Sustainer Ideas

[Franky]

Unless your translator is familiar to rough french expressions, you are ready to laugh a lot (I love using these translators, always fun...)

The scheme is from an old design, which didn't work with the driver and pickup as drawn. The guy had to rewind both to make it work. And I think he came here to find some info..

So the electronic part in the schematic is right, it works, but then he explains how to make the driver (we all know it here, 0.2mm wire, 8 ohms, and about the size, its driver is 8mm long).

But there is a lot of text explaining how and why he failed at first tries.

The Aaron Stompboxes design is great, looks cool, maybe it just needs some pieces to hold it on the strings, like the original ebow..

My way of playing "with infinite sustain" does not involve my right hand that much, so the ebow seems a good device for me, and as you said, it can be used on every guitar..

[psw]

Well Franky, I'd certainly encourage you to develop the electronic eBow and share ideas with variations. I have thought that this is an area I should move over too instead of the pure sustainer stuff.

Another advantage of the eBow is that it can be "played" by moving the driver along the strings. All DIY eBows have seemed to neglected the harmonic drive (although the new official eBow features this) and wouldn't be hard to do).

As I have not really played an eBow it is a bit hard to gauge it's limits. From what I have seen and read, it seems to be that you need (or best) to use the neck pickup while playing it for instance.

A couple of speculative ideas have come to mind though. One was when I was doing things with the HEX drivers. Each driver contained six individual drivers and 12 magnets. A single driver element for instance was 10mmx5x5 with two magnets, so there was the idea of a much smaller ebow like device. Then, perhaps an idea to have the circuit separate from the pickup and driver parts connected by a lead. You could then mount the bulk of the thing and put it into the guitar or more likely a pouch on a guitar strap, perhaps retracting but with easy reach and compact enough to hold both the device and a pick say. Another was a type of driver that I made which was very sensitive to alignment. Moving the driver from one side to the other alternatively increased drive in either the fundamental mode or harmonic mode. The potential there would be to alter the angle of the ebow driver in relation to the string (twisting it) to create more or less drive and harmonic control.

The more simple LM386 circuit or a Ruby type can be used if the eBow pickup is matched to the input of the amp which is how the actual ebow is set up. Somewhere in this thread I think you will find actual pictures of a destroyed ebow showing what is in it. They actually set the circuit and drivers completely in epoxy as a part of the case and this is why it is a little elusive. One thing discovered from this is that the ebow driver and pickup seem to have a metal shield around it. Basically the coils are flat and round and I suspect a metal pipe could be cut to encircle the coil and allows the two coils to be as close together as they are.

Very early in this thread, page 2 I think, I succeed with a fabulous coil, 10mm round and made with thinner wire I believe and around a ferrite "bead" as the core and a small magnet on the back. With the full power of the circuit being run into this it produced enough drive to bounce the strings off the frets! In the early stages I was working on principles so I made a lot of things as single string drivers. A bit of a cheat of course as you are using the whole coil to drive on one string instead of spreading the force across all six, but that is one of the reasons that the eBow is more efficient, another is that it only has to deal with a single string sound source, not a chord or anything, and you can move the device to get the best position and avoid nodes along the string.

So...like any major variation in my designs (such as the dual core parallel or series drivers) my specifications of 0.2mm wire only really applies as best or essential to my original full sustainer coils. All bets are off for a single string device or multi coil design. The 0.2mm is a good place to start, it was arrived at by extensive trial and error and for my design 0.05mm up or down has a dramatic effect to the point that it will not work! Similar to a proposed pickup coil in an eBow, it needs to match the input impedance of the circuit to prevent internal loading effects and be efficient. So, typical pickup wire may not be the ultimate. As a guide though the pickup will require significant turns of a much thinner wire (often difficult to get unless you actually wind pickups and fairly fragile and difficult to work with) and the driver thicker wire with fewer turns (to about 8 ohms)

Potting is also essential of course. The DIY eBow I posted from the thread at Aron's DIY stompbox forum (just another contribution supplied here by the still missed lovekraft, RIP) is great in it's detail. The coils are wound around fender type magnetic pole pieces and covered in glue. You can see how small the size of the actual windings and how few the turns. I never had audio of this device but the maker seemed to suggest that it worked very well and I have no reason to doubt it. The circuit here is also a basic LM386 design. A ruby with an added buffer or our F/R or modified or other sustainer circuits would equally work and might give more flexability to the pickup design.

I hope more people explore the eBow type of thing, but as always often just buying one produces the best and cost effective results. You really need to want to DIY and enjoy challenges to do something like this or a sustainer, but at least with an eBow your experiments wont involve any modifications to the actual guitar!

pete

[Franky]

OK, I've read the end of the french tutorial, it's a little confused, I don't really know what he used for the input coil..

Anyway, I've just hacked a cheap Tele bridge pickup, which gave me 6 polepieces, 18 mm long. I've got to find some powerfull magnets, I think I found some neodymium ones in a dead CD player, they're powerfull but really small..

Edited July 26, 2008 by Franky

[psw]

Anyway, I've just hacked a cheap Tele bridge pickup, which gave me 6 polepieces, 18 mm long. I've got to find some powerfull magnets, I think I found some neodymium ones in a dead CD player, they're powerfull but really small..

So...planning and eBow...alright!

Try to find the stuff on eBows that has come up from time to time in this thread, there were quite a few photos that might give you a better idea of what was actually in a real one.

As for "powerful magnets" you can try neomags but be careful, they need to be very small. Most magnets in disc drives are easily strong enough to pull a string out of tune and seriously effect the vibrations of a string. This is what I described in a recent experiment with a surface mounted driver with 4mmx5mm(L) round mags...way too strong. Instead ceramic magnets, even from a fridge magnet or craft shop is going to be a much better thing I would immagine. Perhaps something from a tiny speaker even.

