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.
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.
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.
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.
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.
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.
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.
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.
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.
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
Hello, does the pickup still function as one with the driver turned off, as with sustainiac and fernades types?
Nope
hi everybody, this is my last post, as i don’t think i’m going to find
any stuff here to help me with the sustainer thing.
i just wanted to share what i found out after doing lots of tests
in making a proper sustainer driver.
turns of coil doesn’t matter alot. the thing is that you should
find a happy medium. as you know many turns of coil makes the
electromagnetic field stronger, but keep in mind that we are not
going to make a pickup, quite the reverse, our driver must be
powered by an amplifire, like LM386. yes lots of turns makes the emf
generated by driver stronger, but many turns of coil is going to give the
amplifire a hard time as the resistance of the driver adds up by adding
turns. yet we also know that by not adding proper number of turns
dc current that powers the amp, will go up, and may damage the amp
because of the load being too low. this is where happy medium
comes into play,meaning, getting max vibration of strings by proper
number of turns.
they say you should aim for 8 ohms of resistance for the driver because
LM386 amp works best at an 8 ohm load,wether a speaker,or in our case
a sustainer driver.
that ia a good suggestion, however, during my testings, at one point i did
200 turns to see what was going to happen, by the way the suggested
turns is about 165. when i measured my driver resistance at 200 turns
was 11.5 ohms. and string vibrations was OK,believe or not.
at 140 turns i got 8 ohms, string vibrations THE SAME. i’m serious.
at 70 turns i got 4 ohms, considering,4 ohms was a bit too low a load
for the amp, i disconnected the power at once.
so according to my testings, number of turns,not a big deal, as long as
you don’t go below, say 100 turns
the only thing that amazed me was strings vibrating at 200 turns when
the resistance was 11.5 !
so, happy sustaing,,, i just love it, i hope you do too,,,
hi,everybody, just a question,does anyone know if LM 386 amp which
i’m using for my driver,can run a 6 ohms load,whether it’s a
speaker or a sustainer driver,or should it be around 8 ohms.because i don’t
want my amp go up in smoke.
i tested my driver having 6 ohms resistance,and it worked,i mean strings
sustained well . i used stronger magnet though.
in fact i have to correct myself,having done lots of tests. there is no secret to
make the driver. turns doesn’t matter a lot. a few turns up or down is ok.
in my case stronger magnet made a big difference, and as you might guess
fewer turns,say around 50, YES you read it right,i said around 50. much fewer
than they suggest, put it this way, at 8 ohms the intensity of sustain was half.
i know it shouldn’t be that way, but it just is, don’t blame me for that, as i have
no explanation why that is so.
hi, i made my first driver one day ago and it didn’t work at all.
as most of the instructers suggest,the secret is how you make
the driver. i think any half watt to 1 watt amp should be fine.
so when my first driver failed i was so disappointed. but i didn’t
give up.by the way i use lm 386 half watt amp,very basic one.
you know what is the secret? Exact Turns.
we are supposed to get 8 ohms,right? ok,on my pickup 125 turns
gave me 8 ohms, not 160 turns as most of the driver makers
suggest.but keep in mind turns from pickup to pickup differs.
that’s it. my driver works now,i mean strings sustain,and it is
so magical.i have to mention that with my first driver with 160
turns i got 10.5 ohms which was too high and that was why it didn’t work.
Tnx for the comment. Did you calculate 160 turns for your core or used someone else’s calc? It will depend on geometry of the core.
hi again,sorry it took a while to respond. i just check the site once in a while.
i counted the turns as i wrapped.simple as that,wrapping is a bit frustrating
though.because you have to wrap tightly to avoid acoustics.
i should mention i once had a fernandes sustainer,not too bad,but too many
knobs,for me anyway.i just needed a basic sustainer.i didn’t and don’t need
harmonics mode,etc.you may ask why? well here goes,i am not a guitar player.
i play the ukulele and sometimes the mandolin.i just need the notes prolonged
on different pieces of music. so i don’t play chords and that’s an advantage for
the sustsiner thing. the fernandes one didn’t work for my purpose. it gave me
the microphonic feedback. so i thought maybe it was because of complicated
design of the circuit,and i still think that was the case. so i decided to make my
own. after reading so many articles on diy sustainer forums,i rolled up my
sleeves and started making the thing. i never thought it was going to be so easy
to sustain the strings. to be honest i was over the moon the first time my driver
sustained the strings. i’ll keep posting stuff here as i progress.
