Sustainer Ideas

[psw]

That steel bottom does seem to be a good idea, I think I could squeeze something in mine, as long as it was pretty thin!

As I said, the green stuff can be deceiving: with a few tweaks to the upper and lower bound settings in femm, the field shape in that hex model would start looking a lot more like the dual core version you posted (which incidentally looks a lot like many of the different models I've made of bi-lateral drivers, and also similar to some of the bi-longitudinals seen from the end).

Well there may be hope yet for that bilateral design, this when together a lot easier, how it works, well only testing will show, it's a starting point. I take all of your points too, most valid, however, we just don't know enough about how this kind of design will work compared to the sustainiac model or the thin drivers of mine...potentially it could fail miserably, but still, I worked out how to make some cool coils that came out potted and wired in series. I can also play around with it a little more, sure I can't change the core material, but I could stick a couple more magnets below it for instance to make it taller.

Its not true that all parts of the permanent field will be equally effected by the electro magnet - that depends on the position of the electromagnet relative to the permanent magnet - this is one reason why it may be a very good idea to use a soft magnetic core with the magnet at one end and the coil at the other.

I don't think it will act equally, if I said that, I stand corrected, but it will effect all of the field and in turn anything magnetic it is close enough to. As for the location of the coil, in all my recent designs I have located the coil at the very ends of the core where the fringing effects take off. If this is of particular benefit or why I don't know, but the closer the core and the windings seems to have worked the best for me. On this one I wanted a different design with a wider pancake like coil similar to the ones I have been working on in the upper part of these internal magnets, but it was not to be. I have a few other ideas and even some neodymiums of various sizes that might work for this application. The SCN fender pickups seem to combine ceramic and solarium colbolt magnets in it's design which is interesting.

The closeness of the lines depends on how many lines you choose to use which is again purely arbitrary, you can change it in the femm settings.

Unless I am really misunderstanding it, the closeness of the lines indicates the strength of the magnetic field...sure you can change the settings and create more lines, even more domains in the mesh, but the relative number and spacing of the lines in a given model will still be the same, there will just be more of them surely?

If you want to reduce the side throw of a bi-lateral, one way might be to make it taller - this makes the flux more likely to go from one core to the other rather than to its own opposite pole. The flux that still goes from top to bottom of the same core will be projected further, but there will be less of it.

I guess this is true, however if the distance to the opposite pole of it's own magnet is further away, there may be more attraction or deflection from nearby pickup magnets, something we are seeking to avoid as both me and curtisa are attempting to locate it in the middle position between two pickups. At least with a tele I have more distance, it will be a major achievement if it works for curtisa between two HB's...if you pull that off Mr C there will be a lot of people emailing you too!!!!

My plot was for visualization purposes and nothing like to scale. My mags are 22x5x5mm with just short of 10mm (say 8mm) of space between them and so the gap I think is a little larger. Do you draw your things separate and import them to FEMM, I am not sure I can do vector graphics to do this...

Ok...I did another one with more realistic relative dimensions...

So, in this I added a plate the one on the left is air, the right is steel. True very thin steel, but a lot of the magnetisim is running through this, is this what we want? Also, diminishes the green but the lines are fairly similar, perhaps I am doing it wrong...

pete

[Dirge for november]

Thanks for the link!

I have had some experience with electronics at school, but somehow not of it seems to stick.

You should change the name of this thread to "the sustaining thread" Biggest thread I ever saw

Edited March 21, 2008 by Dirge for november

[psw]

It is not really a hard project really, most circuits are fairly easy, check out the circuit from that page, you will have to download the free software, you may even need to tinker a little with it. I may even get around to doing a version with the add on's I keep suggesting. Getting the switching right so it doesn't pop when I switch it off has always been a headache and we don't have a real solution. Some are wotse than others I suspect. A lot of these more recent colorful posts are for people who have really been bitten by the bug. Once you have made one, you will likely want to make something better.

The designs mainly being discussed at the moment are bi-lateral, that means they have two coils and opposing magnets a bit like a humbucking pickup, except that in this, one coil is under the lower three strings and the other the top three...a bit like a split bass pickup or fenders old z-coils and 12 string pickups. The idea is to reduce the amount of distortions and squeal and to make it more efficient directing the power towards the strings where you want it, and lass towards the pickups where you don't.

The colorful pics are FEMM models. This is a program that allows you to visualize the magnetic field of various magnets and metal structures. It gives a bit of an insight as to what the magnetic field would look like if you could see it, roughly. Also, only in 2D and you need to be able to interpret it for any real detail or data comparison, as col has been pointing out.

At the moment, curtisa is making a kind of copy of the essential elements of the sustainiac device drawing from the patents and intends to get it to work in the mid position. This is something I have tried and failed to do for a long time, so not to be out done...errr, I mean inspired by....curtisa's terrific construction, I have made my own different compact version. Curtisa intends to use a similar kind of circuitry to sustainiacs, where as I will be using more conventional linear amps based on LM386.

What I want to achieve is a very compact driver that can surface mount (stick to without routing) the scratchplate of a telecaster and work with both pickups. If on a strat, such a device would have to replace the middle pickup and could have a slightly different design and mounting of course...perhaps more like what curtisa is making. This has been a theme of my work, I am not trying to make "the best" driver, but the best it can be within the goals I am setting. In this case it needs to be very low profile and so, I have made the magnets within the core and used epoxy to hold it together without bobbins. Anything higher than 5-6mm is not going to work in this application. Some discussion is being had whether I should use a deeper core or have the magnets under, etc...but this simply wont work for this application. However, if necessary and it looks promising, I may well make it into a deeper pickup like device.

It may be that I won't be able to get it to work at all in the mid position, then I may well simply make a tele neck pickup sized driver and use it as a one pickup guitar...there appears to be no problem with this set up for others like col who have single pickup guitars and on a tele is perhaps not a great loss.

I still have a lot of faith in the single coil piggyback pickup/driver though...if not for the switching noise, I would continue developing this. For now, I am taking a bit of a break and waiting for something or someone to come along to help or inspire me to find the solution to this problem. Having a driver work in the centre position would be a prety cool consolation prize and full marks to anyone who thinks they can do it.

Anyway...that is for the many people who look in and are wondering what the heck is going on here and why is this thread so darn long. Don't worry about that, check the shorter links below and the one posted earlier and just join in...no problem...pete

[col]

What happens to the pattern/intensity of the field if the steel bar at the bottom of the sustainer is removed?

