col Posted September 29, 2006 Report Share Posted September 29, 2006 well, I tried a 10u in there, and it made sod all difference compared to a 4.7n so apologies for ignorant nonsence Link to comment Share on other sites More sharing options...
custom22 Posted September 29, 2006 Report Share Posted September 29, 2006 (edited) Alright guys, time for the question of the day...which is the correct way to wire the sustainer to the bridge pickup? Please no guesses...I'm not quite sure where to implement to driver so i need a little help, and please give me some direction if none of the above are correct. Edited September 29, 2006 by custom22 Link to comment Share on other sites More sharing options...
col Posted September 29, 2006 Report Share Posted September 29, 2006 Alright guys, time for the question of the day...which is the correct way to wire the sustainer to the bridge pickup? Please no guesses...I'm not quite sure where to implement to driver so i need a little help, and please give me some direction if none of the above are correct. the driver goes on the right hand side - it replaces the speaker symbol that comes after the LM386 chip Col Link to comment Share on other sites More sharing options...
psw Posted September 30, 2006 Author Report Share Posted September 30, 2006 the driver goes on the right hand side - it replaces the speaker symbol that comes after the LM386 chip correct...think of the driver as a speaker coil and the strings like the speaker's paper cone! Similarly, the pickup connects (one wire) to the ground (arrow symbol) and the (other wire) input to the pot. It also connect to the gutar's ground and to the guitar's volume control pot as normal... Does this make sense...so drawing 3 seems to be most correct...hope that makes sense... pete Link to comment Share on other sites More sharing options...
custom22 Posted September 30, 2006 Report Share Posted September 30, 2006 (edited) Sorry, I didnt mean driver. I am aware that the driver is where the speaker is. I meant how do i connect the bridge pickup to the driver circuit. PSW- I'm sorry but i dont understand. The black is the pickup's normal input, and the green is its normal ground. Do i connect the ground wire like normal, with the black wire going to the hot output and the preamp? Or is it one or the other? Thanks Alot! Edited September 30, 2006 by custom22 Link to comment Share on other sites More sharing options...
ebenezer shred Posted September 30, 2006 Report Share Posted September 30, 2006 so which works best for the sustainer, the "champ" or the fetzer/ruby? Link to comment Share on other sites More sharing options...
psw Posted September 30, 2006 Author Report Share Posted September 30, 2006 Ok...E.S. so which works best for the sustainer, the "champ" or the fetzer/ruby? The Champ is available in kit form with a circuit board and I used this as the basis of my LM386 section. The mods are listed in the above post and runs at full gain in my set up. You could put in a 1k trimmer pot in there between pins 1 and 8 with the 10 uF cap for variable gain between 20-200x gain. You still will however need a preamp. The fetzer or any number of booster circuits will do the job. I have a preamp with a lot of gain and filtering, but the fetzer is smaller and works. My preamp is confusing and built on a PCB so is not really suitable for vero or perfboarding. I'm sure could be done better. PSW- I'm sorry but i dont understand. I really should draw this out...no time just now...however Leave the pickup connected to the guitar's controls as normal. Then take another set of leads form the Hot and ground leads of the pickup, hot to the IN and ground of pickup to ground of circuit. Hope that makes sense... pete Link to comment Share on other sites More sharing options...
