Category Archives: Electronics

Modula Pre-Production Prototype

      Modula, Modula Series, Pickups

Cycfi’s new baby is coming very soon: A full-range, semi-modular pickup: Modula. If you haven’t heard about this yet, go check out the New Breed of Pickups post. These aesthetically pleasing, sleek Lo-Z multi-coil pickups were designed from the ground up based on our experience with the Nu and XR pickups. This baby sports dual-coil humbucking with dual rails design for each module and powered by a fully balanced, high headroom rail-to-rail output (5v to 18v), low-noise preamplifier.

Nu v2 Capsules

      Nu Capsule, Nu Series, Pickups, V2

The Nu version-2 capsule is ready to go!

  1. Thicker permalloy ring for improved electromagnetic isolation, better string focus and crosstalk reduction.
  2. Bobbin-less coil to make room for the improved permalloy ring.
  3. Lower magnetic pull.
  4. Epoxy impregnated injection molded capsule.
  5. Improved preamplifier.
    1. Low noise discrete/Op Amp hybrid differential preamplifier for improved immunity to electrostatic noise.
    2. Less stringent requirements on power supply regulation and noise (although I still highly recommend using a very low noise power supply suitable for low noise audio).
    3. Expanded power supply range. You can now power the capsules from 5v up to 18v. A higher supply voltage will give you a significantly higher dynamic range. Nu v1 maxed out at 5v.
    4. Instrument-level, like before, but not as hot as Nu v1. Roland synth users say the output of Nu v1 is too hot.
    5. Better output drive. Nu v1 has a 10k output impedance. Nu v2 has a very low output impedance with a 17 mA current drive capability.
    6. Rail-to-Rail Output. Which also translates to optimal dynamic range.
The preamplifier design changes follow developments in our preamp research for the Modula line of pickups. See Modula Update: Preamp Performance Tweaks.
Technically, this is v3 now, if you count the Neo as v1. I almost forgot the Neo and the Six-pack project, where it all started.

 

 

Fast and Efficient Pitch Detection: Bliss!

      DSP, Electronics, Pitch Detection, Software

In my previous post, I introduced my invention, Bitstream Autocorrelation: an accurate, extremely fast and efficient, time-domain pitch detection scheme. I argued that it can be as accurate as standard Autocorrelation based pitch detection schemes, especially, or at least, for very specific source inputs, such as the guitar.

As far as I can tell, this is a new invention and has not been done like this before. And so, the past few weeks, I investigated deeper and studied its performance and characteristics on real world guitar samples. For analysis, I recorded single-note samples for all strings (6 strings for now) at various fret positions. Additionally, I also recorded various guitar audio samples incorporating techniques such as hammer-ons and pull-offs and fast right hand arpeggios. I am impressed!

Here are my findings and some direction changes and updates along the way…

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Fast and Efficient Pitch Detection: Bitstream Autocorrelation

      DSP, Electronics, Pitch Detection, Software

So, since last year, I’ve been mulling over a unique, and extremely fast(!) Autocorrelation scheme for monophonic pitch detection. Last weekend, I finally got myself to write the proof of concept. It’s not like any autocorrelation scheme I’ve seen before. I am still wondering why no one has thought about doing it this way. As far as I can tell, this is my invention, but please tell me if there’s something I am missing and if I’m not the first to actually do it this way. I dubbed the technique Bitstream Autocorrelation.

Unlike standard Autocorrelation, my scheme works on single bit binary data streams instead of floating point (or fixed point) real numbers. Compared to standard Autocorrelation, Bitstream Autocorrelation is wicked fast. As I’ve been working on multiple channels of audio on small Microcontrollers, I’ve consistently shied away from Autocorrelation schemes for pitch detection (see my original article: Fast and Efficient Pitch Detection). Popular time-domain Autocorrelation (ACF)  based pitch detection, including variants such as AMDF (Average Magnitude Difference Function), ASDF (Average Squared Difference Function),  YIN, and MPM,  are quite expensive in terms of CPU cycles required (ACF is basically an N² operation for N samples).