In the eBow I recently pictured, the long pickup poles are actually alnico magnets, you could make the coils more compact with a steel core (perhaps cut from a bolt shaft), say 5mm round 5mm long and gluing a magnet to it's base behind the coil. This is essentially what I did to make my original little coil that ended up about 10mm round and probably used something like 0.15mm wire (though I cant be sure) which would account for how I was able to get about 8 ohms on there. I still have the coil somewhere, but it did get damaged from about a year of playing with it so that the fragile wires broke off it. Make sure you plan to pot it perhaps using the same PVA wood glue idea shown in the linked pictorial for a sustainer driver pickup.

Winding round coils are a lot easier and neater than the longer sustainer coils as there is equal tension as you go

The real problem is the pickup coil. You will likely need very fine wire that can be difficult to get and to wind. This is the more difficult part but with the right materials could be made in a similar manner to the driver. You might consider using a drill to wind the thing even. Check the specs on the input impedance of the LM386 or whatever amp you are considering to get an idea of what you should be aiming at as far as resistance of a pickup coil. Consider where you might get a premade coil. For instance, it might be possible to use a tiny speaker coil such as you get in a cheap headphone if you include a preamp or buffer in the circuit (eg a typical suggested sustainer circuit). If this was used, perhaps the cone and voice coil could be glued in place. If you really wanted to hack into such things, you may fine an 8 ohm speaker to be hacked of this kind of size and experiment with this as the driver coil as well. As always, it takes some experimenting to get something that will work.

The other thing to consider is the balance of forces, both magnetic and electromagnetic. You are going to want the driver and pickup reasonably close together so that the unit is compact, to do this you will not wnat too much power, just enough to get it to sustain, no more. The more power, the further apart they need to be and it could be difficult to tell as with an ebow, there is no audible output to hear if it is going into oscillation (though I imagine if you put it near a live pickup you will soon hear it, it may even start to vibrate from the internal oscillation).

Anyway...a few tips...try and think laterally and you may come up with some really cool premade components...

pete

PS...still haven't got round to reading the thread myself!

[Franky]

Okay, here's what I've made:

(click on the pictures to see them larger)

I used a 5 euro cent coin as a template for the epoxy bits, they are 5mm centrer drilled, and the polepiece is inserted by force, hammer-style..

I let the polepiece out on a side to be able to fix it to the handle once it's done.

This makes a coil height of 11mm, and the diameter of the epoxy rounds is about 21mm.

For the pickup wire, I've got some small DC motors, maybe it can be helpfull..

Edited July 26, 2008 by Franky

[psw]

Great stuff...and

We have just passed the 170,000 visit mark for this amazing thread so thanks again to all those who have contributed over the years and all the people currently submitting posts that keep this thread alive!

I have been trying to find something on the new Moog Guitar which features some advanced sustainer technology, purportedly automatically damping unplayed strings. At US$6,500 this new guitar is still something of a mystery. So, been trying to find something in the Patents. Not having much success so if anyone has any clues to the moog patent, much appreciated.

The eBow patent is a classic and a good place to start with anything sustainer.

eBow patent Link

Patent searching is a little like a treasure hunt, but here is a big clue. If you look up the above patent by Heet for the eBow, you will find that there is a blue hyperlink just above a list of names and patents saying "referenced by". The list below it are the patents that have influenced or relate to the viewed patent but clicking this link will reveal a list of patents that have referenced this one. As the Heet patent is such an important one in sustainer technology, it would be difficult for an inventor not to cite this as relevant to any electromagnetic sustaining device. You may need to download and activate a free program like alternaTIFF to see the all important images. The hyper link will reveal patents by hoover and osbourne who are associated with the sustainiac product, rose (yes, it is floyd) who also claims to have invented such a device and many, many others. In fact there are patents that go back to the 19th century on such devices.

Looking good franky...keep at it... pete

Oh...in the application section I found this new one (to me, actually 2002) for sustainiac LINK

this gives a fair overview of their work and also describes and confirms some of my "theories" about the fizz phenomenon...

[0071] Automatic gain control (AGC) circuits have been described for sustainers. These circuits are used to provide high gain when the instrument vibrating element (or string) vibration is small, in order to provide robust sustain of played notes. Once the vibration reaches sufficient amplitude to be heard adequately, the sustainer amplifier gain should be reduced. Otherwise, amplifier clipping can occur, leading to distortion in the sustainer output signal, which can then be magnetically coupled to the instrument pickup from the driver. The result is a distorted sound, which is undesirable.

AGC is something that Col worked on quite a bit and my newer circuits have a very basic function as well.

Edited July 26, 2008 by psw

[Franky]

Yeah, patents are a good source for inspiration, but that does not make all the work..

The input impedance of the LM386 is said to be 50kOhms, which is really high for a coil, I wish I can reach the kOhm.. The DC motor didn't work, the wire broke after a few turns.. I grabbed a little transformer, the secondary coil seems to be made with 0.3 wire (looks little thicker than my 0.2 wire), and the primary is made with a very thin wire, I hope it will hang on a manual winding, to make the pickup coil. My DMM is out of battery, but I've got to check the primary impedance before to start winding. If it's too small, it doesn't worth it..

I just hope the dimensions of the driver chassis are right..

On the french forum, the man said some people use some wood glue to waxpot their drivers, on my first driver I used some first price glue in tube, which didn't dry at all.. Maybe some hot pistol glue could do it, when it's all done..

I also drilled two little (0.8mm) holes on a side of the driver chassis, to have an easier access to the wire once wound.

It's night here, so time to sleep, I continue tomorrow..

Edit: ahh, the CAG (french acronym for AGC), it was my electronics practice test in the final exam for graduation this year.. Passed well! But the design was awfully thought, with inductors and filthy filters..

Edited July 26, 2008 by Franky

[psw]

Yes...patents are misleading as well...

Really, people have had virtually no success reusing wire from other devices. New wire is always preferable and reliable, but I do appreciate it can be difficult to get.