psw Posted September 30, 2006 Author Report Share Posted September 30, 2006 (edited) As noted earlier...you have to check your layouts more than twice...I think this is right now for the LM386 module, as per my modified champ circuit...let this be a lesson to us all!!! I do think the modular system will have a lot of merits...plus some down sides I have added the LED pull down resistor to this circuit as I am envisaging a type of installation where this module (or something like it) is placed close to, or incorporated into the driver design in some way (can you imagine how small you could make this with SMD components!!!) Switching would be on the incoming signal so keeping the driver wires as short as possible and so be more efficient and also to keep these EMI producing wires out of the rest of the guitar. (I found that I had to run the wires through the trem cavity but they still come together at the circuit and so close to the raw signals) This module is only a part of a system however, and not one that I have fully worked. There needs to be a preamp and the switching system will require a rework, but this modular schema is I think preferable and allows for more experimentation and development as well as options. You could for instance build a fetzer as a separate module... ...and place the controls between the two modules, or perhaps the AGC part of col's circuit...or some other idea. These two circuits in combination could be used as per the present system however, so it is something to work with, while we contemplate issues of changing the switching to between the preamp and amp sections and reversing the signal for the harmonic mode vs the driver wires. Of course, the idea of the "thin driver" DIY sustainer design was to produce a driver that did not require complicated circuitry (eg phase compensation, etc) but simple amplification to work. I am still commited to the idea of a driver that has the qualities that are desired built into its design and more developments are sure to come in time (eg the rail driver). Any of these modules could be replaced with alternate preamps, amps, conditioning circuits...and of course...you can use this circuitry to run any kind of design of driver that you can come up with. If nothing else...at least you could test each module separately and they would be a lot easier to find room in the guitar for them...if only the battery was so easy to fit in a standard guitar!!! pete Now to sketch up some driver ideas...generate some comment. Although I have missed out on a house to rent, and so a place to start constructing stuff again, someone may want to take a run with them, so may as well put a few out there... p P.S. I'd be inclined to put a 100uF cap between 9V+ and GRD to filter the power, and a diode to protect against connecting the battery back to front (and frying a component!)...I'd then run the power from this module to the amp module. Any number of booster circuits could be used and there are a few that can be downloaded already "laid out" (like this one of the fetzer) from the DIY Layout Software's layout library...pretty neat. Hope I got this version of the LM386 thing right this time!!! Edited September 30, 2006 by psw Link to comment Share on other sites More sharing options...
psw Posted September 30, 2006 Author Report Share Posted September 30, 2006 well, I tried a 10u in there, and it made sod all difference compared to a 4.7n so apologies for ignorant nonsence No appologies required....I am very limited in my circuitry logic I am afraid (I tought myself for this project so I am always open to correction or alternate view...especially correction ) Anyway...was checking out the ROG site and I note the Ruby circuit has a 100nF cap from pin seven to ground. I never thought to try anything else, and it may help my "pop" problem too (primal experienced much less). I do think that anything that helps stabilize things is worth looking into and as you found out, that cap to ground does seem to be important. But, there may be no reason to have such a huge cap in there. I went to a lot of trouble reducing the height of my cicuits by laying things down on their sides (see the last pic) but you can see a lot of big caps in there...I noticed that I even put a few SMD's on there as well. Next time, I will be reducing this cap to save space...don't see any reason for it to effect gain though, but then I don't understand the bypass pin anyway or what it would be used for (why not ground it internally, some circuit must have a call for it, but I have never seen one. I have been told that the 10 ohm resistor and little cap to ground just before the output cap (pin 5) is important to stability too...a "Zobel Network" I believe. I have to say that the LM386 is a remarkable chip. My first experiments I used only an output cap! I have soldered them in upside down and applied power, desoldered and reused them, even trided the tiny SMD version and I have not killed one yet. If only it contained a non loading preamp, this project would be so simple... pete Link to comment Share on other sites More sharing options...
col Posted September 30, 2006 Report Share Posted September 30, 2006 I do think that anything that helps stabilize things is worth looking into and as you found out, that cap to ground does seem to be important. But, there may be no reason to have such a huge cap in there. I went to a lot of trouble reducing the height of my cicuits by laying things down on their sides (see the last pic) but you can see a lot of big caps in there...I noticed that I even put a few SMD's on there as well. After some research, it turns out that the cap from pin7 is for power supply filtering and that 10u is a good value - 100n is a bit on the low side. My success with a 4.7n was because the problem I had was high frequency oscellation - a 4.7n wouldn't help with lower frequency noise. My guess is that a larger 10u cap would become much more important if we tried to use phantom power. I have been told that the 10 ohm resistor and little cap to ground just before the output cap (pin 5) is important to stability too...a "Zobel Network" I believe. Not sure about a Zobel network, I looked that up, and most of the examples I saw were a lot more complicated. I think (whatever it is) it has something to do with compensating for some of the effects of a speaker coil ?...... ok, you're right its a zobel network.... heres some info i found: A Zobel is a series resistor-capacitor (R-C) network that is connected in parallel with a loudspeaker driver in order to neutralize the effects of the driver’s voice coil inductance L(e). Figure 1 below shows a Zobel consisting of resistor R1 and capacitor C1. Because a loudspeaker’s voice coil is itself an inductor, the impedance of the driver increases with frequency much like an inductor. When a woofer is used with a passive crossover the driver’s L(e) has the effect of spoiling the crossover filter action. A Zobel can be used to restore the impedance of the driver to the nominal value in the high frequency range. This will allow the crossover filter to operate more effectively in the high frequency range where it is used to attenuate the highs going to the woofer. It may be that we could have better values for the zobel components as we are using a very non-standard 'speaker coil' cheers Col Link to comment Share on other sites More sharing options...