Here are two plots, the first with the bar, the second without - these have been plotted with matching bounds on the colour, so they are comparable (everything else is equal - magnets, core, coils, current etc.)

Although, the one with the bar has a much more focused field that pushed much more of the flux where we want it, it will also have a larger inductance - that iron bar is part of the core, and the one in this plot is hefty. So it makes sense to try a few different things, and remember that as the inductance rises, high frequency response becomes relatively less good, so if the circuit doesn't account for it, a compromise will need to be found. What I'm not sure about is if this helps or hinders the EMI side of things, my instinct says it helps, but its hard to know for sure without testing or better modeling.

------------------------------------------

Ok...I did another one with more realistic relative dimensions...

...

So, in this I added a plate the one on the left is air, the right is steel. True very thin steel, but a lot of the magnetisim is running through this, is this what we want? Also, diminishes the green but the lines are fairly similar, perhaps I am doing it wrong...

Did you click the stripy button and copy down the uppar and lower bound values from one plot, then paste them into the other so the colours would be comparable ?

(you can do a similar thing for the lines too if you want, click the button with all the diagonal lines on it and copy those values accross...)

heres a comparison I threw together to illustrate my point - all these plots are showing EXACTLY the same driver with the same coil, current, core, wire, and magnets. all that I've done is tweak the plot bounds (and one is in greyscale). remember that femm tweaks the plot bounds for you per plot, so unless you manually edit them, its not fair to compare.

e.g. in your plot with the steel bar, the flux through that strip is very dense, so in order for the overall plot to be as balanced as possible, femm sets the bounds to allow most of the dense end of the spectrum (pink) to be used for the bar - this causes the balance of colours to be different, and on casual inspection of your two plots, it seems that the one with no bar has a better field projection where in reality, the opposite is true!

cheers

Col

[psw]

Also, diminishes the green but the lines are fairly similar, perhaps I am doing it wrong...

Did you click the stripy button and copy down the uppar and lower bound values from one plot, then paste them into the other so the colours would be comparable ?

(you can do a similar thing for the lines too if you want, click the button with all the diagonal lines on it and copy those values accross...)

Ahhh...no, I didn't think that it would change anything if the same model and mesh was used...I will play with it again tomorrow and see how that goes. The lines for instance did look very similar, yet the colors changed radically. At the very least the pics do show how radically the metal below changes the field above, and importantly the field at the ends which one would expect mirrors that of the top and side view to some extent (any side throw) so it is reasonable to expect that a similar thing is possible if we were able to model it where the energy is passing between the two core structures.

Thanks, will see how they look with my internal magnet structures. Fortunately, regardless of overall performance, I suspect that various metal bars could easily be attached to my model to see the effect on things like EMI and I will be sure not to get too carried away with the aesthetic side of things till these things can be trialled in various ways.

pete

[utopian isotope]

Again one possible way to make a bobbin...

I dug my stuff, and found about 1mm thick plywood. It can be cut with scissors, filed and/or sanded.

I did also cut 5mm pieces out of pickup polepieces, that were lying around.

Here is result:

No fancy tools or equipment required.

Edited March 22, 2008 by utopian isotope

[psw]

That looks really nice, good work Ui

I am guessing that the core is 25mm long with the magnets filling any gaps and this is one of a pair of driver coils for a bilateral design? If so, I imagine that the two coils will need to be offset like a z or p-bass arrangement, which is cool. One could do a similar arrangement with bolts as long as, as with my last failure, you didn't attempt to remove them later and strip the wire insulation as you do ...and stick magnets below.

You may find that the alnico poles have lost some magnetisim by filing and cutting, this does tend to ruin it, as does heat, however, applying strong neodymium magnets can be used to "recharge them" which is how pickup makers do it.

Generally, one should never cut magnets, alnico like this, or steel poles with a magnet below, are ok, ceramic (the grey ones) are likely to crack and break and wreck your tools trying to cut or file them. NEVER try and cut or shape neodymium "rare earth" type magnets as they will explode and may kill, seriously. They will be destroyed in any case.

However, alnico poles are machine cut and the risk is mainly to do with the loss of the magnetisim which can be restored and you hafve done a very neat job there. I was in a craft shop two days ago when I went bush to get some air...yes, picked up a few mags (they had small discs, 8mm by 4mm, 20 for A$1.50...so now I have 40 of the little buggers)...and they sold these thin icecream sticks in various sizes including large "tongue depressor" sizes that looked useful, and here you have shown what they can do!

To make the temporary bobbins of my latest one, I used flat plastic from an icecream container lid. To stick it to the magnets, I roughened the surface and drilled a few tiny holes which I then superglued them together. The glue will not stick that well, however it did enough to wind the coils, after the epoxy had set overnight, this glue joint was the weak link and they snapped apart pretty easily.

It is amazing what you start seeing once you start building these things, every bit of metal lying around could be a core, andy magnet a possibility, any material a potential for a bobbin!

I also think that you were right to approach it in this fashion rather than to try and make fancy molds and such or grind out fancy bobbins. Make sure you support those tops and magnets during winding, perhaps double sided tape some wood above and below, the glue of the potting will hold all of it together nicely, but while you are winding, the pressure in the coil may push the top and bottom off. Also may be an idea to clamp it while it sets or if they do move, to squeeze the coil a little.

good work... pete

[MUNKIE]

I know this is full of the info but it's so much to go through i thought It'll be easier to ask. I'm looking into this but with a Humbucker driver instead. or at least shape of a Humbucker. I also wanna know if someone has done this with a harmonics setting too. if so can someone please send me the diagrams for it please. I used a copuld of links psw has sent me (single coil driver which then led me to find the Fetzer/Ruby amp).

[curtisa]

Update from me:

All it needs now is a pickup cover and a pair of core "endcaps". The black wire at the top of the photo is the connection to the copper shield surrounding the two cores. I ended up rewinding the two cores using 0.2mm wire, which enabled me to fit 256 turns on each bobbin (over 100 more than the last attempt), plus plenty of spare room for the self-amalgamating tape and copper foil. The cores are connected in parallel-antiphase, the total resistance being 12 ohms, a little higher than I had hoped but still within shouting distance of usable (my first sustainer came in at 13.6 ohms and works fine with the old LM386 circuit, so I don't think an extra 4 ohms is going to cause too much trouble).

