NRG Effects x Home of Tone - FUZZMASTER Pre-Wired Jazzmaster wiring harness w/Si Fuzz circuit | Right Handed

£269.99

Please use the tabs below to read through the information about this Pre-Wired harness kit. From a run down of what the kit does, to important fitting information and full specs.

Order times

I usually make harnesses to order, due to the variety of spec options that could be chosen across the whole range. The current turnaround time for a FUZZMASTER harness order is around 5-7 working days depending on quantity of orders in at the time and your order will be updated accordingly when it is dispatched. This turnaround time doesn't include the transit time. Thanks for your patience whilst I get your harness made!

Model Description

It's no secret that I love Jazzmasters. From the playing comfort of the offset shape, to the intuitive vibrato and ultimately, the sound. I have long offered a number of harness options for Jazzmasters, but I have always wanted to try something a little different to what I normally offer. So I enlisted the talented help of Neil Grimes of NRG Effects, to make use of his awesome pedal circuits, and in particular his in-guitar effects that he has developed over time for luthiers to create a full pre-wired harness with in-built fuzz!! 

I have always been interested in the concept of built in effects, I think it's a cool idea that I wanted to pursue at some point. Retrofitting a pedal style on board circuit into a guitar  usually entails additional routing to the guitar to accomodate, and this aspect of it has always put me off the idea. Although re-routing is viable for some people, I would think it's safe to say that for most people, it would be enough to make it a no-go and make the process a deal breaker. So for me, coming up with an effect loaded harness would need to be done in the least invasive way possible to the destined guitar and ideally no additional major modifications required.

Which then leads to the question, what guitars can accomodate such a thing without extra routing work needed? Well, A traditionally routed Jazzmaster offers such a great base for incorporating in-built effects as they have a large cavity space, as well a pickguard that traditionally already has accomodation for an extra switch and controls. For this particular harness we have repurposed the rhythm circuit to become home for the Fuzz controls. It retains the standard rhythm circuit layout (IE, slide switch and two roller knobs) but this time you have the slide switch engaging and disengaging the onboard fuzz, and the roller pots controlling volume and bias for the fuzz. These controls will suit a standard cutout Jazzmaster pickguard, so no mods to the pickguard required, no extra holes etc providing you already have a traditional full Jazzmaster pickguard of course. (Feel free to message me first to confirm if you JM pickguard is standard first if not sure yourself). 

Your 'lead' circuit remains standard in terms of functionality, with a 3 way pickup selector toggle switch, volume, tone and jack. So with the fuzz off, you’ll have pretty traditional functionality and tone from your remaining lead circuit, but keep in mind you won’t have a rhythm circuit due to the fuzz taking it’s place. 

The fuzz circuit itself is handwired, beautifully I might add! by Neil at NRG Effects. It has been kept as compact as possible to take up as little body cavity real estate as we can. I'll touch on more about the circuit style itself in the section below. It comes with a 'perch' with self adhesive pad, which allows it to be securely mounted to the back of the pickguard within the cavity space and kept clear of other components safely. I have then hand wired it into the full guitar harness.

The fuzz circuit of course does require power, and that is done so via a 9v battery. This again can be accomodated for within the existing/standard traditional Jazzmaster body cavity, and you'll be supplied with a battery connector clip pre soldered.
Important note/caveat: This does of course mean that to change the battery, you will need to remove the pickguard to access it. The decision behind this was that I figured this was certainly the easier option than to expect you to route the guitars body for a dedicated quick access battery compartment! For this reason though, I do highly recommend using a quality, long life 9v battery with this kit. For example, Duracell Plus, Energizer Max or Ultimate, or Ultralife lithium which all would provide long reliable use between changes. But to further this ensure you unplug your guitar when not in use. 

The kit also comes supplied with a ‘Ground Bug’ pre installed on the lead circuit volume pot. If you’re not already familiar with the ground bug, it is a awesome helping hand for making ground connections. No need to solder your pickup or bridge ground wires to the pot casing with the ground bug install, as you simply solder those wires to the neat and easy to solder lugs instead. Full details are covered in the instructions but thought I’d cover a little about them here too. 

Please do take the time to read through the instructions/install details in the tabs below, as there are a few more things consider with installing this kit over a traditional guitar harness. 

The NRG Fuzz Circuit

All well and good putting a fuzz into a guitar, but ultimately you'll want to know whether the fuzz will be one that you like. So let's look at what this one is - 

This fuzz circuit is designed and made by Neil Grimes of NRG Effects. It has been designed to cover a good range of fuzz tones, from classic vintage style 2 transistor fuzz tones, to bigger and bolder modern sounding distortion/fuzz along with that spitty, gated/starved type response too. Have fun experimenting with the wide variety of fuzz tones available, or 'set and forget' leaving it set to your favourite tone ready to be turned on at your convenience! 

