psw Posted October 7, 2006 Author Report Share Posted October 7, 2006 ok...kids have gone for a while again... still... the EMI seems to me to becoming from the coils not the magnets i tried my thin driver coil with no magnet and still got EMI oh the magnets don't create any problem...it is all in the coils actions within the magnetic field...it's what they do to it. Not having a magnet will make things worse...the magnetic field establishes what the driver is working with and contains it. In this regard, the leads going to the driver from the lm386 should all be regarded as an extention of the coil itself. Hence my desire to islolate this part of the circuit and shorten it with a modular system. Anything before it should be safe! As a side note...I experimented with Neodyminium magnets with a lot of power (but not pointed at the strings) and were used extensively in all the hex designs. These create a very strong yet compact field that can have positive effects by creating a preferential attractive force to stray magnetism...over that of the pickup. You don't want them close to the strings...but perhaps placing them under, but not connected to the driver (in the cavity) could provide a very attractive method of shielding or manipulating the shape of the magnetic field and EMI effects...it's a thought...hmmmm My circuit is mounted back behind the controls, but pretty much over the output jack. The passive signal has to connect to the circuit so is close to the driving end of the chain too. The harmonic switch is also connected to the driver wires (I'd like this to be redone some how so it is the signal that is switched). All other wires in my guitar are sheilded cable (as the guitar itself isn't sheilded). The driver wires are plain stranded and thin...but well twisted together to help with EMI. They do drape over the trem block and springs at the back of the guitar. There is plenty of other earthed metal parts around and about. The circuit is however very far from the actual driver...hmmm I think the main concern is that all driver leads and the driver itself not run near (and especially near) any (particularly passive) signal leads (although it is somewhat unavoidable as per my set up).... anyone know how much 'mumetal' costs and where to get it ? I thought we were sticking to DIY....hehehe...mumetal.com supply the miliatary...you and I can not affford it, so they aren't telling how much!!! You could try and locate unmagnetised neodyminium...but again could be hard, and may become magnetised... Maybe I'm sheilding the wrong thing - worrying about the driver and pickup, maybe the circuit need protection - a possible downside of the extra circuitry in my setup... Quite possibly...that fizz is not the typical crosstalk and is typical of EMI off the wiring itself as far as I can tell. That is why I needed elaborate bypassing and such...it wasn't because of squeeling or anything like that. It is a shame if it got worse cause it does look neat... The driver looks good, and I am sure the magnet has detirmined the size somewhat...but I'd be getting those blades as close together as possible. I wonder what would happen if they were angle towards eachother with the strings at a kind of apex of a triangle above...if you follow. I am a little concerned with another source of vibration within the driver design...the blades are attracted to eachother (as was seen in the FEMM) and this will be fluctuated by the coils action...there is no chance of the blades vibrating, is there? Do you feel anything if you place a finger on it when it is in operation? One of the things I found interesting in the HB/rail design...or is it now a "bi-longitudinal driver"...is the amount and strength of the attraction of the magnetic field between the blades. The energy of importance is that running through the core. Although the blades will have a high attraction on contact, how much of it is eminating and in a direction of use to the coils actions? Certainly it is running through the core and some of it is jumping the gap...but not as much as is running horizontally between the blades. This raises the question for me if it is possible that this design could not in fact take much higher magnet strengths without undue pull on the strings themselves. If this is the case then more powerfull and much more compact Neodyminium (cheap and getting more easily available) could be the go for the magnets between the two blades. Such a powerfull force may help the EMI as it would be more attractive to stray EMI than a pickup further away...as a theory. I like that switch pot. I found a source of push button latching 4PDT pushbutton switches with illuminated buttons...very small and cheaper than toggles. I believe they may be related to computer on switches and the like but the button itself is only about 1/4" round clear when off and switch easily... Another thing that occurs to me is that in you schematic pins one and 8 of the LM386 are left open. You could try a 100k resistor and cap (say 10uF) to help with internal oscillation (would still provide minimum gain of 20x) I read somewhere that this can help and the cap is in my circuit...just a thought. Also...My preamp has filtering of frequencies above the audio range...perhaps you need some high end filtering to get rid of the fizz type effects. The fizz really is a feature of the harmonic mode in clean settings on my guitar...I believe it is to do with amplifying and driving at very high frequencies. Once the string starts driving at a harmonic, it is now amplifying signlas well above that normally produced by the guitar. I've raked up some info on the Sustaniac 'magnetic balance plate' It seems that this is some sort of flux conduit - like a partial 'cage' designed to control the flux at the area between the two halves of the sustainiac As I recall...such things were referred to as "shunts" in the patents and were designed for high string response. I have never seen them in use in the actual device...nothing of them in the one that was taken apart for instance. I