '10', the treble bleed cap won't be altering your tone or volume response, it isn't until you begin rolling the volume down on the guitar that it will kick into action. Let's start with breaking down what it is, and what it does.
The idea behind a treble bleed mod is that it takes the 'highs' / treble frequencies that would otherwise be lost whilst rolling the volume pot down and puts them back in the circuit as the signal leaves the volume pot. This means the treble frequencies are prevented from naturally bleeding out of the circuit as your turn your volume pot down. The result is a smoothed out treble response and a more uniform tone from 1 to 10. Depending on method used I'll add. Like with anything guitar tone related, there are a number of ways this can be approached, each with their own merits or downfalls. I want to touch on a few of those today, and maybe it will help you make your decision as to whether you'd like one, and if so, which type would suit you and your playing style.
Different approaches
Some of the most commonly seen styles of treble bleed mod is a capacitor and resistor wired in parallel (like the one shown in the image above), wired in series (also named the Kinman mod), a combination of both parallel and series or perhaps wiring your guitar '50s' style. But it can also be just a capacitor alone similar to what Fender installed in the 60s to their Telecaster models for example, Already halfway down the rabbit hole eh?
Each have their own uses and response and manufacturers can use a variety depending on their preferences, and there's some strong arguement that the length of instrument cable you use will make a difference. It can get pretty messy really, and I really hope I can help guide you a little in choosing the right one for you. I would argue that the most commonly used and see installed on instruments is the cap and resistor wired in parallel, much like the ones I offer on my harnesses as an option for example.
An interesting variation I thought worth noting additionally is the variable treble bleed, these usually feature a trim adjuster meaning you can really dial in the effect of the treble bleed to your tastes should you want to experiment a bit.
Different values of cap and resistor
The values of cap and resistor used can vary too, this is mainly down to manufacturers preferences, but this initial choice can be determined by the length of the instrument cable(s) being used too. Depending on the wiring style, from cap only, to parallel and series wired, you will likely see capacitor values, around .001uF (1000pF), 560pF, 680pF, and .0012uF for example and a resistor value of anywhere between 100k-ohm and 330k-ohm. But realistically, most brands settle for something between 100k-ohm and 150k-ohm, particularly if with a 250k volume pot equipped guitar, whereas you might see the values above that, 200-330kOhm region on humbucker or 500k volume pot equipped guitars for example. What value you choose will have affect on the treble frequencies retained and put 'back' into the circuit, and how that affects the volume pots taper as a result. Although buying a variety of cap and resistor values won't be very expensive, the hassle of wiring up lots of variations is time consuming and frustrating with needing to solder and re-solder parts to your volume pot. This is where the variable treble bleed option may be a great option for ease of use and variety of results, allowing you to quickly and easily adjust the little trim pot to dial in your preferred result.
Using just a capacitor as a treble bleed
Using just a capacitor is probably the least popular approach with players, but some manufacturers still install it on their factory instruments, such as PRS with their 180pF treble bleed cap spec for example. The reason this may not be quite as popular is because when you roll further down the volume pot's taper, more treble/high frequencies will be prominent resulting in what could be perceived as a very thin or brittle sounding response, or even what can perceived as 'added' trebles to your tone to some players. I found this to sound almost artificial the further you roll the volume pot down, certainly not very natural sound really to my ear but who knows, as we say there is no right or wrong when it comes to guitar sounds, just want you like! So you may like the volume control to do this, using it as an effect perhaps, brightening up a dark sounding amp or muddier fuzz pedal and hope for a brighter tone. But for most players, it isn't a very usable or desirable approach and as a result I think appears to be the least popular option for players looking to utilise the treble bleed mod. I tried to live with one wired like this on my guitar for a while for the sake of personal experience/experiments and it wasn't for me ultimately. Not a natural sounding pot sweep or response to suit my tastes or set-up.
50s Style wiring
This is an incredibly popular approach, but perhaps more so with Gibson style guitars due to it being how models like the Les Paul were wired in, you guessed it, the 50s! I mention it after the cap only treble bleed mod as it works in a similar way. Without touching the controls and leaving them on '10', this wiring style can be perceived as a little brighter naturally than it's 'modern' wiring counterpart. But one advantage of the 50s style over modern style wiring is that due to how the tone capacitor is wired (between the output lug of the volume pot and input lug of the tone pot) it can help retain some treble frequencies acting as somewhat of a treble bleed mod too.