It is a Silicon based fuzz circuit design, with lower gain transistors to help volume control clean up. You'll notice a nice prompt clean up via your guitars main lead circuit volume pot too, much like when using a pedal format Si Fuzz for example.

I suspect a lot of the tones on tap here will be super familiar to fuzz enthusiasts, particularly in how the controls interact. For those less familiar with fuzz circuits, I do hope the description above gives you a good idea of what to expect and what tones can be achieved via the circuit. Ultimately, banging a Si Fuzz circuit directly into your guitar isn't exactly for the faint hearted anyway, but do think this fuzz design covers a good range of ground for players so hope you like it!

I have sent my demo Jazzmaster off to a demo channel to have a more formal demo made of this kit and how it sounds, so hopefully that will be here and ready for listening pleasure as soon as possible. 

How your controls work

With the 2 position slide switch flicked downwards, you are in regular lead circuit Jazzmaster town. Here you'll have the familiar lead circuit controls with your 3 way pickup selector switch, master volume and master treble cut tone control. No compromises to your Jazzmasters lead circuit functionality and tones available. 

With the 2 position slide switch flicked upwards, this would have traditionally been engaging your rhyhm circuit, but with the FUZZMASTER harness you have now engaged the fuzz circuit instead! The roller wheel knobs that were previously your rhythm circuit volume and tone, are now the fuzzes dedicated volume and bias controls.
The roller wheel control knob closest to the slide switch is your overall volume for the fuzz. Roll it towards the slide switch to increase the fuzz circuits volume, but a friendly word of warning, it gets real loud when dimed! and roll it towards the other roller wheel knob to reduce it's volume. 
The roller wheel control knob furthest from the slide switch is the bias control, this will take your fuzz from starved spitty tones, through the gain levels right to soaring fuzz. Roll it towards the switch to increase gain and away the switch to starve. The roller wheel directions should feel familiar to JM players. The volume and bias controls are quite interactive with one another too, so do experiment with the two to unlock all the tones possible from the NRG circuit.

With the fuzz on, the guitars 'lead circuit' volume and tone will still work as 'normal' in terms of volume and treble cut tone control. But fans of fuzz circuits will be familiar with how the guitars regular volume and tone will now interact with the fuzz too (I will add that the volume pot cleans up the fuzz super well). So for example. with the fuzz on, you will still be able to roll off the guitars volume or tone as you please, but understandbly you may notice a difference in how those respond much like when you have a pedal format fuzz on too. 

Product Options

Pot value?
This option refers only to the main lead circuit volume and tone controls, and ultimately which you choose may be down to personal preference or what the pickup manufacturer of the pickup set you have installed recommends for optimal use. But here’s some info to help guide the choice if you’re not already sure what you’ll need - 

I offer it with the popular spec audio/logarithmic 1MEG lead circuit pots for both volume and tone. This is perhaps the most popular choice for modern built Jazzmasters as audio taper closer represents how the human ear responds to sound, in a logarithmic manner, and is often the the standard spec on modern day made and reissue instruments. Ultimately, it's personal choice but I would say from years of making/offering pre-wired JM kits, audio taper specs are by far the most popular/most ordered overall. This pot spec will be equipped with traditional JM cap spec of .033uF.

One thing I noticed with Jazzmasters is that due to their naturally bright tone, rolling off the 1MEG audio taper volume pot can naturally lose some of the brightness through the taper quite noticably. For some players this isn't a bad thing and use it to their advantage to alter the tone. But if you like your top end, to help with this and retain the chime right through the pot sweep, I also offer the option of a treble bleed cap too which I'll touch on in more detail below. But in brief, this will help retain the otherwise 'lost' treble frequencies as the volume rolls down and puts it back into the signal helping maintain that JM chimey/bright character right down the volume pot. 

If your Jazzmaster has an alternative style set of pickups, like humbuckers or P90s perhaps, or simply want to tame some of the top end brightness associated with Jazzmasters, then I also offer this harness with 500k pots too. These are audio taper as standard for both volume and tone. This pot spec will be equipped with a .022uF tone cap spec.

With or without treble bleed?
First up, what does it do? Without a 'treble bleed', when you roll down the volume pot it will naturally lose some of the treble frequencies through the sweep. Jazzmaster players in particular might be familiar with this as they are susceptible to it due to the 1MEG pot spec and how they respond overall. A Treble Bleed takes the 'high' treble tone frequencies as they're naturally 'lost' whilst rolling down through the volume pot and basically 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 and a more uniform tone from 1 to 10. Some guitar players wouldn't be without a treble bleed, and many have never used one on their guitars. Truth is, it is very much personal preference. If you like the idea of retaining treble as you roll your volume pot down, then a treble bleed is for you! For the standard spec, I use a ceramic .001uF capacitor with a carbon film 120kOhm resistor parallel wired.

