DIY Sustainer

Introduction

Sustainer is a cool little device originally designed by Fernandes®. The kit contains a sustainer driver which replaces neck pickup on guitar and a circuit board that contains the electronics. The original Fernandes sustainer also has an active pickup which can be used as a conventional neck pickup when sustainer is not used, but this project does not include that feature. This limits guitar tonal options in one way but gives completely new possibilities.

Here’s how it works. When sustainer is turned on, we take the signal from the bridge pickup, amplify it using a simple audio amplifier and use the amplified signal to drive the driver instead of a regular guitar speaker. Think of the driver as speaker coil that cannot move. The driver generates electromagnetic (EM) field that moves the strings instead of moving the conventional speaker diaphragm. Guitar strings are close to the driver and get excited by the EM field, casing them to vibrate indefinitely. In a nutshell, sustainer works exactly the opposite from a regular guitar pickup. Instead of picking up the vibrations of the strings, it is causing the strings to vibrate.

Keep in mind though, that we cannot use a conventional guitar pickup as a driver because it has very high impedance and DC resistance (typically 5K-20K). Amplifiers usually work with loads between 4 and 8 ohms, so we will need to make our driver very similar to guitar pickup, but wind it with thicker wire and less turns to aim for DC resistance of 8 ohms.

Building your own sustainer is not simple and requires a lot of research and experimenting. Make sure you have basic knowledge in soldering, electronics, guitar wiring and pickup building. Otherwise, this can easily prove to be a painful project and you may be better off buying a real Ferndandes sustainer or Sustainiac.

Original Fernandes Sustainer

This photo shows Fernandes Sustainer kit which is cool but very expensive (above 200$). Fortunately, great guys from Project Guitar Forum (most of all Pete/psw and Col) developed DIY friendly project that costs much less than original but still sounds good. Total cost of the build is between 10 and 20 euros (or dollars), depending on what you already have. Also, I’d like to thank PSW Pete for sending me a spool of 0.2mm wire all the way from Australia at no cost.

Step 1: getting a bobbin

You can buy a new single coil bobbin and pickup cover online or try to salvage one from an old pickup. I got a bunch of them from a friend and picked one that had a bobbin I liked. I used a traditional single coil bobbin with 6 pole pieces which makes for a discrete driver, but many DIY-ers had great results with rail-type pickups, and original sustainer is also rail.

old_pickup

Strip the pickup and remove all wire. There’s a lot of very thin wire there so cutting it instead of unwinding is the way to go. In this case, pickup was potted which made stripping wire even harder. Nice thing about this is that pole pieces can be adjusted, so if I end up with uneven sustain I’ll be able to set poles higher or lower to compensate difference.

stripped
Step 2: modifying the bobbin height

Pickup coils are usually wound to around 10mm of height and bobbins are designed to fit a coil that’s 10mm high. For sustainer driver, optimal coil height seems to be around 3mm, which means that we need to modify the bobbin to limit coil height to 3mm. One way to do it is shown below.

glued_plastic

The way I did it was using a thin (around 0.5mm) piece of transparent plastic used for packaging that I bent into L profile and cut to shape with scissors. Then I glued it in place using epoxy glue. Super glue can also be used for quicker setting time.

glued_plastic_cure
Step 3: winding the coil

The recommended wire gauge for winding the coil is 0.2mm (AWG #32). Other gauges might work, but thinner wire will have less resistance, so it would take less turns to get to the target coil resistance of 8 ohms. With less turns we’ll have lower inductance, so our driver will be weaker. Other other hand, thicker wire has less resistance, so we need more turns to get to 8 ohms. More turns of thicker wire would make a physically large coil that might be too large to fit on a guitar pickup bobbin. 0.2mm is a good middle ground between physical size and number of turns needed to produce a coil with DC resistance of 8 ohms. Taking the resistance of copper into account, we can calculate that we need around 14.9m of wire to get the coil to target resistance of around 8 ohms. Using the calculator for estimating number of turns we get around 120 turns on a strat bobbin. It will depend on the geometry of the bobbin, so it’s best to check coil resistance as you go. I used transparent universal glue to pot the pickup after each 20 or so turns to make sure the coil is kept in place and to prevent microphonics.