have been told that there is some dead spot between the two coils (bending the g string for instance) and maybe it is to help bridge this gap...a little mysterious.... I am not at all sure about the cage ideas. Really I feel we should be able to produce something of merit with commonly available materials and approachable techniques...much as I like exploring the posibilities. I have a variation on the split blade for you all to consider...multi splits... Here is the concept... In this version there are blade-poles under each string that alternate and are of different polarity. I'd envision some kind of overlap of the magnetic blades to avoid dead spots. Each pole could be individually magnetised or be magnetised by a conventional magnet below. Now...I don't know if there is any advantage whatsoever of the split blade concept. In this version you also loose the ability of one coil to handle the high and the other the low strings...hmmm. At first it may seem that the split blade has a lot of wasted space in the core...but considering the average pickup has even more space of air dedicated to it...it still has some potential perhaps. I am only presenting it as a "concept" not even a suggestion...if anything perhaps I am swinging a little more towards the conventional rail idea, perhaps with more powerfull and compact magnets between full blades. I really don't think it would be too hard to make such split blades...unless you want to go the full lighted perspex extravaganza...especially if using the coreless coil idea I presented earlier. Simply insert 10mm pole-blades and fill the rest with putty...it would be the same effect. Internal magnets are a possibility. For a thin coil neodyminium / rare earth magnets are probably the go. You'd want a few very tiny perhaps 1mm thick and it would probably be easier to stick them below a blade anyway. If not, a simple mold with an array of tiny magnets filled with metalic putty could make an effective magnetised core. They would have to be very, very small and probably about 12 per blade perhaps. The ones I used a bit were 3x2mm and these would be too powerfull. Such magnets are made in high quantity for the mobile phone industry I believe so the cost is way down...but not easy to source I'd guess. Another idea that has not been mention....is a stacked coil driver... works for pickups...given we are working with dual 4 ohm coils, we should be able to get them pretty thin (say 1.5-2mm each)...if using the bobbinless approach there should be little wasted space too... Any thoughts or comments on this scheme would also be appreciated...looks like an even easier approach than the rail driver and retains all the thin core sensibilities. The internal core could still be 3-5mm thick I guess so a row of small disc fridge magnets (check your craft shop!) could do the trick for an internal magnet core!!! This type of approach could work well on top of a conventional single coil pickup/driver like mine too...so people would not have to invest in rails to dabble in the EMIbucker concept... I still like the pickup/driver idea a lot. One exception would be a pickup sized driver with internal poweramp, but perhaps it is inviting some trouble from driver/circuit proximity...not sure. I believe there would be a way of reversing the signal without too much trouble. I know that it works because originally this guitar had three conventional single coils and three phase switches (that's what those 3 toggles are) but two provided the same number of sounds so one is now a series parrallel switch for the stacked bridge HB (pretty useless BTW). flicking the phase switch changed it to harmonic mode! One approach may be for dual pre-amps, switching to an inverted input for the harmonic mode, perhaps a little more gain or other conditioning... Mainly I like the pickup/driver idea because it is a low mod, easy and neat (and frankly ideal) way of mounting the device. One of the neat things about these driver ideas is that we are approaching pickup design effectively...from a reverse standpoint. It is interesting to contemplate what we are learning if it were applied to pickup technology. For instance...if we were to accept low impedance active pickups (as many EMG users do) then ideas like thin or compact coils are possible there too. Easier to obtain and deal with thicker wire could be used than is conventional. Low winding counts could allow for hand winding and some of opur bobbinless ideas directly applicable. Even some of the circuitry! Many may gasp at the concept of such devices...guitarists are traditionalists and love the "character" of vintage pickup designs. But, no one can deny the prevelance of digital recording. My soundclips were recorded directly into my computer (through a cheap effects box (korg AX1G)into the mic input with Audacity) while I sat less than two feet from a 21" monitor to play (on a jap strat!). Noiseless, full range signals are ideal for such applications. Software can do amazing things with such a signal modeling both amps and pickups (just look at line 6)...perhaps we will soon see USB outs on instruments (it is already starting to happen, certainly on effect boxes). The upshot is that the concepts we are considering for driver designs and the things we consider and discover may well have wider implications. Compact driver coils and pickup coil designs could also be combined into interesting packages, especially in guitars with big HB sized units. Although we may not be able to effectively miniturize things with SMD devices and such, rest assured such circuitry that is required could easily fit within something as big as a pickup (EMG are doing it now and they have fairly conventional sized pickup coils apparently under all that epoxy)... So...it is no wonder this thread is so long when I post things as long as this...I hope this one is a little less rambling...there is a bit more presented here to think about than some and consider for a while to come... pete Link to comment Share on other sites More sharing options...