psw Posted September 30, 2006 Author Report Share Posted September 30, 2006 OK...here it is...remember you saw this concept first (so no one even think of patenting the thing)... I have no idea how this would work...but it sure would look cool Actually, lighted blades aside!...the idea is that the driving blades keep the thin driving concept but the full length coils will benefit the EMIbucking capabilities. I have another idea to add magnetic shielding to it as well. As a side benefit, the split blade would enhance the single coilness of this type of design (seymor duncan does something similar with some of his rails)...but he does not have the lights in it! The lights would light up when the sustainer was on as an indicator...not only looking cool and taking the power from the amp module located nearby...it would also mean one less hole to drill into the guitar. Now...if someone devised an electronic switching system, we could put SMD touch switches top and bottom between those coils and we'd have a complete, low mod sustainer system Anyway...had been brewing in my brain a while, so there it is... pete Link to comment Share on other sites More sharing options...
custom22 Posted September 30, 2006 Report Share Posted September 30, 2006 (edited) Ok...E.S. so which works best for the sustainer, the "champ" or the fetzer/ruby? The Champ is available in kit form with a circuit board and I used this as the basis of my LM386 section. The mods are listed in the above post and runs at full gain in my set up. You could put in a 1k trimmer pot in there between pins 1 and 8 with the 10 uF cap for variable gain between 20-200x gain. You still will however need a preamp. The fetzer or any number of booster circuits will do the job. I have a preamp with a lot of gain and filtering, but the fetzer is smaller and works. My preamp is confusing and built on a PCB so is not really suitable for vero or perfboarding. I'm sure could be done better. PSW- I'm sorry but i dont understand. I really should draw this out...no time just now...however BTW that would be wicked to have that LED thing in the driver! Leave the pickup connected to the guitar's controls as normal. Then take another set of leads form the Hot and ground leads of the pickup, hot to the IN and ground of pickup to ground of circuit. Hope that makes sense... pete Alright, i think i got it. Is the ground of the circuit the same as the ground for the guitar? Edited September 30, 2006 by custom22 Link to comment Share on other sites More sharing options...
Primal Posted September 30, 2006 Report Share Posted September 30, 2006 Yes, they both have a shared ground. Link to comment Share on other sites More sharing options...
col Posted September 30, 2006 Report Share Posted September 30, 2006 OK...here it is...remember you saw this concept first (so no one even think of patenting the thing)... ... Anyway...had been brewing in my brain a while, so there it is... pete Interesting idea. would look cool Question 1, what is the difference between this and a dual coil with one full bar and one full 'air core' (or perspex). Question 2, would it really be worth all that extra juice - half of it not driving the strings ? From my limited but practical experience, a dual core with full bar in each side 'seems' to be more efficient than a single core driver, it also has a pretty good frequency response even with a big gap between the two cores and gives good noise reduction while being simpler to construct... doesn't look so cool though... My only concern is how to get rid of the crosstalk between pickup and driver, and I'm not sure this will have any effect? Col Link to comment Share on other sites More sharing options...
spazzyone Posted September 30, 2006 Report Share Posted September 30, 2006 (edited) hey Pete do you think this would work for the split rail using the jackson preamp i have for its first stage? and independant power for each rail http://www.nxp.com/acrobat_download/datasheets/TDA1517_5.pdf here is a pic of the board. note it still has a 1/4"jack that would be removed http://i32.photobucket.com/albums/d38/femf...tar/Picture.jpg Edited September 30, 2006 by spazzyone Link to comment Share on other sites More sharing options...
