Pekko

I made my first driver with 0,3 mm wire, about 250 turns if I remember correctly. Sustain effect was very powerful on low strings but I couldn't get high strings sustaining at all. With second and third drivers I used 0,2 mm wire (130 turns) and the results were quite even on all strings. Psw has tried thinner wire with poor results. Based on these experiments I would say that 0,2 mm wire is quite optimum for the driver. As you can see from the pictures, you can make a really compact driver with 0,2 mm wire. All the wisdom you need is in the quote above. I suggest you to get some 0,2 mm wire and try to wind a driver according to instructions above. You can also use ceramic magnet as core material if you find something with right dimensions, that's what I'm doing. Pekko

There seems to be a lot to catch up after being two weeks away. Psw, nice work with sustain box. I wonder what keeps you going. Update for my sustainer project: Third driver seems to be a success. I wound 130 rounds of 0.20 mm copper wire around ceramic magnet measuring 50 x 4,6 x 6 mm (actually made from two magnets 25 mm wide). DC resistance is about 9 ohms. I potted the driver during winding with white glue. If you want to calculate the approximate number of rounds needed, you can find a data sheet for different gauge copper wires here: Copper wire data sheet I got all the strings sustaining easily, also the high e. I was able to turn the gain trimmer of LM386 to minimum and there was still more than enough gain available for sustainer. Only problem was that the system was prone to squealing, especially in harmonic mode. I added some shielding to driver wires and experimented with magnetic shunting with piece of steel. I found out that the steel piece was most effective when placed as near the bridge pickup as possible. After these procedures I could increase gain enough to sustain every string in fundamental and harmonic mode without having to fear about squealing. I took the opposite approach to installation as psw and tried to keep everything as simple as possible. Only single bridge humbucker with volume control and sustainer circuit. It's not so pretty, but everything is working ok. Maybe I shoud make a new pickguard later. You can see the magnetic shunt taped over bridge pickup. Battery is located left side of the bridge, open three screws and you get the access to the battery. Controls are master volume, sustainer on and harmonic switches and sustainer sensitivity pot. I do get a slight pop when switching the sustainer on and off, but it's only audible if the strings are muted. Next I'm going to use the sustainer for some time and see if something needs to be improved. I'll also try to make some sound samples. I also have some more pictures of different phases of the work, please let me know if you are interested in some particular part. I'd like to add that all the information needed to build a working sustainer is in this thread. And, like psw has wrote many times, the magic indeed is in the driver. Pekko

Psw, you seem to be right about the switching fault. Thanks for spotting it. Meanwhile, I've finished my second driver. This time it's a short coil with steel core, 0,2 mm wire and 6 rare earth magnets. First thing I noticed was that the magnetic pull was much less than with my previous driver using ceramic magnet. I tested it today with Fetzer / Ruby amp. Performance was much better than with my first version. This time I got infinite sustain easily with every string except high e. I also managed to get high e sustaining, but it's not that easy and consistent as the others. I had both N1 and N3 versions of LM386 around, so I tested both. I was little bit happier with N3, but the difference was not very big. My biggest concern is that the sustainer seems to distort my signal, which is going to amplifier. I suspect that this is caused by interference, I only connected the parts together with some test leads outside the guitar. Another problem is that I couldn't get harmonic mode working properly. All I could get was high frequency oscillation. I was able to change the frequency with my volume pot, so I did get some interesting sounds, unfortunately that was not what I was after. I had exactly the opposite results. Performance was much better without tone capacitor (I've left tone control out from this guitar, so I tested this with separate 22nF capacitor). I guess this depends on pickups, I have a dark sounding humbucker in bridge position and psw seems to be using single coil PU. Next I guess that I'll put everything inside the guitar and see if a proper installation helps with distortion problem. I might also add a Zobel Network to my amp to see if that helps with oscillation in harmonic mode. I also have material for some more drivers, so I might try one using magnet itself as a core. Regards Pekko

I finished my amp circuit on weekend and managed also to do some testing. My preamp is based on exactly the same opamp circuit that Mike was using, which seems to be also close to buffer preamp opamp circuit psw posted a link to earlier. Amount of preamp gain is certainly not a problem, at least not with hot humbucker I'm using. Anyway, I was not happy enough for performance of the circuit to install it to my guitar. It is very prone to interference and oscillation and the operation seems to be a little unstable. I had trimpots on preamp gain and LM386 gain and a pot as a volume control between preamp and LM386. I experienced best performance with both trimpots turned to minimum gain. My LM386 is version N3, which seems to deliver more juice compared to N1 according to data sheet. My driver is also designed like a normal pickup, ie the coil is quite high. My experiences are exactly the same as Mike's with his new driver (Very good performance on thicker strings, next to nothing on higher). When switched to harmonic mode, the results were almost opposite. Thinner string were working ok, but thick ones were a little bit harder to drive and didn't sound very good. It looks like lower coil driver design and J201 based preamp will be my next step. Pekko

psw: Thanks for your warning about using too much power. I didn't have to crank the stereo amp and the experiment was pretty much just to see if the driver is working or not. Core material I used was normal black steel. I might try winding a driver around ceramic magnet or making core from transformer lamination steel plate. This should do the trick for switching power on and selecting bridge pickup with DPDT switch ("tone" side of pickup selector not shown): This will not affect tone side, so active tone controls will be selected with pickup selector.

Hi. I discovered this thread two weeks ago and yesterday I finished my first sustainer driver. 5 mm iron core, 220 rounds of 0,3 mm wire, DC resistance 7,3 ohm, ceramic magnet from old single coil pickup. I tested it quickly today using DI Box -> Mixer -> old stereo amp -> driver as a sustainer circuit. I found out that sustainer effect was much more powerful on lower strings. On low E, the whole guitar was vibrating massively and on high E there were hardly any effect at all. Slightly varying driver height didn't make much difference. My first impression was that the sustain was vary similar than what can be achieved with a loud amp. Is there any experience about the driver design which would give more even response from different strings? As I'm sustaining through mixer, it's easy to test if compressing or eq'ing has any effect on behaviour. I'm going to build an amp with preamp based on TL071 and power amp based on ruby. I'll report back when it's done.