onelastgoodbye Posted October 7, 2006 Report Share Posted October 7, 2006 for reference, here's a pick from the cage in an emg: Link to comment Share on other sites More sharing options...
psw Posted October 7, 2006 Author Report Share Posted October 7, 2006 (edited) Is that a "cage" or the circuit...those squares look suspiciously like SMD devices... I haven't seen any real detail about what is inside an EMG...I suspected they could be conventional pickups with lower mags and good preamps...never really found much on them, certainly no mention of a "cage"... For more on these types of devices...all the lace patents are an amazing source. The lace sensors in particular exploited such devices... Kinnman's too have an interesting steel shield over one of the stacked coils! Oh, and btw...I quoted my own post from here to the sustainer sounds thread...partly for completion and so they can be accessed easily without going through all this to find them...but I did add some annotations as to when the sensitivity control was turned from 7 to 10 for the fizz effect in the first clip. On the second clip...at 0:45-0:56 there is a long note where I manipulate the harmonic switch during the sustain. This was interesting because shortly after I recorded them col posted his idea for his switch pot. We have previously mentioned a desire for momentary control of this device and this is an example of how it could be used to bring out a harmonic at will and on the fly... Now...if only I practiced guitar I'd make a better ambassador for this device. Some may be able to detect how the playing of this guitar is effecting my approach. Infinite sustain is all very well but can become a bit boring...the novelty soon wears off. What I am reaching for are some of the nuances that this thing promises and unique sounds. Some of it is a little subtle...a humming sustain under picked chords, notes that decay into harmonics, notes that swell in volume, use of the tremolo to manipulate the pitch of long sustains, even the chaotic crashing of the strings into the frets has some strange appeal to me... I do believe that there is a wealth of new sounds and techniques possible with this device just waiting for someone of talent to exploit them. Hopefully this project will facilitate it getting into the right hands. In the mean time, I'll just enjoy what it is offering me... pete ps...don't miss my previous long post...there are some interesting ideas up there... oh...and here's a quote I found from Allan Holdsworth... It's been one of the problems I have all of the time with the guitar—I want to make it sound more like a horn. But at the same time, the fact that you have to use any sort of distortion to get sustain is a kind of a catch-22. You have to use something you don't want to use to get something that you want to use. I didn't have any of those problems with the Synthaxe. It was really clear and really easy. perhaps one day someone like this will pick up the sustainer guitar as a source of "clean" sustain... Edited October 7, 2006 by psw Link to comment Share on other sites More sharing options...
col Posted October 7, 2006 Report Share Posted October 7, 2006 Don't have much time, so I won't get into replies righ now. Heres a pic of my driver installed with cage. The cage was made with the sheet metal from a PC power supply casing. I just used tin snips, and a file to soften the edges. Nothing high tech, not even a saw I need to take some material off the fins as they are too close to the blade cores. Also need to cut/drill some gaps particularly along the center of the base. looks cool even if it doesn't do much Col Link to comment Share on other sites More sharing options...