psw Posted September 30, 2006 Author Report Share Posted September 30, 2006 Spazzy... hey Pete do you think this would work for the split rail using the jackson preamp i have for its first stage? and independant power for each rail Probably...you are on a road not often travelled, trying to drive the strings with a conventional pickup. At 12 watts, that is a lot of power, it will need a powersupply (it could never run off batterries) and will get hot (will require a heatsink to avoid destruction). Remember, the devices we are working on are driven by 1/2 a watt! If you have any details on the jackson preamp (chip number, photo, etc) that could be of interest to some people. It should be capable of preventing loading and driving such an amp module. You may wish to seek out some articles with Micheal Brooks, and english guitarist and "inventor" of the "infinite guitar" (before sustainiac, et al) as he devised a way to use a conventional pickup...but he is putting high voltage into it...there is some secret that he is not saying togetting the impedances right and the whole thing working. Stereo...I too am thinking of driving each rail with a different signal for better high string response. More on this later. No reason not to, but without different filtering, it would be the same effect as running in mono anyway. Now...on the Split Blade Concept... Col (and others...) Every nownagain, I just got to get these things out of my system... This is a combination of a number of ideas / principles 1) It utilises the thin core theory...instead of a wider set of rails, each string is driven only by one thin core, much as on my single coil driver now. (note core, not coil...both driving coils are also thin) 2) It is a mash-up of ideas...the rail driver...the bi-lateral driver....the thin core driver...active shielding 3) The dual coil, half string driving...would allow for stereo amplification with a higher treble bias for the higher strings for better drive...opens up areas of conditioning the signal or output for better drive for the various sets of strings 4) the air coil's being so thin and right up close to the strings would still have some effect on the driving of the strings... 5) the single core would have more "throw" of the magnetic field in a narrower space than if it were right up against another rail of the same polarity that was nuetralising and drawing back the magnetic field (both passive and active, electromagnetic drive fields) I have no idea how this would work...but it sure would look cool Ok...so you are right col, there are down sides...but with all those lights and stuff, clearly my focus was not on battery consumption Question 1, what is the difference between this and a dual coil with one full bar and one full 'air core' (or perspex). see above... Question 2, would it really be worth all that extra juice - half of it not driving the strings ? What price cool! Actually, I run a very bright blue LED now, so that is not really the problem. Long term sustainer thread followers may remember the flak I got from some regarding putting lights in the hex drivers (5 LEDS!)...then you see other threads where people are drilling out the HB slugs and installing LED's and proposing chaser circuits...hehehe Anyway...lights aside, I think there are some compelling reasons for considering a split coil design. You could equally address the efficiency issues by making a true bilateral design, maybe keep a full blade but have only half active. This way, all the coil would be driving the strings! There could still be room for lights (actually, there is always room to illuminate devices, it's a question of whether it is worth the effort and you can live with the results...hehehe) It is really offered to stimulate discussion and thought...hope the lights don't blind people. I am not sold on it...the conventional rail driver offers more power per square inch, but is it going to drive the strings as well as a thin core design, or a bi-lateral approach. I don't think this design really offers half the power BTW, might have to drag out the FEMM again...(unless robert is handy and has got the reduction ddown on the graphics ) It is possible there are unseen improvements in efficiency....hard to say without testing something. It is interesting to note that the passive pickup coil, if removed for a driver only unit, would allow plenty of space for a drive module circuit...with or without the split rail idea. From my limited but practical experience, a dual core with full bar in each side 'seems' to be more efficient than a single core driver, it also has a pretty good frequency response even with a big gap between the two cores and gives good noise reduction while being simpler to construct... doesn't look so cool though... My only concern is how to get rid of the crosstalk between pickup and driver, and I'm not sure this will have any effect? Difficult to construct...if that was my concern I would never have made those hex drivers...uhhh...oh yeah, that was a mistake... ...actually, it isn't that much harder unless you must have the lights... I am thinking about the construction problem. I am looking at ways to make driver coils without bobbins or cores...so you insert them after the coils are wound and set. Not having a core would allow for a far easier jig as you could use bolts right through the core that are removed later, for instance. This would make this easier, and open up doors for testing with the same coils different configurations, materials, magnetics, etc. Not to worry...there are more ideas...early Sunday morning again...time to go to work...but there will be more ideas to come...everyone keep at it, pass comment, etc while I'm away... pete Link to comment Share on other sites More sharing options...
