Fresh Fizz

Yes, but the same input signal doesn't distort more with a 16 ohm load. There is only less efficiency with a 16 ohms load. It works the other way around, the bigger the load impedance the more headroom. More voltage but less current. I've been playing with all the parameters in a spreadsheet. A 10 uF cap for Zobel keeps indeed the overall load impedance between 8 and say 11 ohms. Good work! It should surely help when the high frequencies take the zobel route. You got me thinking. Have you ever thought about an ultralinear like design? Create a negative feedback loop with a tap on the driver coil. cheers FF

I use some treble boost (8 dB at 1.5 kHz). But not to get different harmonics. It's more to balance the 'sustainability' of the strings. Give the fundamentals on the high E in higher fretting positions a helping hand. FF

The 'solution' is to drive each driver coil with the required amount of power. So maybe the low E needs only half the power the high E needs. Build a driver that works on the high E and you'll be fine. FF

Can you tell me what this new driver looks like. I can imagine the driver on the right doesn't work properly. The wire is not wound tightly around the magnet/core. Of course it's impossible with a core shaped like that. You need a bar magnet! Is the cover (or top part of bobbin) of your driver made out of iron? That shouldn't be, it should be made out of plastic, or at least a material that isn't magnetic. Like psw told 20 Watts is too much power, the challenge of building a good sustainer is that it's a balancing act. With 20 Watts you have enough power but 1. on the long run you'll fry your driver, 2. string rattling, 3. squeal problems If you say it's the driver that's causing the problem then my advice would be build a new one, use a bar magnet (ceramic) and 0.20 wire. You could show us what you're going to use (picture) before you start building. Cheers FF

That's a good start! Is your end goal a 8 ohms driver? (12 coils of 24 ohms, 2 x 24 / 6) Well, a picture of the coil you've built would be nice. So what is the next thing you have in store for us, a one-string-only sustainer? That is the big challenge with this new design, to get sustain at all! FF

For me it's the other way around. I didn't need a neck pickup. But now something is mounted that looks like a neck pickup I want to use it in that quality. Once you have found a way of creating a driver that functions and looks good it's only a matter of repeating the same trick. But it's very personal. You have to find out what works best for yourself. Yes they need some amplification (some 40 dB !) But the impedance at 10 kHz is around 120 ohms (very low) and I don't have to be worried to lose that classic vintage paf sound (it wasn't there in the first place). My expectations are not that high, how microphonic are coils soaked in wood glue? Cheers FF

No, I meant, double coils for each string, something like that: | *|* | *|* | *|* *|* | *|* | *|* | To save space you obviously have to place them in the alternate order. Your configuration looks like 6 coils connected in parallel? At least the connector looks like just a 2-pin one. It eliminates the whole idea of driving all 6 strings simultaneously. Or, am I wrong? I'm kinda confused again. What are the metal sticks on top of the coils? Does does your driver consist of two rows of coils, in a humbucker-like configuration, 12 coils all in all? The second post ("Why not some web cam pics...") was not related to the hex driver but presented a dual blade HB I just finished building. I understand what you're after but from my picture you get an idea of the proportions. In order to succeed you have to use small pole pieces and wind some very neat coils. There is a guy with a CNC machine that I believe could do this type of precision work but he is living the life of a Chinese dissident at the moment. My hex driver has 6 coils in series. Of course you can use 6 coils (or 12) in parallel instead. FF

yes, a picture of your driver, blink sustainer, whatever would help a lot. Hey man, you're the star. Let the crew work for you Cheers FF

Why not some web cam pics of the new driver? 2 3 Next project will be to make the driver usable as guitar pickup (in order to silence all critics. ). Cheers FF

So agg is your baby, nice to know! I've built a hex driver that bucked the hum. N-S-N-S-N-S and adjacent coils out of phase. Above the magnet it performs well but in between the magnets there is no sustain. That makes sense because in between the string got or pushed or pulled at the same time by the surrounding coils/magnets. Your design would be: N-N-N-N-N-N-N (7x) and adjacent coils out of phase. In between magnets it would function like you explained. But if you bend the string across the magnet you get the old up-down orientation and depending on which of the 2 magnets it will be fundamental mode or harmonic mode. I haven't tried this, it could be useful. But I guess the guitar pickup has to replaced by a 2D type pickup . That looks like a problem to me. Cheers, Fresh Fizz

