Jump to content

Sustainer Ideas


psw

Recommended Posts

hmmm...well, at the risk of sounding like a smarta$$ :D , I don't think so...download the spec sheet on the LM386 from National (link previously provided of previous page of thread) or directly from this link

look on page three Gain Control...

with pins 1 and 8 open the (internal) 1.35k resistor sets the gain at 20 (26db). If a capacitor is placed between pins 1 and 8, bypassing the 1.35k resistor, the gain will go up to 200 (46db).
There is also an interesting bit about some external components and sample circuits later on. The cap from pin 7 to ground helps with stability and in my circuit is a 10uF (bigger than that specified in the ruby). I notice too that the zobel network mentioned in an earlier post is present in the original ruby circuit, but absent in the fetzer/ruby...hmmmm...this has been debated a little, but is supposed to add more stability to the circuit too.

It's interesting as my initial circuit for testing very simple coils on the first few pages of this thread, followed ansil's quick and dirty use of the LM386 which was basically a 100uF cap on the output...that's it! Unfortunately, this little chip and other's like it are not suitable for your typical high impedance pickups as found in most guitars, hence the little preamp is needed to prevent loading. It is a great little chip for experimenting with as it is very forgiving.

ekkk...while posting this, we have something from kowski, welcome mate...yes...like I was saying!! :D

I must look into the posibilities of supplying the kits that I used with the alterations...the exchange rate is favourable from here and post is cheapish...it is possibly the best solution....what do you guys think?

pete

Link to comment
Share on other sites

The other caps are just non-polarized caps. I believe the 22n will look like a green chiclet, and the 100n will look like a small disk with two wires sticking out of it.

Also note that the caps MIGHT also be marked .1uF and .022uF, respectively, rather than 100nF or 22nF. As I understand, thats a thing the really only do here in the US (don't blame us, we can't change what the manufacturers label them as!), so you might also find them in Canada.

Link to comment
Share on other sites

Thanks Primal,

I ordered all the parts from Small Bear Electronics. The fellow there was nice enough to send me a parts checklist for the fetzer-ruby so I know I got all the right parts. I can't wait to start burning my fingers with my iron! I'll let you all know how it goes.

Link to comment
Share on other sites

Thanks for the welcome, Pete!

I came across this thread a week or two ago and I'm going to start putting my own little driver and circuit together starting today or tomorrow. The only thing I need to get before I can start is a piece of steel for the blade. The guys and gals at the local hardware store couldn't seem to figure out where they keep their steel stock... :D

Link to comment
Share on other sites

Hmmm...funny that cause down here in Oz I don't seem to have that much trouble in finding parts and stuff but in the states it seems you have to go through all this mail order things and get stung in the delivery.

The steel core could be anything really. I am always looking for stuff like this and the one thing I found was lying in the gutter (yes, my life has made a turn for the worst). I wondered where the heck this stuff came from...a strip of steel 3mmx1mm so that three cut to length would make a 3mm laminated core with minimal cutting and grinding...you could do it with a file. Turns out, it is a part of the street sweeper brushes the fly off now and then. Steel tines from a rake might do it too (don't see those down here), there could be something around your home already.

Making the bobbin is a little tricky...but I did make one out of laminated paper so anything is possible with some imagination. Magnets? Check your fridge...there might be some suitable stuck to it right now! Most flexible strip stuff (like business cards) wont work because of dual polarity, but I did find some specialist stuff that could work for a core...got to buy 100 metres of it and it isn't cheap...grrr.

Anyway, DIY is a scrounging art....good luck with the project... pete

P.S. How's it going primal...got any sustain joy yet?

Link to comment
Share on other sites

Hi guitartreck and welcome to the sustainer thread proper.

Guitartreck posted in the tutorial section on this but this is a better place for this.

Now this is a common problem but first...I got to assume that you have been able to build this project on your own to the point of working at least to this point, so congratulations and others should take note that it is possible. :D

OK...the high strings. First...thicker guage strings will work better. This will provide more mass for the driver to work on. I use 10's and it works pretty well. The high string on the lower frets are a little more unpredictable, especially in harmonic mode. On the higher frets it seems to be better. This is a result of the strings being closer to the driver as they are being pushed down.