With or without copper foil shielding
This is noted in more detail below in the fitting info section, but in short, we highly recommend, or insist is probably the better phrase, ensuring your Jazzmaster has full copper foil cavity/pickguard shielding with the FUZZMASTER kit. Your guitar may already have this applied throughout, so you can click ‘without’ and continue on, but if you do not have copper foil shielding then you can select ‘With’ and I will ship your FUZZMASTER harness with a roll of quality self adhesive conductive copper foil shielding too. I will supply enough to comfortable apply it throughout your cavity and on the back of the pickguard ready for installation of the harness. I have prepped the harness ground with the use of foil shielding in mind, so please do ensure you have it and it is effectively applied to provide sufficient ground continuity.

Important Fitting information

As this particular harness functions differently to a regular guitar harness, myself and Neil at NRG Effects HIGHLY recommend that your Jazzmaster has quality, and effective, copper foil shielding throughout the cavity and rear of the pickguard. I also pre-solder the harness based upon it being fitted to a copper foil backed pickguard. This will help with noise reduction and get the best from the wiring and on board effect as a result. 

In this section you'll find some important fitting notes that will hopefully help you assess whether the kit is suitable for your exact Jazzmaster, your install ability or what is required to allow it to fit correctly. Please take the time to read through these details.

There are additional steps involved with this kit due to it incorporating the active fuzz circuit, such as securely mounting the fuzz Board, battery and cavity shielding. I don’t mean to scare anyone off, but more-so educate in advance and help you make an informed decision as to whether you fit the kit or have a professional carry out the process for you depending on experience. I hope all of this info as well as my associated install tips guide on the blog, helps the process, and makes it easier to carry out.

Will the kit fit my Jazzmaster?

Perhaps the most important question! This kit has been designed for traditionally routed Jazzmaster bodies. IE one with a full rhyhm/lead circuit layout. If your Jazzmaster currently has a traditional circuit layout, with a rhythm circuit etc, then it stands a very good chance you have a traditionally routed Jazzmaster cavity. If your Jazzmaster has no rhythm circuit, so a lead only circuit which there are a few Fender JM models produced to that spec, then it stands a very good chance your guitar does not have the full traditionally routed cavity. If your Jazzmaster is a 'copy' IE, a model produced by another brand, then I cannot guarantee this kit will fit. It has been designed for Fender Jazzmasters. I have run a trial install in a Squier Vintage Modified Jazzmaster, and it fit nicely, this is because it has Fender spec/traditionally routed control cavities. If you are unsure about suitability to your Jazzmaster, what control cavity it has etc, then please get in touch with some clear photos of the guitar and it's control cavity. 
This same info essentially also applies to the pickguard, if your Jazzmaster has traditional cut-outs for a rhythm and lead circuit, then this kit will fit without the need for a new pickguard. But please note info below regarding pot hole diameters as depending on where your JM is made, will affect whether it has smaller or wider pot holes currently.
If your Jazzmaster has no rhythm circuit, then aside from the body cavities, it will also need a new pickguard to accomodate the fuzz circuit. Again, feel free to message me if you're not sure. 

Can I fit this kit myself?
In terms of soldering upon install, this kit is surprisingly simple, with only your pickup wires and ground wire(s) to be soldered in by the person installing. I have also opted to supply this kit with a ‘Ground Bug’ washer to further simplify your ground wire soldering procedure. The Ground Bug is a solder lug washer design, made from the same material as the lugs on a CTS pot, it is incredibly easy to solder onto, helping make your ground wire connections much easier than having to solder onto a pot casing if this is something you dread doing! There is a little more planning/lining up etc to consider when mounting the components, as you'll need to comfortably fit the circuit and battery within the body routing too. With some care and consideration, it is of course nice and simple so best thing to do is take your time and you're good to go :)

Fitting the kit yourself ultimately comes down to whether you own the equipment needed to correctly and safely install the kit, or how comfortable you feel working on your own guitar.
I do feel that installing a pre-wired guitar harness is do-able for many guitarists but only if the correct tools are used and care is taken to ensure you do not damage the kit, your guitar or yourself! There is a dedicated install guide/tips page for the FUZZMASTER harness, all to help make the process as easy as possible. But if for any reason you have concerns about fitting the kit yourself, then I'm sure you'll agree that it is likely best to have a professional fit the kit and help ensure your purchased kit, and your beloved guitar are both looked after and worked on correctly. 
If you are local to me (Stourbridge, West Midlands) I take on guitar work no problem at all so will certainly be able to help install your Signature Series FUZZMASTER kit.