In Gibson 'modern' style wiring the tone cap is wired to the input lug of the volume pot, but in 50s it is moved over to the output lug, which in turn can act as a rather subtle treble bleed in it's response. Now, I must say that I personally think this method offers the most subtle, natural response out of any option discussed here. I do still think it isn't as noticeable as a parallel wired or series wired resistor/cap treble bleed, particularly further down the volume pot sweep, but it's a helping hand along the way nonetheless and is a very popular option overall. So if subtly is music to your ears, then maybe 50s style wiring is worth a try for you. You don't just have to do it in Gibson type guitars, you could easily wire a Strat or a Tele 50s style if you so desire.
There are some cons of 50s style wiring when comparing it to modern wiring though, and the main one really is that you will notice some volume loss when rolling down the tone control pot. The volume and tone pot becomes more interactive with one-another basically. So that's something to be aware of, many players lean on this and find 50s style wiring a very intuitive way of controlling the guitar's tone via it's pots. You can of course attach a treble bleed mod to a 50s style wired guitar which can make for a more drastic volume pot response in terms of treble frequencies retained and/or lost. The general consensus is that it is best not to add a treble bleed mod to a guitar wired 50s style, as it essentially already is a 'treble bleed' circuit in some form, so the guitar can become bright in the lower range of the volume pot. But again, who is to tell someone how their guitar should or shouldn't sound for them! I have personally tried treble bleed caps on 50s style wiring and found it to be quite useful and certainly further improves treble retention through the lower end of the pot sweep, for some it may be too bright though. I have also offered it as an option on my Gibson 50s style wired harnesses and it is consistently a popular option with solid customer feedback. I guess I would say my recommendation is that if you like a more subtle volume sweep, and don't mind the tone naturally darkening up a touch through that sweep then regular 50s style wiring will suit really well. If you really want to ensure a brighter,clearer tone throughout the sweep, try adding a treble bleed cap to your 50s wiring and see how you get it. It will certainly retain the top end and clarity right through and may be very useful for cutting through the band mix even when your volume is lowered.
Wiring the cap and resistor in parallel
My personal preference (if opinion matters!) for general purposes and most pickup types. I find this to be a good blend of a natural sounding sweep and no sense of additional trebles added. The treble frequencies don't sound anywhere near as 'thin' as the cap only treble bleed method, by comparison. Some would argue that wiring them in parallel can still sound thin and brittle further down the volume's sweep/taper, or have a negative effect on the actual volume pots taper, but to be that sounds more like an unsuitable spec based on their signal chain factors, rather than a line drawn through parallel wired TBs as a whole. With an audio taper pot, and let's say humbuckers and 500k pots, this treble bleed sounds really natural to my ear, and is a really useful tool to have at your fingertips. A single coil 'may' start to sound a bit thinner further down the pot taper, but again with factors like amp choice and settings, pickup type and materials used, pot taper quality, I personally feel this has too many factors to argue for or against. Splitting hairs and ultimately without knowing the exact context of someones opinion it's impossible to gauge! So if you want to experiment for yourself, attach two wires to your volume pot input and output lugs ( with crocodile clips for example could be useful for this) and switch between the different types. Try playing them through your own rig, always the best method. Personally, if you are totally new to treble bleed mods, the parallel wired cap and resistor would be my recommended starting point. Overall it seems to be the most popular and most requested style, and a fairly 'safe' cap and resistor value spec of .001uF and 100kOhm or 120kohm is a great well rounded choice. I've made literally hundreds of these to this spec and the feedback from customers is always good. I also hear good things about the 'Suhr' spec parallel treble bleed which is a 680pF cap and 150kohm resistor, as well as Fender's factory treble bleed spec of .0012uF capacitor and a 150kOhm resistor
Wiring a capacitor and resistor in series
Often named the 'kinman mod' treble bleed, this sees a cap and resistor again but this time wired in series instead of parallel. This is perhaps most commonly done with a .0012uF capacitor and a 130kohm resistor, but kinman does of course offer some advice on what effect changing those values will have. To save miss-interpretation and be true to Kinman's recommendation and words here I will simply quote their information on the subject so please note these aren't my words, but those found on Kinman's website and all info within the quotation below remains theirs -
"The capacitance can be varied slightly from .001 to .0016 to fine tune the circuit to your cable, but you will have to increase the resistor value with the larger cap values and decrease the resistor value with the smaller cap values or else you will notice the curve of the pot starts to become noticeably different with the larger cap values. It's a delicate balance so deviating from the nominated values may excessively flatten the operating curve of the pot unless you compensate with the resistor value. Read more technical guff about this on the FAQ page Q24 . Rule of thumb is the *amount* of brightness that is gained is determined by the resistor's value (less Ohms = more brights) but the frequencies that are present is determined by the Cap value (lower the value the higher the frequencies, the higher the value the lower the frequencies)."