The use of hot melt glue is to be avoided, it really is not suitable for potting where you want the glue to saturate. Have a look at the pictorial for using ordinary white wood glue during the winding process. Epoxies can be dangerous and messy and often set too fast to work with. While I have done things with epoxies in recent times, I built a machine to wind it and went through a lot of wire to get the turns, resistance and tension right, plus about $100 trying different epoxies till I found one suitable for the bobbinless coil process.

The input impedance of the LM386 is said to be 50kOhms, which is really high for a coil, I wish I can reach the kOhm..

Well, lower value pickup coils might work but you will come across loading which will effect efficiency. One way around that is using a buffer before the LM386 eliminating loading by allowing a wide range of pickup signals. A low powered coil though may require some preamp boost though.

The trick to making the pickup is to use very, very thin wire. The thinner the wire, the higher the resistance and so the less turns for a given value. You would ideally use something hair thick as in a traditional pickup wire.

Obviously if you look at this one...

it does not have that much wire on it. Search aron's stombox forum, the thread was titled something like "guess what this is", it was quite a few years back, but there was some discussion here in this thread and possibly a thread in the general PG electronics section. The original thread probably gives more detail of the wire type and resistances.

good luck, sleep tight (7:45am here) ... pete

[psw]

This LINK will take you to the thread of the pictured eBow at Aron's SBF.

There are 200 turns to the driver coil and 1000 turns to the pickup of different gauge wire. Check the thread from more details and search the forum for eBow threads and posts...good luck!

oh...and here is the thread on a gutted real ebow...

Ebow Guts

Edited July 27, 2008 by psw

[Franky]

Thank you for the links!

I just wound my driver, 200 turns with 0.2mm wire (I'm not quite familiar with the AWG norms).. About potting, I used a kind of multi-usage glue, that I used for retolexing a cab.. And I just reduced the coil height, it's about 6mm now. I hope to get a compact design, so 11mm was too much, and all the pictures were showing small coils..

Based on the AWG article on Wikipedia, making 3.4Kohms with a AWG40 wire (like the one I have for the pickup), needs 1km of wire.. This is huge.. With a little math, there must be about 200m of wire in the 1000 turns needed, so yeah, we're still under the Kohm.. But if I had to make a real pickup (understanding "with an impedance about 5Kohms"), around only one polepiece, the diameter would be 3 or 4 times larger than the driver. Which does not seem to be the case in the commercial ebow.

So yeah, there is no really choice but underloading the LM386..

I'm also planning to add some shield to the coils, with aluminium tape.

Edited July 27, 2008 by Franky

[psw]

A low pickup coil will pickup a signal (even single wire will) if might jus be week. If you have a pramp or buffer like the F/R it won't be so much of a problem.

A few misunderstandings though...

Active project guitar member, Paul J. Marossy runs the site http://www.diyguitarist.com/ and now owns the infamous disassembled ebow from the previous link and has a good article on the "technology of the ebow" as well as other great stuff. (It isn't quite true that Heet and the eBow is the first sustainer patent, some go back about 70 years earlier!). More and better pictures are on the previously linked thread...eBow Guts

You can see that the well potted coils sit inside a metal "can" with a magnet inside the coil. This provides magnetic shielding and effectively it looks as if the outer edge of the coil housing is the opposite polarity to the inner coil. This is similar to the way a speaker is made with the voice coil moving within the magnet structure.

I'm also planning to add some shield to the coils, with aluminium tape.

Aluminium is non-magnetic so it will not have shielding properties (one of the differences between a pickup and a driver) from electromagnetic energy, in fact eddy currents will be induced into the coil and if the tape is earthed, will allow signals across (though this shouldn't be much with only tape I guess) possibly creating noise and lowering efficiency.

You can see by the DIY eBows, it can be made without such measures but adding tape is not advisable. If I were to copy the actual design more closely I would cut a steel pipe to the length of the coil depth that the coils can fit into...but you would need even more power I suspect as these things make the need to have the driver and pickup virtually touching the string (which it almost does on the ebow). Using similar strategies around sustainer drivers did help with allowing the driver to get closer to the pickup (see the mid driver experiemnts) but it also meant that the driver was far too close to the strings to get any effect...these things (col called it a magnetic cage I think) are very tricky but are designed to focus the drive. If it was going to be done in this way, you'd want powerful coils like in a real ebow.

Ok...so

I just wound my driver, 200 turns with 0.2mm wire (I'm not quite familiar with the AWG norms)..

I have been trying to stick to metric because there is far less confusion, there are simply too many standards. What resistance is 200 turns of 0.2mm wire? An LM386 can run as low as about 4 ohms, with reduced efficiency so it should be fine. It is easier to get 8 ohms on a sustainer driver because it is substantially longer. A thinner wire such as 0.15 would probably be a better bet, however the 0.2mm should be ok I suspect.

But if I had to make a real pickup (understanding "with an impedance about 5Kohms"), around only one polepiece, the diameter would be 3 or 4 times larger than the driver. Which does not seem to be the case in the commercial ebow.

The commercially wound pickup in an ebow (and the driver) have a lot of wire in them very compacted. Remember the thinner the wire, the less turns required and as you wind the coil grows and the distance around it gets bigger, so each turn is longer. In all, a thinner wire will take up less space and although the driver and pickup coil in the ebow look very simialr in size, the wire size is crucial. Still, as you can see from the DIY ebow, it will work without a lot of these "devices" and the thing is pretty simple. The original eBow is one of those fabulous "elegant" designs that no one has really improved for what it does. I have not seen anything that rivals it in ideas or patents, people have even patented glove mounted devices....hehehehe!

What circuit are you going to be using for this project? The F/R will avoid any underloading problems, whether enough extra boost is up for debate I guess, but it may give better performance than a straight LM386 circuit.

Basically with these things are experimental. There is every reason to think there will be some success in driving the string (the case will decide how practical it is to use) by fairly primitive means.

Still, exiting to see this going ahead on the sustainer thread, yours will be a bit of a first I hope of many. Perhaps if people made them more often they would think of ways to make a new generation of eBow's and variations. It would also be a good alternative project for understanding the technology and make a good stepping stone project to creating a full sustainer.

