PRS taking a page from Reverend’s playbook?

ragingplatypi

ragingplatypi

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I noticed the limited edition guitar just released called the Charcoal Phoenix has mini toggles, but they don’t do the usual coil splitting/tapping. Now they control high pass filters. This seems like a fixed version of Reverend’s bass roll off tone knob. It’s a really great idea I’m surprised isn’t incorporated into more guitars.
 
PRS has been using those for a while I believe. First time I saw them was on the Paul’s Guitar model around 2012ish.
 
I have a lo cut switch on a tele partscaster, although I think having a dedicated pot is better. Most of my main guitars use a pot for that. I like it more than coil splitting or tapping, which never really appealed to me. I'd take a series/parallel switch instead. But having a lo cut control really cleans up the signal and naturally lowers the gain and does so in a more useful way, imo.
 
I have one on one of my PRS, I thought it was called a “sweet” switch or whatever it is. It doesn’t split (it’s got a 5 way rotary) but just changes the tone a little.

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jaxadam said:
I have one on one of my PRS, I thought it was called a “sweet” switch or whatever it is. It doesn’t split (it’s got a 5 way rotary) but just changes the tone a little.

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Love that finish. :love
 
This is a pretty good read:

A lot of people think that the PRS sweet switch circuit is a simple low-pass filter. However, the sweet switch circuit is in fact a very interesting use of an electronic component that is generally not found in music electronics. If one opens up the cavity of a sweet switch-equipped guitar, one will find an odd looking component wired to the back of the switch that bears the number 1513-135Y. Expecting a simple resistor/capacitor network and finding this device is the kind of thing that makes one scratch one's head.

Looking up the part number, one discovers that 1513-135Y is the device number for an electronic component known as a delay line. Furthermore, it is a delay line that imposes a 135 nanosecond (135 billionths of a second) delay on the signal. The device's characteristic impedance is 75 Ohms (most of the common types of coaxial cable have characteristic impedances that fall into the 50 to 75 Ohm range). The characteristic impedance of the device at audio frequencies is only important because a higher characteristic impedance cable usually has a lower capacitance per foot rating, and a lower capacitance per foot rating translates into less high frequency attenuation per foot of cable.

Now, anyone without a background in electronics or physics is probably wondering why the designer of this circuit chose a 135 nanosecond delay line as the filter for the sweet switch circuit. Well, the answer is quite simple after one performs a few calculations. An electromagnetic wave travels at the speed of light through a vacuum, which is 300,000,000 meters per second; therefore, an electromagnetic wave can travel 300,000,000 / 1,000,000,000 x 135 = 40.5 meters in 135 nanoseconds through a vacuum. However, an electrical wave does not travel at the speed of light through a coaxial cable because all coaxial cables have what is known as a velocity factor. A velocity factor is a fraction of the speed of light, which means that a coaxial cable has different electrical and physical lengths. The velocity factor of a guitar cable is roughly around 78%, which means that an electrical signal can travel 300,000,000 / 1,000,000,000 x 135 x 0.78 = 31.59 meters in 135 nanoseconds. That number is important because it roughly translates to 31.59 x 39.37 / 12 ~= 104 feet of guitar cable. In effect, the delay line simulates the frequency attenuation and the phase shift imposed on a guitar signal by a 100-foot-long guitar cable (cables of this length were popular before the guitar world went wireless).

If one researches the history of the sweet switch circuit, one discovers that it was created for Carlos Santana. Carlos was known for using long guitar cables before he switched to using a wireless system. The sweet switch was PRS Guitars’ answer to the increase in brightness that a guitarist experienced when the capacitive loading effects of a long cable were removed from the signal path. There is little doubt in my mind that Eric Pritchard was behind this circuit.
 
I think the current iteration of those high pass filters were first introduced on the John McLaughlin model. They liked the result better than a traditional split sound, so they have reused the idea a few times now.
 
ragingplatypi said:
While I don’t think it looks terrible, I always wondered why they didn’t do push pull, since they’ve done that before.
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Push-pull knobs keep a cleaner look, that is true, but they're also really annoying if you want to use them mid-song. They are okay if you are using a tele style knurled knob, but the PRS knobs are glossy plastic and not ideal for that use. A mini toggle is way more practical for live use.
 
OrganicZed said:
Push-pull knobs keep a cleaner look, that is true, but they're also really annoying if you want to use them mid-song. They are okay if you are using a tele style knurled knob, but the PRS knobs are glossy plastic and not ideal for that use. A mini toggle is way more practical for live use.
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I know what you mean but they look terrible.
 
OrganicZed said:
I totally agree. EBMM seems to be the only major player using them. I have read that the push-push pots have reliability issues long term.
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That has been my experience. The few guitars I have had them in developed issues much earlier than any push/pull pots I have had. When working they are fantastic. One would think there would have to be a way to engineer them to function better/longer. Of the three options, the mini switches are probably the best option considering reliability/usability.
 
QQQ said:
That has been my experience. The few guitars I have had them in developed issues much earlier than any push/pull pots I have had. When working they are fantastic. One would think there would have to be a way to engineer them to function better/longer. Of the three options, the mini switches are probably the best option considering reliability/usability.
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I am 100% certain that someone could design a reliable push-push potentiometer, but the cost to manufacture it would likely be very high because the demand for that type of product is very small and it wouldn't get the benefits of on scale manufacturing.
 
OrganicZed said:
I am 100% certain that someone could design a reliable push-push potentiometer, but the cost to manufacture it would likely be very high because the demand for that type of product is very small and it wouldn't get the benefits of on scale manufacturing.
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Nailed it!
 
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