Sustainer/Resonator/Ebow/Sustainiac devices

[Zhangliqun]

Do they use electromagnets or permanent magnets?

[jonson]

Talk to Peskywinnets he's the man.

[Peter Naglitsch]

There are a huge amount of info about sustainers on the project guitar forum.

[David Schwab]

Permanent magnets. I didn't think the Ebow had a magnet, but I checked mine and it does. It's pretty weak though.

[Zhangliqun]

I just wonder about the Fernandes (and the old Hamer) devices because you can turn them on and off with a switch, leading me to think maybe it's an electro.

[Peter Naglitsch]

A sustainer is more or less a pickup -> small amp -> a driver coil generating a magnetic field that get the strings to vibrate. The driver coils I have seen have been pretty much like a "back wards" single coil pickup with fewer turns. To just turn the the device on/off you just turn the feedback op-amp (or whatever you are using) on/off. But I'm no expert. For in depth info look here:
Sustainer Ideas - Project Guitar Forum
Almost 5000 posts on this specific topic

[David Schwab]

Yeah, they all have an on/off switch, but they all have permanent magnets too. The coil does work sort of like an electro magnet, but it varies with the signal, and the magnet helps to get it going.

The Fernandes and Sustainiac units are very similar.

[peskywinnets]

There are a huge amount of info about sustainers on the project guitar forum.

But, alas a lot of it is borderline wrong/erroneous/misleading...there's some useful info there, but you've to wade through an awful lot of repetiton. (300+ page thread anybody?). Also, the trouble with that thread is that it's pretty much everyone chiming in with their take (or assumptions)....there's just a very small percentage of posters who actually contribute technical info (or have the test equipment necessary to draw meaningful conclusions)...so it ends up all very wordy, mucho debate - with not a whole lot of it based on findings.

The magnets used in a sustainer are of the permanent type ......of course, there'd be nothing to stop you using an electomagnet in place of the permanent magnets, but that would use more physical space & consume extra battery power (albeit minimal if you could squeeze enough windings in)

I'm not overly familiar with the Ebow - but it's my interpretation that it takes advantage of the magnets already present on the guitar (in the pickups), to bolster its own onboard magnet.

[Mark Hammer]

They need to use permanent magnets. The current requirements for charging an electromagnet, on top of what they have to do, would likely diminish battery life significantly (they use a 9v battery), or at least enough to diminish interest and increase frustration with the product.

[peskywinnets]

They need to use permanent magnets. The current requirements for charging an electromagnet, on top of what they have to do, would likely diminish battery life significantly (they use a 9v battery), or at least enough to diminish interest and increase frustration with the product.

A Sustainer doesn't need to use permanent magnets - as it transpires the two big commercial sustainer players do utilize them (becuase most guitarists prefer to power their onboard active electronics via woeful PP3s), but for example, squirting phantom power into the guitar will supply more than enough current (as it goes there's not a whole lot of current needed, but only *if* you put enough windings on your electromagnet substitute.... ie current x turns ...the more turns, the less current required, but like I say, then you run into space problems).

I was only putting the case forward that you don't *have* to use permanent magnets....but of course, in practise, using permanent magnets (for most) is a simpler, more compact, easier solution.

[Mark Hammer]

No, you were correct to elaborate as you did. My intent was to convey that commercial products factor in convenience as a design constraint, which non-commercial versions may not require. And as you correctly noted, there is nothing in the basic precepts of the device that demands it use a permanent magnet, any more than loudspeakers demand use of a permanent magnet.

I'll just note in passing that during correspondance with a DSP programmer at a major effects company, I learned that they had to rethink the design, and clock-cycle requirements, of some of their products so that squeezing several hours out of an alkaline PP3 (9v) could remain a reality. That may not seem like much, but it can easily make the difference between someone buying something in a store that a sales clerk just hands them to try out, and NOT buying something because the sales clerk couldn't find an adaptor and/or available AC outlet. And while getting "only" a couple of hours' service from a fresh 9v may strike many as reason enough to use an adaptor or phantom power, for plenty of people, using up a fresh alkaline over the course of a show is simply a consummable and a normal part of operating expenses.

But again, just to reiterate your point: that doesn't mean we ALL have to do that.

[David Schwab]

I'm not overly familiar with the Ebow - but it's my interpretation that it takes advantage of the magnets already present on the guitar (in the pickups), to bolster its own onboard magnet.

That seems to be correct. You really have to hold it over a pickup to get it going. That's why I didn't even know it had a magnet until I checked it for this thread. But it also has it's own pickup in it, so maybe that's what the magnet is for?

I'l have to check the patent out.

[peskywinnets]

That seems to be correct. You really have to hold it over a pickup to get it going. That's why I didn't even know it had a magnet until I checked it for this thread. But it also has it's own pickup in it, so maybe that's what the magnet is for?

I'l have to check the patent out.

Like I say, I've not had any experience with an Ebow, but if it does have its own (weak) magnet on board, then obviously that's going to be orientated with a certain polarity .....and if it's using a pickup to bolster the field, then that would need the pickup to have a polarity 'in sympathy' ....but surely there isn't a standard with pickups & polarity orientation? (which ought to be a problem with say single coil pickups)

What happens when you place the Ebow over each of the individual coils of a humbucker?....in principle, one coil's magnet should bolster & one should diminish the field? (just wondering what the observed outcome is in practise?)

[David Schwab]

Like I say, I've not had any experience with an Ebow, but if it does have its own (weak) magnet on board, then obviously that's going to be orientated with a certain polarity .....and if it's using a pickup to bolster the field, then that would need the pickup to have a polarity 'in sympathy' ....but surely there isn't a standard with pickups & polarity orientation? (which ought to be a problem with say single coil pickups)

What happens when you place the Ebow over each of the individual coils of a humbucker?....in principle, one coil's magnet should bolster & one should diminish the field? (just wondering what the observed outcome is in practise?)

That's a good question. I just checked my Ebow (which I purchased in about 1986) and I get around 200G North, on most of the bottom area of the Ebow. There is a small gap which reads about 10G South in the middle.

So I got out a guitar with humbuckers, my Univox Hi-Flyer, and noted the orientation of the magnets. The screws are South. I read about 330G right at the screw, and 130G at the string distance.

With the guitar laying on a table, the Ebow starts the string vibrating if I sit it on the strings at the neck pickup. It doesn't seem to matter which pole, as the Ebow covers both, but the screw pole seems a little more sensitive. I can't get it to do anything at the bridge without plucking a string to get it going.

Then I tried sitting it between the pickups. My idea was to stick a 1/4" X 1/4" C8 under the strings to see what happened, but the Ebow started sustaining the string with no intervention. When I stuck the magnet under the string, having the North side facing up did diminish the effect slightly.

[peskywinnets]

Thanks for the taking the time out to experiment & feedback (no pun intended!) ..I guess I'll have to log this one under "needs more investigation if I ever get my hands on one" ....because for the life of me, if the Ebow really does use the guitar's pickups to bolster its own internal magnet....then I've not a clue how it can work above either/both polarity coils of a humbucker!