winding_done

After 100 or so turns you can try to take the insulation off a tiny portion of the wire using a knife and measure the resistance of the coil so far. If you reached 8ohm, it’s done. Otherwise, do a layer or two more and repeat until you get to the target resistance. When it’s done, I soldered leads to both ends of the coil, secured them with a blob of glue and covered everything with insulating tape.

taped
Step 4: the circuit

For the circuit we want to build a real clean guitar amplifier that operates the same way as a conventional amplifier, but instead of driving a speaker, it drives our sustainer. Pretty much any amplifier that can deliver few hundreds of milliwatts of power can do the job. A few people have reported Fetzer/Ruby amplifier from ROG to be performing well, so I decided to use that circuit. It’s got one FET gain stage (Fetzer Valve booster) that amplifies input signal before it hits the LM386 power amplifier taken from Ruby amplifier circuit. Both circuits may be found at runoffgroove.com and it’s just a matter of putting them together. I used trimmers for all controls and omitted Ruby volume control, as we already have one in the Fetzer Valve part of the circuit. 100K bias trimmer on the FET should be set to position that gives us roughly 4.5V at the drain of the FET and the remaining two trimmers should be adjusted at the end when the driver is installed in the guitar.


For my build I used this simple but not very compact perfboard layout. I suggest building as small board as possible, increasing the chance of fitting it inside the guitar without the need for routing.

sustainer_board
Step 5: wiring

By popular request, I updated the article with a proposed wiring for the sustainer driver and circuit. I don’t have ability to test now it as it’s been almost 10 years since I built the sustainer, so if anyone does try it, please leave your comments below. There’s more than one way to do it and it will depend on your guitar. It’s ideal to have only bridge pickup and sustainer in the guitar because it will reduce a chance of interference between the driver and other pickups. Driver emits a lot of EM waves that excite the strings, but other pickups can pick them up too, and that’s not good!

Sustainer can operate in two modes: in phase which amplifies vibrations of the strings making them sustain indefinitely (or as long as the battery has enough juice to power the circuit) and out of phase (harmonic) which makes the guitar feedback with harmonics (listen to some of Steve Vai live performances, like “Building the Church”). The two modes can be toggled using a DPDT switch that flips the positive and negative side of the amplifier output.

As for the main sustainer switch, there’s more than one way it can be wired and in some cases you may need 3 or 4 pole switch. This is the simplest implementation that kills the battery supply to preserve power and when engaged it wires bridge pickup to the amplifier.

sustainer_wiring_v1
Step 6: tweaking

After the driver is installed in the guitar, we need to tweak the Gain and Volume trimmers to make sure that we get enough sustain but not get into feedback and oscillation. I suggest starting with both trimmers around noon and tweaking it from there. We are aiming for infinite sustain that doesn’t increase the level or add distortion. In sustain mode, if you hit the note and it starts amplifying on its own until it goes into oscillation, it means that Volume and/or Gain are too high. On the other hand, if there’s no infinite sustain, we should increase Gain and/or Volume.

Like with the pickups, the driver height will affect how it performs. The closer it is to the string, the stronger it will affect them. Using the same height as a typical guitar pickup is a good starting point and you can tweak it if there’s need.

Useful links

Project Guitar "Sustainer Ideas" thread (very large)
Project Guitar tutorial on building driver
Program for calculating number of turns for given core dimensions and wire gauge
Official Fernandes Sustainer page

Comments
162 Responses to “DIY Sustainer”
  1. Joanchio says:

    Hello, nice tutorial, thanks for it. I have an old Ibanez Gio that has humbuckers. Can I use the Humbucker or it has to be a single?

  2. Andre says:

    Hi guys,
    Iโ€™d like to know if itโ€™s possible to adapt the system to fit the driver coil underneath a Floyd Rose trem block or a tail of a Tune-o-matic bridge, to be able to keep all original pickups in place, and hide the driver.
    Thanks

  3. Roy Clar says:

    Can I use simple lm386 module as amp circuit?

    • bancika says:

      well, this is a simple lm386 module ๐Ÿ™‚ What did you have in mind? Dialing in the gain is crucial, that’s why it has a tiny preamp at the front.