On my guitar I have found that in general the b string works best, especially on the higher frets, both in normal and harmonic mode.

Also...on the technical front...the set up of the guitar is important. You should have the bridge pickup very close to the strings and sometimes the driver set back a little. Also, a very low action can result in the strings crashing into the frets and inhibiting vibration. The magnetic power in the driver could inhibit vibration, so too much power or being too close may cause a problem...try a few adjustments.

Further technical to explore...could be the high frequency response of the driver and the circuit.

You can improve the high frequency response of the circuit by altering the output capacitor. I am not sure what you are using (perhaps 220uF or even 470uF) but you may require a smaller one...I believe my strats is actually 100uF and the single coil pickups themselves have a high frequency response which helps too.

I have also talked about the "speed" of the driver. The coil is an electromagnetic device that changes states at the speed of the frequency of a note played. That means higher notes, and thus high string notes are not only hampered by the thinner strings less mass, but by the speed at which the driver needs to respond.

I believe that my thin driver design allows for this speed without the phase compensation circuitry that the commercial systems use, hence the simple circuit. An overwound driver (8 ohms or above) will slow things down. Perhaps a driver as low as 6 ohms is best...mine happens to be on the low side but I have one exactly 8 ohms that works well too. The construction of the driver is important, if it is not potted enough, some of the efficiency is lost and this is most apparent in the high frequency range.

There are lots of variables, but this initial problem is not unusual. Perhaps some more detail about your driver design and set up, maybe a pic or two, would help. A wider core for instance may make the higher strings more problematic as I explained recently. Sustainiac and fernandes have described "shunts" in their patents to try and focus the magnetic power more...this too could be done, but shouldn't be necessary really, especially with a narrow core (according to my theories ;-)

All in all, this problem can be solved and it sounds as if you are well on the way to a successful outcome with it. First is that I would try variations on pickup and driver height...then, change over the capacitor and see if that helps...heavier strings if you can stand them would be an advantage.

As far as my circuit variations from the fetzer/ruby if this is what you are using, I have a lot more preamp gain but this does not improve the high frequency response of the circuit or really the ultimate power put out by the driver really. The result of this variation is most likely that I produce a more fuzz like output from the sustainer circuit that may be benificial, if the driver has the speed to cope with this square wave signal.

All in all, this problem can be solved and it sounds as if you are well on the way to a successful outcome with it. First is that I would try variations on pickup and driver height...then, change over the capacitor and see if that helps...heavier strings if you can stand them would be an advantage.

I am not sure if you have a fully installed device or you are still in the testing stage (holding the driver above the strings) but as I recall the high string response improved with installation.

Hope all this helps and that your success so far offers encouragement to others following this thread...keep in touch... pete

Link to comment
Share on other sites

Ok, I'm back!

Long story short, I got frustrated with my lack of usable results from this project and I set it aside for a couple months. I came back to it a couple weeks ago and started winding coils. After botching the first two, I promised myself I'd drop the project entirely if I didn't get the next one right. As luck would have it, the coil came out fine, and I now have what looks to be the final version of my driver up and running. It's non-microphonic, fits under my pickup cover, and is about the right impedance. Hopefully it will work fine, but I can't try it out until I finish the fretwork I was doing on the guitar. That'll be another week or so.

Anyway, I have a new method for making these coils to share. My coil is like Pete's in that it's built on top of a working single coil pickup. The main difference is that the pickup cover is one piece, as opposed to Pete's design, where the top of the coil bobbin is also the top of the pickup cover. To get this to fit together right, I needed to have a "semi-bobbinless" (ie: no top) coil. After screwing this up a bunch of times, I figured out how to make it work. I make a temporary top bobbin out of two piece of cardboard (the thin kind found of the back of legal pads) laminated together with CA. I coat the underside of this with epoxy because titebond doesn't seem to stick to epoxy. Next, I rough out the slot for the blade with a utility knife, and finalize it with the appropriate sized drill bit in my press (sort of a very makeshift milling operation). Now I have a slot that's pretty close to the size of my blade polepiece and I'm ready to glue it on with gorilla glue (this is important... gorilla glue expands to fill gaps and it's very strong... perfect for this sort of thing). Also, I wax the bottom (epoxy side) of the bobbin prior to gluing for good measure. If the glue sticks to the bobbin, it will pull the whole coil apart when I pull the bobbin off later. After chipping the excess gorilla glue out of the winding area with a hobby knife, I'm ready to start winding.

