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Hello !

Both drivers look fantastic and the circuit very professional...the proof of course is in the sound clips, the harmonic one a particularly like...nice control for just starting out playing with the device, good technique!

Thanks pete :D

Now of course people are going to want to know more about these circuits, especially the second one. Are you prepared to share? I am surprised that the F/R wouldn't work but I do think there are limitations to the design, using an op-amp for the preamp allows for a lot more control over the gain and so allows adjustment for the guitar.

Of course I'm ready to share. The opamp/preamp come from the bobblick pages, he has developped this shematic

(It can be publied in DIY projects, I've contacted him for the autorisation, that he nicely gave me. I thank him again)

Then, I took the typical application of the TBA820M included in the datasheet :


For making these schematics and PCB :




(these are optimized for fitting into electronic cavity. This is the same circtuit you can view in my last post. => 400DPI images, print them at 25% scale)

Normally I would have suggested that more magnetic and amplifier "power" is perhaps not the best idea...but it seems to have worked for you. In the circuit, are those LED's a clipping circuit or indicator lights...again, clipping has proven not to be such a good idea, but then maybe it provides some compression that is working for you creating a limiter effect. I guess the proof is if you can play the guitar completely clean with the same control.

There is no more magnetic with the little neodymium, just a balanced magnetization of the bar. I've put 2 little magnets for the E/A/D strings, and 3 for the G/B/E .

The leds are supposed to act as clip as you said. The problem I have, is that I must decrease the gain for harmonic mode, because I have an EMI noise if I switch with the same level than fondamental mode...

Must solve this with a larger pot I think.

I'll try to developp a little bit more the system this week end, before thinking about finishing the installation :D

If you need more informations, feel free to contact me B)


Edited by Strib
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Hello again...just looking in after moving to my island...getting a bit chilly down here! Good to see the thread continues the tradition of long threads! Still...the computer didn't survive the mov

Excellent... This will be great, and I hadn't thought about that but the 4 ohm coils would take half the time and be easier to wind....alowing the use of quick epoxy like this...hope you wore rubbe

The problem I have, is that I must decrease the gain for harmonic mode, because I have an EMI noise if I switch with the same level than fondamental mode...

Must solve this with a larger pot I think.

Yes, this can be a problem between modes. Perhaps there is a way of setting a trim pot to decrease gain between switching modes.

The TDA820M puts out 1.2 watts at 9 volts so this is higher than the old LM386 but may give cleaner headroom and so be a better choice. I am not sure how easy it is to locate, but with mail order being used by many anyway, shouldn't be too much of a problem.

The preamp could be an even simpler op-amp design I suspect, but this one looks neat, so why not use it.


There is a few things that could be played with in this circuit and people would need to convert it to vero if they can't do PCB's . One that has been discussed is the output cap (just before the speaker). In this circuit it is 330uF which is pretty high, this could be reduced to provide a mixed mode especially on higher strings (a kind of harmonic bloom that mine produces using a 100uF in this part of the circuit). Perhaps this could be switched in and out for yet another couple of modes as an option.

It only goes to show again that it is not so much some hidden circuit trickery or mojo going on and much more of the success lies in the care and construction of the driver.

Notice too that again this is a single pickup with driver guitar and so the installation and switching is far less of an issue. Problems with the pickup/driver and multiple pickup guitars are yet to be addressed, but in this application not an issue!

There is no more magnetic with the little neodymium, just a balanced magnetization of the bar. I've put 2 little magnets for the E/A/D strings, and 3 for the G/B/E .

This is a good idea and may be balancing the response from low and high strings. In the past some people have tried to use very strong neodymium magnets to make the device more "powerful". This is not a very good strategy in that the strings need to vibrate in the magnetic field and if it is too strong, the strings will be dampened or pulled out of tune by the field, even when the thing is off. Obviously the magnets must be fairly small. A pic of the underside and magnets might be nice.

So, again congratulations and thanks for the circuit and for showing how it can be done successfully, especially those sound clips which may help any skeptics out there or who wonder what kind of performance and effect they should be aiming for. Well done...