  4. Maiden88 says:

    Has any one here divided to make a few of there own sustainer kits to sell? Iโ€™ll buy one if itโ€™s decent and didnโ€™t cost and arm how will I play?
    Anyone a lot of ppl want these but canโ€™t install or afford or both any DIY-ER make a drop in pre soldered kit Iโ€™m down to buy email me
    LESRICH57@aol.com thx

    • Rob Long says:

      I just finished making one – boy is this quirky.
      I still have something wrong.

      The only issue you have is even if I sold a kit – you would still have to modify the Guitar Body (routing) for the 9v batter, the circuit, the switches etc…

      Soon i’ll be posting the video even though I still haven’t got it working as it should.

  5. Rob Long says:

    I found out I uploaded a bad quality … for part 1 of this Sustain Project. The new YoutTube is:
    https://youtu.be/qCIJ-IlPAhs

    Also on Facebook “Guitar Sustainer Project”

  6. RobLong says:

    Hey all – I got Step 1 finalized https://www.youtube.com/watch?v=TJdBUeXihFU
    This is the driver or Pickup wiring … it measures out great… Seems 120 turns is it for everything.

    Join FB Group too to help out with getting this down to an easy step by step & understandable.

    https://www.facebook.com/groups/827134577475681/
    (Guitar Sustainer Project)

  7. Peter says:

    I’m building a bass guitar version with specially made drivers. I’m getting sound from the driver, but not from the string, and I can’t get sound from the string below 20 watts. Any suggestions?

    • bancika says:

      wow 20 watts is a lot, you need a big power supply to feed it. Is your driver impedance correct?

  8. ultra says:

    hi ^^
    i have two questions

    1.is it possible using a smokey amp?

    2 drivers ohm is 8 ohm? or 8 Mega ohm?

    • bancika says:

      In theory it should work with smokey amp, it’s similar to the amp used here, but I can’t tell for sure. It should be set for clean sound, we don’t want to feed distorted sound back to the strings. The output impedance is 8ohm, not megaohm.

  9. Hi!,
    Thanks for a nice blogpost!
    I will use this sustainer for my double bass with 40 sympathetic strings:
    http://joelillerhag.com/instrument/

    I have trouble to find the transistor J201.
    I bought a couple of transistors and one of them is this:
    https://dk.rs-online.com/web/p/bipolaere-transistorer/0295501/?sra=pstk
    Will that do or should I find an alternative? What specifications are most important?
    Thanks!
    Regards.
    Joel

  10. Rob says:

    Anyone out there want to work with me on this?
    Iโ€™m not smart.. I just follow schematics pretty good. I never worked with trimpots … trying to understand settings…

    I have mostly everything on a solderless breadboard but not so sure of external wiring.

    Jasper175@gmail.com

  11. Allan says:

    Hi I’ve roughly wired everything up, i havent wired the bridge pickup in, i seem to be only getting the feedback function, would wiring the bridge in solve the issue?

    • bancika says:

      what do you use as input signal for the sustainer circuit? It needs bridge pickup signal to amplify and drive strings harder.

  12. Mathieu says:

    Well the circuit is working well. I plugged a 8 ohm HP instead of the driver and I perfectly hear my guitar. OK. The driver is now my problem… can you estimate the inductance it needs to have?? Mine is less than one mH. Not enough I guess….

  13. Mathieu says:

    Hi guy,
    I found your article so incredible that I decided to build my own sustainer. I manage to put a “single coil shaped” humbucker in neck position, aside the driver. And to change the 2xon/on sustainer switch for a 3xon/on one, in order to disconnect my neck humbucker as soon as the driver is on.
    All the stuff are ordered, can’t wait to start!!!
    Seen you soon ๐Ÿ˜‰

    • bancika says:

      Cool, good luck. Let me know how it goes.

      • Mathieu says:

        well, the circuit is done, except for C1 that I’ve unfornately replaced for a 0.22uf (bad reading of the scheme…) but anyway i’ll change it tonight.
        The point is: when you talk about 4.5V, between which two points whould I have this measurment??? I assume the trim is VR1 but where have I to have those 4.5V????? please help me!!!

        • bancika says:

          it says in the schematic that drain of the Q1 FET is supposed to measure 4.5V. That’s the terminal that is connected to the trimmer and the coupling capacitor.