Will the pots/jack fit my pickguard and jack plate?
The components I use in my Signature Series wiring kits are for the most part, USA imperial specification, and will be a direct replacement for a genuine USA or Mexico made Fender Jazzmaster. If you're fitting this harness to different model/spec of Jazzmaster, Squier or MIJ for example, then you may (most likely will) have to widen the holes in the pickguard to accommodate for these imperial measurement pots. 
The CTS pots and stereo jack have a mounting thread shaft diameter of 0.369" / 9.38mm so I recommend for ease of install a pickguard with 0.394" / 10mm pot/jack mounting holes. You can easily widen the holes in the Pickguard if you would prefer not to buy a new pickguard, and I recommend doing this safely with a step cutter drill bit. But I also offer this as a service so if you would like me to widen your plate for you, do please get in touch and we can organise this additionally.

What control knobs will fit?
The kit uses CTS split shaft pots as standard in the lead circuit Split shaft pots have a adjustable split shaft diameter of 5.95mm w/ 24 splines. You will need control knobs that push-fit and suit these measurements. 
Do not attempt to force fit smaller, metric/import spec control knobs onto the imperial USA spec pots, doing this can damage the pot.

If you do require a US spec control knobs, I do carry a selection of popular options in stock and they can be viewed in the Control Knob category on the store.

The harness does come supplied with the roller wheel control knobs pre fitted on the fuzz controls for you. Those secure to the pot shaft with a grub screw, and you may need to loosen/adjust their precise position depending on the exact pickguard as they can all ever so slightly differ. 

Which switch tip will fit?
Much like with the control knobs, the lead circuit Switchcraft pickup selector in this kit is USA spec, with imperial thread sizes. Therefore you need a imperial thread switch toggle tip to suit Switchcraft toggles.

If you do require a US spec switch tip, I do carry a selection of popular options in stock and they can be viewed in the Switch Tips category on the store.

Grounding/shielding
As noted above, when fitting this FUZZMASTER harness we highly recommend that you have full copper foil shielding throughout the cavity. If your Jazzmaster already has this applied, then great! If not, then you can choose to have a roll of shielding tape included with your harness order. If this isn’t something you feel confident doing, then feel free to contact myself if you're local to carry out the application and install, or your local trusted guitar tech to carry out the application and install too.

Specs/Parts included

- Choice of lead circuit pot values/specs:
2x CTS 450 Series 1MEG Audio taper (volume and tone)
1x CTS 1MEG Linear taper for Volume w/ 1x 1MEG audio taper for tone
2x CTS '450' Series 500k audio taper (Volume and tone)
- Choice of lead circuit treble bleed mod (.001uF cap w/120kOhm resistor in parallel)
- 1x Ground Bug - ground wire soldering washer
- 1x .022uF or .033uF Mustard tone capacitor in the lead circuit
- 1x Switchcraft right angle 3 way toggle switch
- 1x Switchcraft 2 position DPDT slide switch
- 1x Right angle rhythm circuit mounting bracket
- 2x Roller wheel control knobs for fuzz controls
- 1x Alpha B100k mini pot (fuzz volume control)
- 1x Alpha B10k mini pot (fuzz bias control)
- 1x 9v Battery Clip (Battery is not included with kit)
- 1x Velcro 9v battery pouch
- 1x NRG Effects FUZZMASTER circuit
- Gavitt USA made cloth covered 22AWG wire

- Soldered using R-Tech Premium Lead-Free (Sn95.5Ag3.9Cu0.6) 22swg Solder wire 
RoHS Compliant

Please note - wiring kit does not include new lead circuit control knobs/switch tip etc but does include the switch/pot/jack mounting nuts, washers & screws and does include the roller wheel control knobs for the fuzz controls. Please see above spec/item list for full detailed run down of what is included or drop me a message if you aren't 100% sure.

Harness FAQ's

I've been proudly making, developing and installing my pre-wired guitar harnesses since the beginning of the Home of Tone back in 2015 (time flies when you're having fun right!). Although I feel I do my best in covering as much information as possible across the various product listings, fitting guides, wiring diagrams and more, I thought it might be helpful to put together an FAQ's page that covers some of the general additional questions I get asked. You can view these Harness FAQ's HERE

Do you make custom harnesses?

I'm afraid I do not offer a custom harness service. Only kits developed, tested and listed on my website are the available kits. So no custom schematics etc. If you happen to be local to my office, then I do carry out custom work in house, but in regards to shipped out pre-wired harnesses I do not offer custom kits. I am however happy to use different pot values or cap values within reason if you have a specific requirement that differs to the specs listed above. If this is relevant to yourself then please get in touch to discuss further to ensure the request is possible. 