P.S. I have quoted both of strib's picture posts above into the "tutorial section" with a direct link back to these pages so it won't get lost in this huge thread over time...thanks again Strib.

Edited by psw
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Welcome K.I.P.....

Would I be able to bring my trace-killed fernandes fsk-401 back to life if I wire my own chipset? It has a lot of nice capacitors, resistors, and pre-amp circuits.


You know, I am not sure if I follow you...you have a fsk-401 but it has been damaged somehow? I contributed to afew threads in the PG electronics forum with some minor problems with damage but I am no expert on such commercial systems. In fact, there are some mysteries to the fernandes like the transformer on the back of the circuit baord and other parts (I suspect the switching circuit) that are coated in black goop!

Often. such problems are minor and fixable, unless they were burnt out (unlikely with only battery power)...but I/we would need to know a lot more and pictures too.

How was this damages, what went wrong, show the damaged area, etc. If it is that the traces are damged, these can be fairly fine, but can be repaired if you have a steady hand and a good iron. Sometimes, as in some recent threads, the trim pots can get damaged and so no longer are connected, these can also be replaced with care.

Otherwise, the actual circuit is a little unknown.

This huge thread is about all manner of sustainer ideas to all comers, including the commercial systems, especially if they can be looked at to get ideas for the DIY versions. It was also a kind of a blog not just for discussion but my experiments in the technology. Over the years, a lot of others become interested and you can see it is a very long lasting and uniquely popular thread even after almost 5 years running.

Eventually I was able to produce a DIY suitable sustainer of my own design that is simpler in concept and design. The heart of my design is the "thin driver" which seems to negate the need for extensive phase correction circuitry. There are interesting twists to this like the pickup/driver combo. These design ideas are freely available and supported by me and others who have made them to help the project along. It is kind of an open source model that encourages more people to be involved and bring ideas and work that I couldn't think of or have the time to do.

As such, it is very tricky working with the commercial systems because the details of the circuit are largely hidden. Basically it is just a driver (wire and magnets kind of reverse pickup) and an amplifier. However, there are different ways of approaching this and marrying the impedances and controlling phase and power (limiting) as well as switching circuitry (something I really would like to know more about) are all features that are difficult to address.

Anyway...give us more, details, damage, symptoms and pics and we might be able to help...

welcome aboard both PG and the sustainer thread...


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Hi all!

My DIY E-bow on LM386 working perfectly! :D

Here is a video of my project:

1) Power supply: 9V battery

2) Power consumption: 4 mA in idle mode

3) Power consumption: 42 mA in maximum level mode

Edited by yakuzaa
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Welcome yakuzaa to PG and the sustainer thread!

Well done, and I was the first to comment! However, you don't really think you are going to get away with no details did you? :D

We have discussed eBows a little along the way here. For those that don't know they are like a self contained one string sustainer that sits on adjacent strings in small grooves and contains a pickup coil and a driver coil with a simple amp between (here and apparently in the real ebow an LM386 by all accounts) and a battery.

I did a couple of my own scratch experiments but not until after I had already had a completed sustainer (very much like a large 6 string fixed ebow) and tried to get a little too "clever" instead of following the original design of the ebow. An early one was during the "hex" era when I had been working on miniture drivers and later a cheap hack job using relay coils to avoid having to wind the coils...as I was feeling lazy and wanted to provide a dirty project. Both worked to a degree but I didn't take them far as I already had a sustainer that kind of makes an ebow obsolete.

The ebow however is a very elegant design and with practice I have heard some amazing things with them.

Your version works well, were you influenced by the project on Aron's stomp box forum?

Could you post some pictures of the coils and such and include things like the pickup and driver wire guages so that people could make their own. In pics posted here of a destroyed original ebow, the coils seemed to be shielded in steel (I assume to cut EMI and bring the two coils closer), did you do this or find that necessary?

Generally, ebows work with the neck picup engaged (I have never played with one BTW) and I see your demo does the same...what happens if you change or combine pickups? Another effect is that if you get close to the neck pickup, the driver signal couples with the pickup signal...you can see this in the vid...what happens if you roll over it, does it get a lot louder, screeching, etc?