Some interesting new developments! I had similar ideas. Take thicker wire but keep the old amount of turns. Compensate with an extra resistor. Add a capacitor parallel across the driver coil to create a parallel notch. I don't know the English expression but this should multiply the current times Q at the resonance frequency. Phase shift at resonance frequency is 0 degrees. But at other frequencies it's not Anyway, I've built a new driver. 2 x 90 turns 0.25 wire, 8.5 ohms, 1.8 mH. There is a bigger gap between the blades than on the previous version, the blades are somewhat thicker and I used an iron bottom plate (instead of plastic on the previous one). My first impression is that the new driver is a lot more efficient. Loose plain E string swings a lot more. Cheers FF

This appears to be a theoretically sound idea to me. If that 40% increase can be achieved remains to be seen. But since nobody else ever did this experiment I can only say: go for it. I've read about mutual inductance, but I have no idea how it plays out. make love .and. war cheers FF

Therizky is telling that he is experimenting with 0.1 wire. I don't see what is wrong with col's reply. My own proposal was a push in the right direction, but still not optimal (r², it's 4 indeed!) and: That got me thinking, 0.3mH. By splitting up a coil into multiple coils in parallel one could reduce the self inductance. That would be ideal, because we want the self inductance to be as small as possible. We want a driver that is 'ohmic'. I only think that in our case the inductance doesn't equal 0.3mH because the 4 coils are coupled on the same core. But what if the 4 coils have their own core? Then the next logical step would be to wind 4 coils 32 ohms/4.0 mH. Thicker wire and more turns. Cheers FF

Hi therizky, What you could do if you have plenty of 0.1 wire is the following; measure the resistance of your sustainer driver coil. Calculate how many turns of windings you need to get 16 ohms. Let's say you measure 64 ohms then you need 300 * 16 / 64 = 75 turns. What you have to do now is to wind 2 coils with 75 turns on top of each other and connect them in parallel. Then you obtain an 8 ohms driver. Some solutions for a buffer. The bipolar transistor with the 2 resistor voltage divider seems to be the most appropriate solution. (below Dr. Quack) Good luck FF

Thanks, Yes I get inspired to write some killer lullabies The neck and middle pickup were sacrificed long before I even thought of making a sustainer. I guess I'm more influenced by Edward Van Halen and Malcolm Young than by Mark Knopfler and Richard Thompson. For me the same thing, I see it as a gadget I think my HB driver is more height sensitive or maybe I should put it the other way round, further from the driver it loses efficiency compared to a strat-type driver. But it has its charms, when playing 'camp-fire' chords you're not disturbed by aggressive sustain while on the other hand you get a quick response when playing solos. Yeah, the LM386 is all right. I could make it work in my sustainer. With AGC with a long release time. There is no need for more headroom. In my case the Ross compressor limits to 1 W. So my TDA7231A never distorts. But when is that much power applied? Most of the time the other FF AGC limits below 0.5 W. To use that 1 Watt I have to dampen all strings but the high E play open E and wait for the sustain to build. Very unnatural way of playing! Cheers FF

Thanks As soon as you start to use AGC you don't need that much power. With 0.5 watt all notes sustain! The problem is that 0.5 watt is way too much when playing higher fretting positions. It's impossible to play a decent scale legato-style, especially on the bass strings. It's more like pick a note, hold it tight, palm mute a bit, go to the next note. Therefore I can't see why an LM386 is a bad choice per se. There are some versions with less power, so make sure to choose the right one. And without AGC you're going to overdrive the IC anyway. It's that or else you use low gain in your positive feedback loop. Then you wind up with a rather weak sustain that builds very slowly but not a steady-state sustain. The idea you came up with (AGC with a feedforward sidechain) is indeed a big improvement. No more string rattling. Any more eureka moments? I think it was 2 times 65 turns of 0.2 wire, 8 ohms Picture 1 Picture 2 TDA7231A poweramp, 12V outboard power supply. Cheers FF

I have some clips if anyone is interested. It's on mediafire so you have to download, no pass, no viruses! The signal goes from built-in fet treble booster into the sound card. ( No FX, no speaker sim) The sustainer itself uses 2 AGCs, the Ross compressor mod does the lion share of compression and there is a AGC with a feed forward side-chain to tame the strings. My goal has always been a without hands sustainer. There are no controls & only fundamental mode. And some very old strings, 2 years I reckon and after many turns of restringing. Results feedback on open strings and 2nd (12th fret) and 3rd (7th fret) harmonics open strings Playing the big trouble spot, only second harmonics feedback, no fundamentals 2nd fret All across the fretboard, at the end of the clip you can hear how the sustainer performs with open chords. more sustain Cheers FF