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The Last of the XRs

      Evolution, Pickups, Uncategorized, XR Series, XR Update

Almost immediately after I announced our Roadmap for 2018, the XRs and the current Nu modules went out of stock as people hurriedly grabbed what’s remaining in our inventory. I am very sorry that I had to turn down orders after the stocks were depleted.

Dan Rhodes sent me these nice pictures of his electric with Cycfi XR dual pickups, Cycfi Resonant Filter, Warmoth body and neck with a Decoboom pick guard, Fender locking tuners, roller bearing nut and Wilkinson tremolo.

“Looks and sounds amazing Joel! I spent some time with it last night and the tonal range of these pickups is amazing. The openness with the tone and Q maxed out is a sound I’ve never had before.”

Thank you very much for such nice appreciation. I am missing the XRs already!

But watch out. We are still actively pursuing the Modula, a new breed of pickups and the next evolutionary step for the XR. It didn’t die, it simply evolved! 🙂

Modula 8 and 9 String Prototypes

      Evolution, Modula, Pickups

So many things to do. So little time! I think Karl Steinberg was right in remarking that I have too many projects happening all at the same time. Oh well, these Modula prototypes are good to go. We worked so hard for this. These are custom made pickups. We do not have injection molded enclosures yet, so these are hand crafted, painted and buffed to perfection. This is already the third version, but it was all worth it! The next, and the most stressful step: Production!

Modula is our next gen, full-range pickups. Leave a comment if you are interested in these pickups!

8-String, 3-5 split Stereo Modula Pickups

9-String, 4-5 split Stereo Modula Pickups

9-String, 4-5 split Mono Modula, Nu Combo

Fast and Efficient Pitch Detection: Double Trouble

      DSP, Electronics, Infinity, Pitch Detection, Software

This D string was driving my pitch detector nuts. It’s jumping from fundamental to octave and back all over the place. Can’t make up its mind! The effect is like a wacko version of Satch with a whammy pedal gone haywire.

What the hell am I talking about? Last month, I wrote about a fast and efficient software multichannel pitch detection scheme using dual peak-detectors. I needed it to be as efficient as possible, so I can run multiple detectors simultaneously using a small 32 bit microcontroller (MCU). Most of the time, it works really well, except in some cases, like that troublesome D string.

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Modula Update: Magnetics

      Electronics, Modula, Pickups

I find it amusing when people talk about the “sound” of the magnet in pickups :-). The magnet has no sound! If you don’t believe me, perhaps you might reconsider if it’s coming from Bill Lawrence. Here’s what he has to say on the matter:

When I read that ceramic magnets sound harsh and alnico magnets sound sweet, I ask myself, ” Who the hell preaches such nonsense?” There are harsh-sounding pickups with alnico magnets and sweet-sounding pickups with ceramic magnets and vice-versa! A magnet by itself has no sound, and as a part of a pickup, the magnet is simply the source to provide the magnetic field for the strings. The important factor is the design of a magnetic circuit which establishes what magnet to use.

It does not really matter which magnet you use as long as the magnetic circuit is properly designed within sensible parameters. One design consideration is the total magnetic pull the magnets exert on the strings. Too strong, and you’ll get “stratitis” (No, it’s not some kind of ailment amongst guitar players ;-). Another important factor is magnetic flux variance versus distance, following the inverse square law. Simply put, magnetic pull decreases as the square of the distance from the magnet. Hence, the choice of magnet may influence the string displacement as it vibrates over the magnetic field.

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Modula Update: Preamp Performance Tweaks

      Electronics, Evolution, Modula

I can’t recall how many times we went back to the drawing board. Design, test, rinse repeat. I only wish turnaround time is shorter than it is now. After initial design, planning, and breadboarding, we start off with dead bug prototyping and do a barrage of tests to validate the design. Then, we do PCB layout using Eagle CAD (although we might be switching to KiCAD soon) and send the design to PCB manufacturing. A cycle takes around 1 to 2 weeks depending on complexity. PCB layout itself can be a demanding task, especially if space constrained, like the Modula preamplifier. What’s painful is when you are in the final stages, and there’s that yet one more test that breaks to design! It happens! And it happened again with the Modula preamp.

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