The baseplate is made from two layers of 1.5mm thick black plastic I had lying around, superglued together, and cut to shape. Two rectangular windows (25mm x 11mm) are cut into the baseplate for the two magnets to sit into, and a U-section of plastic is fitted underneath the magnets to stop them falling out the bottom of the driver. The U-section also enables me to slide a piece of steel underneath the magnets to experiment with focusing the magnetic field more upwards, a la Col's FEMM plot above.

There are actually two layers of copper foil - a narrower layer (6mm) that wraps around the two bobbins that fits within the upper and lower flanges of the bobbins, and a second full-height layer (10mm - the one that's visible in the photo) that is soldered to the inner layer so that it doesn't slide off.

I'm really pleased with the way this has turned out this time. Given how much longer it's taken me to build it, the damn thing had better work or I'll be pissed off!

[psw]

A beautiful work of art and I think rewinding it will pay off, even if a little enthusiastic with the winds, still with the D-class amp thingy it may not matter, col might even say the more winds the better and if I recall is similar to the sustainiac resistances. Back to the magic 0.2mm wire too I see.

I'm really pleased with the way this has turned out this time. Given how much longer it's taken me to build it, the damn thing had better work or I'll be pissed off!

Be prepared, but you have given it more than your best shot at success. My concern is in the application, squeezing it between two HB's...as a fall back it may be tried in a strat middle position I guess. Remember my mid driver, that took a lot of work to make and failed in a similar application (quite a different and possibly overblown build)...looked cool, but a no show as far as performance, particularly in this tricky mid-pickup application.

I know that feeling all too well though, and I am presently much jaded, hence slow progress on mine. I have stuck the driver to the guitar and even have a spare circuit already built but I have been avoiding actually hooking the thing up and trying it. I even have a plan b if the response is lackluster, building a parallel version...then there is plan c,d,e etc involving ideas col has presented over reservations with the core material, depth and such. Fear of failure I guess...I used to handle it a lot better and anyone serious about being involved with this level of experimentation and construction had better be prepared and strengthen their constitution!

After col's comments and looking at my 8 ohms worth of series winding (2x4 ohms) I am wondering if mine will be enough, there is certainly room for more and still fit my specifications I suspect. Are you not tempted to hook this up to your existing LM386 powered guitar to compare it in a more conventional application?

All in all, it is a remarkable build demonstrating that DIY does not need to be low in quality nor a successful design take more than care and a lot of planning really. Quite remarkable and throws the gloves down for those who may wish to follow. I can see that this has encouraged others to do the same and I am impressed by UI's latest one too. Simple, resourceful, and as a result, beautiful...all a good sign. Such builds certainly encourage me to lift my game...well done, I hope my mini driver can measure up, the pics are still in the camera I am afraid...

pete

[utopian isotope]

It is amazing what you start seeing once you start building these things, every bit of metal lying around could be a core, andy magnet a possibility, any material a potential for a bobbin!

pete

Hehee, same here. It's amazing how much material you can reuse.

--------

Anyway, when looking for magnets, I found this site: http://www.supermagnete.de/eng/index.php?switch_lang=1.

They have those tiny disc magnets, that could be used instead/with steel polepieces.

Since those are neodymium magnets, maybe smaller size would be enough, to avoid excess string pull?

There is also magnetisation strength grades, that are too much on theory side for me.

[psw]

Some SUCCESS...

I finally got to wiring this new bi-lateral driver into the tele and it works fairly well. I can get infinite sustain on all string even though it is a pretty light set (I think they are 09's) so a little less responsive on the high e and d (the inner core of d strings are lighter than a g), Best response is from the g and b strings. This may be a factor of my amp bias as this is true of the single coil versions also.

As a preliminary test, I taped the driver into the middle between two cheap SC tele pickups (so true single coils) on my no name copy. The driver sits about 4mm from the open strings. Action effect is less in the middle position as it is closer to the bridge providing a more even response. At higher gains I do get fizz, especially on the neck pickup (oddly, as becuase it is not angled, is a little further away) to the point of squeal if set too high, though this setting will work with the bridge and both pickups together ok....hmmm

On the down side, it doesn't have the power of the SC designs I have been working on, but this is a first of a new design that could be tweaked further. Like my recent devices too, it doesn't respond in the reverse phase harmonic thing, even on the lower strings. Harmonics are possible with higher gains and pick attack though.

I tried it with a steel ruler under the mags to bridge them, perhaps slightly better, no real loss or gain but fairly thin metal. I also tried the staple cage idea, same thing, maybe a bit better but not a lot.

SO...lacks power but works. I could make a 2x16 ohm version with the same wire, this would make the coils considerably bigger with more turns for the same resistance...quite a bit of work but definitely worth it for comparison. I could try a preamp on it, these pickups are fairly low in power and I have no real preamp gain. I could try a different amp, but again a bit of work in this. I could try building one with a steel core and a different magnet arrangement. I could lift it a little closer to the strings (it does not seem to have the "throw" of a SC but much better than the rail thing I made.

I definitely need to try it with a new battery...

I am also taking the signal directly from the selector output, this is perhaps not the ideal. This means that the circuit gets the signal of what ever pickup is selected. This gives variety, but some lack of consistancy and tele neck pickups are notoriaously underpowered and so far gives a bit of squeal. Perhaps it would be better to connect the circuit directly to the bridge pickup selector in so that whatever pickup is going to the guitar amp, the circuit always hears the bridge pickup. I will mess with some of these options first as it is only a few solder joins.

On the up side, it is incredibly easy to wire and install, just connect to the existing circuitry. So far no real switch noise (I simply disconnect the battery)...perhaps a little in switching on, but it is not a "pop" and would be acceptable and maybe fixable.

One question is, would making a driver with more turns effect performance in a positive way, and would more power from the driver result in more EMI? I guess I will just have to try it and see. Making dual parallel drivers is a little trickier, not only in the extra winding, but in the need to wire them correctly so they work together properly.

Another interesting idea may be to use a stereo amp each running a coil perhaps with a slightly different treble bias for each set of strings. This may enable a compromise where you could have two separate 8 ohm coils instead of 4's (as I have now) or 16's (if It were paralleled)...