onelastgoodbye Posted September 30, 2006 Report Share Posted September 30, 2006 (edited) mmm...lights.... 3) The dual coil, half string driving...would allow for stereo amplification with a higher treble bias for the higher strings for better drive...opens up areas of conditioning the signal or output for better drive for the various sets of strings My only concern with stereo driving is that the 2 coils would have to be in parallel, which means each side of, say a stereo lm386, would only be driving a 4 ohm load... i think we established early on that the lm386 was most efficient on 8 ohms loads; So you'd need either bigger coils (not-so-thin-driver) or a different amp configuration. 5) the single core would have more "throw" of the magnetic field in a narrower space than if it were right up against another rail of the same polarity that was nuetralising and drawing back the magnetic field (both passive and active, electromagnetic drive fields) One question: is the magnetic output of the 2 coils the same, or is one inverted (right hand rule ). Anyway, this is something I've been pondering on for a while now... I don't think the two cores are necessarily working aginst eachother. Certainly at higher frequencies/harmonics, it seems quite possible that one core would be pushing the "peak" and the other core pulling the "valley" of the same wave, or even pushing the peak of the next wavelenght, depending on the answer to my question, thus summing their (electromagnetic) output. To that extent, maybe the rail driver is already a bit of your "wave-driver". Theoretically , that would also mean that spacing of the driver cores would have considerable effect on the frequency range of the driver itself. Now, i realize, your "throw"quote is more about the shape of the magnetic shield itself and the speed and ease at which it can change. Looking at the femm diagram of my own driver, I think it could really benefit from some sort of a center laminate of inverse polarity. N-S-N, like the Tumura side drivers. As it would really focus the field upward. But then it wouldn't be humbucking anymore I guess. Or not? Aww,... confusing . Any way we could easily impement the 3rd "active shielding" blade without going for a full-out side driver? And if somebody could please do a femm analysis of a side driver, that would be great !? Tim 10 pages in 2 weeks Edited September 30, 2006 by onelastgoodbye Link to comment Share on other sites More sharing options...
spazzyone Posted September 30, 2006 Report Share Posted September 30, 2006 (edited) The preamp is a jackson j1200 mid boost is out of a charvel model 4 the numbers on the chip are 0628 JRC 00195 i could layout the whole circut but that may take a little time http://i32.photobucket.com/albums/d38/femf.../Picture005.jpg that pic of other amp has no heat sink thats the way it came out om my other computer it was a built in head phone amp and its power came from the 5v supply line i was thinking that one channel could power each blade of the driver so as to add more power to the high strings feed me JOHNNY#5 NEED INPUT Edited September 30, 2006 by spazzyone Link to comment Share on other sites More sharing options...
ebenezer shred Posted October 1, 2006 Report Share Posted October 1, 2006 anyone have any idea on how to make an e-bow. I tried one out today and liked it, and thought it might be a good starter sustainer project. Link to comment Share on other sites More sharing options...
Primal Posted October 1, 2006 Report Share Posted October 1, 2006 anyone have any idea on how to make an e-bow. I tried one out today and liked it, and thought it might be a good starter sustainer project. Ebows are just like this project, only in a compact case (and some fancy circuitry, but the concept is the same). It has its own pickup to pickup the strings and a driver to drive the strings. You will NOT be able to build one of these, as it is MUCH more complicated than this sustainer project, for many reasons, one of which is EMI issues (which is solved in the Ebow by secret, patented means). Link to comment Share on other sites More sharing options...
psw Posted October 1, 2006 Author Report Share Posted October 1, 2006 (edited) You will NOT be able to build one of these, as it is MUCH more complicated than this sustainer project, for many reasons, one of which is EMI issues (which is solved in the Ebow by secret, patented means). Not so...on this very thread Ebows have been discussed. They apparently use a LM386 without preamp (couldn't be easier) but the real problem is making both the pickup and driver, and then getting it into a usable format. It has been done, but it is not easier. Part of the ebow secret is the enclosure that slides along the strings...tricky to make. Search here for ebows or look through this thread. There was a dutch(?) site that Tim/onelastgoodbye translated and I know of one with pictures built over at the stompbox forum. Anyway...I like the ebow principle, but the sustainer wins out for me (as a playing instrument) and is probably easier to make (thanks to this thread...try to find anything else of use on DIY sustainers ) Anyway, hope that helps... pete Thanks spazzy...as long as you have a means to power it, that circuit is probably a better bet than the PA you have been using to power the thing. Having never gotten a conventional pickup to work as you have done...I don't know how it would perform. At least it is a little more disposable and portable than your PA rig Edited October 1, 2006 by psw Link to comment Share on other sites More sharing options...