Please use the tabs below to read through the information about this Pre-Wired harness kit. From a run down of what the kit does, to important fitting information and full specs.

I usually make harnesses to order, due to the variety of spec options that could be chosen across the whole range. The current turnaround time for a FUZZMASTER harness order is around 5-7 working days depending on quantity of orders in at the time and your order will be updated accordingly when it is dispatched. This turnaround time doesn't include the transit time. Thanks for your patience whilst I get your harness made!

It's no secret that I love Jazzmasters. From the playing comfort of the offset shape, to the intuitive vibrato and ultimately, the sound. I have long offered a number of harness options for Jazzmasters, but I have always wanted to try something a little different to what I normally offer. So I enlisted the talented help of Neil Grimes of NRG Effects, to make use of his awesome pedal circuits, and in particular his in-guitar effects that he has developed over time for luthiers to create a full pre-wired harness with in-built fuzz!! 

I have always been interested in the concept of built in effects, I think it's a cool idea that I wanted to pursue at some point. Retrofitting a pedal style on board circuit into a guitar  usually entails additional routing to the guitar to accomodate, and this aspect of it has always put me off the idea. Although re-routing is viable for some people, I would think it's safe to say that for most people, it would be enough to make it a no-go and make the process a deal breaker. So for me, coming up with an effect loaded harness would need to be done in the least invasive way possible to the destined guitar and ideally no additional major modifications required.

Which then leads to the question, what guitars can accomodate such a thing without extra routing work needed? Well, A traditionally routed Jazzmaster offers such a great base for incorporating in-built effects as they have a large cavity space, as well a pickguard that traditionally already has accomodation for an extra switch and controls. For this particular harness we have repurposed the rhythm circuit to become home for the Fuzz controls. It retains the standard rhythm circuit layout (IE, slide switch and two roller knobs) but this time you have the slide switch engaging and disengaging the onboard fuzz, and the roller pots controlling volume and bias for the fuzz. These controls will suit a standard cutout Jazzmaster pickguard, so no mods to the pickguard required, no extra holes etc providing you already have a traditional full Jazzmaster pickguard of course. (Feel free to message me first to confirm if you JM pickguard is standard first if not sure yourself). 

Your 'lead' circuit remains standard in terms of functionality, with a 3 way pickup selector toggle switch, volume, tone and jack. So with the fuzz off, you’ll have pretty traditional functionality and tone from your remaining lead circuit, but keep in mind you won’t have a rhythm circuit due to the fuzz taking it’s place. 

The fuzz circuit itself is handwired, beautifully I might add! by Neil at NRG Effects. It has been kept as compact as possible to take up as little body cavity real estate as we can. I'll touch on more about the circuit style itself in the section below. It comes with a 'perch' with self adhesive pad, which allows it to be securely mounted to the back of the pickguard within the cavity space and kept clear of other components safely. I have then hand wired it into the full guitar harness.

The fuzz circuit of course does require power, and that is done so via a 9v battery. This again can be accomodated for within the existing/standard traditional Jazzmaster body cavity, and you'll be supplied with a battery connector clip pre soldered.
Important note/caveat: This does of course mean that to change the battery, you will need to remove the pickguard to access it. The decision behind this was that I figured this was certainly the easier option than to expect you to route the guitars body for a dedicated quick access battery compartment! For this reason though, I do highly recommend using a quality, long life 9v battery with this kit. For example, Duracell Plus, Energizer Max or Ultimate, or Ultralife lithium which all would provide long reliable use between changes. But to further this ensure you unplug your guitar when not in use. 

The kit also comes supplied with a ‘Ground Bug’ pre installed on the lead circuit volume pot. If you’re not already familiar with the ground bug, it is a awesome helping hand for making ground connections. No need to solder your pickup or bridge ground wires to the pot casing with the ground bug install, as you simply solder those wires to the neat and easy to solder lugs instead. Full details are covered in the instructions but thought I’d cover a little about them here too. 

Please do take the time to read through the instructions/install details in the tabs below, as there are a few more things consider with installing this kit over a traditional guitar harness. 

All well and good putting a fuzz into a guitar, but ultimately you'll want to know whether the fuzz will be one that you like. So let's look at what this one is - 

This fuzz circuit is designed and made by Neil Grimes of NRG Effects. It has been designed to cover a good range of fuzz tones, from classic vintage style 2 transistor fuzz tones, to bigger and bolder modern sounding distortion/fuzz along with that spitty, gated/starved type response too. Have fun experimenting with the wide variety of fuzz tones available, or 'set and forget' leaving it set to your favourite tone ready to be turned on at your convenience! 