A lot of this thread has followed my ideas and designs, but the thread was intentionally called "sustainer ideas" specifically to include all ideas, the eBow, normal sustainers and acoustic vibration designs and anything else that people can think of. Potentially you could do something with sampling, but I suspect such electronic sustain is beyond most people's skill set, certainly mine! Such things keeps me interested and it is only through these projects and variations coming up that this thread survives as it does...

Good work Franky, I may well be following you in a DIY ebow in time. My earlier ideas were not so serious and I tried to used pre-made coils as in your french link with mini transformers...

The above is a "sugar cube" relay with a very compact coil of fine wire and a steel core for instance. It is not too difficult to take apart and has some promise for a pickup coil but as I did not go all the way or get satisfactory results, I did not post any of these "experiments".

pete

Edited July 27, 2008 by psw

[Franky]

Thank you for the enlightments Pete!

About driver shielding, I was thinking about interferences, but it's something that only the pickup needs (the driver is powered by a great energy source, so the interference may not be that important..)

You're right, it's the magnetical shielding we're seeking, so maybe only a small partition made of steel between the two coils would be enough to stop the EM field leaks. But as it's spread in the direction of the strings, and not in a radial direction, it might be useless. I'll see about that later.

About electronics, yeah, maybe the classic F/R, I've got enough parts to experiment a little.. But not like Col did, with its AGC, anyway it wouldn't fit into the case.. Which would be a simple piece of wood, that holds the PCB, the coils and the battery. On each end, some PCB guides to hold the eBow on the left & right strings, and maybe an LED to make it easier to find the position.

For what I can see in the orginal eBow, it makes me want to say: the simpler the better. But I pretty love the glove idea, that would be really tricky to get something out of it, but it could open some new ways of playing guitar.. The best would have been to have 6 fingers, but..

Night time again (f***ing time lag), tomorrow's program: circuitry..

Oh, last idea, don't really know what it's worth: did you try push-pull with 2 LM386? I don't even know if it's possible..

Edited July 27, 2008 by Franky

[psw]

About driver shielding, I was thinking about interferences

Well, the driver is the source of the interference, specifically magnetic coupling between the pickup and driver. This is a real potential problem necessitating in sustainer a considerable distance between the large powerful bridge pickup and the similarly large full driver near the neck. The ebow can be more compact becuase the coils are more compact, but even there there needs to be some distance depending on the coil size quality, power of the amp and perhaps magnetic shielding.

The best thing to do is like all the other DIY ebow things, and indeed the sustainers, keep it simple. I have made some complex devices before with magnetic shielding and multiple coils, but generally the simple single coil is best. Now, I was just testing an old mid coil design with a view to salvaging the circuit from it which has a bilateral surface mounted design with some magnetic shielding which did kind of work (I just plugged it in again) but it is only when you want to try to do this kind of thing that you have to get real clever.

The fact appears to be that these very basic coils and circuits do work without all that, so that is at least where you should start.

About electronics, yeah, maybe the classic F/R, I've got enough parts to experiment a little.. But not like Col did, with its AGC, anyway it wouldn't fit into the case..

No, you don't want that, a fetzer ruby with the mods I suggested a few pages back and incorporated by risingforce will work and the preamp stage will allow a huge input impedance potential so just about any coil will stop loading. The more simple LM386 only circuit may well work too. The ebow has no AGC and the fact that you can move the device around allows you to manually control the gain, so it is not necessary to get fancy with the circuit. Reversing the driver wires might be a good addition on a phase switch to get a harmonic mode, LED is a good idea so you don't leave it on and and on off switch so you can turn the thing off!

But I pretty love the glove idea

Actually, the patent is pretty funny, I think they actually proposed a mini speaker in the palm of the hand...hehehe.

I had come up with ideas like this to Velcro a box with battery and circuit to your wrist and a much smaller driver and pickup coil that could be hidden in the palm while you pick. I am sure you could make up all kinds of variations!

Considering the cost of patents, it always surprises me what is out there with perhaps 50 or more sustainer patents most of which never went anywhere or possibly wouldn't even work.

Still, if yours works maybe a MKII version could be mounted in a glove and you could become the micheal jackson of the guitar world!

pete

Oh....I have finally bitten the bullet and de-wired my guitar again and am working on the surface mount driver after a challenge by email a little while ago. I just wound the coil and spent the day developing yet another way of building such a thing. Unfortunately, the epoxy seems to be having trouble setting (maybe it's the cold weather down here) so I hope it works out, otherwise I will have a very sticky mess. The idea on this one is to be compact, I have used 4 ceramic magnets with a steel 3mm core glued to them. A coil is wound around with the magnets as the base. Instead of a bobbin, I have used some plastic stuck to the top which I intend to remove so that the whole thing is held together by the epoxy and you will see the coil. I was able to make an 8 ohm coil 10mm wide and 6mm high including the magnets. I curved the top of the blade and this extra room in the middle follows the fretboard curve and takes up the bulge to the sides that often occurs with such coils. The intended guitar in my project is a telecaster and the driver will sit between the neck pickup and the neck. I am going to try a preamp on the whole guitar and switch the sustainer circuit in a hope that this will somehow address the pop problem. The preamp will give an extra boost to the AGC "fireDrive" circuit and provide a considerable low impedance boost to overdrive any amp as well! Unfortunately, I have taken the thing apart without a proper plan to wire it all back up again!

[psw]

Ok...I am at it again!

I am currently building a new version of the DIY sustainer and thanks to my epoxy setting, the driver is almost finished. Still a little sticky, so I will post some pics perhaps tomorrow.

This is a surface mount driver, a little fiddly to make but nothing too exotic (except perhaps the slower setting epoxy that holds it all together). My driver winder uses a cordless drill and a calculator counter activeated by a reed switch and would you believe that both failed (flat battery in both) after I had set up and mixed the epoxy. The result is that it was virtually hand wound.