@camilo I would add the Zobel network, like C7 and R8 in this schematic. For the rest I would say: Stick to your plan and build it! @col and everybody who likes it longwinded -if not, sorry guys [Yawn on] I think that there are 2 types of people who visit this forum. People who want to build a sustainer device but aren't interested in theories at all. And then there is a group of people who like to brainstorm and show up with new schematics and theories, the visitors of the forum that stick, I would say. Personally I don't believe in a scientific approach if that means we need to know scientific theories in order to build a sustainer device. (Though that doesn't mean that I'm not interested in theories.) And it's certainly possible that a new aquired insight could help us develop a completely different and better sustainer device. But something else is missing. A systematic approach to get the optimal performance. Systematic is a big word for collecting data while changing one parameter at a time. That's how Pete has optimized his driver for use with an LM386. In my first post I came up with a calculation method for the phase shift of a sustainer driver. The electric specs of my driver appeared to be optimal. The bigger the self-inductance, the stronger the magnetic field. But when the self-inductance gets too big compared to the 8 ohms (real component) resistance you loose bandwidth. How did Pete do it? He took copper wire of different thickness and made 8 ohm coils using the same type iron core and magnet and compared the drivers. I applied the same method while building the electrical part of the sustainer device. I tested the driver with a simple preamp (TDA7231A). In my case that didn't work well, I couldn't get decent sustain on a large part of the fretboard. In Pete's case this simple configuration worked. I would say it's because the difference in guitars. Maybe my guitar doesn't sustain as well or the sounds per string per note are not so well-balanced. I had to resort to performing enhancing drugs! First came the experiments with overdrive. But no matter how I varied gain level, output level, pre distortion eq, post distortion eq, I always ended up with good sustain that was no matter what accompanied by fizz. So there was no way around building a limiter. I chose the MXR Dynacomp/Ross because I'm familiar with that one. My sustainer performs really well except for some fizz on the bass strings when playing more than one string. But I only did one rough setup for the output level, ± 1 Watt (circuitry at midpup position, too lazy to remove, put back and tune strings!) But I'm confident that when I would experiment with output level, compression level and low-cut I could reduce fizz significantly or even make it disappear. I've listened to some of the sustainer videos on YouTube. The only thing I like to know is how to get that mixed mode sound, it starts with a sustaining fundamental but then goes into a harmonic note. What I'm trying to say is that there is no reason not to have an operating sustainer even when using a simple LM386 and a simple compressor. What I feel is needed is a sustainer endorsed by the forum and a sustainer cookbook with instructions how to build that sustainer. That would be basically a recap of the mainstream of the 300 pages up to now. Take a few drivers to choose from: single coil strat-like, single coil with blade and ceramic bar magnet, humbucker. Use a design based on the LM Squeezer as sustainer/poweramp. Of course I would appreciate it when somebody would elaborate on the cutting edge sustainer he is designing. But I can tell how it works for myself, I'd like figuring out things by myself and have the honor be the first to publish it on the forum. [/Yawn off] Cheers Fresh Fizz

Hi camilo, I see no fatal errors, nice fancy switch on your tone pot! 1. In your configuration the signal that is used by the sustainer is the same as the one that is selected with the pickup switch. The bridge position should work properly. The middle and combination postion could give squeal noise, but that is nothing unusual. 2. No cap in series with VR3 (between pin 1 and 8). This could affect the DC offset (voltage at pin 5 not exactly 4.5 volt). This is not a big problem. Without limiter/compressor the IC will go into overdrive anyway! 3. No Zobel network. (100 nF cap + 10 ohm resistor.) This could lead to oscillation. I see you have some space left on the printboard so If you have oscillation add the network after C5. Good luck with the installation and tell us the results Fresh Fizz