Anyway, would like to hear your thoughts and ideas. It is certainly some vindication of the merits of the bi-lateral design and may encourage others like curtisa who are taking this road. Mine is working, but I would like to get a lot more out of it before I would rank it along side the SC neck drivers that I had been working on. On the other hand, the ease of wiring, installation and choice of pickups plus, lack of switch noise, is a real boon. I expect it would work on a strat too if you ditched the middle pickup for it or something like curtisa's, even with LM386 like power...tre cool!

later pete

Perhaps it would be better to connect the circuit directly to the bridge pickup selector in so that whatever pickup is going to the guitar amp, the circuit always hears the bridge pickup.

Ok...I tried this, and it is a bit of an improvement. What is particularly interesting than at a fair gain there is fizz in the neck and bridge postions (plus harmonic response) but in the combined selection, FIZZ FREE!!! I am not sure if in this position the guitar is humbucking (rwrp) but an interesting phenomenon. I wonder if it relates to the open earths on the unused pickups in these positions (the driver and both pickups are connected to ground regardless of selection, in the middle position, both the pickups ground and hots of both pickups are connected, so no open connections...hmmm).

I set up for a new parallel driver wind, but the winders battery needs recharging so a bit of a delay...regardless this series 4 ohm is working and still useful for further experimentation.

pete

Also...massive dead spot when bending g string between driver coils/cores. The g sustains well but sustain drops out almost completely as bent away from lower coil. As this is a mid driver, the lower bends are not to bad, but everything bent above the twelth fret is really noticable. I don't think the plates overhanding the coils sustainiac style are really going to fix this as it may effectively create almost a bridge between the two cores like the steel bar under it and so massively stop "throw"...any ideas on this aspect?

p

Edited March 24, 2008 by psw

[Fresh Fizz]

Also...massive dead spot when bending g string between driver coils/cores. The g sustains well but sustain drops out almost completely as bent away from lower coil. As this is a mid driver, the lower bends are not to bad, but everything bent above the twelth fret is really noticable. I don't think the plates overhanding the coils sustainiac style are really going to fix this as it may effectively create almost a bridge between the two cores like the steel bar under it and so massively stop "throw"...any ideas on this aspect?

I've installed my new sustainer driver. It has 6 strat-type rod magnets with alternating orientation (N-S-N-S-N-S) and 6 copper coils. I don't know how you call it, hexalateral perhaps? Another thing I did was to use more windings for the higher strings. But I wanted to keep the maximum humbucking effect so it's done in pairs, 90 turns for E and A string, 110 turns for D and G, 145 turns for B and E. Good guesswork from my side, I ended up with a total of 8,5 ohm.

When it comes to throw this new driver is a big improvement over the previous one ( with the blades). The new driver is much more sensitive in the lower fret positions and increasing the amount of turns for the higher strings improved string balance.

The biggest drawback is what is mentioned by Pete. When bending the string in between two magnets the efficiency drops. In the worst cases the sustain stops. Not so good! I think there has to be iron core or magnet underneath the string to make it work. Make the gaps as narrow as possible, leave only enough room for the copper I would say.

My configuration with lots of overdrive doesn't seem to work well. I hoped that a more sustainiac-like driver would diminish the fizz, but that's not the case. At least I could remove my dummy coil without getting the squeal back! I'm afraid that the overdrive is on its way out.

Cheers

Fresh Fizz

[col]

Also...massive dead spot when bending g string between driver coils/cores. The g sustains well but sustain drops out almost completely as bent away from lower coil. As this is a mid driver, the lower bends are not to bad, but everything bent above the twelth fret is really noticable. I don't think the plates overhanding the coils sustainiac style are really going to fix this as it may effectively create almost a bridge between the two cores like the steel bar under it and so massively stop "throw"...any ideas on this aspect?

...

The biggest drawback is what is mentioned by Pete. When bending the string in between two magnets the efficiency drops. In the worst cases the sustain stops. Not so good! I think there has to be iron core or magnet underneath the string to make it work. Make the gaps as narrow as possible, leave only enough room for the copper I would say.

Hmm, this is something I've been thinking about while pondering femm models.

I have another idea about what the cause might be.

It seems to me, at least from models, that the field is fairly even accross the string area - Petes does have a slight dip in the centre, but I wouldn't have thought it to be enough to cause dropout?

Heres the idea:

The bi lateral driver generates a loop of flux. Where the strings are above the poles, the flux is more vertical, where they are between, it is more horizontal.

Depending on how the coils are wired, is is possible that the strings vibrate in a different plane depending on their positin within the field. If you bend a string so that it moves from a vertical vibration position to a horizontal one, there will be a loss of volume as the string vibration 'polarizes' - this of course will cause a drop in the drive signal, so may kill the sustain.

This is just a 'maybe', but if it proves to be a real issue, then more careful design of the field will help, as will a heftier drive.

I think that the most likely reason though is that the field of either or both of the magnets (permanent and electro) is too uneven, and more careful design will improve this problem dramatically.

cheers

Col

[Fresh Fizz]

Heres the idea:

The bi lateral driver generates a loop of flux. Where the strings are above the poles, the flux is more vertical, where they are between, it is more horizontal.

Depending on how the coils are wired, is is possible that the strings vibrate in a different plane depending on their positin within the field. If you bend a string so that it moves from a vertical vibration position to a horizontal one, there will be a loss of volume as the string vibration 'polarizes' - this of course will cause a drop in the drive signal, so may kill the sustain.

How about this:

The bi lateral driver generates a loop of flux. Where the strings are above the poles, the flux is more vertical, where they are between, it is more horizontal.

The electrical signal applied to the driver only can attract or push away the string. When the string is in between the 2 cores, or in my case 2 rod magnets, there is mostly horizontal flux. This also goes for the flux created by the driver coil. But the fields of the 2 cores (magnets) work in opposite direction! Both cores attract or push away the string at the same time. So the horizontal component of the flux field is canceled, leaves only the smaller vertical component.

Cheers

FF

[Captainstrat]

Is anyone familiar with the "original" Sustainiac circuit, the one co-designed by Floyd Rose? Just saw one in the classifieds, the seller states "with Floyd Rose's signature at the back of the circuit"...?

[psw]

Interesting theories that are tying in with my experience with this thing.

When the string is in between the 2 cores, or in my case 2 rod magnets, there is mostly horizontal flux. This also goes for the flux created by the driver coil. But the fields of the 2 cores (magnets) work in opposite direction! Both cores attract or push away the string at the same time. So the horizontal component of the flux field is canceled

Yes...well, the drop out is worse than lack of sustain, bending the string virtually stops it from vibrating completely. This was a major drawback of my HEX designs of old. I mentioned that in these, alignment was critical. Each driver was only 10mm wide and actually worked entirely across the strings.

