Pickup construction

Gil Berry · From: Westminster, CA, USA

Just killing a little time and trying to get a feel into the the pickup construction process. I have a couple of questions: First, does using a very strong magnet core (like alinco) or even some of the "supermagnet" stuff make the pickup hotter? And a second (stupid) question: when winding the wire around the frame, what winding scheme is used - for example, like a level-wind fishing reel, or a spinning reel? Or just hand feeding? Does it make a big difference to the finished product? I can see that the "level wind reel" would enable more wire (and turns) for the same coil diameter because less space would be lost between overlapping wires. Just curious. Rolling Eyes

Nicholai Steindler · From: New York, USA

I am so far from the expert on this, so double check me, but I have been doing research, I'm building some pickups for myself.

The stronger the magnet the stronger the signal.

I don't think it matters how the wire ends up on the spindle, but it will change the tone. You will want to probably build a rig of some sort to wind it, like a drill or slower motor. Holding the wire tensioned in your hand will work. The more tension, the more winds you will be able to get but don't pull too hard. Gibson used to wind until the spindle was full, until they automated. Check your resistances when done. 4k-9k is typical of guitar, depending on pickup. PSG seem to go 17k or so. The pickup supposedly gets hotter the more winds, but who knows.

EDIT! just read this. Mr. Green

http://www.stewmac.com/freeinfo/i-1465.html

Gil Berry · From: Westminster, CA, USA

Wow, nice referral. I never thought about distributed capacitance. But it makes sense. The closely wound (in my venacular - level wind fishing reel) coil would have a higher capacitance which would tend to offset the inductive reactance gained by the additional number of turns in the same diameter pickup. And also interesting to note that the higher the magnetic flux density the greater the pickup output. This does indicate that some of the new supermaget materials might make a better pickup...thanks for the info. I wonder if anyone has tried it? I ran into a small "refrigerator" magnet once that you simply could not pull off the 'frige door without sliding it to the side. That thing would probably snatch your bar out of your hands. lol

Jerry Overstreet · From: Louisville Ky

Wow! Stew-Mac really has a lot of good free info. I haven't seen that pickup tute before.

Nicholai Steindler · From: New York, USA

There is a company that uses neodymium magnets, I;ve been really interested in trying one, but I don't have an excuse.

http://www.q-tuner.com/

Keep in mind the stronger the magnet the less sustain you will get from the string because the magnetism dampens its ability to vibrate.

Alnico 5 and alnico 2 and 3 seem to be the most common. Five is stronger.

Steve Waltz · From: USA

I bought a pickup book from Amazon. On the cover it has a red truck hauling different pickups. It goes into how different pickups are made and discusses how each aspect of the pickup design effects tone. A bigger magnet does more than just increase output just like more winds does more than just increase out put. The book doesn't tell you how to build one and it also spends more time than I would like talking about current custom builder pickups. It does have some good history and is worth it.

The Jason Lollar book is going to be reprinted but as of last week I couldn't get it from him.

Nicholai Steindler · From: New York, USA

I might have to try to get that book.....

Good point. I htink the weaker the magnet the warmer and fatter the tone if I remember right. I'm trying Alnico 3's. I'm sure thats oversimplifying.

Bent Romnes · From: London,Ontario, Canada

I am a total beginner in the pickup building. I have yet to make my first one. Just today I completed my PUP winder.
Basically it has a sewing machine motor with variable speed, a counter fashioned out of a magnet, a reed switch and a calculator. I was planning on fastening the bobbin on the small wooden wheel with double sided tape.
From what I have read, Alnico 5 magnets are most common. Also, I got a spool of #42 wire, 125000 feet of it, on ebay for about 1/3 of the price of stewmac.

Be interesting to see how they turn out.

_________________
BenRom Pedal Steel Guitars
https://www.facebook.com/groups/212050572323614/

Frank Sprague · From: Custer , Washington, USA

That's pretty cool Bent - I love this kinda stuff ! I built a fishing reel line winder that has the same engineering ,and looks comparable to your "wire winder" - Sure beats watching TV ,but drives the wife nuts . .
_________________
The only things in life I truly hate - fleas , fruit flies , and building furniture

John Groover McDuffie · From: LA California, USA

Bent, you may be a novice to pickup building, but you are obviously an Ace at jig and tool building.

Bent Romnes · From: London,Ontario, Canada

Thanks guys, but I can't take the full credit. Youtube has several "inventions" on the subject.

I have one small problem: either the calculator is too slow or the reed switch is if I go over approx 300 rpm it seems there is not enough time for the counter to count. Would that be the magnet, reed switch or the calculator itself? Solutions welcomed!
_________________
BenRom Pedal Steel Guitars
https://www.facebook.com/groups/212050572323614/

Bent Romnes · From: London,Ontario, Canada

double post
_________________
BenRom Pedal Steel Guitars
https://www.facebook.com/groups/212050572323614/

Georg Sørtun · From: Mandal, Agder, Norway

Bent, it's probably the calculator that's too slow in scanning through the keys, as it only has to be a little faster than your fingers for normal use, and low scanning-frequency saves battery energy/life.

Reed switches also can't handle really high switching speeds because of mechanical limitations - the larger they are the slower they are too. Tune the distance and angle for the magnet vs. the switch - get the magnet closer to the switching-end of the switch and twist it a bit to get optimal polarity for quick and well-defined close and open, to see if the reed-switch/magnet coupling is part of the problem.