The new ebows have a "harmonic" function. I am sure that this is achieved in the same way that we do by reversing the phase, you could try the same by reversing the driver leads with a phase switch to get a harmonic drive effect...try it and let us know what happens. Something an ebow doesn't have but may also work, is to lower the output cap in the circuit. Often LM386 have 220uF or higher just before the driver, 100uF provided for a "mixed mode" giving a kind of harmonic "bloom" effect. Again, this function could be switched fi you wanted.

Anyway, I am not the only one who would like to know more details and I hope you feel like sharing your work with us. It appears to be working excellently, but of course everyone wants to know more. Half the fun of DIY is not just showing that you can or have done something, but letting others in on the game!

Thanks...an inspiration, makes me want to build one (er, again) myself...hehehehe


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I was asking myself one question:

I've got a P90 pickup in neck position, and generally there is some space available in those pickups, do you think I can wind a driver around the actual pickup winding, and switch between pickup/driver?

The only problem would be that there would be no core, and the inside diameter of the driver winding would be pretty large..


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Hi Franky...

Before your question, sustainer-adics may like to look at the new moog sustaining guitar...see this thread

Ok...well, the P-90 is just a single pickup and I see no reason why it couldn't be adapted as per my strat sized pickup/driver idea with the driver coil on top of the pickup and hidden under the cover...however...

What you are proposing wont work. For a number of reasons the main ones being described by you...

The only problem would be that there would be no core, and the inside diameter of the driver winding would be pretty large..

How do I know this? Because I tried something similar as well as coils below the pickup, etc. You need to have the driver coil close to the core and you need to have it condensed (at least following my ideas and with simple circuits) close to the strings in a "thin" configurations. Potentially then, you could strip a p_90 and wind the driver into the top half and rewind the entire pickup over it and wire the two in parallel...but this is probably not advisable.

Best to wind a thin coil over that would fit over the protruding poles and make or modify the cover to suit.

Hope that helps a little. The specs for such a conversion and my driver winding pictorial linked below will give you a lot more information on how to do this...


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Thank you Pete, I already tried a classic sustainer, but it didn't work (maybe because I was testing it the wrong way).. I understand about the P90 issue, and I don't want to unwind it, so..

Anyway if I can't put a sustainer on my guitar (a singe-sized driver would look bad sticked to a P90), maybe the e-bow solution..

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I already tried a classic sustainer, but it didn't work (maybe because I was testing it the wrong way)

Maybe...are you talking "classic" as in my design, or a commercial unit?

Anyway if I can't put a sustainer on my guitar (a singe-sized driver would look bad sticked to a P90)

Well...actually it wouldn't "look bad", it could be invisible. But it depends like so much DIY on you skills and determination. For instance, my "ultra-thin" design is only 1mm thick and has no bobbins, this I imagine would fit onto t picku[ and with a little fiddling around the original cover replaced with only a slight lowering of the original poles below the cover, a P-90 with screw poles, none at all. You could make a bladed coil that sits on top or extend the poles a little more for the DIY version.

Still, there are limitations to what each of us can DIY. Recently I have been exploring some of the things I have learnt along the way here, to motors and recoverable energy in vehicles. Lots of great "ideas" but not the skills to really make much of them. Were I younger, this is an area that would have been something I would have looked at and developed more as some of the secrets of successful electric vehicles for instance is in the recuperative energy from breaking and rolling along to extend the range and make them a more practical proposition.

Much of the things we are looking at in the sustainer project is a great introduction to some of the principles and processes that are involved. Oh well, we all have our limitations and I guess I will have to sit and watch the progress of others. Interesting stuff and if you want to see what an electric car could do check out the Eliica which uses a lot of this kind of ideas with 8 wheel drive, out accelerate a porshe and run at over 350kmp with a range of about 300km..plus seats 4!!! That's faster than a formula one and built in Japan without any help from car makers.

On a more realistic front, I might be investing in a folding e-bike with a range of 30-40km at 20kph so that I can drive within a striking distance then scoot about on this from where I can get free parking and save gas...or take it on the train! Even some of these have recuperative energy systems so you get some recharging as you roll down hills and in breaking, or pedaling for that matter. The fact is that such a bike will cost about 1c per litre in comparison electricity costs and at 20kph is faster than a car in traffic situations anyway and no parking costs! Plus, it is still a valid light weight bike so you can't get stuck with it if it goes flat!!

keep sustaining...and lets see more about the DIY ebow...