Hi Hank, some more crazy ideas It could be important information to know how much power exactly is needed for a single string driver. It would be great if you would be able to use a quadopamp IC like a OPA4134 together with a dualopamp OPA2134. Of course the driver's specs have to be changed. Higher impedance, more windings(?). Two batteries instead of one for more headroom. 6 LM386s deliver way too much power and take too much space inside a guitar! How about using PIC only as a switching system? For instance build 2 poweramps. You need 6 pickups to be used as sensors (which string is played). The actual sound signal could be taken from the bridge guitar pickup. When you play the high E string it will be detected by the sensor and PIC will, according to a decision table, connect the high E string driver to poweramp A and the B string driver to poweramp B. I wonder if the data can be meaningful. Guitars are so different. Some guitars have a good sustain by them self. In that case you probably won't need that much power to obtain endless sustain. I have no idea how efficient my driver is compared to what other people built. I just used the scrap materials that were available to me. It's every guitar for itsself I'm affraid. I would certainly experiment first with the hexapup you are planning to use. Is it a Roland synthesizer type, a piezo type or a home made one? I've managed to build a hexaphonic pickup out of 12 relay coils (Never implemented though, too much work! - And it looks pretty awful). Build a simple analog sustainer for the high E string only. Because the hexaphonic pickup is so close to the bridge and because of the use of different technologies (in case of the piezo) it could be a pain in the ass to get sustain at all. With your hexaPIC mcSpankster you are certainly entering unexploited territory. Anyway good luck may the MMF be with you Fresh Fizz

400mV pp seems pretty o.k. for me! 400mV / 2√2 ≈ 141mV. Driver current should be 17mA. That's 0.141*0.017=2.4mW ! Does that mean that 6 single string drivers are more efficient than one large driver? 6 * 2.4 mW = 14.4 mW compared to the nearly 1 W I use. I. How fast does your sustain set in? I can imagine that when you use that little power it can take some time to achieve a sustaining tone. I hate to wait for sustain to happen. II. How focussed is the magnetic field? If you bend the string do you still have sustain? And I'm curious how you solve that issue with bending strings. Is that a matter of PIC, like when you play the high E-string your E and B driver work. (I don't know if that makes sense, I'm not familiar with PIC). Or do you build drivers with some sort of overlap (when a string is bent it is still above the driver). Or are you fully focussed on sustaining chords? III. There is a chance that when your sustainer is operational the drivers could have a negative effect on one another. You stated that you needed 400 mV pp for your E-string, but what if your B-string is sustaining at the same time? It could be that because of interference of the 2 signals it's a lot harder to get good sustain. So maybe I should operate my sustainer (Steady Steed) with less power. (There is a trimpot inside my strat.) Could be that with less power I still have a good sustain but without the funny fizz effects on the low strings when playing chords. I will do some test with the LM Squeezer to get the signal limited at a lower level (like 400 mV pp) and will post it. Greetings Fresh Fizz

As an aside, your scope trace shows the peak to peak voltage nearer 7.5V, (5.3V RMS)...which works out at 662mA into an 8 Ohm coil = 3.5W - positively nuclear! The 4V peak-peak was wrongly stated, ofcourse it's 8V pp. But to calculate RMS you need to divide by 2.82 , not 1.41 . With a symmetric signal you take one half of the sine wave (peak to X-axis) and divide by 1.41 . It's 1W, really! FF

A bad screen shot.... You're looking at a digital fotograph. I'm still using my good old Handyprobe (connected to the parallel port) running on MS-Dos (floppy). It worked well in Windows 95 on an AT286 but not so in XP. The Y-axis (voltage) is accurate but the X-axis is in need of a new calibration. The vertical lines is another peculiar phenomenon, when wave shapes get weirder it occurs even more. It's not oscillation. No it's less, 4Vpp, 2.8V rms, 1W @ 8 ohms. But you know, I'm not so sure about that figure. After a while the driver runs hot(ter). Copper wire's resistance goes up? My goal was to develop a simple design that at least is capable of producing enough output to produce sustain. Now I know that 1W is the max with the LM386. By increasing the feedback (trimpot Rv) the output level can be lowered. I only hope there is enough output signal to go low enough, otherwise some extra DC voltage has to be added somehow. But not the Aussimart way, that makes long release times impossible. Cheers Fresh Fizz

I did some tests with the LM386. This is the simplest limiter I could come up with. Boy, that IC gets hot! It gets easily as hot as my circuitry with the TDA7231A which produces more output. Heatsink required... Or class D. Also a pic of the wave shape on computer. You can see the even order distortion, but it's not that bad for a simple device like this. Input signal was a 1000 Hz sine wave. 100 Hz or 5 kHz gives similar results. Cheers Fresh Fizz

Hi Pete, I tried to google up that island you mentioned. No luck. There seem to be penguins everywhere! Anyway good luck to you, Pete. I hope that you will feel at home on your island very soon fresh fizz