Product Spotlight - Treble Bleed mod

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.

Treble bleed kit parallel wired

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.

50s style wiring

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) 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
It doesn't end there unfortunately! The values of cap and resistor used can vary too, this is mainly down to manufacturers preferences. 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. 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. 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 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.

Treble bleed kit parallel wired (Suhr Spec)

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, but much further improves the volume pot sweep as a result. Very useable! The treble frequencies don't sound anywhere near as 'thin' as the cap only treble bleed method. Some would argue that wiring them in parallel can still sound thin and brittle further down the volume's sweep/taper, but my personal opinion after experimenting with this is that it is perhaps more down to other factors such as pickup type or pot value for example. As I haven't found this method to sound thin or brittle in any instance. With an audio taper pot, and let's say humbuckers, 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 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

Kinman Mod treble bleed


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! I believe many of Fender's more recently models come with the series wired treble bleed mod. This works really well and is certainly a side by side comparable choice to the parallel wired mod.

Variable treble bleed mod

Variable treble bleed
I think these are truly a superb option, a few brands offer them but I have personally only tried the kit made by 'PMT' with their V-Treb.
These are usually a very small PCB with a cap and resistor and trim pot. Mount the PCB directly onto the back of the pot (or remotely via wires) and solder to the input and ouput 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. It honestly works brilliantly well, as I recently found for myself - 
I actually had a bit of an ongoing battle finding just the right treble bleed option for my main Millimetric guitar. It 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 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 onwards 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. 

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 Capacitor & 120kOhm Resistor (Parallel) - General purpose popular choice, same spec as the main seller on my site. A popular all-rounder
.001uF Capacitor & 100kOhm Resistor (Parallel) - Popular choice on Seymour Duncan wiring diagrams for their pickups
680pF Capacitor & 150kOhm Resistor (Parallel) - Commonly seen installed on Suhr instruments
560pF Capacitor & 300kOhm Resistor (Parallel) - Popular choice on DiMarzio wiring diagrams for their pickups
.0012uF Capacitor & 150kOhm Resistor (Parallel, with an additional 20kOhm resistor in Series) - Commonly seen in factory Fender instruments for example
.0012uF Capacitor & 130kOhm Resistor (Series) - The popular 'Kinman' mod mentioned in this article

James

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