gpdb

Guitar Pickup Database
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May 13, 2022
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Hi everyone - Ever since the TCI nomenclature came out, it's been incredibly confusing to follow. From many posts I've seen on the internet about it, it seems that a lot of other people were confused too. So I did a bunch of research, and I think I've written a clear and concise article describing its history and what it really means. Here's the link to the full article:


I'll create a summary here though for anyone who just wants the main points. The TCI name was first released at the end of 2018 when PRS announced the 2019 Paul's Guitar. It had the first "TCI" pickups, and were named exactly that. When it was first announced, there was no mention of a process, and they focus on the mini-toggles. In the video overview, Bryan Ewald mentions that the TCI pickups and the way they switch came from research between Paul and John Mayer on the Silver Sky, so technically the 635JM was the first TCI-tuned pickup. I'll get to the mini-toggle system later as that's still a part of this whole thing. At the end of 2019, PRS announced that all core models for 2020 would be getting the TCI treatment, which was one of the first mentions of TCI being a process. There was an earlier mention in Guitarist Magazines May 2019 issue, and there they go into a bit more detail. However, I'm sure many people didn't have access to that.

In January of 2020, PRS posted a video titled "TCI Pickups with Paul Reed Smith." This is the first full communication from PRS about TCI being a process. Paul mentions how inductance and capacitance combine to create a whistle/note, and that they are trying to approach pickups now by targeting that note. The whistle Paul is talking about is the resonance curve of the pickup. Every pickup has a resonance curve and peak, and the character of that peak is what more or less defines the sound of the pickup. I have the equipment to measure this curve, see below for the curve of the 85/15 "S" pickups:

85-15-S2.png


If you can hit consistent capacitance and inductance numbers on your pickup, you can consistently replicate this curve, and therefore make a consistent sounding pickup. This is the core of what TCI is - find the best sounding pickups, measure them, and recreate them. As for their measuring process, there's a bit of confusion here. There's been mentions on this forum from an employee that Paul was using technology from his other company, Digital Harmonic, to measure pickups beyond what a simple oscilloscope and drive coil can create. However, in the Guitarist Magazine article, they show an image of a basic oscilloscope (exactly what I used to make my charts above), with the caption that reads “this signal analyser allows PRS to ‘see’ how its pickups will sound.” So whether they're just using that or Digital Harmonic is a mystery. Regardless, the outcome is still the same. Get the measurements, and recreate them.

As to how they are intentionally hitting inductance and capacitance numbers, my theory is they've created a winding machine that measures those numbers in real time. That's just an assumption though, they may not be doing that. But that would explain what they mean when they say they're targeting those metrics.

Now for the mini-toggles, which are also part of the TCI system. While mini-toggles may seem like a simple convenience to the player instead of push-pulls, they actually are doing a couple other things. First, they allow a humbucker to be split into an isolated single coil. This means that instead of sending one coil to ground, it gets removed entirely from the circuit. PRS claims this is better, but they still sell many guitars that split their humbucker by sending a coil to ground. Secondly, they allow for additional sound tuning when engaged. In the same way that a pickup has inherent capacitance, you can also add more capacitance to affect the sound before the signal leaves the guitar. This is what they do on the mini-toggles, they're effectively reshaping the sound of the pickup without having to design it in a way that would affect the humbucker. This feature only appears to be on the core models, as the SE Paul's guitar doesn't do this. I've got an image in the full article showing the wiring.

So overall, TCI is a pickup model name (TCI and TCI "S"), an updated version of many pickup models since 2020 (you could almost think of it as a v2), and for guitars with mini-toggles like the Paul's Guitar or 24-08, it's also an electronics system.

For anyone that's interested in the resonance curve of other SE pickups, I made a post yesterday with all the humbuckers curves: https://forums.prsguitars.com/threa...resonance-curve-comparison.51736/#post-715199
 

RonHal

New Member
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May 3, 2012
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36
Thanks for your explanation.
First, they allow a humbucker to be split into an isolated single coil. This means that instead of sending one coil to ground, it gets removed entirely from the circuit.
Ground is ground. The shorted out coil still has resistance, possible induction with capacitance. There maybe some induced noise that the working coil may pick up. I dont hear it on my guitars, but I dont have Paul's magic ears. In the end, its the consistency we want. Another win for PRS .
 

gpdb

Guitar Pickup Database
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May 13, 2022
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Thanks for your explanation.