onelastgoodbye Posted October 7, 2006 Report Share Posted October 7, 2006 (edited) Another idea, based on the tri-blade concept as to concentrate the field upward, this time using internal neodymium mags as proposed by psw two posts up. I'm kinda curious how the field would look, so if anybody wants to have a go in FEMM.. Is that a "cage" or the circuit...those squares look suspiciously like SMD devices... from the emg catalog: "Coils are sometimes places side by side, or stacked, but in both cases each coil is treated independently by the preamp. Instead of having the coils in series or parallel with a single output, they are electronically summed so their attributes can be controlled individually. " ... Another benefit of the internal preamp is noise reduction. By integrating the preamp into the housing, all the elements of the pickup can be shielded. By matching the coils to a high degree the low frequency hum and buzz are virtually eliminated. In addition, each EMG is housed in a composite cover cap that eliminates all other forms of interference. Mmmm..It does look more like an smd preamp. I could have sworn I read something somewhere on a cage, but as there is indeed "reasonable doubt", I'll withdraw my testimony Also found this: from the sustainiac site, on the ga-2, which is their early model also used by fernandes,... www.sustainiac.com/ga-2%20troubleshoot.pdf Battery life depends on how often the unit is turned on, and also upon the setting of the STRING VIBRATION control. Typical battery consumption is 10ma in STANDBY, and 80 ma during a low note in FUNDAMENTAL mode, which is a maximum condition. 9v alkaline batteries are typically rated at 500 ma hours. Actual battery life is usually around 15-20 hours. Don’t use regular “dry cell” batteries. Use only alkaline. Also, Nicads have short life, and only produce about 7.5 volts each. If you want to use a “wall wart” supply, you must get a REGULATED SUPPLY of 15-20 volts. Voltage must be within these limits at all times. Edited October 7, 2006 by onelastgoodbye Link to comment Share on other sites More sharing options...
col Posted October 7, 2006 Report Share Posted October 7, 2006 (edited) Also found this: from the sustainiac site, on the ga-2, which is their early model also used by fernandes,... www.sustainiac.com/ga-2%20troubleshoot.pdf Hmm something on this page sounds like it may be related to thoughts I've been having related to signal polarity and grounding... We know that for best berformance with a humbucking pickup and bi-longitudinal driver, the inside poles need to be the same magnetic polarity so they repel. We also know that for non-harmonic mode, the signal to the driver must be in phase with the signal from the pickup. One potential concern that I had not considered up until recently is: Both the pickup and driver have one side attached to ground and therefor (assuming no fancy isolation techniques) each other. The circuit (sum of all active components) will be either inverting or non-inverting. If the circuit is inverting, to keep it in phase, the positive rail of the driver signal will be attached via ground to the negative rail of the signal from the pickup. If the circuit is non-inverting, the opposite will be the case, negative rails connected to each other... Edit: More thoughts - the driver coil not only acts as a driver, but as a pickup - the string moving in its field will generate a current. With the earth connections required for an inverting circuit, the 'pickup' signal of the driver will be oposite in polarity from the bridge pickups signal... I wonder if this can have an impact ? Also noting that Pete only gets the fizz/crosstalk problem when he uses harmonic mode - and he gets harmonic mode by switching the driver leads... attaching the pickup and driver in an opposing manner via ground.... hmmm... will have to get my soldering iron out again later this evening. This seems to be related to what sustainiac call 'postitve on pullaway' (they mention that this is not important with the stealth and stealth plus, just their older systems - Maybe a spin-off from their class D amp tech). Edit: actually, I think this may just be their fancy way of explaining that the inside coils have to have the same magnetic polarity.... except with a bilateral driver in which it doesn't matter either way (checking my circuit, it is inverting.) If this does have an effect, it would add more credence to Curtis' idea for a center tapped earth with the signal swinging +ve and -ve. A good setup in that config might be to have two batteries on for +ve and one for -ve, and take three wires from the humbucking pickup and to the dual core driver... Its possible to use some additinoal circuitry to get +9v and -9v from one battery, but it does add complexity, and has the potential for adding even more noise (although not so much extra Magnetic radiation) Does anyone have any thoughts on this? Col Edited October 7, 2006 by col Link to comment Share on other sites More sharing options...
www.5zhi.com Posted October 7, 2006 Report Share Posted October 7, 2006 (edited) short circuit? ARC Edited October 7, 2006 by www.5zhi.com Link to comment Share on other sites More sharing options...
col Posted October 7, 2006 Report Share Posted October 7, 2006 short circuit? yes - who designed this PCB layout ? (just shows you, shouldn't trust anything you find on the web ) Col Link to comment Share on other sites More sharing options...
www.5zhi.com Posted October 7, 2006 Report Share Posted October 7, 2006 short circuit? yes - who designed this PCB layout ? (just shows you, shouldn't trust anything you find on the web ) Col BUT I ambiguity 9V battery build in what about? excuse me! My english isn't good enough Link to comment Share on other sites More sharing options...
col Posted October 7, 2006 Report Share Posted October 7, 2006 short circuit? yes - who designed this PCB layout ? (just shows you, shouldn't trust anything you find on the web ) Col BUT I ambiguity 9V battery build in what about? excuse me! My english isn't good enough Pin 6 on the LM386 should go to +9v (battery +) pins 3 and 4 should go to earth/0v (battery -) so there would be a short in that pcb (with the switch on). Col Link to comment Share on other sites More sharing options...