FF...I've installed my new sustainer driver. It has 6 strat-type rod magnets with alternating orientation (N-S-N-S-N-S) and 6 copper coils. I don't know how you call it, hexalateral perhaps? Another thing I did was to use more windings for the higher strings. But I wanted to keep the maximum humbucking effect so it's done in pairs, 90 turns for E and A string, 110 turns for D and G, 145 turns for B and E. Good guesswork from my side, I ended up with a total of 8,5 ohm.

Ah...you beat me too it, this is the scheme I was putting forward in a FEMM recently, a good idea if the winds are uneven to have done it in pairs...send some pics.

col...Heres the idea:

The bi lateral driver generates a loop of flux. Where the strings are above the poles, the flux is more vertical, where they are between, it is more horizontal.

Depending on how the coils are wired, is is possible that the strings vibrate in a different plane depending on their positin within the field. If you bend a string so that it moves from a vertical vibration position to a horizontal one, there will be a loss of volume as the string vibration 'polarizes' - this of course will cause a drop in the drive signal, so may kill the sustain.

Yes, well this is another way of looking at it. Another is this.

If you make a coil that transverses the string (at right angles to it) with one side north and the other south, when you bend a string up it will sustain longer, down and it goes into harmonic drive...this was a large part of what I was keeping back from all of those hex designs I was doing, transverse individual fields. The idea worked well with low EMI effects but, not only was alignment critical, so too was not bending strings (although, it was an ultra cool effect to bend a string one way and it go to a harmonic, the other and it would swell!!!).

So, my present driver is working and throwing up some very interesting effects including ideas about fizz and multi-pickup guitar installations. For instance, I connected the circuit directly to the bridge pickup, the neck and bridge in combination is by far the best as far as fizz reduction. Using a magnet, it would appear both pickups are the same polarity...hmmm With the neck or bridge alone, there is a fair amount of fizz at higher power levels. Additionally, the neck pickup (which on a tele is typically very dark and lower powered) is bright and gives a good harmonic response. Clearly it would seem that it is transferring the sound of the neck pickup to the pickup coil. The effect of the other pickup being connected to signal ground, as is the driver and all other components seems to be important. Could it be that the effect of some components being out of the circuit results in a half wave distortion effect, creating that characteristic "fizz" sound. A sound largely eliminated by the combined pickup selection with a mid driver where everything is connected...

FF...How about this:

The bi lateral driver generates a loop of flux. Where the strings are above the poles, the flux is more vertical, where they are between, it is more horizontal.

The electrical signal applied to the driver only can attract or push away the string. When the string is in between the 2 cores, or in my case 2 rod magnets, there is mostly horizontal flux. This also goes for the flux created by the driver coil. But the fields of the 2 cores (magnets) work in opposite direction! Both cores attract or push away the string at the same time. So the horizontal component of the flux field is canceled, leaves only the smaller vertical component.

I think that there is a zone operating between coils and cores and polarities, a dead zone. A zone where the opposing forces of each result in the killing of the strings vibrations. This too harks back to my novel hex designs. I think I called it a "balanced magnetic field". The intention was to have the string vibrate between two strong opposing magnetic fields, N one side of a string, S the other and alternating with each string. Effectively, I created a coil between and aimed at these magnets perpendicular (across the strings), the idea that the electromagnetic effect would result in these opposing magnets becoming stronger or weaker, upsetting the balance and the strings neutral field now being more N of S resulting in a movement of the string from side to side, not so much vertically. The EMI reduction was in part by the electromagnetic forces working in a completely different direction and plane to the guitar's pickups, BTW.

I think something similar is happening here, but worse. One core is N and the other S, what polarity is it between the two...effectively none. The result may be similar to that of a coil without a core, or worse, the equally but opposing electromagnetic fields, without magnetic bias (neither north or south) are killing the strings vibration...not good!

After playing with it a day, this dead zone is really unacceptable. In some respects, perhaps the mid driver makes it worse, in the neck position, a whole tone bend pretty much bends the string from one side of the dead zone to the other, but in the mid position, the tendency is that all bends fall between the two cores, especially bending higher up the neck (observe string bends over the mid pickup on a strat to demo it for yourself). Perhaps this sheds a little light on the failure of some rail designs, the closeness of the coils means that there is more "vertical" flux between them and the "throw" much less. The result was with my mid driver, that it needed to be excessively close to the strings to work. Col's HB sized version is more successful as with a wider gap between them, more vertical flux is apparent...there is more "throw".

Another important "symptom" of the bi-lateral driver is that the strings are massively unbalanced in drive. The a and b strings respond very well and powerfully, the others much less. From the FEMM's you can see that in the middle of the cores, you get a much stronger vertical flux between both cores, while on the ends they are largely attracted to their underside polarities. This means that effectively, only that coil is working on the string and the field is a lot smaller (less throw) and more vertical sooner, as the gap between the opposite poles, at least on mine, is only 5mm!

Col's FEMM models of the idea of the underside steel plate shows that this strategy may have some effect. I have tried a few simple ideas, but the steel has been very thin and may not be enough to really tell.

For instance, the above extreme example in black and white shows that the flux is little to non-existent under the two e strings on the ends of the cores, there is a strong vertical component under the and b strings (the middle of the cores) and lots of dead zone horizontal flux (effectively neutral in polarity with respect to the coils and the string) in the middle (d and g strings). However, as with mine, there is enough at the edge of the two coil gap to give good drive on the d and g string, slightly bending it between the gap creates a dramatic effect as it leaves the strong N or S vertical bias and into the "dead" zone.

Col had been advocating a wider gap, perhaps a narrower one would be more effective, as is created by the sustainer's top plates that bridge this on an angle. I would be concerned that the flux would largely jump directly from one pole to the other and reduce vertical flux, but perhaps it actually removes some of this horizontal neutral effect by doing that?

To me, it shows a little of the benefits of the single coil design in creating a flux flow in the direction that you want it, even if in doing so, it sends it to places you don't, prohibiting a mid-driver for instance. Neck drivers seem to work pretty well with a basic design if this ilk and the benefits of this kind of design are outweighed by that of the simpler and efficient all power and polarity even and generally vertical of the SC. Not all SC drivers are equally good, but I have found my more recent creations to be very effective and suffer none of these "symptoms".