The coil is a little narrower than some and a little more than 3mm deep, but is an even 8 ohms all the same. I potted it in epoxy around a 3mm ordinary steel core shaped to the string radius and will sit on top of the pickguard even with the top of the fretboard. The driver wires will go under the scratchplate and the driver stick on with double sided tape.

What is cool about this driver is that it is rare that I have shown stand alone designs (normally I have incorporated them into a pickup but this is not possible on a tele) and I was able to wind it with a temporary bobbin top stuck to the coil. Once set, the bobbin top could be removed, the blade cleaned up and the whole thing coated in another shiny layer of clear epoxy (which is drying now). So, it looks small and compact, shiny and transparent (you see the silver blade, copper coil and black magnets underneath) and will blend in with the neck and other themes in this guitar and looks a bit like a secondary matching coil to the tele's chrome neck pickup. It shares the same polarity as the neck pickup so I hope this is right and does not cause any adverse effects to this pickup. The neck pickup is a new SCN and sounds great. This unusual stacked pickup has a central magnetic core with powerful solariaum colbolt on the outside. The similar driver may spread the pickup area a little but it should be fine and in fact the near by field may even add to the driver magnetisim. The added driver has no adverse effects on the string vibration as far as I can tell.

I had tried to install a tremolo modboard and I was very disappointed and the thing had to come out. Noisy and possibly faulty and once installed I did not feel it was something I would use that much anyway. After installing the thing, the guitar still sounded great but had a dramatically lower output for some reason, so the whole guitar need a rewire.

Unfortunately, this may be a complicated proposition. I am thinking of adding an active preamp and I have to fuss about with the sustainer circuit as well both of which are salvaged from previous projects and prototyping. The switching is not standard tele but has the volume moved to the front followed by a gibson like three way selector. Some how I need to fit volume tone (possibly sustain drive control) plus large 4pdt on off toggle, harmonic switch and a phase switch for the neck pickup. Under these controls I need to fit the battery and some circuitry and a fair amount of wiring so there is not a lot of room in a little tele control cavity and definitely not the depth for push pull pots.

Anyway, hopefully this design will encourage others in similar ideas and show some alternative material and construction methods.

pete

[Franky]

Okay, I didn't do anything about the eBow today, I just finished my little tube amp this morning, and I couldn't resist to play it all day long.. :D

I did measure the impedance of my driver, it appears to be 4ohms.

[psw]

Ok...success so far...my latest offering

SURFACE MOUNTED DRIVER

The idea is as described in the above posts, to make a driver that is amll and slim enough to surface mount (with double sided tape) to the pickguard of my ongoing tele project next to the SCN neck pickup and the neck.

I used 4 square craft magnets, all the same size up and made a "blade" of ordinary steel that matches the radius of the fretboard...

I then superglued the magnets together and the blade centred on top of this...

I then made a bobbin top of plastic layers (the first slotted for the blade) and stuck it to the top with very strong carpet tape along the blade and reinforced with some scrap PTE plastic for support...

I then mounted this to a spindle but unfortunately both the winder and the counter malfunctioned. Luckily I was able to wind it effectively by hand turning the winder since I had mixed up the slow setting liquid epoxy already!...

The top of the bobbin was removed after setting and another layer of epoxy was brushed on at the end to make it all shiny and protect the blade and coil...

Did I mention it is shiny...

Ok...so the idea is that it mounts like this next to the neck pickup...

In the background you can see the "fireDrive" circuit that I intend to use. This is an LM386 prototype with some basic AGC.

To mount the driver, I will be double sided taping it in position and leading the fine wires under the scratchplate where I have a small gap between it and the neck and tape it along the back of the plate to the bridge pickup cavity.

So, pretty pleased with the results so far and the method seems to work as far as it goes. One bit about this that I was particularly pleased with is that the curve of the blade in the middle allowed the slacker side winds to be pushed in to avoid any bulging typical in such coils.

I just hope that the increased magnetisim under the strings does not effect the vibrations or the sound of the neck pickup. The SCN is a different kind of pickup with side central magnets and the driver seems to pick up a lot of this and so gives extra power to the ceramic magnets I chose. The driver sits pretty much level with the fretboard and I won't be able to adjust it unless I were to hack into the pick guard.

So...now my kitchen table is covered in guitar...I suppose I will be eating out!

pete

[Franky]

Great work Pete, congrats!

If your driver is still too high, it might be due to the thickness of the magnets?

Anywar it looks great, and your circuit seems to be very compact, how did you make a AGC fit into this? Is it a special feature of the 386?

[psw]

Thanks Franky, I still need encouragement like everyone else! I mean it!

So...

If your driver is still too high, it might be due to the thickness of the magnets?

Yes, or the coil, or the scratch plate...hehehe. The magnets are a given, never a wise idea to cut or alter magnets. Also, they have to have some strength, I tried to put the magnets in the core (if so the height would only be 4mm) but that didn't work out too well. These are a cheap craft magnet and seem to be a good strength, cheap and I had them. I was going to use 6x10mm round ones, that too would probably have worked.

I like the minimalism of this design, magnets core and wire...nothing more...and it's pretty cool being able to see the thing too. Also, the color goes with the theme of this guitar which has a bit of tortoise shell on it...here is the massive and rare bridge pickup with custom made aluminium racing stripe design to get a bit of the idea...

There is one out for adjustment, tilt the neck back a little bit. Otherwise, hack the 3mm scratchplate! The whole thing exactly matches the height and curve of the neck radius. The main thing to watch for is that the magnet strength does not create wolf tones in the strings natural vibration...especially on the lower strings. I have ripped all the wiring out, so I cant tell yet how it sounds, perhaps I should have reversed the magnet polarity to opposite the SCN but the side rare earth's in this design would be fighting the ceramics, probably even demagnetizing them over time. This way, they add, otherwise the strength would have been fine. As always, aim for moderation with the sustainer.