For potting, I've been using titebond "moulding" glue, which is just (I think) thick PVA. Regular white glue probably works as well, but now that I have a successful formula, I don't want to mess with it. First I tack one end of the wire in place on the bobbin with CA. I then wind the coil as per Pete's method, adding glue as necessary, and making sure to keep the coil tight. When I've got all the wire I want on, I tack the other end of the coil wire into place with CA (making sure to keep it tight), and leave the whole thing to dry for a couple days. I have not been wrapping my coils in electrical tape after winding, as this seems to inhibit the glue from drying. Once it's dry, I'm ready to peel the top bobbin off. This is the "make it/break it" procedure. First, I chip away all the excess gorilla glue, then I just peel the top off slowly, making sure that none of the coil comes with it. If all went well, I now have a nicely potted coil with no top, and I'm ready to put it together. Last time, I let it sit for another couple days after peeling the bobbin off, just to make sure the glue was thoroughly dried.

Sorry I don't have any pictures of the winding process or the finished coil. I can get one of the coil if anyone wants to see, though. For now, here are a couple pictures of the whole thing installed in my pickguard. Notice the snap-in connector that lets me remove the pickguard without soldering. :D

sus10.jpg

http://www.ece.utexas.edu/~wrobert/sus11.jpg

And one of my "rapid prototyping board" with a Ruby Fetzer on it. I plan to build an eBow-style amp and a modified "Aussie compressor" as well. I'd like to evaluate all three before I commit a design to solder. I'd also like to check out some alternative harmonic modes, like half-wave rectification and the eBow-style thing (which I still haven't totally figured out).

http://www.ece.utexas.edu/~wrobert/sus12.jpg

Anyway, just wanted to let y'all know I'm still out there working on this thing :D

Edited by fookgub
Link to comment
Share on other sites

the driver its in testing mode after some hours of work around it finally i solved the high e and b strings, i changed de strings , now i use 0.10 package and they all play B)

Fantastic Guitartreck...I am very impressed. I did find that the thing worked even better once fully installed. Sometimes holding the driver above the strings means that excess electromagnetic energy is being radiated out so as to be picked up more than if it were under the stings on the same plane as it.

Yes 10's do work better, glad it was as simple as that, there's not much steel in a 9 to push around I'm afraid. The high string will always be a bit weaker and you will find that the guitar will have it's own "hot spots" according to the position of the driver. My B string is pretty good and you will find that your playing will likely become more linear, playing along the string when sustaining.

Also, in harmonic mode, different harmonics will sound in relation to the position of the driver and the length of the string. What you may find is the same note played on different strings/frets will produce different harmonics...it's kind of cool once you get used to it. The main playing tip I can offer is a light touch and inventive string damping techniques to stop the lower strings playing themselves.

Anyway, I have a new method for making these coils to share.

Sounds like you are getting somewhere fookgub and the "aussie compressor" sounded promising I must say. I like the bobbinless coil idea...mine has an almost paper thin plastic (from a folder) that I reinforced with cardboard while winding. The PVA didn't glue to it but you do need to be careful, with extended use, the driver will get warm and soften the glue. Sometimes a high string has got caught under my plastic top and I have it stuck down with sticky tape at the moment to prevent that happening. :D Otherwise, I have had no problem with the coil potted in this way. Sounds like a good tip, thanks.

Well...it's great that a few are making progress and there is a little more verification that the thing works...and it's not just me...you guys have had me worried. Keep up the good work... pete :D

p.s that's some equipment you got there, and very neat...very impressive!!!

Edited by psw
Link to comment
Share on other sites

Has anyone ever used this ( http://www.mwswire.com/bond1.htm ) self bonding magnet wire? Would it help with our microphnic coil issues?

Also, could a fetzer-ruby be used to amplify my piezo saddles effectivley. Can I use one amp for piezo and sustainer in the same guitar?

Thanks,

Dezz

fookgub said: "Sorry I don't have any pictures of the winding process or the finished coil. I can get one of the coil if anyone wants to see, though."