www.5zhi.com Posted October 7, 2006 Report Share Posted October 7, 2006 short circuit? yes - who designed this PCB layout ? (just shows you, shouldn't trust anything you find on the web ) Col BUT I ambiguity 9V battery build in what about? excuse me! My english isn't good enough Pin 6 on the LM386 should go to +9v (battery +) pins 3 and 4 should go to earth/0v (battery -) so there would be a short in that pcb (with the switch on). Col thank you,I goto chance.hope IT OK. Link to comment Share on other sites More sharing options...
www.5zhi.com Posted October 7, 2006 Report Share Posted October 7, 2006 short circuit? yes - who designed this PCB layout ? (just shows you, shouldn't trust anything you find on the web ) Col BUT I ambiguity 9V battery build in what about? excuse me! My english isn't good enough Pin 6 on the LM386 should go to +9v (battery +) pins 3 and 4 should go to earth/0v (battery -) so there would be a short in that pcb (with the switch on). Col thank you,I goto chance.hope IT OK. S2 closed circuit,equality 9V + - connexity(short circuit)? Link to comment Share on other sites More sharing options...
col Posted October 7, 2006 Report Share Posted October 7, 2006 S2 closed circuit,equality 9V + - connexity(short circuit)? Yes Link to comment Share on other sites More sharing options...
axe_2_grind Posted October 7, 2006 Report Share Posted October 7, 2006 OK. So I've been messing around with my original Fetzer-ruby build, and found that if I just omit the 68K resistor on the input, I get a loud clear signal, and (as an amp) it seems to work really well. Next I'll take it back to the studio & try it out on my 4X12. Also i think I'll mount this thing in a pickup box (I have a few seymour/duncan plastic boxes sitting around) with some jacks and use it for testing on future driver builds. Next I'll have to build a new driver. ( kinda got frustrated with my old one and tore it apart. I still have the coil though! Looks nice & tight!) Hopefully it should work this time (fingers crossed) Link to comment Share on other sites More sharing options...
psw Posted October 7, 2006 Author Report Share Posted October 7, 2006 Anyone any thoughts on the stacked driver ideas? Not sure if I had completely thought that one through! hello www.5zhi.com, sorry we only have english! I would be trying this on perf board or vero board, not a PCB. It is expensive ($$$) and difficult to change things. It is very easy to make a mistake. The on switch is only good for single pickup guitars. Your switches are fixed in one place so that the circuit and the switches must be mounted in one place which might be a problem if you don't have room in the guitar. Hope that makes sense. Thanks col for trying to work that circuit out. Perhaps someone should contact ROG about their circuit and see if they could make up or suggest something...it is their circuit ideas afterall. Another option, which I prefer is that between us we create some modules! For this I'd be suggesting a basic LM386 stage and a preamp stage of some type with variable gain. Unfortunately...I can't test that for some time...need a house and such...even though my guitar would be the obvious test bed as we know it works in it's own way. I'd like to see primal's guitar back up and running...he appeared to have a similar result to my guitar's performance with his Les Paul...he also needs some kind of circuitry in there. I have also seen some candidates for off the shelf PCB kits which could work with a few mods. This is how my circuits were made. There are plenty of LM386 based amps around for instance, very cheap. This and a fetzer and you would be right to go! I have also found some that have a simple "mic" preamp in them whic could work ok with a little adjustment (most important is that circuits designed for or with condenser mics have the input power to run them left off). I wouldn't want to suggest any without testing them, but it is an option that people really should explore... have a good time experimenting... the sun is about to come up here sunday morning and it's time for me to hit the road and earn a living again... see ya... pete Link to comment Share on other sites More sharing options...
col Posted October 7, 2006 Report Share Posted October 7, 2006 Anyone any thoughts on the stacked driver ideas? Not sure if I had completely thought that one through! More questions really. I've often wondered, and never found the answer - Do 'stacked' humbuckers have one magnet per coil stacked in a NSSN (or SNNS) config ? I don't really see how else they could work... It would be interesting to see if it would be possible to have the lower coil custom designed to control the field - maybe some very low impedence coil using thicker wire that has little effect on the driving efficiency. Similarly to how the lower coil in a Kinman pickup is designed to kill noise, and not intended to produce tone. As far as trying it out, it seems like a reasonable idea, but I guess as usual it's about where to get suitable magnets from. I have some magnets from old pickups, but no stacked humbuckers... I think if I get around to making another driver, it will be a bi-lateral one - to see if there really is some magic in that patent. ie. is it the bi-lateral tech, or something else that makes their system production quality. ...I wouldn't want to suggest any without testing them, but it is an option that people really should explore... Yes, at this stage we don't know enough about what makes thingswork and not work. Ok, I'm of to modify my circuit to be non-inverting... (/me crosses fingers) cheers, Col Link to comment Share on other sites More sharing options...