Anywar it looks great, and your circuit seems to be very compact, how did you make a AGC fit into this? Is it a special feature of the 386?

The circuit is a bit of a secret I am afraid and I know I get flack from this kind of thing but I still hope to have somethinglike this available as a kind of kit. As it is my own design, I kind of want to keep it that way and not pass on schematics. It took a lot of work and I still think it needs a little more development and maybe switching know how...any experts in the area please email!

It is basically a LM386 circuit with a buffer that also reacts to the signal coming out of the LM386. If the signal gets too hot it will back off the input evening out the effect. I also have a control in it to adjust the total output that interacts with the AGC. At extreme levels, the AGC can't react fast enough so it is kind of let loose like the F/R straight LM386 designs I used to use. This gives more outrageous drive and often some distortion. There is a trim pot that adjusts the maximum extent of the effect that you tune till the thing just short of squeals in max drive.

The whole "concept" is called the fireDrive and is my proposed "commercial" version of the kinds of things that I have been working on here. Part of the secret to getting the thing so small is to use a mix of SMD and through hole components...as they are hand built, I am not sure of the cost effectiveness of it (as a product, I would propose machine manufacture). I have been thinking that I may sell these units as they are (though I would still need to hand build them) but I don't know the market.

For those who have come lately, the whole thing started off to try and address the difficulty in supply and circuits and peoples skills. As is often the case, things got more and more out of hand! First, I thought a kit of components and enough wire. Then I thought, I was not happy with any of the circuits and I shouldn't really "steal" an existing design, so I set about designing a "standard" amp. Then I thought, even with the wire, people may still have problems winding the things...so I came up with a winding machine and epoxy setting thing. Then, I had to settle on a standard coil shape...so I designed the ultra-thin coil for strat pickups...and so it goes.

For a couple of reasons, the thing shuddered to a halt.

This new one is the fireDrive SM (surface mount) I guess. The circuit is fairly universal but it has no real gain in the preamp. It doesn't address a lot of the switching and installation issues that I find the hardest and the least work has been done on. Doing this project may have some clues as to how I might solve these problems.

This kind of making is very advanced and I still advise against epoxy, plus it can get expensive. This one went together ok, but the bobbinless coil will only work with suitable epoxy, not your 5 minute stuff! A lot of people have inspired me on these things along the way, Tim/onelastgoodbye made the first epoxy bobbinless coils way back. Col did a lot of work on AGC circuits and there were so many others over the years.

This is why it is great that people keep coming along and showing there efforts. I need a bit of a kick and inspiration, plus a little or even a lot of encouragement. I, like others see things like this and think...hey I could do something like that! Your eBow project Franky for instance has made me reconsider it. Some approach me by email or from other forums...in fact we may soon have someone new just from today with a different approach again from the DIY stompbox forum.

Very rarely, I will hear from someone who has succeeded by going it alone, which is great (and I wonder how they did it now the thread is so huge) but it is always good to share. Also, I am not the only one, so feel free with suggestions or to add a comment or question...even those who just look in out of curiosity.

We recently passed the 170,000 visits (I think there were over 300 visits in the last 2 days!) but another milestone is soon approaching...4000 posts! Thats a lot of typing.

Anyway...thanks to all out there and everyone who has kept this thing alive...probably some kind of record for longest ongoing post or something. Also, the mystery person that recently had this pinned, probably long overdue, but it is amazing that so many found it as it went up and down and back pages in this obscure part of the forum. Oh, and thanks to PG for hosting it and overlooking my frequent picture posting violations, as in the post above!

pete

PS...if I ever finish this guitar to my satisfaction, I may put it in GOTM and I'll be expecting a few sympathy votes for the sustainer alone!

PPS...if anyone is in Melbourne, Australia...I have a bunch of cheap guitars going cheap. These would make ideal project guitars as they are good for parts. Strats, stratalikes, f-hole acoustics, a few electro acousitcs and some great basses. Postage may be difficult or not worth it. I may strip the things down to parts though if anyone is interested...however, I did say cheap (as in ply bodies, etc)...oppps, wrong section!

[psw]

So...old news, not posted earlier...

Some months back I was working on the bi-lateral thing as many others were at the time and yet another attempt to make a mid driver and a surface mount thing...

Here is some pics of this experiment that didn't quite work out as I had hoped...

And the driver...

This driver has two coils and internal magnets of opposite polarities and is connected via a line from the pickup switch (so is intended to work with any pickup and take it's source from whatever is selected. This is a bit of a holy grail as potentially you greatly simplify the installation with the most basic on off switch ragardless of any other perceived or actual benefits you might be seeking from a choice of pickups. The surface mount would allow installation with out mods, or very low mods on a guitar like this cheap tele (also for sale...errr...cheap, or buy two!).

You may also see a little magnetic shielding being tried here...

So, did it work...kind of you can get sustain, but also a lot of squealing in some pickup settings. The big fault is that the close driver is in the way of picking as with the last mid-driver that I tried and I still do not feel that the percieved tonal gains are worth it over a conventional driver. Why I keep coming back to it is because of the installation cures...but it either works or it doesn't, and in this case although promising, a little too frustrating fro me to pursue.

For those getting into this, returning or thinking about it, it does show what you might like to attempt if you want a challenge! The circuit is my own but a F/R would be ok too. With a spare circuit and some PVC tape different driver ideas can be tried out and tested fairly easily, though it helps to have test guitars like this.

For now, I am waiting on parts for the other tele project. Although a lot more "professional" there is still no guarantee that this new SM version will be satisfactory, but it has a fair reason to work out ok, so here's hoping. For now I am trying to work out control placement in a very tight space. I am considering a sensitivity drive pot, so I may use a push-pull for the harmonic switch on that. I still need to install a 4pdt toggle to switch the thing on and this guitar really benefited from a phase switch on the neck pickup to give an interesting "quack" sound to the combined pickups, so I want to keep that too. Unfortunately, push pull pots go fairly deep and I have to fit the circuitry and battery, selector, pots, switching wires and circuitry into the tiny little control cavity.