BTW: just delete the last post when you accidentally double-post, instead of just editing it.

Bent Romnes · From: London,Ontario, Canada

So what we're saying is that both the reed switch and the calc are too slow. The magnet is so close that I had to file a bit off the plastic housing so it wouldn't rub.
I have some rare earth magnets, strong ones. Maybe I should try one to see if that makes a difference.
In the meantime, I have lots of time and likely 300 RPM will be my speed for the first few pups Smile

..I didn't think it was possible to delete a post. How do you do it?
_________________
BenRom Pedal Steel Guitars
https://www.facebook.com/groups/212050572323614/

Georg Sørtun · From: Mandal, Agder, Norway

You don't need a stronger magnet for the reed switch, but you may need a faster reed switch and better tuning of the magnet's orientation. Faster usually means smaller switches, as read switches have a mass to move to open and close. Don't think switching-speed is particularly important for that type of switch, as even the largest/slowest variants will be fast enough for its intended "window alarm" use.

Bringing the switch and magnet closer to the axle may help, as an RPM counting reed switch usually works optimally when it is pulled "on" around 1/4 of the time and "off" 3/4 of the time. When mounted near the edge of the wheel as you have now, the ratio is more like 1/10 "on" and 9/10 "off", which leaves a very small window for the calculator to register "on" as "key-pressed" on.

I'll have a look in my shop to see if I got a few leftover reed switches and magnets from my MIDI days - they can register much higher "magnetic field change frequencies" than 300 RPM. If so I'll bring one or two sets along in March so we can do some testing on your rig.

Of course: a faster reed switch arrangement won't help at all if it switches faster than the calculator you use can register its keys. Can't let you have my zero to 100 MHz puls/frequency counter, I'm afraid Smile

You can always delete your own post as long as it's the last in the thread. Go to the Test section and try out use of the [X] button alongside [EDIT], or delete while editing. Ideal for deleting double-posts, and also comes handy for "bumping to the top" without creating long-tailed threads.

Derrell Stephens · From: Shreveport, La. USA

Magnetic proximity switches (and a magnet embeded in the wheel) will catch revs at high speeds ... I have seen them as high as 2 rev/sec in these applications ... very accurate. Off course a PLC/DCS was attached (or a PC based controller I/O PCI slot card with Digital Inputs [DI's]).

D

Bent Romnes · From: London,Ontario, Canada

Georg Sørtun · From: Mandal, Agder, Norway

Derrell, 2 revs/second is only 120 RPM, so that's slow. A small reed switch can manage 10 to 15 revs/second in a good mounting, which equals 600 to 900 RPM. Should be enough for a PU winder if that calculator can handle it.

Of course: even a very cheap optical switch with a flag can easily manage 5000 RPM, but needs an interface. Probably much too fast for that calculator anyway, so if such speeds are needed it'll be better to buy, or build, a dedicated counter.

Bent Romnes · From: London,Ontario, Canada

Georg, re: your post about the reed switch... I took it to mean that a switch with shorter "arms" would make for a faster switch? In case I am on the lookout for one...
Also, I will experiment with the switch and magnet closer to the shaft.
Also: The reeds are in a plastic housing. I wonder if it would be better for the magnet if I cut away the housing so I could get the magnet that much closer to the reeds and also eliminate the plastic restriction for the magnet attraction?

In the meantime, yes, please do bring some switches with you...
_________________
BenRom Pedal Steel Guitars
https://www.facebook.com/groups/212050572323614/

Georg Sørtun · From: Mandal, Agder, Norway

Bent, leave the reed's housing in place. It won't really make a difference, and you risk damaging the switch. You have what looks like an enormously large magnet on your winder, so lack of magnetic force isn't a problem.
"On/off ratio" matters more for high speed - especially on a slow reed, so take it closer to the axle - but not so close that the axle starts contributing to the magnetic field.

Small, mercury-wetted reed switches are often used for high speed counting - like for your PU winder. "On/off ratio" matters for those too, and they're usually even more sensitive to residual magnetic fields.

Anyway, it'll be easier to tune it all for optimal counting performance when I'm there, so just "take it slow" for a while Smile

Mike Wheeler · From: Delaware, Ohio, USA

You should consider that the RPM's will affect how you need to feed the wire onto your bobbin. I used to custom wind pickups back in the 60's and quickly found that, without a mechanism to control the tension on the thin pickup wire, it was VERY easy to break the wire.

300rpm seems pretty fast to me. Now, if you were winding a round bobbin speed isn't as much of an issue. But, with the oblong shape of a pickup, you'll get quite a jerk on the wire as the bobbin turns.

Just something else to consider.
_________________
Best regards,
Mike

Bent Romnes · From: London,Ontario, Canada

Scott Swartz · From: St. Louis, MO

An optical sensor is the way to go for accurate counting.

Basically a optical source and receiver, one on each side of a disc with a slot to let the light through once per rev.

This is what the Schatten winder uses, and many of the DIY guys also.

Go here and start searching, all will be answered, save you a lot of wheel re-inventing

http://music-electronics-forum.com/f11/

they even have a sub forum dedicated to building winders

Personally I use the Schatten winder, its a little expensive for what it is, but works well and you can be winding 5 minutes after you open the box.
_________________
Scott Swartz
Steeltronics - Steel Guitar Pickups
www.steeltronics.com

Forum Index > Electronics		Next oldest topic :: Next newest topic