psw Posted October 1, 2006 Author Report Share Posted October 1, 2006 Tim...good questions... Anyway, this is something I've been pondering on for a while now... I don't think the two cores are necessarily working aginst eachother. No...not like a "wave driver" though you have a bit of how I would envision this working. You couldn't really do it with conventional coils I don't think. A rail driver is just like a humbucking pickup. Although there are two coils and blades, they are wound in opposite directions (or at least wired that way) and, they are magnetised opposite. So they don't push and pull really, they work much like a single coil in effect, but with a core equivilent of the width of the two blades together...well effectively. Bear in mind that my theories are ideas, nothing really has been proven as such. For instance... I believe a thin core is of benefit...however a core of 1mm for instance would lack the mass to generate and hold a significant magnetic field for this application. I believe a thin coil is of benefit...however, there is a point in which a coil may be too thin to generate an effective north south polarity diferential...so...the coil's electromagnetic function may have less influence than a slightly deeper coil. Perhaps col's single coil driver of 2mm thick 1/3 thinner than mine, crossed that threshold. I have made them deeper 4-5mm and it worked well BTW. The thin coil idea is to limit EMI by compacting the electromagnetic fluctuations into a small space directly under the string, and, to increase speed so as to avoid excessive lag that is accentuated as the frequencies get higher. The reason for this "lag" is that the coil has to have some time to change magnetic states and the faster it is asked to do that (high notes) the more lag there will be. Rather than try and address that by creating a complicated circuit to compensate (as the commercial units have done), I have tried to address it by driver design. The thinner wire (0.2mm) is also helpful here and seems to be important. There are also some unknowns regarding the resonant frequency of my 8 ohm thin coil. Now...the rail driver changes that formula quite a bit. Do the same principles apply? You have less windings around blades of less mass. You have a magnetic field in which a substantial amount of the magnetic energy is being transferred 90 degrees between the blades and not working directly upon the string. The split blade design tries to address that a little by having blades of similar mass to my single coils, but for only half the string. I do have concerns that these factors may effect efficiency. A Humbucking pickup has more windings than a single coil...but then maybe it has too, the magnetic pull is much less due to the opposing fields. In the two coil 4 ohm drivers though, you have not increased the nuber of windings and they have half the overlaping windings of the single coil design...this does concern me a little. Now...stereo...you can get stereo chips that will drive two 4 ohm loads or, perhaps there should be slightly deeper 8 ohm pairs of coils. Given that col seems to be able to drive his driver at 20x amplification and I use 200x...perhaps I could use two 386's at minimum amp (or something similar) without much increase in power consumption (especially if it is more efficient). My battery consumption is quite acceptable as it is BTW.For it to work effectively, I imagine you would need separate drivers for each set of strings (or as in the hex designs, each string) and so something like a bi-lateral or my split blade idea (or something else) would most likey be the ticket for this kind of thing. Anyway...the rail driver is still a good concept but a different beast. I think the basic principles still apply but I think there needs to be a bit of experimentation with things like core depth and mass as well as width and there are still plenty of ideas still to explore. (I spent an our today sketching different mag/blade arrangements to get a tri blade thing much like you were hinting at, but it is tricky and I don't have it yet.) What I do have, is a way of making self bobbining, coreless coils!!! A simple jig and method should do the trick but I will probably have to draw it up to explain it fully. Basically, the coils would be wound on a form and then compressed to make a solid coil. The jig comes apart and you could use it to experiment with different blade types, and it could make single 8 ohm or dual 4 ohm coils. I don't know if this would be for everyone, but for the experimenter it would be well worth while. Maybe I will make them at some point. For me, I still like the idea of a driver/pickup and the easiest way to achieve this, at this point, is to modify existing pickup designs. My aim (once I overcome my housing crisis) is to develop a driver design that meets col's concerns about EMI enough to get something going in the mid position of a strat. Many will remember that this was kind of the aim of a lot of the projects here...to be low mod, easy, cheap and effective. At least a mid driver allows the use of the neck and bridge pickups and may make installation a lot easier. A strat like guitar is a very good platform, and, as the main concern with cheap copies (besides playability which has improved a lot in this CNC age) is their lack of sustain...such an instrument is perhaps ideal for this kind of mod. The EMI issue can be resolved enough to do this...my hex designs operated within 2cm of the bridge pickup, for instance...and I don't think it needs to be so radical as a "wave driver". Dizzy did it with a bi-lateral driver very effectively (though it lacked the harmonic function). Such things would perhaps be appropriate for a very thin mid driver between two humbuckers perhaps where there is no cavity...but I am not putting too much thought into this as it achieves only a similar result as what can be done already, so why build a better mousetrap. Now if it could be incorporated into the bridge some how...hmmm...perhaps not!!! At some point, I may turn my attentions to pickup designs. A lot of the difficulty here is a way of constructing bobbins and obtaining materials...as well as making something that is not only possible, but worthwhile. What is it that I could offer that would be different and desirable enough to make such a venture worthwhile? Well, one thing would be the driver/pickup. Another would be an alternative low impedance active pickup to EMG's perhaps. It could be that a sustainer/pickup system is the go for someone like me, if I were to do something of a commercial nature, or develop something for someone else But for now, it is sustainers all the way! 10 pages...whew...well, a lot of interesting ideas have come up and it has certainly enthused me. I can't wait to try out some of these thoughts, or to hear reports of your findings. I will be putting forward more ideas, do a little FEMM stuff perhaps (or though this can be misleading) and look forward to seeing what you think... mmm...lights.... Yes Tim, I couldn't resist...I really did think of the split system as a driver design first, then I thought plastic would be best for the non magnetised half of the blade, then I thought...3mm perspex would be esiest to obtain and I have used it before (or moulded resin maybe)...and then...well it's clear...so it could be...yes...let there be light. If ever I do make an active pickup...you can be sure that something like this split blade light idea would be a part of it!!! pete Link to comment Share on other sites More sharing options...