The parts I am waiting for is an active preamp that is tiny but provides a 25db gain boost with a 50K volume pot from guitar fetish. Part of the hope is that a preamp will provide the sustainer circuit a real kick and because the battery will always be connected via the preamp perhaps it will aid in the pop problem as well providing vital clues to developing my circuit further.

The guitar will effectively be active and not run without the battery even though the pickups are normal passives but as I have finally succumbed to valve amps, I am hoping that this power will give those tubes a kick on the clean channel and so do away with the need for channel switching by simply turning the thing down!

Rather than use a preamp circuit that I already have, I am going with a commercial circuit because it is small and I hope is tried tested and works! Still, I have been wrong before...

pete

[Franky]

OK, i've just finished all the thing, it works, but it makes an awful noise in the amplifier, and it takes a long time to the string to vibrate..

It looks like this:

Edited July 31, 2008 by Franky

[psw]

Looks great franky, lets see if we can get it working better!

Remember I was saying that there needed to be some distance between the driver and ebow pickup and that the ebow seemed to have used metal sheilds around it perhaps to stop cross talk between them. This is effectively squeel. On a sustainer you hear this squeel/oscilation through the pickup but on the ebow you may not hear it so much but it will still be there...

What you need to do first is try and reduce the power as much as possible and bring it up to find the balance just before this squeal is happening and then what you will get is all sustain. The amp is amplifying this oscillation (the coupling between the coils) instead of the string, if the string gets to be louder than the oscillation, then sustain can start to take over, and that's why it works at all). If you don't have a gain control...disconnect pins 1 and 8 to start with this drops gain considerably and makes it cleaner (which will also help if this is the problem). If this drop in gain is too much, you may need to reconnect with a 1k pot there, or maybe a 10K pot between the pickup coil and circuit.

Failing that, the coils...are they glued tight? Potting is very important as the coils will try and vibrate. Anything loose in the coils or magnets will mean that this will try and vibrate causing frequency oscillation and often you will feel the vibration in the coils. You want the strings vibrating not the coils...lost efficiency and more noise again, not good!

I would say moving the coils apart, but you may not be able to do that, plus you wouldn't want them any further apart than that, already further than an ebow or the DIY I posted. I liked the idea of putting the batter between them btw.

Hang on....take the battery out...the metal is probably metal and the coils will be bridging magnetically throuhg that! See if moving the battery well away helps...might not have been such a good idea afterall...notice how an ebow's battery is much further away...maybe there is a reason, I had never thought of that before...maybe mine didn't wok so well for the same reason.....interesting...have a go!

Oh...another possibility. Have you tried reversing the wires on the pickup OR (not both) driver...you may be running at a harmonic...does the string when it does vibrate, vibrate at pitch or higher? Before that, try reversing the magnet on the driver OR pickup coil...this should have a similar effect. Try a couple of different combinations of these...and the tips above.

so...

move the battery away...

reduce the gain...

reverse a magnet...

reverse a coil...

make sure the coils are not vibrating...

woke in the night...so back to bed...hope it gets better...looks great!

pete

[Franky]

Looks great franky, lets see if we can get it working better!

Remember I was saying that there needed to be some distance between the driver and ebow pickup and that the ebow seemed to have used metal sheilds around it perhaps to stop cross talk between them. This is effectively squeel. On a sustainer you hear this squeel/oscilation through the pickup but on the ebow you may not hear it so much but it will still be there...

Actually, it does not sound sharp like the time I tried the sustainer.. It's more like this:

http://rapidshare.com/files/132240551/ebow_prueba_1.wav

I didn't record it, someone had the same problem, it sounds a little like this.. And it gets really loud when the driver comes close to the active pickup.

Ahh, I didn't mention it before: I've got a strat, with 3 single coils..

What you need to do first is try and reduce the power as much as possible and bring it up to find the balance just before this squeal is happening and then what you will get is all sustain. The amp is amplifying this oscillation (the coupling between the coils) instead of the string, if the string gets to be louder than the oscillation, then sustain can start to take over, and that's why it works at all). If you don't have a gain control...disconnect pins 1 and 8 to start with this drops gain considerably and makes it cleaner (which will also help if this is the problem). If this drop in gain is too much, you may need to reconnect with a 1k pot there, or maybe a 10K pot between the pickup coil and circuit.

Hum okay, I'm going to try to play with the circuit...

Failing that, the coils...are they glued tight? Potting is very important as the coils will try and vibrate. Anything loose in the coils or magnets will mean that this will try and vibrate causing frequency oscillation and often you will feel the vibration in the coils. You want the strings vibrating not the coils...lost efficiency and more noise again, not good!

Yep, anyway I wound them by hand, so they must be not as tigh as if I used a mechanical winder.. I finally found some super-glue, which i couldn't find the composition, but it did work pretty well on the pickup. Indeed the driver is vibrating a little, when I try to remove the magnet from it, I can hear a really tiny noise coming from it, and some vibrations..

I would say moving the coils apart, but you may not be able to do that, plus you wouldn't want them any further apart than that, already further than an ebow or the DIY I posted. I liked the idea of putting the batter between them btw.

Hang on....take the battery out...the metal is probably metal and the coils will be bridging magnetically throuhg that! See if moving the battery well away helps...might not have been such a good idea afterall...notice how an ebow's battery is much further away...maybe there is a reason, I had never thought of that before...maybe mine didn't wok so well for the same reason.....interesting...have a go!

I tried, just after taking this picture, to put the battery elsewhere, on the top of the PCB bar that holds the coils. So now the battery AND the circuit are on top of this bar, cause anything put under blocked the vibration of the strings (that wouldn't have happened if the polepieces were 0.5mm longer.. grrr)

And the noise is still here.

Oh...another possibility. Have you tried reversing the wires on the pickup OR (not both) driver...you may be running at a harmonic...does the string when it does vibrate, vibrate at pitch or higher? Before that, try reversing the magnet on the driver OR pickup coil...this should have a similar effect. Try a couple of different combinations of these...and the tips above.