hi i made all of this it worked but somehow sound is very noisy when sustainer drive on sound goes crazy like a tractor when i turn it off its clear as heaven what i did wrong?
sorry for bad language greetings from Turkey
Do you have a regular pickup near the driver? Could be interference with the pickul
i have a bridge pickup and driver on the neck when i move the driver to far away from the pickup its still noisy i think it have very high magnetic field what can i do about it
Are you sure it’s not the circuit that’s interfering? Make sure that the amp is not near signal lines and that outpjt leads from the amp are not close to signal lines. If the driver is too strong, try lowering the output from the amp or add some gap between magnet and poles to weaken its effect.
i forget to say i didnt have 3mm space for driver wiring i didnt do any space and i dont understand why we have to 3mm space if i have 3mm space its can be my solution? thanks for the replies by the way i will check the amp again
Hi,
I’m currently trying to get my sustainer working, however I can’t seem to succeed. I’ve rebuild the circuit multiple times, and i am 100% sure it’s correct now, because when i hook up a real speaker to it, it gives the guitar sound.
So I think the problem should be in the driver. I’m using an old single coil pickup, and wound it over a width of 3mm with 0.2mm wire. When I measure the ends I get around 8 Ohms, so it should be correct, but still it is not working. I’ve even made a second driver and the problem persists. I also tried new batteries.
In my setup I only have a bridge pickup, connected as input to the circuit and the driver in the neck location. I’ve also tried adjusting the height of the pickup. The string do seem to buzz a bit, but it’s nowhere near sustain.
Have you got any advice because I am completely lost and it’s so time consuming!
Thanks in advance!
Do you have a magnet in your pickup?
Yes it’s on the bottom, exactly where it originally was, didn’t touch it. In my first driver build I used a 3mm metal plate directly on the magnet, isolated the plate and magnet from the wire, but this also did not do the job. I have also saturated it with wood glue.
I was wondering if this could be adapted to an eBow like configuration where the sustainer is self-contained in a project box that you hold above the guitar or more specifically, for pedal steel. eBow stopped making a multi-string unit some time ago (not much demand I guess) so something portable and hand held like this could replace it for DIYers.
Yeah. Build the same driver and just don’t install it in the guitar. That’s how I tested mine, handheld.
Hi,
I just bought a sustainiac pedal off ebay for £11.61 but without transducer pickup, would your pickup work with the sustainiac?
Cheers
Gary
Not sure, sustainiac has a pretty distinctive pole pieces, it would definitely not be the same, but may be worth a shot.
How does this mount onto the guitar? A pic would be really useful as well as a description.
So I was thinking of building this. Basically this doesn’t hook in the guitars electronics and instead, works more or less like an ebow. Is that right?
Yup
The hook up diagrams are on both fernandes and sustainiac’s websites
Where is the calculator D:???
Nice idea and I’ve already got Ruby amp parts for 9 volt kits. Please show finishing details. Driver hooks to amp output? Input is switched from other pickup? How to combat microphonics? All these details would save countless experience hours thanks.
hi, did you have any success with this? While the post gives instructions on how to build, it doesn’t say whether it worked for you or not. From what I can gather online, a lot of people try making PSW’s sustainer and a lot fail. I’ve tried a few times and have had various problems, mostly to do with my electronics skills, and not having the right components. Do you have any video of this working? I’d be really interested to see this if so! I’m planning on making an instrument for an art installation that will feature dozens of strings and up to 15 sustainers, so am trying to get as much info from people who have successfully made ones. Cheers!
Worked for me first try! (Well, I had to correct an error I made when putting the circuit together, but it was a mistake on my part not the diagram on runoffgroove)
hi i may have over looked but i cant find the link for the coil winding calculator would you please send me the link
by the way nice pics
thanks very much
Allan
http://pickups.myonlinesite.com/pickup.php?unit=mm&cl=60&cw=6&ch=3&bw=14&bt=1&ends=round&wd=0.2&id=0.22&show=on&avt=100&adj=ohms&avo=8
This is the link bud! Good luck! 🙂
I would like to know if you have instructions on how to build the board?
could you please send me the diagram and instructions. i would love to build one for my new ibanez guitar.
thanks!
This is great help and everything, but no one yet has been able to tell/shw me where the wires from thie driver hook up to the p/u and the rest of the guitars control system. Any further help with this bit would be of great help.
Wow, lots of NFO here thanks! how I wish to see a useful diagram for the complete project.
you bro banchika,
please send the diagram and instruction wiring to my mail benny_wibowo@yahoo.com
I would be really appriciate that
thanks a lot bro