I'd love to see this coil of yours.

Edited by Tony Enamel
Link to comment
Share on other sites

Has anyone ever used this ( http://www.mwswire.com/bond1.htm ) self bonding magnet wire? Would it help with our microphnic coil issues?

Also, could a fetzer-ruby be used to amplify my piezo saddles effectivley. Can I use one amp for piezo and sustainer in the same guitar?

Dezz...the LM386 part of the circuit is a poweramp and would generate too much current really to run piezos. The fetzer part could be used but would probably be not too desirable. The sustainer amp is just a little practice amp really and not that sonically plesant or clean which is what you'd want in a piezo preamp. I think it better to keep the two systems separate. In fact I'd keep the power separate as the sustainer draws a heavy load on any battery while a typical preamp will last a long time. There could be noise problems between the two systems also.

As for the wire, it is interesting but probably not available in small quantities and the bonding process could be a little tricky, especially winding by hand which leaves much larger air gaps between layers than a machine wound coil would. The glue method is a lot cheaper and easier and allows time while it sets to push in the sides (which in a long coil tends to be looser than the ends) and for winding by hand...the glue tends to fill the possible air gaps too. Coils as small and thin and shaped like this, don't really suit machine winding so we are lucky with the sustainer that it uses thicker wire and fewer turns than a pickup for instance.

On a commercial basis it would be of interest though cause you could set the coil by running a high current through the coil, heating it up that way...but you would have to be sure of your temperatures and timing lest you risk burning through the insulation and shorting out the coil in the process.

You do have to be careful with these types of projects that you don't end up spending a lot more on it than simply buying a commercial unit. There are advantages though to the DIY project as it can be customized to each application and could be significantly cheaper for the same or similar effect. Given the complexity of installing even a commercial unit, DIY looks attractive anyway. The frustration people are having getting the thing together is a shame but probably the result of too few making it...you guys are the trailblazers and I suspect we are moving closer and closer to a consistant and reliable method of construction without exotic materials.

Keep up the good work... pete

Link to comment
Share on other sites

Alright, I have been working on this project since I found this thread last year. My original drivers lacked the power I needed, but my 386 circuit was pumping out the juice. Now I have a good driver, but I cannot get any of my 386 circuits to produce enough power. My first "Ruby" amp that I built is LOUD but my other circuits drive a speaker at less than half the volume than the Ruby. I have built many 386 amp variations to try get this sucker to work but I cannot coax the power out of these chips.

I also salvaged and installed a preamp from an oven control panel and installed it under the neck pickup, then built a preamp so I could use the piezo as the sustainer pickup. The main problem I found is that it really likes to sustain its own resonant frequencies.

Anyways, I thought I would contribute by sharing my driver design. I could get it working in harmonic mode with one of my circuits that had barely any output at all, so I'm pretty sure this thing is working better than expected. All I did was raise the poles on my middle pickup and make a ciol from the pole ends. After coiling I slipped the cover over it and reinstalled the pickup. My main concern was fitting all that wire on top while leaving the poles far enough down to contact the magnets at the bottom of the pickup.

http://pg.photos.yahoo.com/ph/big_thurs/al...m/ph//my_photos

Link to comment
Share on other sites

Thanks Primal. You've been a great help both here and at my Fetzer-Ruby-Nooby thread.

A couple questions:

1. The driver will have a start and finish lead. One is soldered to the output of the amp. Where does the other go? (same with the bridge pickup. One to input, the other to...?)

I guess what I need is an idiot proof wiring diagram!

2. Does my driver coil have to make direct contact with the metal core, or can I use a regular pickup bobbin which has plastic between the coil wire and the pole peice(s)?

Link to comment
Share on other sites

1. The other lead will go to ground. As for the input from the pickup, I've found it easy to keep the wiring intact and just solder a wire going to the circuit from the guitar's common ground (i.e. the back of one of the pots) and the terminal on the pot where the pickup connects to it.

2. The coil contacting the metal core would have absolutely no affect on the coil itself. You should definately follow Pete's instructions for making a driver, though. I used a pickup bobbin for mine, and I'm having a few problems getting mine to work well. I haven't figured out if its my coil or my circuit yet (I've got some distortion problems that I need to work out).

