PRS offered the Sweet Switch feature from the mid ’80s until 1991, so it is long out of production and no longer available. The story goes that Carlos Santana used very long guitar cables on stage, and when he switched over to a wireless system, his overall tone changed drastically. That is the nature of the beast, because the capacitance of the guitar cable is always part of the overall tone of an electric guitar. You all know the formula: the shorter the cable, the more high-end you will have. Translated into technical terms, this means the shorter the cable, the less capacitance it will add, resulting in more high-end. It was only natural that Santana talked to his friend Paul Reed Smith about this problem, and PRS came up with the Sweet Switch as a solution.
The Sweet Switch is a mini-toggle switch with a fixed SIP delay line (high-frequency type 1513-135Y), which has a delay time of 135 nanoseconds and an impedance of 75 ohms. This SIP delay line is long out of production. But it was still in use in the ’80s, inside conventional (non-flat) televisions using line transformers. Since it’s no longer available, when you have a faulty Sweet Switch, or if you want to build a new one into your guitar, you will have to find a substitution.
From a technical point of view, a SIP delay line will work in a passive system, but only with the correct impedance—75 ohms for the one used in a Sweet Switch. Inside a guitar, that impedance does not arise though. Instead, when you use such a HF delay line in a LF device, like an electric guitar, it acts like a capacitor, not as a delay line.
So, when you want to repair a faulty Sweet Switch or add one to your guitar, you can simply use a small capacitor on the switch to add some capacitance to the circuit, resulting in the exact same effect as the mysterious SIP delay line.
That’s our starting point. I will show you how to add this Sweet Switch substitution into any electric guitar, and, as a bonus, how to use this technology to sonically enlarge short guitar cables.
Each meter of guitar cable will add a certain amount of capacitance to the circuit, dampening some high frequencies, so the tone gets warmer or sweeter. Modern guitar cables have an average capacitance of approximately 100 pF per meter, which is very low and allows long cable runs without audible degenerations. Some high-end guitar cables only have a capacitance of 60 pF per meter or lower, but there are also old guitar cables, especially the coiled ones, that easily can add up to 400 pF per meter. Players like Hendrix, Clapton, Gilmour, May, Blackmore, and many others are well-known for using very long coiled cables in their early days on stage. So, this is part of their trademark sound, and often a piece of the puzzle that is missing when trying to come close with a modern setup.
The added capacitance will lower the resonant frequency of the pickups, so they will sound warmer, especially when using overdrive or distortion.
As a little guideline to calculate the best additional capacitance, you can use this chart:
10 ft. cable (approx. 3 meters): 1 nF
15 ft. cable (approx. 4.5 meters): 1.5 nF
20 ft. cable (approx. 6 meters): 2.2 nF
30 ft. cable (approx. 9 meters): 3.3 nF
Ultra-long cable: 4.7 nF
You should have no problem getting capacitors with these values in any local electronics store.
The added capacitance will lower the resonant frequency of the pickups, so they will sound warmer, especially when using overdrive or distortion. By the way, this is exactly the reason why a lot of distortion and fuzz boxes with a vintage voicing use an additional cap at the input section. The resulting overdrive tone is fat and warm.This mod works best with typical Strat or Tele vintage pickups (approximately 2.4 H inductance) or a typical vintage PAF (approximately 3.8 H inductance). Modern high-output pickups often have an inductance of 6 up to 8 H and don’t sound very good with this mod. If you want to make your Strat or Tele sound more Les Paul-ish, you should try 4.7 nF for the additional cap. Your Strat will sound kinda muffled when playing clean, but ultra-fat and punchy when using overdrive. Values higher than 4.7 nF are not recommended, because single-coil pickups will start to lose definition with that much capacitance.
Illustration courtesy SINGLECOIL (www.singlecoil.com)
Performing this mod is very easy. All you need is one of the caps I mentioned above and an SPST on/off mini-toggle switch. You can also use any push/pull or push/push pot to switch the mod on and off. If you want to be more flexible, you can use an on/off/on toggle switch and two caps to choose from. If you want to go wild, you can also use a rotary switch with several caps. Feel free to be creative.
As mentioned earlier, it’s all about where to place the additional cap. It’s best to insert it between hot and ground in the circuit.
If you don’t want to add an additional switch on your guitar, there is another way to perform this mod, as long as you are using conventional guitar cables, not going wireless. You can build yourself a kind of “fake cable” by simply soldering an additional cap between the hot and ground directly on the plug of the cable. For example, if you have a standard modern three-meter guitar cable but want to simulate the typical 15-meter Blackmore cable from his early Deep Purple days, try a 3900 pF cap in the plug of your cable. If you have a six-meter cable, try 3300 pF for the same effect. The plug with the additional cap should be marked and will go into the guitar, not into the amp or the first stompbox. This is a very cool way to add the desired tone to your setup without drilling any additional holes into your guitar.
That’s it! Next month we will have a closer look into Eric Johnson’s 1954 “Virginia” Stratocaster wiring and how to adopt it, so stay tuned!
Until then ... keep on modding!
A 4-wire humbucker ready for modding.