Some really interesting info and insight there, that may help you in your own experiments! This works really well and is certainly a side by side comparable choice to the parallel wired mod.
Wiring a capacitor with both parallel and series wired resistors
This method is essentially a combination of the two noted above, and might serve as a useful way to 'fine tune' a pre-existing parallel wired treble bleed too. If you have a parallel wired treble bleed mod, but feel it's not quite handling the frequencies as you would hoped, adding an additional series wired resistor usually on the input end of the volume pot, can help fine tune and tweak the response too. You'll generally see something like a 15kOhm or 20kOhm resistor wired additionally in series for these, but again it might vary depending on recommendation or requirements. 
Variable treble bleed
I think these are truly a superb option, a few brands offer them but I have only personally tried a couple, the 'PMT' V-Treb which I also stock, and a newer option to the market made by Alexis at ADR pedals in Greece (Pictured below). There is also the Mars-tronic 'Treblemaker', one I have been following for a while, made in the UK by Ben Marshall but I am yet to personally try out one.
These are usually a very small PCB with a cap and resistor and trim pot or mini switches. Mount the PCB directly onto the back of the pot (or remotely via wires) and solder to the input and output lugs of the volume pot as per the other treble bleed kits and you can tweak to find the perfect balance for the guitar and your personal preference. I would say all of these are set and forget types of things. Although they do offer lots of adjust-ability, I suspect once you have spent the initial time dialing in the adjustment you like, you'll seldom touch it again, but it's nice to know you can if you want to continue to experiment with the effect.
I would say the PMT V-Treb is the most straight forward design of the few variable kits on the market. This is a simple pre-set cap and resistor value but with an adjustable mini trim-pot where you simply play and turn it one side to the other to find the balance of effect you like, or what best suits that specific guitar. I really like the simplicity, yet ability to dial in easily. It honestly works brilliantly well, as I recently found for myself after using one in my Millimetric guitar. For example, that guitar came supplied with just a cap for the treble bleed, which was a bit too bright when rolled down for my personal tastes. I do rely on the volume pot quite a lot when playing, and this was my first time owning a guitar with gold foils so it was a new tonal experience I guess you could say! With the cap treble bleed mod not working for me, resulting in an overly bright rolled off volume tone, for the sake of testing the opposite first, I tried it without for sometime and found things gotten a little too muddy further down the volume pot so it clearly needed some form of treble bleed mod. I then tried 50s style tone cap wiring, which I did like overall, found it still got a little dark sounding further down the volume pot. So onward with finding the right treble bleed mod spec for me, which to be honest I was a bit bored of by this stage which lead to me giving the easily adjustable variable treble bleed a try. Honestly, brilliant! As the pots are all accessible from the back of the guitar, a little like a Les Paul or SG for example via a removable cover plate. I was able to play whilst making small adjustments to the trim pot and very quickly finding a setting that suited the guitar and my tastes perfectly well. If you want to dial in the right amount of treble retaining, but really don't want the hassle of buying a bunch of caps and resistor and spending a day at the soldering iron swapping them over, then this really is the winning solution. If you have a guitar like a Strat for example where accessing the back of the pot isn't simple due to needing to remove the strings and pickguard, then you can also remotely mount these. Simply solder a couple of wires to the PCB eyelets, choose a place that is more easily accessible, perhaps the strat jack socket cavity for example, and solder the other end of the wires to the volume pot. You can then remotely access the trim pot and dial it in without needing to remove everything for each adjustment. 