spazzyone Posted October 8, 2006 Report Share Posted October 8, 2006 (edited) to Quote Col "More questions really. I've often wondered, and never found the answer - Do 'stacked' humbuckers have one magnet per coil stacked in a NSSN (or SNNS) config ? I don't really see how else they could work... It would be interesting to see if it would be possible to have the lower coil custom designed to control the field - maybe some very low impedence coil using thicker wire that has little effect on the driving efficiency. Similarly to how the lower coil in a Kinman pickup is designed to kill noise, and not intended to produce tone." Ive had both a Duncan and a Dimarzio and they only had the one magnet. though the Dimarzio had 6 slugs i think just cant remember (many years ago) and i need to learn how tro use this damm quote system and i realy recomend spending the $14 bucks on the rail i have as the complaints everyone seem have are null and void with it i know its a 14k ohm pickup but it runs good at 4/8 or 16 ohm and Pete i just need an adress and ill send you one free of charge as promised Edited October 8, 2006 by spazzyone Link to comment Share on other sites More sharing options...
lovekraft Posted October 8, 2006 Report Share Posted October 8, 2006 This thread needs a full-time historian/anthologizer! Seriously, I've been "away" for a while, and just recently got my computer back up to full working status, so I've missed and/or skimmed through a lot of the recent developments. Anybody up for a semi-current "State of the Project" report, so we can avoid tripping down the same blind alleys we were exploring back in 2004? Apparently most of the recent work has been in driver design - can somebody do a basic comparison of the current ideas, contrasting the pros and cons of each design? I'd be ever so grateful!! If we can catalog what has ( and more importantly, what hasn't) worked in the past, we might narrow things down a bit, and not waste time pursuing approaches that have been proven repeatedly unsuccessful. Just my two cents - now I've got some in-depth reading to do. Link to comment Share on other sites More sharing options...
custom22 Posted October 8, 2006 Report Share Posted October 8, 2006 To those who use the Fetzer-Ruby, what do you turn the trin pot to? I believe it has something to do with biasing, but what is the general consensus with this? Link to comment Share on other sites More sharing options...
lovekraft Posted October 8, 2006 Report Share Posted October 8, 2006 Adjust the trimpot until you measure 4.5 - 5.0 volts from the drain of the FET to ground - this is to compensate for the huge variations in devices, an unfortunate by-product of the manufacturing process. The Fetzer Valve page has an in-depth explanation of this. Link to comment Share on other sites More sharing options...
onelastgoodbye Posted October 8, 2006 Report Share Posted October 8, 2006 This thread needs a full-time historian/anthologizer! Apparently most of the recent work has been in driver design - can somebody do a basic comparison of the current ideas, contrasting the pros and cons of each design? I'd be ever so grateful!! Well, lets see... - spazzyone took a generic dual rail pickup and put a 15 w p.a amp through it, which worked great as a driver with no EMI (even works in the mid position); So me and Col got inspired to build a humbucking driver. Same principles as the thin driver, this time using two 4 ohm coils in a classic humbucking config instead of 1 8 ohm coil. It has good efficiency and really good emi rejection. A lot of variants (sp?) have been proposed, but those have yet to be built. - psw and me developed some jigs for building bobbinless coils. The latest incarnation (psw's idea) is really simple, really cheap, and can produce bobbinless, coreless coils, so experiments with different core materials can be made. -and here comes the big one...col designed a great acg circuit which basically reduces power consumption and increases efficiency. It uses a "dynamic range inverter" that increases gain when input volume is low, and decreases gain when input volume is high. psw is working on modular circuits. -there's also lots of research and reverse engineering going on; the fernandes patents, the sustainiac application notes; some great pics of sustainiac internals which googlymoogly linked to; shielding cages; FEMM diagrams; etc.. One main problem remains (as far as circuit/driver design) to be solved: there is still crostalk between driver and pickup. A slight background distortion or fizz that is leaking into the pickup signal. The source of it is still unclear. Could be the driver + pickup acting as a transformer, could be bad shielding of driver and/ or circuit, could be common grounds, could be phase-related. Link to comment Share on other sites More sharing options...