ebenezer shred Posted October 1, 2006 Report Share Posted October 1, 2006 You will NOT be able to build one of these, as it is MUCH more complicated than this sustainer project, for many reasons, one of which is EMI issues (which is solved in the Ebow by secret, patented means). Not so...on this very thread Ebows have been discussed. They apparently use a LM386 without preamp (couldn't be easier) but the real problem is making both the pickup and driver, and then getting it into a usable format. It has been done, but it is not easier. Part of the ebow secret is the enclosure that slides along the strings...tricky to make. Search here for ebows or look through this thread. There was a dutch(?) site that Tim/onelastgoodbye translated and I know of one with pictures built over at the stompbox forum. Anyway...I like the ebow principle, but the sustainer wins out for me (as a playing instrument) and is probably easier to make (thanks to this thread...try to find anything else of use on DIY sustainers ) Anyway, hope that helps... pete Thanks spazzy...as long as you have a means to power it, that circuit is probably a better bet than the PA you have been using to power the thing. Having never gotten a conventional pickup to work as you have done...I don't know how it would perform. At least it is a little more disposable and portable than your PA rig I could've sworn earlier someone just took a computer speaker and ran it to a screw wound about 20 times with thick guage wire, and that managed to sustain one string. My idea is to put something like that in my guitar, with a retractable wire that ran out of the guitar and do e-bow type stuff, then retract it back into the guitar to the point where it just look like a screw sitting there. (there would also need to be an on/off switch of course). Then I could do e-bow type stuff without having to pick it up and put it down during live stuff. (plus I think it would look really cool). I also like the e-bow idea because you don't have to adjust it like some of the sustainers created by people on this thread. Link to comment Share on other sites More sharing options...
col Posted October 1, 2006 Report Share Posted October 1, 2006 I believe a thin core is of benefit...however a core of 1mm for instance would lack the mass to generate and hold a significant magnetic field for this application. A core 17mm wide works well. You can detect a roll-off of response compared to a 2 mm core e.g. my 2mm cored single coil driver could sustain 5th fret harmonics well, whereas the 17mm dual core turns them into fundamental (it can do 12th fret harmonics fine and some 7th fret ones). This effect is also related to the circuit response which I have changed for better fundamental response. The overall impact of this response roll-off is minimal and anyway, 17mm is much wider than necessary, it would be simple enough with the right magnets to produce a dual core of 10mm - this would have a response that in practice wouldn't have any disadvantage over a 2mm core. The thin coil idea is to limit EMI by compacting the electromagnetic fluctuations into a small space directly under the string, and, to increase speed so as to avoid excessive lag that is accentuated as the frequencies get higher. The reason for this "lag" is that the coil has to have some time to change magnetic states and the faster it is asked to do that (high notes) the more lag there will be. Rather than try and address that by creating a complicated circuit to compensate (as the commercial units have done), I have tried to address it by driver design. The thinner wire (0.2mm) is also helpful here and seems to be important. There are also some unknowns regarding the resonant frequency of my 8 ohm thin coil. [Devils advocate mode] I thought that the speed that the magnet can change polarity had more to do with the core material rather than the winding arrangement. Is it not possible that the issues that occur with deeper coils with more turns are related to a much higher inductive reactance and therfor a greater roll-off of high frequencies - all that zobel network malarky... The 'thin' driver will still have a phase response that varies with frequency, but maybe it isn't as dramatic or doesn't have as big an impact because of the lower reactance of the coil... Now...the rail driver changes that formula quite a bit. Do the same principles apply? You have less windings around blades of less mass. You have a magnetic field in which a substantial amount of the magnetic energy is being transferred 90 degrees between the blades and not working directly upon the string. The split blade design tries to address that a little by having blades of similar mass to my single coils, but for only half the string. I do