Ground is ground. The shorted out coil still has resistance, possible induction with capacitance. There maybe some induced noise that the working coil may pick up. I dont hear it on my guitars, but I dont have Paul's magic ears. In the end, its the consistency we want. Another win for PRS .
Yeah I've never played both options to know if it really makes a difference. I think the bigger selling point of the mini-toggles is the extra tone shaping from the capacitors. And this is only a core-line thing. Even though the Paul's Guitar SE and 24-08 SE have mini-toggles, they don't add the capacitors.
 

gpdb

Guitar Pickup Database
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May 13, 2022
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Any word if the tci process has made its way to S2 lines? I see mention of it in CE, cores, and some SE. I have new S2 594 and never saw any mention of it.
From the info I've gathered, it wouldn't be in the S2 594. Those use the 58/15 "S" pickups, and there hasn't been official word on those going through the process. The S2 Custom 24-08 actually uses the TCI "S" pickups, though it's marked as the 85/15 "S". I confirmed this through the PRS customer service, I'm not sure why they haven't updated it yet. So that model is the only S2 with TCI-tuned pickups.

As far as CE goes, they are using the core 85/15 pickup which has been TCI-tuned, so I can't imagine they're producing older pickup designs specifically for that model when all the other guitars using that pickup aren't. So its a safe bet that the CE24 is TCI-tuned.
 

cjlloyd

Modern seagull
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Mar 8, 2021
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I've always been under the impression that the TCI process is basically a more considered selection of components - specifically pots - when wiring up the guitar. What they started doing on the Silver Sky is taking readings on individual pots, and matching them with certain pickups such that the variance in the pots counteracted the variance in those specific pickups, thus achieving a more consistent end result from guitar to guitar. I believe they only mentioned resistance at the time, but I see no reason why the same can't be applied to C/L. Effectively, they are tuning the whole circuit rather than just the pickups themselves.
 

gpdb

Guitar Pickup Database
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May 13, 2022
Messages
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I've always been under the impression that the TCI process is basically a more considered selection of components - specifically pots - when wiring up the guitar. What they started doing on the Silver Sky is taking readings on individual pots, and matching them with certain pickups such that the variance in the pots counteracted the variance in those specific pickups, thus achieving a more consistent end result from guitar to guitar. I believe they only mentioned resistance at the time, but I see no reason why the same can't be applied to C/L. Effectively, they are tuning the whole circuit rather than just the pickups themselves.

I don't doubt that they implement extended quality control when selecting pots, but I don't think that's part of what's considered TCI. If you have information to support that I'd love to see it, but I suspect they were doing that prior to 2019. When they talk about tuning the whole circuit, my research indicates they're referring to the mini-toggles and the added tuning that's included in those. I own a Silver Sky and can confirm that there's no extra caps or wiring apart from what would be on a standard strat. Yet, the 635JM is considered a TCI-tuned pickup.

What I suspect Paul and John Mayer did was measure the resonance curve of his personal vintage strat pickups, and recreated the 635JM to match that curve. Or, match it and then change some things that he would have wanted. I mention this in the article, but this is pretty much exactly what Fishman Fluence pickups do, they just do it in an active way vs. passive. That's how they can accomplish multiple voices, the DSP changes that resonance curve.
 

gpdb

Guitar Pickup Database
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May 13, 2022
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Would it be reasonable to think that the TCI process might be different with single coils vs humbuckers?

I don’t think so. It’s honestly even strange to call it a process. The simpler way to think about it is that instead of targeting a turn count, they’re targeting a capacitance and inductance number. They’re still just making a normal pickup, they’re just focusing on a different metric. Turn count gets you a certain capacitance and inductance but there will be error. By targeting an actual capacitance and inductance number, you reduce that error dramatically.
 

LSchefman

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Yes, very nice read!

I mentioned in another thread that the resonant frequency in a filter creates distinctive tones of various kinds, which is why nearly all synths have frequency-adjustable lowpass filters for the high frequency cutoff point, coupled with resonance controls. These have a huge effect on the sounds the synth makes.

And of course, the resonances of a guitars components and materials also matter, together with the electronics.

A 4-5 dB rise in frequency response in the 1 kHz to 6 kHz range is also pleasing to the ear; lots of recording engineers refer to this as a "presence lift" that's often found on microphones, especially condenser mics. It increases intelligibility, and helps the voice cut through better in a mix. It also gives vocals a little sparkle, sounds good if it's done right, and gives a vocal a polished, "sounds like a record" vibe.

In most mics, the peak isn't coupled with a low pass filter. It's just a lift in the "magic frequencies" that engineers sometimes talk about.

However, it's a two-edged sword: If the presence/resonant peak has too much amplitude, instead of sounding pleasing, it sounds harsh. So having a good way to measure what the pickup is doing, and being able to repeat this in production, helps create a better sounding instrument.

In fact, a well-known and highly respected compressor made by Maag has a circuit that can be switched in to specifically tame frequencies centered on 3 kHz to reduce harshness.

Anyway, it's interesting that the TCI pickup pays special attention to measuring/controlling this resonant peak in the very same frequencies.
 
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