It is a Silicon based fuzz circuit design, with lower gain transistors to help volume control clean up. You'll notice a nice prompt clean up via your guitars main lead circuit volume pot too, much like when using a pedal format Si Fuzz for example.

I suspect a lot of the tones on tap here will be super familiar to fuzz enthusiasts, particularly in how the controls interact. For those less familiar with fuzz circuits, I do hope the description above gives you a good idea of what to expect and what tones can be achieved via the circuit. Ultimately, banging a Si Fuzz circuit directly into your guitar isn't exactly for the faint hearted anyway, but do think this fuzz design covers a good range of ground for players so hope you like it!

I have sent my demo Jazzmaster off to a demo channel to have a more formal demo made of this kit and how it sounds, so hopefully that will be here and ready for listening pleasure as soon as possible. 

With the 2 position slide switch flicked downwards, you are in regular lead circuit Jazzmaster town. Here you'll have the familiar lead circuit controls with your 3 way pickup selector switch, master volume and master treble cut tone control. No compromises to your Jazzmasters lead circuit functionality and tones available. 

With the 2 position slide switch flicked upwards, this would have traditionally been engaging your rhyhm circuit, but with the FUZZMASTER harness you have now engaged the fuzz circuit instead! The roller wheel knobs that were previously your rhythm circuit volume and tone, are now the fuzzes dedicated volume and bias controls.
The roller wheel control knob closest to the slide switch is your overall volume for the fuzz. Roll it towards the slide switch to increase the fuzz circuits volume, but a friendly word of warning, it gets real loud when dimed! and roll it towards the other roller wheel knob to reduce it's volume. 
The roller wheel control knob furthest from the slide switch is the bias control, this will take your fuzz from starved spitty tones, through the gain levels right to soaring fuzz. Roll it towards the switch to increase gain and away the switch to starve. The roller wheel directions should feel familiar to JM players. The volume and bias controls are quite interactive with one another too, so do experiment with the two to unlock all the tones possible from the NRG circuit.

With the fuzz on, the guitars 'lead circuit' volume and tone will still work as 'normal' in terms of volume and treble cut tone control. But fans of fuzz circuits will be familiar with how the guitars regular volume and tone will now interact with the fuzz too (I will add that the volume pot cleans up the fuzz super well). So for example. with the fuzz on, you will still be able to roll off the guitars volume or tone as you please, but understandbly you may notice a difference in how those respond much like when you have a pedal format fuzz on too. 

Pot value?
This option refers only to the main lead circuit volume and tone controls, and ultimately which you choose may be down to personal preference or what the pickup manufacturer of the pickup set you have installed recommends for optimal use. But here’s some info to help guide the choice if you’re not already sure what you’ll need - 

I offer it with the popular spec audio/logarithmic 1MEG lead circuit pots for both volume and tone. This is perhaps the most popular choice for modern built Jazzmasters as audio taper closer represents how the human ear responds to sound, in a logarithmic manner, and is often the the standard spec on modern day made and reissue instruments. Ultimately, it's personal choice but I would say from years of making/offering pre-wired JM kits, audio taper specs are by far the most popular/most ordered overall. This pot spec will be equipped with traditional JM cap spec of .033uF.

One thing I noticed with Jazzmasters is that due to their naturally bright tone, rolling off the 1MEG audio taper volume pot can naturally lose some of the brightness through the taper quite noticably. For some players this isn't a bad thing and use it to their advantage to alter the tone. But if you like your top end, to help with this and retain the chime right through the pot sweep, I also offer the option of a treble bleed cap too which I'll touch on in more detail below. But in brief, this will help retain the otherwise 'lost' treble frequencies as the volume rolls down and puts it back into the signal helping maintain that JM chimey/bright character right down the volume pot. 

If your Jazzmaster has an alternative style set of pickups, like humbuckers or P90s perhaps, or simply want to tame some of the top end brightness associated with Jazzmasters, then I also offer this harness with 500k pots too. These are audio taper as standard for both volume and tone. This pot spec will be equipped with a .022uF tone cap spec.

With or without treble bleed?
First up, what does it do? Without a 'treble bleed', when you roll down the volume pot it will naturally lose some of the treble frequencies through the sweep. Jazzmaster players in particular might be familiar with this as they are susceptible to it due to the 1MEG pot spec and how they respond overall. A Treble Bleed takes the 'high' treble tone frequencies as they're naturally 'lost' whilst rolling down through the volume pot and basically 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 and a more uniform tone from 1 to 10. Some guitar players wouldn't be without a treble bleed, and many have never used one on their guitars. Truth is, it is very much personal preference. If you like the idea of retaining treble as you roll your volume pot down, then a treble bleed is for you! For the standard spec, I use a ceramic .001uF capacitor with a carbon film 120kOhm resistor parallel wired.