Still, no single coil has been able to create the effect this driver does in the middle position, or even closer to one pickup over the other. EMI is definitely reduced by it, but a lot of other problems are created also. I should say, that although the b and a strings are more responsive (the b will predominate in a chord for instance) all strings, even on this light set, are sustaining if not bent.

The best part in this has been the ease in installing and operating the device. This has been my major concern, massive 4pdt or larger switches, electronic switching...none of that. Siply hook the circuit to the pickup selector on one side, the driver on the other and a switch to turn on the power...just as with a single coil installation. The ability to use different pickups a bonus for sure and does create different effects. You could get all fancy and have the bridge pickup with the neck used for the circuit signal for a smoother more fundamental sound for instance, but I wouldn't go that far. Both running the circuit from one pickup or the selector (although in the middle position I suspect that both are connected anyway) is more than enough.

Of note is that the middle position, both pickups are far less "fizzy" to the point of no fizz at all! People may wish to ponder this, but really I think people will have to make one and observe the effects to get a good handle on it.

Another thing is that, compared to my SC drivers of the last year, this driver in the middle position requires a lot more power than those. In fact, I had to run out and buy a pair of 9v super batteries (A$10!!!) with a massively improved response over the older ones, but the drain was substantial with it needing a "rest" after about 10 minutes. I am getting no real heat from the circuit or the driver, perhaps a little warm. Except on the a and b strings (which may in fact be better), the SC designs are seemingly more efficient.

However, not a bad result from a first prototype. Sustain on all strings, easy installation and fitted the application (very thin, internal ceramic magnets, driver cost of $A2!!!). A lot of interesting effects to study and I am getting sustain on all strings, some have struggled with this on even simple designs and I appear to have light strings. No switch noise, easy installation, bonus pickup positions...all very encouraging.

I was planning to wind a parallel version today, I even have the winder charged up and the bobbin thing all glued up and ready to go (my bobbin plates are reusable). I am wondering however, if I shouldn't get a bit trickier in the design rather than simply repeat it in this format. I only have so many of these magnets to play with and I can't seem to locate more at the moment.

For instance, would I be better off, attaching a small neodymium magnet to extend the core a little and create a large vertical component between the gap, stick with the easier and more compact 2x4ohm coils, maybe a little thinner? Generally, using neo-mags pointing at the strings would be a pretty bad idea, however, in this case where opposing mags are next to each other and canceling out some of this attraction, and a lot of this attraction being horizontal anyway, perhaps it doesn't matter. However, of course I could be very wrong in my presumptions, perhaps the close opposing fields actually are stronger and not canceling, explaining the deadening of a bent g string for instance!!

This is just a 'maybe', but if it proves to be a real issue, then more careful design of the field will help, as will a heftier drive.

I think that the most likely reason though is that the field of either or both of the magnets (permanent and electro) is too uneven, and more careful design will improve this problem dramatically.

Well...a more heftier drive goes against my aims and undoes some of the advantages of the design. Yes, it reduces EMI problems and allows for more drive, however, all of the problems still exist with the use of more power, the thing is not fizz free! Rather one should aim to have it working efficiently so it has more effect with a given power, as it is, I need to run it at a lot of power, more than a SC for a similar effect with resulting battery drain and such being a major problem too.

My configuration with lots of overdrive doesn't seem to work well. I hoped that a more sustainiac-like driver would diminish the fizz, but that's not the case. At least I could remove my dummy coil without getting the squeal back! I'm afraid that the overdrive is on its way out.

I am so glad to here that as I believe that it has really been holding you back, I understand why you may have gone in this direction, but I always believed it to be folly. I was never taken with the idea of the loop thing either, and interesting effect that was worth looking into, but never one I would have entertained as a feature on a real world device. If you could loose that, and the huge amp, you may be a lot better off in many ways. One proven way of reducing EMI and fizz is to lower the power, simple as that. If the driver is efficient enough, then the effect will be there without extra power or loops or fuzz. That is my concern when it is mentioned that problems can be solved with increased power. It seems that even as a design is made to address the EMI, fizz or whatever issue (in my case the main motivation was switch noise and installation issues on multi-pickup guitars) the result is less efficiency or strange phenomena in performance.

That said, my experiments with this particular prototype bi-lateral mid-driver have been very encouraging and I hope to hear soon of some more ideas to improve it so I can make a modified model. There are still a few things I can further experiment with on this one of course. For instance, I could tilt the neck back on the tele to give a bit more space and so allow bigger steel pieces to be used below the driver. This would still fit the no route application as I could in a real world situation, simply cut into the scratchplate (3mm) to accommodate it without routing.

Have fun contemplating these things... pete

[psw]

Is anyone familiar with the "original" Sustainiac circuit, the one co-designed by Floyd Rose? Just saw one in the classifieds, the seller states "with Floyd Rose's signature at the back of the circuit"...?

It is not a sustainiac, but the same idea. Floyd claims to have come up with it on his own with no reference to the Micheal Brooks' infinite guitar or any other source (sure, and his fine tuners aren't the exact same mechanism used on violins and cellos...hmmm). He has his own patent. The device being hawked by EVH in the day. It is an early version of the technology but does work I am sure although I have heard that many early commercial units from all manufacturers suffered switch noise.

Oh...thanks for the message, but that ebay link doesn't have the item, or he has sold them. I recall that kevin on this forum sells them though. We had discussed in PM's, for others, the use of these pickup tops that are for changing the colour of your pickup covers as a possible way of making bobbin plates. I am not sure if there is much substance to them, for all I know, they may well be just stickers/decals and of no use at all!

I am going to have to try and put my thinking hat on with this driver problem. I was going to make a coil first thing this morning (now!) but now I am having second thoughts...any input in the near future may find it's way in there. I am not sure that a parallel driver will in anyway solve the problems of the series device and limits what I can do as the coils will have to be considerably larger and so necessitate a larger gaps. I quite like the idea of using the neo-mags in the gap, extending the cores a little and using compact series coils again. It is difficult, at least for me, to work out what this would do in FEMM though, but I will give it a go.

pete

[Captainstrat]

It is not a sustainiac, but the same idea. Floyd claims to have come up with it on his own with no reference to the Micheal Brooks' infinite guitar or any other source (sure, and his fine tuners aren't the exact same mechanism used on violins and cellos...hmmm). He has his own patent. The device being hawked by EVH in the day. It is an early version of the technology but does work I am sure although I have heard that many early commercial units from all manufacturers suffered switch noise.