Next up is the ADR Pedals treble bleed kit (pictured above). A very similar look to the PMT V-Treb kit, but the main difference you'll notice is the set of mini switches. This allows you to flick between different treble bleed methods, and cap/resistor values, as well as a trim pot for further personal preference refinement. I feel this really builds on the simplicity of something like the PMT V-Treb for example, giving the player much more adjust-ability and refinement. So if you want the do-it-all spec variable kit, this is a superb choice and one I really liked on testing. I will note, Alexis did send me one for free to try out, but I wasn't paid to try it nor paid to add it to this article. He was merely interested in hearing my thoughts on it and I decided to add it to this article as I think it is a more than valid addition to the world of treble bleeds and something many players would find useful. It is certainly way, way easier than swapping out and soldering loads of different values. Plus look how neat it is, a great bit of kit and enjoyed having the chance to try one. I would perhaps say that this particular one is perhaps better mounting remotely, or using a short pair of jumper wires between the PCB and your pot lugs, I attempted soldering it to the pot lugs like how the V-Treb does, but the slightly smaller PCB eyelet holes made it tricky on the ADR. Wasn't a problem by any means, I would just personally say pop some wires on even if you are sticking it to the pot casing, the whole install will be much easier as a result. Tonally though it works brilliantly well and the ability to very, very easily switch between settings is user friendly. A great kit!
The Mars-Tronic 'Treble Maker'
This again is a variation on the variable treble bleed idea, but has some quick connects allowing you to fit whatever cap and resistor values you choose, then you can at the flick of switch change them from parallel to series, and tweak via the trim pot too. Ultimately, this really is the most versatile variable/adjustable treble bleed idea on the market today, offering the more curious guitar nerds the chance to really get stuck in and find their perfect spec without purchasing lots of different components separately and arming yourself with the soldering iron for ages. Everything comes in a neat package, ready to get stuck in.
It is ultimately a product more aimed at the gear nerd I would say, rather than a casual user, but that's not to say someone with a casual interest in this wouldn't still benefit, but it is more in depth solution. Still usable and user friendly don't get me wrong, but due to the wide variety of specs you could try, for some players it might be a little too much. If you love experimenting, have some prior experience with guitar wiring and don't mind getting stuck in yourself with trialling a wide variety of specs, I would say this is the best option for you. This allows you to try a huge variety of spec/value options simply via quick connects (once you've done the initial solder install of the variable PCB of course). An impressive option for sure! The Mars-Tronic Treble Maker
Summary
I hope this look at the different styles of treble bleed mod helps in your own guitar journey, if you find your favourite as a result feel free to share your thoughts, preferred method and why (with details of the guitar's spec and your rig for reference) it would be interesting to hear what everyone likes and why!
If you would like to buy a treble bleed mod, or the parts to make your own, they're all available on my website via the shop. Below is a brief list of some common value pairings (and a mention of which manufacturers use those specs). As you can see, there really is no 'industry standard' or preferred choice, it's all down to pickups installed & your personal preferences so it may well be a case of experimenting if a particular manufacturers recommendation doesn't cover it.
.001uF cap & 120kOhm resistor (Parallel) - This is a solid choice for most players and guitar types. To make things a bit easier, I have been offering this as the standard choice in my wiring harness kits for years and customer feedback has been great.
.001uF Capacitor & 100kOhm Resistor (Parallel) - Popular choice on Seymour Duncan wiring diagrams for their pickups
.001uF cap & 150kOhm resistor (Parallel) - Popular choice on TV Jones wiring diagrams for their pickups (Photo of this spec to follow)
.0012uF Capacitor & 130kOhm Resistor (Series) - The popular 'Kinman' mod. (to install, position the resistor lead out side on the input lug of the volume pot)
.0012uF Capacitor & 150kOhm Resistor (Parallel, with an additional 20kOhm resistor in Series) - Commonly seen in factory Fender instruments for example. (to install, position the series resistor lead out side on the input lug of the volume pot)
560pF Capacitor & 300kOhm Resistor (Parallel) - Popular choice on DiMarzio wiring diagrams for their pickups
680pF Capacitor & 150kOhm Resistor (Parallel) - Commonly seen installed on Suhr instruments
680pF Capacitor & 220kOhm Resistor (Parallel) - This spec was seen on the original run of Tom Delonge Signature Fender Stratocasters. I have been using this spec on my Delonge pre-wired volume pot kits, but thought it might be useful to offer it separately.
James
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