          • Mathieu says:

            ok, so I can check the 4.5V in the path between Q1 and C3. Am I correct? (sorry for my random english, I’m french and not really specialized in electronics…)

        • bancika says:

          yes

  14. Peter says:

    Thanks for this article. More information about your choice and decision making process for the 0.2 mm wire would be very handy. Thanks.

    • bancika says:

      Hi. I can’t take the credit for coming up with the wire gauge needed for the driver. Late Pete Warmington was the man when it comes to DIY sustainer.

      Here’s how I see it. If you use very thin wire, it will have higher resistance, so you will have only few turns of wire to get the driver to measure 8ohms (you need around 8 ohms because 386 drives low impedance loads). With less turns you have less inductance, so the driver will produce weaker EM field and won’t be able to excite the strings.

      With thick wire you will need more turns, but the coil would become huge and won’t fit inside the single coil bobbin. 0.2mm wire is a good balance between size and inductance.

      120 turns is enough to fill the top 3mm of the bobbin. You could try to experiment with thicker wire and fill the whole single coil bobbin, but I assume that Pete already did that ๐Ÿ™‚

      Cheers

      • Peter says:

        Thanks for your reply, I only just saw it. ๐Ÿ™‚

        I have been trying a similar system for my diy build jazz bass. My plan is not to build a sustainer, but something that could boost the harmonics.
        Obviously I have heavier strings to move, but so far, using a variety of amp boards, and a driver unit made of a 3D printed chassis, a strip of soft iron and some #32 copper wire, I have only got sound out of the driver unit itself, presumably the bar is able to move in the chassis. I can not detect any vibration in the strings. Any ideas how I can improve this?

        I’ll keep you posted with my progress.

        • Cole says:

          I’m putting the pieces together to try and make a Bass version too. Something I thought would be helpful would be to put them off axis so the magnetic field encompasses more of the string.

          With regards to Pickup placement v. Sustainer placement, I think they would be in different places. It looks like you want the sustainer on the node of the harmonic, like the 12th fret, or where a 24th fret would be. correct me if I’m wrong.

          Peter, for Bass have you tried wiring it at 4 ohms? If inductance of the driver is the same as my dodgy knowledge of speaker impedance – your magnet would be displacing more string. I think. I don’t think you should be getting sound from the driver, because you want all of that electromagnetic energy moving your strings, maybe repot your iron bar in something more rigid. Are you married to the Iron bar? I’m going to experiment with some neodymium I’ll let you know how it goes.

  15. guitar says:

    Hey can I put this next to a regular passive pickup and put them both in a humbucker slot? Or would that cause too much interference? I don’t want to lose the tonal options 3 pickups give me.

    Is there anyway to shield the adjacent pickup to reduce the interference?

  16. Travis says:

    can i use a passive double coil pickup in the bridge or do i have to use a single? i have an ibanez rg470 with the single in the middle just in case. just curious. thanks

  17. Jonathan says:

    Hi guys, I asked that if it is posible to use an active humbucker than a single coil with this sustiner, I know I have to buy another pick up selector but it is not problem, but I have a guitar with 2 single coils and an active pick up and I want to put this sustiner with this guitar, I don’ t know if my question is undersendable hahaha, but yea, can you help me with this/?

  18. Rodrigo says:

    Hi!!
    This pickup driver, when sustainer off, will be like a normal pickup?
    thanks

    • bancika says:

      No. Normal pickups are wound with thinner wire and measure 5K-20K. The driver measures 8ohms. You can try to build a preamp and try to make it into an active pickup, but not sure how it would work.

  19. Jonathan says:

    hi guys, I want to put this sustainer in my guitar that is an hybrid sistem between active and passive, how can I do it?
    Thank you so much

  20. Chris says:

    Thx, yeah i had an mistake in my Brain…….. BUT btw, you have to adjust the 100k trim to get 4,5V at Q1, not the 22n ๐Ÿ˜‹

    • bancika says:

      when did I say otherwise? Btw, it’s all the same, they connect to the same node in the circuit.

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    The idea behind this site is to share my experience with Do It Yourself approach to guitars, amplifiers and pedals. Whether you want to save a couple of bucks by performing a mod or upgrade yourself instead of paying a tech, or want to build your own piece of gear from scratch, I'm sure you will find something interesting here. Also, this is the home of DIY Layout Creator, a free piece of software for drawing circuit layouts and schematics, written with DIY enthusiasts in mind.