Yeah, when I swap the driver, it enters harmonic mode, but when the string starts moving, there is a fuzz effect (like a crazy setting on a Fuzz Factory) on the sound in the amp, even if the eBow is far from the PU..

Swapping the magnets and input coil didn't gave anything concluant about the noise..

Anyway it works, when I put the driver above the 17th fret, there is no more hearable noise, but you were right, it's really hard to play it.. And only the 4 biggest strings are affected, nothing happens with the G B E strings..

Good end of night! (or good morning when you read this.. )

[psw]

Not sleeping to well, but I will try and make sense...but first, coffee time!!!

The ebow MKI seems to be suffering from some of the problems of a full on sustainer...bad(that it didn't work first go) : good (because maybe we have some answers or at least clues)...

Getting really loud when it get close to an active pickup is actually something that I think that the ebow does also. What they dont tell you about eBows and I have never played one, is that generally you use the neck pickup on (just as the sustainer uses the bridge) and slide the ebow towards the neck pickup to increase volume. The loudness and resulting is described as a feature...in the sustainer we often call it fizz and is something we have tried to minimize. It only stands to reason that you are sending a very strong magnetic pulse out of the ebow driver and that the pickup will...pick it up!

Ahhh...good...coffee...

Now, let's talk speed!

I have at time described my driver designs as "fast". What I mean by this is that the driver needs to pulse at the speed of the vibration of the string, and in time with the string. On higher strings/notes the speed the speed of the vibrations of the strings will be faster. The pickup needs to transfer these vibrations into electrical pulses, process it through the circuit then this needs to be replicated in the driver coil as electromagnetic energy. In the time it has done this, the string will have moved, perhaps even be moving out of sync in the opposite way, perhaps moving different in the place of the driver to that of the pickup. Commercial sustainers have addressed that through phase compensation circuits.

I don't have the electronics knowledge to make such circuits and the ebow does not have them. What I aimed to do is build drivers that were efficient enough (fast enough) not to require such complications. So, I advocate a simple amp circuit with clever driver design to get the thing to work. In the DIY project, the driver is the key!

As a double whammy...the higher strings have less metal in them to work with...so faster and less metal. No high string drive is a symptom most often of a poor driver response...or speed.

As a triple whammy...the higher the frequency running through the coils...the more they lag in response...they tend to slow down through inductance...

Another feature that will really effect efficiency is a coil that vibrates. Instead of vibrating the strings, some of the energy, especially high frequency energy will be lost if there are loose windings or mounting of the driver. Often you can hear, and feel these vibrations...sometimes they create heat as well. Adding more power...something a lot of people asume will overcome the problems of poor drivers...makes it worse!

Ok...I have just listened to the clip...and I realize that isn't you...what is that clicking...grrrrr (might be to close to a monitor or something)

That is virtually no sustain at all!!!! Where did that come from?

So, you may need to work out a way to get more out of the pickup and the driver, pot them and amke them fairly tight (perhaps use a slow drill to wind them).

For potting, I have a pictorial linked below that shows the white PVA glue that I recommend. It needs to be applied while winding not after. Superglue (CA) must not be used. It has no filling potential and can be dangerous. Epoxies can work, are expensive and the 5 min jobs wont cut it...It took a lot to find something suitable for the coils I wind now...but I also use a machine and a lot of practice...not a DIY proposition nor necessary.

The magnets...are they ceramic? If so, fine but if rare earth...possibly too strong...the strings will struggle to vibrate within their pull.

It may be that you will need to rewind the coils...but before you do that, try a few things first and see if that provides some more clues.

I must say that I got kind of similar problems from my ebow experiment (I found it again the other day, so I will try and take a pic soon) and gave up on it as I was still working on yet another sustainer.

While an ebow would appear a simpler proposition, it holds all the same problems of any sustainer...it just saves modifying the guitar. If we could develop a strategy where you say, do this, this and this and it will work that would be great. However, like the sustainer, there are a lot of inconstancies in build quality. The result is that people who essentially do as I have done, or others that have been successful have found it to work...those that have gone their own way with circuit concepts, driver designs, left out potting or less quality winding, people who have used old recycled and incorrect wire gauges have resulted in poor or non-working results. Not that my way is the only way, but as with the ebow, I don't know yet a way that can guarantee results and only know what has worked for me and a lot that hasn't worked.

Keep at it, it may come to life yet!

pete

[flickoflash]

Is there any boutique sustainers builders ? I would like something that was stealth in my 7 string fender strat.

Edited July 31, 2008 by flickoflash

[psw]

Is there any boutique sustainers builders ? I would like something that was stealth in my 7 string fender strat.

Not yet there isn't. One problem is that even if a circuit and coil or driver were made, it would still be something of a DIY job to install it so it would still have to rely on the person installing it for success.

Also, it depends a lot on the guitar the type and size of the driver. A lot of 7 stringers use neck HB pickups, often 14 fret boards...that leaves no room really for a stand alone driver like the one I am working on in my tele project pictured recently (probably previous page) and hb pickups present a problem.

The most viable DIY version for such guitars is probably to hack a cheap replacement seven string pickup to completely replace (and so loose it) but not many would want to do that!

There is no reason that it wouldn't work, thicker strings are easier to drive and even bass guitars can be made to work. Sustainiac used to have a seven string model but it appears to be long gone with no sign of them developing a replacement.

I have seen a few concert clips of vai lately (not on a seven string) making good use of his fernandes sustainer while playing with an orchestra. He uses it to get the high gain sound and sustain without the huge volume and amps plus with perfect control.

I have been enjoying my own brand of "natural sustain" lately by breaking out of mothballs my late 60's gibson LP that hasn't been played for perhaps 10 years...the thing was still virtually in tune!!!! I had forgotten how heavy the thing is, but these things are remarkable guitars.

pete