psw Posted October 8, 2006 Author Report Share Posted October 8, 2006 Welcome Back Lovekraft...you have been missed... I've often wondered, and never found the answer - Do 'stacked' humbuckers have one magnet per coil stacked in a NSSN (or SNNS) config ? I don't really see how else they could work... no...it is simple... the bottom coil is reverse wound as in a humbucker but is reverse polarity due to being on the opposite end of the magnet. How or if this will work as a driver, I am not sure... So...LK...since you've been gone... Primal made a successful version on a Les Paul converting one coil of the neck HB to a "thin driver"... Spazzy has taken a PA (!) to drive a conventional rail pickup to sustain without excessive EMI...and has a vid to prove it (see the Sustainer Sounds thread...) Tim/onelastgoodbye has been busy with his amazing original carbonfibre topped and fretboarded guitar in Merbu with an amazing graphic on the back that extends all the way up the neck...check it out here!!! Tim you will recall did those fantastic realizations of guitars and the "sustain box" ideas we were working on in the mid-30's (pages that is!!) and has recently gotten a job...good stuff col has come in with some fantastic ideas for improved circuitry which we'd all like some comment on... it has a buffer preamp stage...an interesting AGC circuit and the old LM386 poweramp stage... He is getting much better power consumption and a more refined amplification than mine... both Tim and Col, representing the europeans, are working on various rail driver ideas, using my thin core, thin driver ideas and taking them to the next step in an effort to reduce EMI... As for me...I am still going through some bad personal problems (as you will recall) and am frustrated that I can't contribute more in a practical way and be involved with this a bit more... My sustainer guitar is still running well but still seems to be a bit of an enigma...nothing like the EMI problems some are getting despite having three cheap pickups and the scratchplate not even screwed down anymore! I recently posted a few clips to show the "fizz" distortion that I do get on ultra-clean settings in harmonic mode. The pop on turn off is still there but otherwise working pretty well... Back on the otherside of the world...A german site has taken our ideas and run with it....in german. It was brought to our attention because someone posted extensive picktures of the sustainiac stealth driver...in various stages of dismatling, including measuring the coils and such...nice find... I have to confess that I have particularly been breaking the picture rules and have put in some long posts of the ilk not seen since the heyday of this thread...and I think we clocked up 1,000 visits last week and 20 pages in the last few...lots of stuff, generally... (LK is a moderator so we had better limit that...oh this post has two pics...hmmm) All in all this thread has been jumping...and it hasn't been all talk, a lot of practical experimentation and some success has been had... Our latest addition has been www.5zhi.com, (from china judging from the web site name) who is presently trying to get the fetzer ruby onto a PCB...not sure this is the best approach, but hey!!! Good to see you back online and in amoungst it...the sustainer thread is as lively as it has ever been and I really can't explain it. We have a steady stream of really good ideas and help from various people and a constant stream of "guests" always viewing... My aims...when I get to do some practical work myself...and so am encouraging others to do the hard yards for me...is to make a driver/pickup with suffiecient EMI reduction to work in the mid position of a strat and retain the use of both the neck and bridge pickups (I'm thinking the rail driver should be able to do it if it's done right...so I'm letting others make the mistakes before I make my own...mistakes that is ). I also want to do something with the circuitry. I'm thinking modular with the LM386 part close to the driver, a preamp stage (and possibly a buffer for the guitar signal as col has done) and I think col's ideas have a lot of merit for control and power consumption and just general responsiveness of the instrument. For the modular thing to work, we really need to reverse the signal for the harmonic effect, rather than the driver wire phase thing. It would be good if we could isolate the earth too... So many things. Perhaps there is another approach to the AGC thing too....I think last you popped up is with the "aussie compressor"...col's is a bit more specific to this application though and I know he is keen to get some comments, etc (couldn't get much on a thread over at Aron's) For those not familiar yet with LK and his association with this thread... LK has been a good contibutor, mentor and friend to me and supporter in many ways to this thread. To this whole site in general I must say! Particularly in the early days we exchanged views, he lent his superior understanding of electronics and kept my flights of fancy in check. He has/had a fernandes sustainer guitar and is the only one besides me to see one of the early Hex design elements (now abandoned you will note) and can confirm they are not just a figment of my imagination. To me, the major contribution LK has made to me and to this thread, has been to encourage me to work on the driver technology and to see through the hype of the patents and such...to go my own way. The end result, after many dead ends has been such devices as the pickup/driver combo and the use of very basic amplification to drive simple, but effective driver designs. This has been the key element in the approachability of this thread and the reality of the DIY Sustainer... But LK is not adverse to contemplating the far out, so don't hold back with the magnetic sheilding, the lighted split blade ideas or anything else... Ok...now that is enough of a rap for Lovekraft...I hope you have been well and happy in the offline world and that you visit when you can...great to have you back... pete Link to comment Share on other sites More sharing options...