Well...seeing that my handiwork isn't doing any better, I'm tempted to go for it: at the very least the driver part will be covered, and I'm sure the solder work on that circuit is cleaner than what I can accomplish...and seeing the seller's asking under $100.00 for it (have you seen how much the Fernandes kits cost?)...I'm very, very tempted! Since my current setup also has the switch noise well...

Do you know if Floyd's version of the driver also works as a regular pickup?

[psw]

For under a hundred, seems ok. Don't know much about it, I suspect it won't work as a pickup. definitely not in the mid-position either. These things cost a lot of a reason, you pay as much for a pickup which is known and relatively simple technology without any of the circuitry or innovation required of a sustainer. It is closing this gap that was the aim of my commercial ambitions, by combining an existing pickup with simple coils and circuits I hoped to make it more affordable, versatile and flexible while still giving a good performance, if not for the switch noise and the complications of installations, I would have done it too...

On that last point, make sure there are instructions with the floyd version. It is not a copy of the sustainiac and if simply ripped out of a guitar (usually a kramer) then you may have problems. If you really want to be sure, I think musician's friend were doing a deal on a kramer barretta sustainer entire guitar pretty cheap...or someone like that, you may want to consider this, I think it worked out similar to a fernandes system or sustainiac with installation with the guitar thrown in for free!

With anything eBay, it's buyer beware and no use asking for help from the seller, it may be the lack of knowledge or problems that is why it is being sold. Or, it could be a bargain. On the other hand, this was a very early model and may have it's own problems inherent in the design. Also, no one has experience with this so although we might try, we can hardly "fix" it without having hands on with it I suspect...being in Oz makes it pretty difficult in that regard!

good luck... pete

pete

[Captainstrat]

The dude emailed me a pic of what hes selling...

For under a hundred, seems ok. Don't know much about it, I suspect it won't work as a pickup. definitely not in the mid-position either. These things cost a lot of a reason, you pay as much for a pickup which is known and relatively simple technology without any of the circuitry or innovation required of a sustainer. It is closing this gap that was the aim of my commercial ambitions, by combining an existing pickup with simple coils and circuits I hoped to make it more affordable, versatile and flexible while still giving a good performance, if not for the switch noise and the complications of installations, I would have done it too...

On that last point, make sure there are instructions with the floyd version. It is not a copy of the sustainiac and if simply ripped out of a guitar (usually a kramer) then you may have problems. If you really want to be sure, I think musician's friend were doing a deal on a kramer barretta sustainer entire guitar pretty cheap...or someone like that, you may want to consider this, I think it worked out similar to a fernandes system or sustainiac with installation with the guitar thrown in for free!

With anything eBay, it's buyer beware and no use asking for help from the seller, it may be the lack of knowledge or problems that is why it is being sold. Or, it could be a bargain. On the other hand, this was a very early model and may have it's own problems inherent in the design. Also, no one has experience with this so although we might try, we can hardly "fix" it without having hands on with it I suspect...being in Oz makes it pretty difficult in that regard!

good luck... pete

pete

[psw]

Nice, it would be a really cool circuit to get a reading on the driver and as they are all through hole components, the entire circuit could be mapped out for duplication. I am pretty sure that it works solely as a driver, but I couldn't be certain. Also of interest is what appears to be a small transformer between the two switches there. I think fernandes has a similar thing. It may be a way of using the driver as a pickup or perhaps a noise or switch popping strategy, I don't know...I guess someone here should buy it, or at least who ever does, if they frequent here (which is possible) they could take some readins and better pics, maybe scan it, that kind of thing.

Since the last post, I have been in deep thought and tried a few femm ideas. What I keep coming back to is the way the SC style still has such a good "throw" and all the flux is transversing the strings in a vertical direction unlike any other dual polarity design. This means a single coil. So, with some success of the mid-driver I have to wonder if I could make a single coil version with some kind of strategy that might address the issues EMI with single coil drivers and the size factor.

I started to build one and would you believe, the whole thing flew apart just before the windings were finished. There is a lot of pressure in there, don't underestimate it in designing stuff. I have scrapped the wire in a big epoxy mess and reglued it with the remaining epoxy so hopefully the whole thing will be ok to wind, maybe tonight.

Basically, I got some very small powerful neo-mags, 3mm discs, 2mm deep. Thes are easily powerful enogh to pull a guitar string out off tune and very directional and localized. I joined a row of six top and bottom with thin steel so that most of the field circulates between these through the gaps between magnets and diffuses any magnetizim coming off the top. Most of what comes out will no doubt be turning in the sides and headed for the opposite pole. Using this as a core, I was/am hoping that perhaps this very thin core may create a very condensed coil with lots of turns (due to the narrow core) and the field be so powerful that most of it is being drawn back into the bottom or through the air gaps. My aim with this design is that the field is contained pretty close in to the driver and coil with little straying to the pickups on either side or along the strings.

If such a strategy were to work (only testing will be able to really tell) then it will have to work a fair distance from the strings to prevent wolf tones, tuning problems and loss of natural sustain. There may be a bit of a catch 22 there then, but I guess only testing will really be able to tell. Shame the thing self destructed, but this is no unusual in such development, I really thought the superglue that was holding these strong magnets to steel would have been enough, what a shame. Anyway, the epoxy is pretty strong so perhaps once this has dried enough, I will try again...god it's stick though, made a real mess!

pete

Put a watch on the auction...are you bidding CS?

EDIT:

Well that didn't work. One ugly driver, 8 ohms neodymium's magnets. Doesn't work in the middle, hardly works at all!!!!

You know, although I have remained faithful to the sustainer idea, I love the sound of the guitar and the act of playing with it. The kind of music I am enjoying at the moment has nothing to do with "sustain" and while I'd love to have this thing up and running and it would be a really cool addition to any guitar, it would only be that for me, an addition. I hope that others like UI and curtisa can lend me some more inspiration, While the bi-lateral of mine does show some promise of what might be possible, there are problems inherent in the design also that at least mine doesn't address. The uneven drive characteristics and the gap between the g and d strings plus a lot of power is a major concern. I could improve or try a number of things, but I am not sure they would address it's inherent faults. On the other hand, the solution a mid driver offers to the switching noise, complexity of installation and very low modifications to the existing wiring and guitar in general are major pluses.