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Maybe...are you talking "classic" as in my design, or a commercial unit?

Classic as the first design, with the F/R amp and an 8R driver..

Well...actually it wouldn't "look bad", it could be invisible. But it depends like so much DIY on you skills and determination. For instance, my "ultra-thin" design is only 1mm thick and has no bobbins, this I imagine would fit onto t picku[ and with a little fiddling around the original cover replaced with only a slight lowering of the original poles below the cover, a P-90 with screw poles, none at all. You could make a bladed coil that sits on top or extend the poles a little more for the DIY version.

Okay, I'm going to look at this.. But yes, invisibility is what I look for my driver..

Edited by Franky
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Well...I think that the P-90 would work out ok in exactly the same way as the driver/pickup with a little ingenuity, but as always DIY=do-it yourself, as far as I know if was attempted once but never finished, but the p-90 is a single coil pickup with a plastic cover so it is a good candidate for such a modification. No commercial unit seems to fit the bill for such a unit.


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Especially these ones...I would have thought the potential was obvious. Be warned though, pickups can be delicate and difficult to fix if you break something and you will need planning and preparation.

Here you have screw poles that protrude the base plate. Obviously they could be raised by the amount of that protrusion, a few mm's. So, if you got some 2mm steel and drilled holes in line with the screw poles and mounting bolts and arranged a very thin bobbin top on this you could screw a temporary support piece to the bobbin for winding support. All exactly like my pictorial. When the cover is replaced, the screw poles will then look exactly as stock at the tom but not protrude at the bottom. You could make it a little thinner than my 3mm one for a strat, because you have a little more width to wind with, but the coil will not be as big as this if wound properly.

Of course, there are risks and building a pole blade with holes in it drilled accurately is going to take some precision that I would find difficult. You may need to find someone with accurate drilling, cutting and grinding skills and tools to make the piece, you want those pole pieces to be fairly tight so they make contact with the blade core.

Again, this is a DIY project and it does take some ingenuity to work these things out. A bigger problem would be something with fixed or magnetic poles, but even this can be possible. Also, this has not been done before really and I have not taken one apart either, but in many ways it should be easier than some to modify.

Planning and preparation is key to getting the job done well without damaging anything. It may be a better appraoch to wind a test coil before modifying a pickup so that you know the whole system works and is within your capabilities before you permanently hack a pickup in this way. This is exactly what I did and still do and the practice on the test coil will assure better quality of the final one on the actual guitar. As I recall, the last p-90 attempted failed through the lack of quality in the circuit construction, over confidence and overambitious in the installation from which the member began (something about rotary switching as I recall) not the coil winding. In fact this is almost always the case, so keep it in mind and recruit people who may be able to assist where you can...


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Thank you Pete, I've got the skills to do it myself (I've made a lot of DIY projects for the last 3 years), but yet I don't have any real experience in sustainers.. The driver I made last time was maybe OK, but I had some troubles to make the circuit work, and I didn't had a dedicated guitar to try it...

Building the top plate is not really a problem, I've made some precision work like this before.

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Ok...well for the circuit see the layout and suggestions from me a few pages by Rising force for an improved F/R. For switching on even a two pickup guitar it is likely that you will need a 4pdt toggle and a dpdt for the harmonic function, but worry about this after testing.

In my last lot of testing with this and from suggestions from, I forget who perhaps 6 months ago, I experimented with running the driver coil of about 8 ohms with a single coil pickup underneath it in parallel with some interesting results. This is something that can also be tried and may even make switching a little easier. Three pickup guitars have additional problems.

For a bobbin, I have even made some out of thin cardboard and the one in the pictorial was very thin plastic cut from a folder. In some ways the cardboard stuff was better with the PVA method as the plastic did not attach to the glue. In order to wind a coil with something as flimsy as cardboard, stiffen it with superglue and protect the windings with tape on the inside of the core and around the outside of the coil after winding. Have this prepared in advance. Have some clamps or something also for while the glue dries and something double sided taped to the bobbin top to give it strength (or better yet screw it down with the pole screws so it stays aligned).