With or without copper foil shielding
This is noted in more detail below in the fitting info section, but in short, we highly recommend, or insist is probably the better phrase, ensuring your Jazzmaster has full copper foil cavity/pickguard shielding with the FUZZMASTER kit. Your guitar may already have this applied throughout, so you can click ‘without’ and continue on, but if you do not have copper foil shielding then you can select ‘With’ and I will ship your FUZZMASTER harness with a roll of quality self adhesive conductive copper foil shielding too. I will supply enough to comfortable apply it throughout your cavity and on the back of the pickguard ready for installation of the harness. I have prepped the harness ground with the use of foil shielding in mind, so please do ensure you have it and it is effectively applied to provide sufficient ground continuity.

As this particular harness functions differently to a regular guitar harness, myself and Neil at NRG Effects HIGHLY recommend that your Jazzmaster has quality, and effective, copper foil shielding throughout the cavity and rear of the pickguard. I also pre-solder the harness based upon it being fitted to a copper foil backed pickguard. This will help with noise reduction and get the best from the wiring and on board effect as a result. 

In this section you'll find some important fitting notes that will hopefully help you assess whether the kit is suitable for your exact Jazzmaster, your install ability or what is required to allow it to fit correctly. Please take the time to read through these details.

There are additional steps involved with this kit due to it incorporating the active fuzz circuit, such as securely mounting the fuzz Board, battery and cavity shielding. I don’t mean to scare anyone off, but more-so educate in advance and help you make an informed decision as to whether you fit the kit or have a professional carry out the process for you depending on experience. I hope all of this info as well as my associated install tips guide on the blog, helps the process, and makes it easier to carry out.

Will the kit fit my Jazzmaster?

Perhaps the most important question! This kit has been designed for traditionally routed Jazzmaster bodies. IE one with a full rhyhm/lead circuit layout. If your Jazzmaster currently has a traditional circuit layout, with a rhythm circuit etc, then it stands a very good chance you have a traditionally routed Jazzmaster cavity. If your Jazzmaster has no rhythm circuit, so a lead only circuit which there are a few Fender JM models produced to that spec, then it stands a very good chance your guitar does not have the full traditionally routed cavity. If your Jazzmaster is a 'copy' IE, a model produced by another brand, then I cannot guarantee this kit will fit. It has been designed for Fender Jazzmasters. I have run a trial install in a Squier Vintage Modified Jazzmaster, and it fit nicely, this is because it has Fender spec/traditionally routed control cavities. If you are unsure about suitability to your Jazzmaster, what control cavity it has etc, then please get in touch with some clear photos of the guitar and it's control cavity. 
This same info essentially also applies to the pickguard, if your Jazzmaster has traditional cut-outs for a rhythm and lead circuit, then this kit will fit without the need for a new pickguard. But please note info below regarding pot hole diameters as depending on where your JM is made, will affect whether it has smaller or wider pot holes currently.
If your Jazzmaster has no rhythm circuit, then aside from the body cavities, it will also need a new pickguard to accomodate the fuzz circuit. Again, feel free to message me if you're not sure. 

Can I fit this kit myself?
In terms of soldering upon install, this kit is surprisingly simple, with only your pickup wires and ground wire(s) to be soldered in by the person installing. I have also opted to supply this kit with a ‘Ground Bug’ washer to further simplify your ground wire soldering procedure. The Ground Bug is a solder lug washer design, made from the same material as the lugs on a CTS pot, it is incredibly easy to solder onto, helping make your ground wire connections much easier than having to solder onto a pot casing if this is something you dread doing! There is a little more planning/lining up etc to consider when mounting the components, as you'll need to comfortably fit the circuit and battery within the body routing too. With some care and consideration, it is of course nice and simple so best thing to do is take your time and you're good to go :)

Fitting the kit yourself ultimately comes down to whether you own the equipment needed to correctly and safely install the kit, or how comfortable you feel working on your own guitar.
I do feel that installing a pre-wired guitar harness is do-able for many guitarists but only if the correct tools are used and care is taken to ensure you do not damage the kit, your guitar or yourself! There is a dedicated install guide/tips page for the FUZZMASTER harness, all to help make the process as easy as possible. But if for any reason you have concerns about fitting the kit yourself, then I'm sure you'll agree that it is likely best to have a professional fit the kit and help ensure your purchased kit, and your beloved guitar are both looked after and worked on correctly. 
If you are local to me (Stourbridge, West Midlands) I take on guitar work no problem at all so will certainly be able to help install your Signature Series FUZZMASTER kit.

