Ok, now I can see that we're in agreement ...it's the word 'external current' which made me raise an eyebrow.
Clearly the pickup signal has no capacity to drive a sustainer coil, so an 'external' power supply is needed (to buffer the pickup signal, then amplify it ...then driving AC signal...
In your first post you said...
"There is no external AC current applied, the AC signal is created by the vibrating of strings"
perhaps we're at crossed lines, but there is very much AC current applied to the driver coil (the bridge pickup AC signal get amplified & then it's fed into an...
This thread seems to be going off in a tangent!
The AC signal fed into the coil comes from the guitar's bridge pickup (it's buffered & amplified & fed into the sustainer driver coil)...the resulting current through the coil generates an alternating magnetic field. Because a magnetic force can...
Thanks ed...that's just the type of input I seek, alas because I want to mount this device on the guitar body (as opposed to fit into an existing pickup routue ...which is deep), I'm somewhat constrained by height, but I'll take those points on board.
dgallup - re augment/decrease the pull -...
I did search, & yes whilst there are threads discussing such a device, my actual reason for posting is less to do with the makeup of a sustainer (which seems to be what most other threads discuss), but how best to choke off a magnetic pull using an AC coil.
In other words, If I put alnico pole...
Trying to wrap my head around the optimum design for a sustaining device for guitar.
What would be the best arrangement (material/magnet wise) for the following...
Think of (loosely) a guitar pickup...permanent magnet on the bottom, a coil with a steel core. This results in a 'throw' (for want...
Ok, next dumb question(!)
When I fitted & played the guitar sustainer, I noticed some minor sparking when the guitar string (the string is grounded) touched the sustainer (mild steel) core....I measured about 3V DC present on the mild steel core, so obviously when that 3V gets grounded via the...
Does anyone hold a view on how well an alnico magnet rectangle (ie like a blade ina guitar pickup) would work as the core/centre for a sustainer?
I was thinking about getting some magnets made for guitar pickups anyway & perhaps it might be worth investigating getting a few made for a sustainer...
Re current density - dunno...how do I work that out?! There's about 120mA flowing through the coil & about 200 windings.
re am I looking to build?. Well, I'm just dabbling but this has become a bit of an obsession! I've made a lot of circuits, wound a lot of coils, tried a lot of different core...
As you say you are guessing!
A little bit more info (because it seems there's many trying to tell me how a sustainer works!)...I've actually got the sustainer working well (it has been a long journey & belive me, I've tried every permutation known to man!), the last 'challenge' is the magnetic...
No, it doesn't wok as you say.
Sure, a guitar pickup senses the string...that signal is then buffered/amplified and fed to the driver coil. The AC signal (i.e. as sourced from the pickup) modulates the permanent magnet field acting on the string...which causes the string to move in sympathy...
The permanent magnet on the bottom of the core acts akin to a 'bias' ...it attracts/pulls the strings down in the absence of an AC signal through the coil. When an AC current runs through the coil, then the core's magnetic 'pull' is both reinforced & (to an extent) negated ...this is what causes...
Hi Bill, You raise a good point about the coil being the potential source of the high heat, my plan of attack...
Substitute the present steel core for a temporary lash up made with electrical steel laminations (it'll look ugly, but it';s just for a test)...carry out the same sustain tests at...
the problem is, the thinnest strings on a guitar need quite a bit of current through the coil (& quite a few turns too!)...in fact I've been on a fair while getting as much magnetic drive into the core as possible (to assist in getting the thinnest strings to sustain well), so any thought of now...
Corrosion on a guitar could be a bit of an issue (sweat dripping onto the sustainer from the guitarist's hand, beer spillages, humid environments etc)....and a rusty looking core won't look nice, so actually 430 FR quite appeals! (I'd actually been fretting how to make silicon steel a bit more...
Re 430fr stainless....every bit of stainless I've tried wasn't magnetic?
The core of the coil needs to be magnetic to (for want of a better word) 'conduct' the permanent magnet's flux attached to the base of the core up through the coil & out the top which results in a quiescent magnetic...
Thanks...option 2 is going to be a killer to put together...the dimensions of the inner core is just 4mm high x 2mm wide x 54mm long.....so I'd be looking at about 100) strips of 0.5mm thick electrical steel in a tiny 4mm x 2mm (it ain't gonna happen!). I was hoping that option 3 would be...
So I made a guitar sustainer (basically an AC electromagnet, with a permanent magnet on the bottom top pull the strings down in the absence of any AC signal going through the coil) - it works ok but the driver coil/core gets extremely hot ...especially at high frequency (frequency range is up to...
The acrylic most definitely isn't for show...how else am I going to hold six small coils vertically in place below each string?!! Yes, I guess I could mould the coil into some form of mouldable material...but I have no moulding equoipment (nor experience). I have a hobby CNC machine, so I can...