Once the glue dries and the cover is on you won't know what it looks like anyway so that should be fine as a construction method. In use, the pickup/driver will have to be adjusted very close to the strings, as close as possible. As the pickup coil will be 2-3mm or so lower because of the driver on top, it should be fine. Adjust the bridge pickup as close as possible to the strings also to maximise string signal and minimize EMI effects.

Such modifications to pickups are permanent, you may wish to sticky tape the pickup to a piece of wood to prevent it getting damaged in winding the driver on top. However, should this not work out for you, then at least the driver coil will be invisible and work as a pickup as normal without anyone being the wiser for it :D . Sometimes if things fail you need to give them a rest (that's partly what I am doing now) and this way, you will be half way there for the next try should the circuitry fail you again.

Ok...must run but it sounds like a good plan...

pete :D

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Bad news.. The coil is glued to the plastic case.. I can remove the polepieces and the magnets, which means that I could put the driver under the P90, but it wouldn't work..

Sorry to hear that, I have not played with p-90's so I don't know enough about them. I thought you had originally shown a pic of the pickup coil without the cover...when you suggested winding around the outside of the coil?

Gluing the cover on sounds a little strange, certainly the pole screws are likely to hold it on...usually the covers can be set in wax to prevent vibration which is much like gluing...it could well be glued though and wax is vers similar and taling it apart may cause damage to the fine wires.

Perhaps someone has some experience with these things and their typical construction.

No, you can not put a coil below the pickup!

Also, depending on the guitar, there may be the potential to build a surface mount driver to fit between the neck and neck pickup. I am doing a few experiments along those lines at the moment inspired by an email. I am considering testing such a driver on a tele between the neck pickup and the 21 fret neck. This gives a space of 65mmx12mmx6mm(high) to build a driver in that would stick to the top of the scratchplate.

My first thing was to try neodymium magnets but these were found too strong, actually pulling the strings out of tune and affecting the neck pickup adversely. I am now considering a row of 4 small ceramic blocks abut 4mm thick and mounting a blade and coil on this of 2-3mm.

If anyone has some suggestions for this kind of driver, let me know. Over the last few years all of my devices have typically been combined with pickups. Some things like my bi-lateral mid-driver experiements used internal ceramic magnets as the cores, but this seemed to have little throw and not drive the strings as well as hoped. These bi-lateral designs mounted close to a pickup was also found to adversely affect the balance of the pickup. One side will reinforce the pickups field, the other would cancel it!

I have a feeling that the coil mounted to the top polarity of the magnetic core...not the whole thing, has some beneficial effects. If so, the depth of the driver may influence effects and "throw". Compact drivers may then hold some special challenges.

Anyway...a bit of other stuff going on, but I will be tinkering about with this after a bit of a break in coming weeks.


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I'm not really surprised that it's glued, a lot of cheap pickups are made that way (and it's a cheap one)..

Well, I think a permanent sustainer is not a good solution for me, it needs to mount and unmount the strins a lot, which I can't stand, and it leaves the problem of routing a cavity for a driver..

With an "external" sustainer maybe, like an ebow, but 6-strings wide (you guys must have think about this) would fit on every guitar, and would not affect them permanently in their look.. And a standard guitar is ideal for testing, as the circuit is not electrically related to the signal..

So yeah, the ebow project that was released a few posts ago seems intersting.. even if it is one string wide, there must be a way to extend it..

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where can i buy a circuit board?preamp piece.....any links?

can any one make a short video a sustainer...

i have this pick up

i paid 20 buks for it would it work to make a driver


......as for the pre amp stuff im still clue even when ive looked at about 80 pages....do u guys buy pre made or make it?

B):D until then ill keep on :D

Edited by jrojas159
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:D :D

Stop reading!!!! Now read the thread backwards, the first 100 or so pages are obsolete...better yet, read the sustainer tutorial and pictorial driver threads linked at the bottom of my posts!