Will the pots/jack fit my pickguard and jack plate?
The components I use in my Signature Series wiring kits are for the most part, USA imperial specification, and will be a direct replacement for a genuine USA or Mexico made Fender Jazzmaster. If you're fitting this harness to different model/spec of Jazzmaster, Squier or MIJ for example, then you may (most likely will) have to widen the holes in the pickguard to accommodate for these imperial measurement pots. 
The CTS pots and stereo jack have a mounting thread shaft diameter of 0.369" / 9.38mm so I recommend for ease of install a pickguard with 0.394" / 10mm pot/jack mounting holes. You can easily widen the holes in the Pickguard if you would prefer not to buy a new pickguard, and I recommend doing this safely with a step cutter drill bit. But I also offer this as a service so if you would like me to widen your plate for you, do please get in touch and we can organise this additionally.

What control knobs will fit?
The kit uses CTS split shaft pots as standard in the lead circuit Split shaft pots have a adjustable split shaft diameter of 5.95mm w/ 24 splines. You will need control knobs that push-fit and suit these measurements. 
Do not attempt to force fit smaller, metric/import spec control knobs onto the imperial USA spec pots, doing this can damage the pot.

If you do require a US spec control knobs, I do carry a selection of popular options in stock and they can be viewed in the Control Knob category on the store.

The harness does come supplied with the roller wheel control knobs pre fitted on the fuzz controls for you. Those secure to the pot shaft with a grub screw, and you may need to loosen/adjust their precise position depending on the exact pickguard as they can all ever so slightly differ. 

Which switch tip will fit?
Much like with the control knobs, the lead circuit Switchcraft pickup selector in this kit is USA spec, with imperial thread sizes. Therefore you need a imperial thread switch toggle tip to suit Switchcraft toggles.

If you do require a US spec switch tip, I do carry a selection of popular options in stock and they can be viewed in the Switch Tips category on the store.

Grounding/shielding
As noted above, when fitting this FUZZMASTER harness we highly recommend that you have full copper foil shielding throughout the cavity. If your Jazzmaster already has this applied, then great! If not, then you can choose to have a roll of shielding tape included with your harness order. If this isn’t something you feel confident doing, then feel free to contact myself if you're local to carry out the application and install, or your local trusted guitar tech to carry out the application and install too.

- Choice of lead circuit pot values/specs:
2x CTS 450 Series 1MEG Audio taper (volume and tone)
1x CTS 1MEG Linear taper for Volume w/ 1x 1MEG audio taper for tone
2x CTS '450' Series 500k audio taper (Volume and tone)
- Choice of lead circuit treble bleed mod (.001uF cap w/120kOhm resistor in parallel)
- 1x Ground Bug - ground wire soldering washer
- 1x .022uF or .033uF Mustard tone capacitor in the lead circuit
- 1x Switchcraft right angle 3 way toggle switch
- 1x Switchcraft 2 position DPDT slide switch
- 1x Right angle rhythm circuit mounting bracket
- 2x Roller wheel control knobs for fuzz controls
- 1x Alpha B100k mini pot (fuzz volume control)
- 1x Alpha B10k mini pot (fuzz bias control)
- 1x 9v Battery Clip (Battery is not included with kit)
- 1x Velcro 9v battery pouch
- 1x NRG Effects FUZZMASTER circuit
- Gavitt USA made cloth covered 22AWG wire

- Soldered using R-Tech Premium Lead-Free (Sn95.5Ag3.9Cu0.6) 22swg Solder wire 
RoHS Compliant

Please note - wiring kit does not include new lead circuit control knobs/switch tip etc but does include the switch/pot/jack mounting nuts, washers & screws and does include the roller wheel control knobs for the fuzz controls. Please see above spec/item list for full detailed run down of what is included or drop me a message if you aren't 100% sure.

I've been proudly making, developing and installing my pre-wired guitar harnesses since the beginning of the Home of Tone back in 2015 (time flies when you're having fun right!). Although I feel I do my best in covering as much information as possible across the various product listings, fitting guides, wiring diagrams and more, I thought it might be helpful to put together an FAQ's page that covers some of the general additional questions I get asked. You can view these Harness FAQ's HERE

I'm afraid I do not offer a custom harness service. Only kits developed, tested and listed on my website are the available kits. So no custom schematics etc. If you happen to be local to my office, then I do carry out custom work in house, but in regards to shipped out pre-wired harnesses I do not offer custom kits. I am however happy to use different pot values or cap values within reason if you have a specific requirement that differs to the specs listed above. If this is relevant to yourself then please get in touch to discuss further to ensure the request is possible.