Jump to content
Voting in Guitar of the Month April 2024 is now open! ×

Cycfi

Members
 View Profile  See their activity

  • Posts

    67

  • Joined

  • Last visited

  • Days Won

    4

 Content Type 

Everything posted by Cycfi

  1. Cycfi
    Yes, I'm aware of that. Sounds good. I'll give it a try when I get a chance. FEMM is indeed interesting. BTW, are those vertical ferrite bars between the coils? There's no space there anymore, but there might be in front and behind the coils. It's also interesting how some space between the magnet and the ferrite affects the whole.
  2. Cycfi
    Thanks for the explanation. Isn't that the same idea presented here: http://music-electronics-forum.com/t26380/ ? That project was plagued with weak signal and too much crosstalk. Maybe his inductors are too tall and his magnet too weak?
  3. Cycfi
    That is indeed very interesting. Could you explain a bit more?
  4. Cycfi
    I'd definitely love to incorporate newer/better ideas, but I also want to get this out the door sooner rather than later. So, for this project, I'd say I've satisfied all my initial requirements. I don't consider noise an issue anymore as I've far exceeded the desired SNR (>80db). I also no longer consider crosstalk a problem as I am confident that this can be mitigated through cancellation in the DSP. Tell you what: how about collaborating on a new PU project with your ideas in mind? Yes, we can probably squeeze in some more room. What do you have in mind?
  5. Cycfi
    I agree 100%. We should play the instrument more Thanks for reminding! Thanks. Well, I haven't deviated from my original goal: to create new sounds. I'm tired of the old vintage sounds, to be honest.
  6. Cycfi
    Well, since you are the Central Scrutinizer, you can probably start scrutinizing :-) It's interesting how the design got scrutinized in the music-electronics-forum the past few days starting from this post. In the end, I learned a lot! And got some exciting ideas.
  7. Cycfi
    Here’s the V1.1 prototype based on the V1.0 design and specification. The version is bumped to 1.1 since there are slight modifications from the original 1.0 design. Follow this link for more… Fully Assembled Hex Pickup Neo-2 PCB with components Neo-2 Fully Assembled
  8. Cycfi
    Thanks! I just googled a bit after relying. I'll definitely look into that. For now, I'm quite satisfied with the coils and it serves its purpose well. There are still bigger fish to fry and I need to move on.
  9. Cycfi
    Yes. Scroll down a little bit: OPA376 is a lower power option at 760μA. Even lower power? Then how about OPA314 at 150μA. I have a list of Op Amps here: http://www.cycfi.com/projects/six-pack/op-amp-shootout/ And... in yet another development, I might be considering an alternative floating, single-ended, pseudo-differential design. For low-power, single stage discretes rule. Please tell me about FEMMs and why they would be better. It turns out that the current design is already optimal WRT noise and I was not able to squeeze more from using bifilars. A better approach, and one that I am taking now, is to take advantage of the multiple coils and have the coils alternate from north-south pole orientation, clockwise winding for the 1st, 3rd and 5th coils and south-north pole orientation, counterclockwise winding for the 2nd, 4th and 6th coils. That way, the sum of the pickup outputs will cancel some more of the noise the same way humbuckers do. It is possible to isolate the noise from the signal as well as do more advanced cross-talk cancellation in DSP. Thank you! I appreciate all the inputs I get.
  10. Cycfi
    Hi! After countless hours experimenting and iterating over the basic design, I think I’ve reached a point where I have something that I am actually finally satisfied with. Here now, let me present version 1.0 of the Six Pack Hexaphonic Pickup. The design is modular. Visible in the xray view below, the Hexaphonic Pickup actually contains three smaller dual active pickups sitting on a main board which contains no more than biasing electronics and a micro-miniature header connector. Read more about it following this link. Features: Six low impedance coils (2000 turns, 450Ω D.C. Impedance, flat frequency response, 20Hz-20kHz). High performance, ultra low noise OPA209 (OPA2209, dual) differential Op Amps. Single supply (4.5V to 36V). Stainless steel height adjustment screws and springs. Gold plated, 1 mm pitch micro-miniature positive lock connector (Hirose). Premium 0.1% thin film low noise matched resistors. Fender Stratocaster Profile (11.8 mm height excluding connector).
  11. Cycfi
    Woa! Nice find! My best guess is that both the pickup and the drivers are phase-inversed (humbucking style) to cancel out the actual EM being generated.
  12. Cycfi
    Hi! This is part 3 of the “Let it breathe” series. For proper context, you might want to check out Part1 and Part2. This third and last part of the series concludes with actual frequency response measurements for various coil configurations of the Hexaphonic Pickup Project and with the Fender Stratocaster middle pickup as benchmark to compare against. In addition to standard windings with 500, 1000, 1500, 2000, 2500 and 3000 turns AWG 42, we also tested bifilar windings (see Alternative Ideas) with 500 and 1000 turns AWG 42. Like before, the low-power LME49726 OP Amp is used in the differential preamp stage with a gain of 5. See this link for more: Let it breathe (part 3): Frequency Response
  13. Cycfi
    Very good points. Moog filters are nice, but having them always on? That's not good. I'm assuming it's all analog, am I correct? I'd expect that from Moog. I believe that a pure analog approach would be difficult to achieve. Well, I know Moog did it but I also know that it can get better still. A DSP based system has the clear advantage of having the ability to analyze the sound and react dynamically. An "active-resonance" system, as I fondly call it, should be able to give just the right amount of pull (pull only! no need for push! magnets are only able to pull the strings anyway) at exactly the right time and phase. IMO, the analog approach we see in the current generation sustainers use a brute force approach that requires and wastes lots of energy. I imagine it like a swing. You need only a little nudge at exactly the right moment to get it going indefinitely. Hey, you can make even the strongest bridge collapse with just the right amount of force by tuning in on its resonant frequency. IMO, an active resonance system is the key.