Link to comment
Share on other sites

1. The other lead will go to ground.

yep...as primal says, it connects to the circuit just like a speaker...one end is effectively ground and connects to the ground "rail" in the circuit.

2. The coil contacting the metal core would have absolutely no affect on the coil itself.

well...you don't want to risk shorting out the winding against the core itself, now or in the future. I used a layer of pvc electricians tape aroung the core that also held the bobbin in place a bit (I cut a slit in the plastic bobbin piece and scored it so that 1.5mm bent down on each side of the 3mm slot and the tape holds it against the core).

I used a pickup bobbin for mine, and I'm having a few problems getting mine to work well.

I have used a pickup bobbin, but it was unusual and very thin. It may be that a coil closer against the core will be more effective.

I haven't figured out if its my coil or my circuit yet (I've got some distortion problems that I need to work out).

I am not sure what you mean by "distortion problems". Ideally, the device should make no difference to the output of the guitar in volume or tone, the only effect should be infinite sustain. The guitar's signal does not go through the circuit to the amp to be actually heard...well, that is the idea. It can, however, if the bridge pickup is picking up the driver's signal and sending that to the amp. This can be tested for by moving the driver away from the pickup which should solve this in testing. The other possibility is that some signal is getting through the ground of the guitar...on a single pickup guitar this should not be a problem but on my strat I had to completely disconnect all other pickups via the bypass switch (hot and ground) to avoid noise.

One thing that is noticable is that you can get distortion when the battery is running low. I am not sure exactly why this is so, but fernandes mentions it in their instructions also. Perhaps it is because the batteries -ve is connected to ground when the device is activated and with insufficient power this ground is not consistant and creates distortion. A new battery always solves the problem though.

Oh yeah...just remembered, one more possibility. The leads to the driver are really just an extension of the coil itself and can also put out EMI that can be magnetically coupled to the pickup or the guitar circuitry. Twist the wires and try to run them away from the circuitry if possible. On my strat I have actually sent the wires through the trem cavity. It is always a comprimise because eventually the signal wires will have to join at the circuit but if you run signal wires alongside of the driver wires you run the risk of the driver's signal being "picked up" and distortion will be the result.

Are you getting sustain anyway, primal?

Anyway, thanks primal for keeping tabs on the thread and answering the questions so well...bye for now... pete

Link to comment
Share on other sites

Yes, I'm getting sustain, and even though the driver doesn't work perfectly, I can still get some pretty cool sounds happening, so it was worth the mod already. I'm going to try building the amp again and do some more tweaking.

The first thing I want to try is disconnecting the single coil pickup that is right beside my driver to see if that helps any. I wish I was able to record the distortion I am getting, but my amp is way too far away from my computer, and there is no room for an amp next to my computer.

Link to comment
Share on other sites

I'd love to see this coil of yours.

Here you go. It's kinda hard to see with the flash and the coil and electrical tape both being red, but I did what I could.

sus20.jpg

http://www.ece.utexas.edu/~wrobert/sus21.jpg

http://www.ece.utexas.edu/~wrobert/sus22.jpg

http://www.ece.utexas.edu/~wrobert/sus23.jpg

Link to comment
Share on other sites

That's fantastic...looks better than mine!!!

sus21.jpg

This shot is great as it shows how thin the driver really is!!!

sus23.jpg

Thanks a lot for posting those fookgub...

The main difference to mine is that your blade extends above the coil a little and is curved where mine is flat and level with the coil. This is possibly better and ensures that the windings don't come off on the ends where it is tighter (also illustrated in the photos if you look close). You can see that the glue has permeated the entire coil and is set tight, I doubt there will be any internal vibration there. This is exactly what you should aim for in driver construction...now refret that guitar!

Oh...ok primal...the distortion is most likely coming from that pickup. The coil of the driver and the nearby pickup can act like a transformer and I found that unless it is completely isolated (removed, not just shorted out or one end lifted from the guitar circuit) a weird distortion would creep in. My bypass switch disconnected both of my other pickups before they went anywhere near the selector switch or any other circuitry.

great stuff... pete

Link to comment
Share on other sites

Guest
This topic is now closed to further replies.
×
×
  • Create New...