col Posted October 8, 2006 Report Share Posted October 8, 2006 (edited) I've been doing some googling on magnetic shielding, there are quite a few companies offering various different types of foil and plate for magnetic shielding, also found a very interesting type of magnetically shielded cable that could be extremely useful here are a few links some snazzy animations of how shielding works - one is for eddy current cancellation which sounds very interesting, although I couldn't find any freely available papers discussing the technicalities. Cool shielded cable. This has an external braid with magnatic shielding properties, and uses some sort of proprietary patented alternative to the usual 'twisted pair' configuration internally, there is a very nice little diagram of this further down the page which might be worth experimenting with more companies punting various foils and sheets here, here, and these guys again. Even the 'lab kit' samples cost too much and provide more material that we would need I think. (although the magnetic-shild companies kit comes with a rather nice probe that enables you to use a DMM to measure magnetic field intensity ) Does anyone know either of some cheaper source of similar products, or some sort of consumer product that uses either magnetically shielded cabe or sheeting - e.g. monitor shields... I've searched some of the online electronic suppliers for cable with braided shielding, but it is almost exclusively tinned copper shielding In other news: One thing I've noticed is that my bridge humbucker is not very securely mounted in that it has just one mounting screw and spring on each end. This means that the angle between the plane of the top of the pickup and that of the neck is somewhat variable. Just very small differences in this angle on my guitar can make a large difference in crosstalk and EMI feedback !. On my guitar, there is a tendency for the pickup to sit so that the inner coil 'slug' side is angled closer to the strings than the bridge coil. Making sure that the top of the pickup is completely level makes the noise significantly less severe, although still unacceptable. Maybe some very slight tweaks to the angle of the driver and pickup in this way could be useful to others. Cheers Col Edited October 8, 2006 by col Link to comment Share on other sites More sharing options...
psw Posted October 8, 2006 Author Report Share Posted October 8, 2006 errrrr...it's 4am monday...time for work again... anyway, was just thinking...that coreless jig of mine, I am not sure that it will be able to hold together under the internal pressure of the windings (lengthways) supported by paper when there is no core inside...hmmm using epoxy would probably fix it...as long as it sets having a stiff piece to stick too on the bottom may fix it too... some experimentation will be required...or a better plan along similar lines.... also...I am not sure if col's circuit schematic in the post above was the latest version...I know there were a few minor mods and is currently being modified a little bit further... goodmorning and, goodnight... pete Link to comment Share on other sites More sharing options...
psw Posted October 8, 2006 Author Report Share Posted October 8, 2006 In other news: One thing I've noticed is that my bridge humbucker is not very securely mounted in that it has just one mounting screw and spring on each end. This means that the angle between the plane of the top of the pickup and that of the neck is somewhat variable. Just very small differences in this angle on my guitar can make a large difference in crosstalk and EMI feedback !. On my guitar, there is a tendency for the pickup to sit so that the inner coil 'slug' side is angled closer to the strings than the bridge coil. Making sure that the top of the pickup is completely level makes the noise significantly less severe, although still unacceptable. Maybe some very slight tweaks to the angle of the driver and pickup in this way could be useful to others. Ahhh...yes... The pickups do need to be adjusted...not just the driver. The bridge pickup and the driver need to be as close as possible...my driver is set so that it is just shy of being hit by the vibrating strings when fretted on the top frets... The bridge pickup too needs to be adjusted so it is close. You also need to be sure that both the pickup and the driver are securely mounted. If the device can move the strings it will certainly be able to move a loosely mounted pickup...even if this movement is very small, it will be sensed by the pickup just as the strings above it moving are... Damping it by putting a finger on it should be enough to see if this has an effect. Such adjustments are specified as required with the sustainiac installation procedures as I understand it...see if that helps... pete Link to comment Share on other sites More sharing options...
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