I have a guitar that I would really like to add a sustainer too, I suspect this will become my main guitar, a very customized unique tele with rare fender HB and SCN pickups, roller nut, locking tuners and a kahler trem. It would be a shame and an irony if after all this, this is not is some way a feature. Still, instead of waiting, I have made a bit of progress on the thing and hope to have it up and playing soon... p

Edited March 25, 2008 by psw

[utopian isotope]

Plan 9 from outer phase again..

Is it possible to replace permanent magnet(s) (be it neodymium, ceramic, or whatever) with electromagnet(s)?

I'm aware that it wouldn't be too practical and requires more coils, more work etc.

What I have in my mind is to have some kind of "virtual"(instead of real one(s)) and an "adjustable" magnet(s).

I guess that it wouldn't be too efficient, if using same current/voltage, that driver uses?

Anyway... just a thought.

Edited March 25, 2008 by utopian isotope

[psw]

Is it possible to replace permanent magnet(s) (be it neodymium, ceramic, or whatever) with electromagnet(s)?

Well...besides there being absolutely no good reason to replace a free and cheap source of energy such as a permanent magnet, the one thing that most people focus on here is EMI, "electromagnetic interference"...so having what would need to be a powerful electromagnetic coil in there just to establish the a static magnetic field seems like the last thing you'd want to do. Think of the signal coming out of that thing...how are you going to keep that from affecting the magnetic pickups or the natural vibration of the strings...and more importantly....why?

Establishing a magnetic field can take a lot of energy, we use electromagnetic forces to simply manipulate an already established field. I kind of visualize the device as being invisibly linked to the strings via the magnetic field, move the field and the strings, caught in their sway will also move. But this "link" is kind of elastic so it is difficult to get an immediate response from the strings. The amount of power required to move the things, depends a little on how stretchy the link is and whether you are pushing or pulling at the strings within their established vibration and resonances.

So, you need to be pushing and pulling in time, if you try to push when you should be pulling, if a little off, then you will have to pull a lot harder. For instance, if you have a pendulum swinging and you want it to swing left instead of right, it's going to take force to stop it and more force to move it the other way....a child however can maintain a swinging motion or increase it by simply moving in time with the swinging motion, out of time and you stop.

Ok...so it is a little early in the morning, but this is kind of where I bring in my "fast" driver idea. It takes time to establish an electromagnetic field and time for the string to respond to it, in that time, the string is still moving. The closer to the "phase" you get between the actions of the driver and the vibration of the string, the easier it is going to be. Perfectly in phase and it is not going to take much force at all. Further, if it is in phase, the pickup (which, being electromagnetic also has response time lags) requires only a bit of a nudge to keep it going or increase in vibration.

This is why I get a little funny about the idea of more power or stronger magnetics or anything like that being a solution. The idea of correcting an inefficient "slow" driver by applying more power is not sensible to me for instance. If the design is good, it will work with a low power and with reduced EMI and other unwanted effects, if it is not so good, more power indicates, at least to me, that you have a design that is working against the vibration of the strings.

While potentially debatable, I also feel that one should aim for a drive signal which is as close to that of the natural vibration of the string as possible, not only in time but in nature. So the idea of clipping the signal intentionally now seems wrong to me, it is like you are pushing the kid on the swing with short forceful hits, not only will he not like it, but if out of time (which we will be, lags and phase problems are inherent even in the pickup that sends the signal) you will set up disruptive distortions in it and possibly stop the normal swinging action.

Hmmm...perhaps I am stretching this a little far. But generally when looking at driver designs I am looking for something that responds as "fast" as possible and as close as possible to that of the natural string vibration and running with as little power as is required to create the effect. More power should produce more bloom or perhaps harmonic effects not be a requirement of the driver working at all. Notice, I haven't mentioned yet the desire to have the thing run on a battery inside a guitar.

There are a few components to the system. The driver and the amplifier essentially. Build a circuit suitable for the project...a more powerful amplifier perhaps because you could run it with less distortion for a given power, but not because you need excessive power because the driver design is faulty...it will likely only amplify the faults! Test the drivers with the same circuit. Build a driver design and develop it till you know that it at least works, before trying to better it.

Also, back up ideas and models with real world experimentation. Is an idea not working because of build quality, share it anyway, perhaps someone else will find a way or show you a different approach to it. Things like FEMM models are very limited and don't take in all the factors, useful for visualizing ideas, but not really useful till tested out and the results of these things really looked at. I have made at least 4 drivers in the last two weeks...yesterday I made an SC driver with a very thin narrow powerful core, complete failure. Before that the bilateral design, some interesting and encouraging results...

-------------

What I am thinking about now is a bilateral driver pair with cores that extend and overlap between the d and g strings. Something like this...

Again, I don't really know how you would visualize this in FEMM or if it offers a solution to the gap problem of the last driver. Either way, it is possibly only a partial solution as it did produce a fairly uneven drive. Perhaps because of this, I am wondering if the HB design isn't a better option, being pretty much two SC pickups. However, what would be cooler perhaps is a better SC design that somehow contained the field and was compact enough to fit in my application....hmmm.

pete

EDIT: Taking my own advice, I have built a new bilateral driver, am waiting for the epoxy to set. This has thinner magnets but longer, I made it by gluing together 3 little ceramics end to end, so each coil is 30mm long, 5mm wide and about 3mm deep with a condensed full epoxy coil of 4 ohms each wired in series, no bobbins.

These can be arranged in a couple of ways, one is to close the gap between the cores, the other is to slightly overlap as above. The magnets are half the depth of the last one, but I have the option of adding more magnets below for instance and still slide it in under the strings. I decided to use the series winding because it is a lot easier with no connections required and because they are much smaller and so allow closer spacing and condensed size. It will also allow a direct comparison with the last series coil of similar design which, after all, did work. If this arrangement is an improvement then I guess a parallel option is the next obvious move, perhaps with increased magnet depth and strength. If not, well am awaiting other ideas and results of UI's and curtisa's similar models.

p

Edited March 26, 2008 by psw

[Captainstrat]

pete

Put a watch on the auction...are you bidding CS?

[

Indeed! Oh, and I think this is the model in particular:

http://www.musicyo.com/planet/metallist.asp

If I win the auction I'll have to take careful measurements to make sure the routing I've done a few months ago is sufficient. And if it is indeed the same driver/circuit it works with a pair of 9V batteries in series (ouch, more routing? ) but on the plus side it would also work as a neck pickup!