When you have a humbucker with a traditional 2-conductor wiring, you don’t have any sound variation by itself—only together with another pickup that you can put in parallel or in series with it, in phase, out-of-phase, or half out-of-phase, and so on. With a 4-conductor wiring on your humbucker pickup, you have access to the start and the finish of each coil, and this can be used to get a total of four different tones out of it, whether it’s a bridge or a neck pickup. A 4-conductor wiring results in a total of five wires coming from such humbuckers:
- North coil start / north coil finish
- South coil start / south coil finish
- Ground = bare wire (goes always to ground)
The possible combinations and sounds you can dial in are:
1. Both coils together in series = standard humbucker operation mode.
This is the factory standard way all humbuckers are internally connected when they have a 2-conductor wiring with only hot and ground. This is also the standard way in almost every guitar loaded with one or more humbucker pickups, producing a warm, loud, and fat tone with maximum output and the humbucking function engaged.
2. Single-coil-esque humbucker wiring (both coils together in parallel).
This option gives you a single-coil-like tone but keeps the humbucking function engaged. You won’t get a crystal-clear Strat or Tele tone, but to me it sounds at least single-coil-esque, maybe closer to a P-90 than to a standard single-coil. It sounds different with any humbucker, so it’s a matter of trying it out.
Fig. 1
3. Coil-splitting to the south coil.
This wiring is splitting the humbucker in half, shunting one coil to ground, leaving the other coil engaged like a true single-coil pickup. In this mode, the humbucking function is no longer active, so you’ll receive all kinds of hum and noise, just like with any single-coil pickup. Don’t expect a true Strat or Tele tone. If this is your goal, there are special humbuckers made of two real single-coil pickups. The downside of this special breed is they don’t sound very good as a full humbucker, so it’s always the art of compromising. Splitting to the south coil of the humbucker, which is the screw side, is recommended for neck humbuckers, but can also sound good for bridge humbuckers.
4. Coil-splitting to the north coil.
This wiring follows the same idea as #3, but will leave the north coil, which is the slug side, active. This version is recommended for a bridge humbucker because it gives a fuller sound compared to the screw side.
To clear up some terminology, there are several descriptions given to the individual coils of a humbucker and depending on the manufacturer of the pickup, they are sometimes used side by side: The (non-adjustable) slug coil is also called north coil or inside coil, while the (adjustable) screw coil is called south coil or outside coil.
Having two 4-conductor humbuckers in an HH guitar will result in four different sounds from each pickup. Plus, you can combine them for a total of 16 different sounds, which is a lot of choice, not counting possible additional options like phasing.
What sounds like a good plan or must-have often turns into a real issue, because space is your enemy! Try to do this on a Les Paul and you’ll face that there isn’t enough space for all the additional switches that are needed, and that’s the same with a lot of other guitars. So, some years ago Seymour Duncan came up with a clever product called the “Triple Shot.”
The good news is, you can get the exact same performance from a rotary switch, which costs only a fraction of a Triple Shot. The sad news is, you need one rotary switch for each pickup, and, naturally, you need space to place them somewhere on the guitar.
This is a humbucker mounting ring with two integrated slide switches and a ribbon cable going from the switches to a small printed circuit board (PCB), which is the connection terminal for the five wires coming from the humbucker plus a shielded output cable. The Triple Shot is available in different colors and shapes, so it’ll fit virtually any guitar, no matter if it has a flat (Strat, Tele, SG, etc.) or arched (Les Paul, 335, etc.) top. With the Triple Shot, you don’t have to drill any new holes into your guitar, and you don’t lose any controls by replacing them with switches or the like.
Operating the Triple Shot is easy, but it takes some getting used to. Because of the two slide switches, you need to know what combination will produce each sound, which can cause some confusion at the beginning. Another benefit is that the optical appearance of your guitar is not altered in any way and it’s easy to remove if you need or want to. An often-heard downside is the high price for the Triple Shot ($39 street). Personally, I think it’s worth the price because it’s high quality, but if you’re on a budget, this can be a deal-killer.
The good news is, you can get the exact same performance from a rotary switch, which costs only a fraction of a Triple Shot. The sad news is, you need one rotary switch for each pickup and, naturally, you need space to place them somewhere on the guitar.
For this you need a 2P4T rotary switch, which means it has two poles (comparable to the standard 5- and 3-way switches you all know) and four switching positions. Physically you have five lugs on each switching stage, with one of them being the output of this stage. The lugs are numbered from 1 to 4 and the output on a rotary switch is always labelled with a “C” for “common.” The rotary switch wiring you need is illustrated in Fig. 1.
Take care to get a good-quality switch. These switches are available in a wide range of quality and prices. There are open ones, like the one shown in the diagram, and closed ones. The trick is to connect both switching stages (output of stage #1 goes into stage #2), which is something you already know from your standard 5- or 3-way switch.
Fig. 2
Fig. 2 shows how to connect your 4-conductor humbucker to the rotary switch. With this wiring you receive the following switching matrix:
- Both coils in series (standard humbucker)
- Both coils in parallel (hum-free single-coil-like tone)
- Slug coil as single-coil
- Screw coil as single-coil
I chose the Seymour Duncan color chart for the diagram, but you can transfer it to any brand humbucker using color code transfer charts on the internet.
That’s it for now. Next month we’ll continue our relic’ing project, focusing on the neck and fretboard. We’re getting close to the finish line on that one, so stay tuned.
Until then ... keep on modding