  14. Cycfi
    I honestly don't know. I haven't tried this before and to be honest, electromagnetism is by and large still a mystery to me. I am learning each day. People who did it sing praises. For example: The noise level is so low I can't hear anything even with my headphones set to max. I reckon I can hear it if I boost the signal with ample gain, but I haven't done that. I'll try when I get the chance.
  15. Cycfi
    So... we are currently using single-coils in floating differential mode. The coils are connected to the + and - inputs of the differential amplifier without any direct path to ground. This configuration is inherently noise canceling. Should we be using double coils in humbucking configuration instead to get even better noise cancellation? Here, we talk about the limitations of passive humbuckers and propose possible alternatives such as the Bifilar Coil winding. Read the rest here: Singles or Doubles?
  16. Cycfi
    I am currently working on the tests for 500 turns, 1000 turns, 2000 turns and 3000 turns so we can see the freq. response side by side. I also rigged an (core-less) 8 Ohm driver-coil placed a few millimeters on top of the pickup-coil which is then driven by a 20Hz to 20kHz sine sweep while monitoring the preamp's output response. This will give us an accurate profile of the actual frequency response curve of the coil + preamp. I like the sound of this one too. I can probably re-test the older circuit, but I doubt if it contributed to the 'color'. The changes in the electronics were meant to give improved CMRR (by using matched/precision resistors and better Op Amp) as well as lower the noise floor (lower noise Op Amp and lower valued resistors). I believe the pickup design with a more focused magnetic field and lower string pull (thus closer proximity to the strings) contributed a lot more to the color than anything else. If there's such a thing as proximity effect on pickups, I guess this is it (it would be easy and interesting to test that conjecture). Thanks for your input! I really appreciate it. In the end, we can probably have a set of samples to choose from and have a poll which one you guys think is the best.
  17. Cycfi
    Let it breathe (part 2): More Frequency Analysis Last time we did some (very rough) preliminary tests comparing an early version of the hex pickup with a Fender Stratocaster and a Gibson Les Paul. The initial test was done using a 2000 turns AWG 42 coil and the cheapo TL072 Op Amp in differential configuration. The goal basically was to see the frequency spectrum of lower impedance coils side by side with that of the single-coil Strat and Les Paul humbucker pickups. Here we will continue with the tests, this time focusing only on the Hex pickup installed on a Strat while continually improving on various aspects of the pickup design. Tell me what you think.
  18. Cycfi
    Oh it is noticeable. The pickup itself is a second order low pass filter. HIgh impedance designs have the cutoff point in the audible range. It's the thing we associate with the color or flavor of the pickup (e.g. dark, bright, etc.). It's easy to trim high frequencies with a second order low pass filter to shape the sound later, but not the other way around. IOTW, you can remove what's there but you cannot add what's not there to start with (i.e. higher frequency harmonics). That way, the player has the flexibility of tone shaping rather than having the pickup itself hard-wire the tone for you.
  19. Cycfi
    The higher the inductance, the lower the cutoff frequency and the darker the sound will be. There *is* merit with low impedance pickups below the 1k range. No wonder Les Paul himself favors a low impedance pickup of 10 Ohms! (see Les Paul’s Favorite Les Paul – The Recording Model). He sends the balanced output direct to the mixer. I've had very good results with small, low impedance pickups in the 100 ~ 300 ohm range. Here are some preliminary spectrum analysis of low vs. high impedance PUs on the Strat and the Les Paul and a Bösendorfer grand.
  20. Cycfi
    I won't use an lm386 as a preamp. It's not designed to be used that way. You are right, it will oscillate like crazy if the gain is set high. And you need a high gain since you have very low impedance (220 ohm) pickups. I'd use an Op Amp wired balanced like an XLR mic preamplifier. You can see lots of schematics of these if you do a search for "balanced preamplifier schematic". As for the Op Amp, yes, the TL072 is better suited. I have here a list of some more Op Amps: http://www.cycfi.com/2013/04/choosing-good-audio-op-amp/
  21. Cycfi
    Those are very good points actually. I thought at first that this would be a portable instrment, but it seems it's not. So DarkAvenger is right, it does not matter much.
  22. Cycfi
    Wonderful idea! I too am going into "acoustic synthesis" starting with the hexaphonic pickup project thread in this forum. I'm very interested with your results, especially the drivers. I'd prefer class D amplifiers for efficiency, BTW.
  23. Cycfi
    How low is the impedance of the Les Paul Recording anyway? I read here (from the comments): Les Paul’s Favorite Les Paul – The Recording Model that it's a stacked humbucker design with 5 Ohms per coil, for a total of 10 Ohms! Can anyone here verify that?
  24. Cycfi
    Oh of course you are :-) Indeed. Anyway, obviously I am a fan of low impedance PUs. BTW, there's this guy at the music-electronics-forum who tinkered with extremely low impedance pickups with "proprietary" active circuitry. He proclaims that "nothing else sounds quite like a 10 ohm humbucker". 10 ohms! Now that got me thinking...
  25. Cycfi
    Not sure if you know this, but Les Paul actually favored low impedance pickups that are DI'd directly to the mixing board. He favored the wider frequency response and the possibility of sending the signal through long cable lengths (in a differential manner of course): The orphaned (and very rare) Les Paul Personal, Professional and Recording models use passive low impedance pickups. They didn't catch on at the time because the outputs were very low and couldn't drive guitar amplifiers.
×
×
  • Create New...