have concerns that these factors may effect efficiency. A Humbucking pickup has more windings than a single coil...but then maybe it has too, the magnetic pull is much less due to the opposing fields. In the two coil 4 ohm drivers though, you have not increased the nuber of windings and they have half the overlaping windings of the single coil design...this does concern me a little. When i put my magnet on its side and put a 2mm thick drive core on each side, the magnetic attraction along the top of the cores was considerably greater than in single core configuration. Just like a horse-shoe magnet, there is less air between the N and S, so the magnetic circuit flows better... when the strings are close to the driver as they need to be anyway, it seems to be a much more efficient configuration. My battery consumption is quite acceptable as it is BTW. Would you be able to measure the milliAmps that your circuit is drawing while sustaining (and while on but with the strings damped) ? It would be very useful for comparison. There's not much point in basing a discussion on subjective analysis . If you are running with no AGC and only using 20 - 40 mA, then I need to re-think my driver and/or circuit. On the other hand, if your setup is drawing 90 - 130 mA, then it will eat through batteries quickly no matter what your perception... For it to work effectively, I imagine you would need separate drivers for each set of strings (or as in the hex designs, each string) and so something like a bi-lateral or my split blade idea (or something else) would most likey be the ticket for this kind of thing. It sounds like a different take on the 'woofer/tweeter' idea that I posted a few pages back. I'll try to explain that idea better in case it sparks some ideas for anyone else. What I was thinking is that the signal the guitar produces ranges roughly between 80 and 10000 hz. Thats a broad band of frequencies to efficiently process with a single magnetic driver.... So the idea was that IF drivers could be made more efficient by targeting a smaller band, we could have two drivers say one for 80Hz to 1k and the other for 1k to 10k. These would both have to target all six strings ( there is not such a significant difference between the frequency bands of the top three strings and the bottom three strings - they have more overlap than seperation). For this idea to work, the two coils would probably be quite different - different wire guages, different number of turns, different core dimensions etc. There also would not be so much of a 'humbucking' effect - although I can't see the need for that anyway (its a driver not a pickup) - but there may still be some potential for emi reduction due to the magnetic circuit being tighter... This approach would also help to sidestep the small ammount of high frequency damping caused by a 'wide' dual core. It would however be a lot of work - building and testing different coil/core configurations for frequency response, efficiency etc... designing a 'crossover' circuit... not to mention the cost of stocking up on all the wire guages etc. The EMI issue can be resolved enough to do this...my hex designs operated within 2cm of the bridge pickup, for instance...and I don't think it needs to be so radical as a "wave driver". Dizzy did it with a bi-lateral driver very effectively (though it lacked the harmonic function). Such things would perhaps be appropriate for a very thin mid driver between two humbuckers perhaps where there is no cavity...but I am not putting too much thought into this as it achieves only a similar result as what can be done already, so why build a better mousetrap. Now if it could be incorporated into the bridge some how...hmmm...perhaps not!!! EMI in terms of squeeling feedback only starts to happen on my setup when you get past about half way between the neck and bridge. The real problem is the 'crosstalk grunge' as described on the sustainiac website. I think its also worth noting that I can drape the long driver lead pretty much anywhere - over the circuit, accross the pickup etc without it having either a positive or negative impact on crosstalk noise or EMI feedback. btw, I'm not just sitting here be negative I'm trying to come up with solutions as well cheers, and keep on sustaining (as much as I detest them, we really need a recursive acronym for this project - it would be so apt) Col Link to comment Share on other sites More sharing options...
ebenezer shred Posted October 1, 2006 Report Share Posted October 1, 2006 could someone please explain to me if the e-bow type idea i stated in my last post is possible? And how i coudl do it? Link to comment Share on other sites More sharing options...
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