No...that pickup is sealed so no good for a driver...no way into it.

This is also a DIY project so no kits or such at this stage. I think there is a couple of things on youtube but it is something I have yet to figure out how to do...so no video from me. I have tried to put sound links up but event they were stretching my old brain to do. I did recently by some web space, but have yet to get to use it that I hoped I could do something with and which is also linked below. I had hoped to produce a kind of kit, but at the moment this is on hold.

It can take quite a bit of work to get this thing to work properly, but it is possible. The wire gauge and such is important for this design so despite the principle being easy, the details are important, the rewiring can be difficult and the project should be tested before attempting to modify the guitar...you will need it anyway for testing.

Franky...I started a reply but my internet went down before...I think I saved it...ahhh, here it is!

No franky, I think you have got the wrong idea about a compact surface mount sustainer. The electronics and all associated wiring and installation is in the guitar and permanent, the surface mounting and compact design is specifically to avoid any routing as long as there is adequate space between the neck pickup and the neck itself (tele and strat, but not a LP for instance). It would look like perhaps a small single coil pickup in profile I imagine.

The ebow patent which is very old now details not only a prototype of the eBow device (without detailing the case design) and proposes a fixed i9n built version of six ebows effectively operated by little levers or piano like keys behind the bridge. I don't think this is really practical. A six string ebow is a little tricky as well...it is kind of a different thing.

Improving an ebow is tricky as the design is very effective and elegant for what it does. This is a sustainer ideas thread and the eBow equally is considered and uses much the same technology. A six string ebow would be a little difficult to achieve...but maybe. It is a different device but with practice can be very effective...check out some proper Youtube videos...

A quick search gets gems like one of the best ebow players about Phil Kleggy...http://www.youtube.com/watch?v=NIWMrK67_bk...he makes it look so easy, all those pingpong delays and bagpipe imitations, but it is a lot harder than he makes it look. You can get sounds out of it that the sustainer can't do in general. However, the sustainer can do other things. Certainly though in the hands of a master, the eBow is a pretty amazing thing. Making your own is probably not really worth it unless you can improve upon the design in some way. At least there is no mods to the guitar and you can use it on other instruments.


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Ohhh...look what I found...a hidden sustainer under construction!


Ola Stradberg has a great thread on building an ergonomic guitar with twisted helix neck in composite materials here at PG...but I see there is a secret weapon in the works as well...good stuff


PS...still playing with a new surface mount idea. Neodymium magnets really didn't work at all (actually interfered quite a lot with vibration) but I found some craft magnets (4) that look like the go, about 4mm thick so just enough room for a blade on top and winding a thin coil...a low priority however.

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I found a french tutorial on how to make an ebow with a transformer.. I don't have read all the tutorial so far, but if you guys are interested I can try a translation..

I warn you, it's heavy.. He's unwinding a transformer to get the 8 ohms for the driver..


There's a video from the man using the thing:


Edited by Franky
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I recognize that circuit diagram from a Belgium tutorial a few years back that we discussed. This one though actually shows pictures and the finished device. I take it the next step is to work out a better housing, maybe more like the eBow itself...

This is the big problem with DIY eBows as no one has come up with a suggestion that beats the original design and making it could cost as much as an original and not be quite so compact. Notice how it was harder to play in this size and without the string guiding grooves.

It is a nice find though and people should note that the fetzer ruby would be as good a circuit for this application.

In my last DIY eBow experiments I used a transformer like this as the driving coil and a reed relay (with the reed removed and magnets added to both driver and pickup coils. It did kind of work but very fiddly to make and without a casing very difficult to use.

A good one was made also at Aron's stompbox forum as well, it looked like this...


Again, tricky to hold this just right above the strings.

The ebow is a great device (though I don't have one myself) and is slightly different again from a sustainer. It's great benefit is that it involves no modification and can be used on any instrument. The benefit of the sustainer is that it is only the driver (not the pickup) and circuit, my problems have mostly been in installation and switching. Playing wise it does not restrict the picking hand, can play chords and utilizes the existing pickup to provide a source.

Thanks for the link, I'll apply FOXLingo to it for a translation later and see if there are details I may have missed...


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