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Diy guitar ebow

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Blueteeth

Well-Known Member
does any one know if you go into this circuit like an amp or do you just connect if to a battery and hold it over the pickup of a guitar.


https://www.logosfoundation.org/elektron/ebow_amp.gif


Also are the coil sizes critical?

It's an e-bow, that means you hold it over the strings. I believe it is battery powered. If you plug it into your amp...would cause issues (would overdrive the input with whatever the coil pickups, probably mains hum).

Its pretty simple, picks up the vibration of the string using the 'pickup coil', amplifies this using a power amp in positive feedback configuration, then drives a second coil, which vibrates the string. I would have thought the pick-up coild would be a coil surrounded a permenant magnet, so it can pickup the vibrating strings (air coil would do sod all)

The circuit looks easy, the hard part will be putting it in an enclosure that can be easily used by a guitarist...and finding the optimal position/configuration of the coils. I say experiment!

Might even have a bash at building one myself..perhaps making it over complicated by adding a distance sensing circuit :D


Blueteeth
 

marcbarker

New Member
This is really neat! I think I'll make one and try on my Gibo LP!

Can get audio transformers out of discarded cordless telephone.
 

Mdkanz

New Member
I understand what to use for the input transformer but i don't understand the output one. could someone explain what transformer to use for the output.

Also i could not have a 1N4002 would a 1N4003 work?
 

audioguru

Well-Known Member
Most Helpful Member
I understand what to use for the input transformer but i don't understand the output one. could someone explain what transformer to use for the output.

Also I could not have a 1N4002 would a 1N4003 work?
The input is not a transformer. It is a telephone pickup coil.

The output is the "E" laminations and coil from a transformer with the "I" laminations removed so it projects a magnetic field to the strings.

A 1N4003 is exactly the same as a 1N4002 except it survives a higher reverse voltage. It is fine.
 

audioguru

Well-Known Member
Most Helpful Member
What are ''E'' and ''I'' Laminations?
They are the iron core strips. The wire is wound on the center prong of the E and the I closes the magnetic loop. You want to remove the I iron strips (laminations) so that the magnetic field can escape to the guitar strings.
 

marcbarker

New Member
They are the iron core strips. The wire is wound on the center prong of the E and the I closes the magnetic loop. You want to remove the I iron strips (laminations) so that the magnetic field can escape to the guitar strings.

Good explanation AG! :)

8395-EI_2.jpg
 

Mdkanz

New Member
Thanks, what 2 out of the 5 wires do i connect the amp to? (Would this transformer work? https://www.radioshack.com/product/index.jsp?productId=2103254)

Also does any one know how to play the guitar with it? do you touch one of the coils and hold the other one over the pickup? do you touch both on the strings? do you pluck the string first then touch the ebow on it...


and is there a way to test the amp without the coils to make sure it works?
 
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marcbarker

New Member
Thanks, what 2 out of the 5 wires do i connect the amp to? (Would this transformer work? Audio Output Transformer - RadioShack.com)

Also does any one know how to play the guitar with it? do you touch one of the coils and hold the other one over the pickup? do you touch both on the strings? do you pluck the string first then touch the ebow on it...


and is there a way to test the amp without the coils to make sure it works?

It's worth a try. I have a good feeling about that transformer if it helps.

No idea what wires, just use trial and error. I think you'll need some permanant magnetism somewhere as well.

I tried an e-bow in my local music shop when they first came out in early 80's, I didn't buy it because it was too expensive for what it was. It was just before MIDI synths came out. You just hold it over the strings instead of picking, the movement of it towards the stringa starts the bowing. Makes a different harmonics depending how near the bridge.
 

Mdkanz

New Member
ok, i took a part a cordless phone i got at a thrift store and the pickup (i'm assuming that is the part you talk into) is two little black 1'' diameter mics is that what you are supposed to use? the speaker looks more like what i was imagining it is aboutt 2'' diameter would it work?

I think you'll need some permanant magnetism somewhere as well.

What did you mean by this?
 

marcbarker

New Member
ok, i took a part a cordless phone i got at a thrift store and the pickup (i'm assuming that is the part you talk into) is two little black 1'' diameter mics is that what you are supposed to use? the speaker looks more like what i was imagining it is aboutt 2'' diameter would it work?

What did you mean by this?

look for one of these inside it.
8397-Telecom_Transformer.summ.jpg
and remove the 'I's to leave behind the 'E' + windings

Maybe you can hack the earphone out the phone and/or use that too?

by magnetism, I mean something to make the strings detectable. There's also a magnet in the pickup.
 

audioguru

Well-Known Member
Most Helpful Member
The telephone pickup coil is a recording accessory and is not part of a telephone. It picks up the magnetic field of the earphone of a telephone.
 

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Mdkanz

New Member
OK, i built the whole thing exactly how it said to and it 1/2 way works. it will sustain (but not infinite) it if i pluck the string then put the pickup up to the string and the transformer kind of under the string really close to the coil any ideas? also i thought ebows are supposed to change the sound this just sustains the normal noise.
 

marcbarker

New Member
OK, i built the whole thing exactly how it said .

Nah! No one builds the "whole thing exactly how it's said". Cos if they did, they wouldn't be saying it don't work! Plus if we all did the exact same thing it'd be well boring.

Have you tried adding magnetism to the sensor?
 
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marcbarker

New Member
the sensor is the pickup coil. If it hasn't already, add a magnet to it. Attach with a bit of blu-tac that's all! I think it will increase sensitivty of pickup
 

audioguru

Well-Known Member
Most Helpful Member
About 50 years ago they made the same "elbow" circuit you made to make a guitar sustain.
Today they use a DSP circuit bark like a dog and make many other sounds.
 

Mdkanz

New Member
I tried the adding a magnetic to the sensor and it made it a little bit more sensitive but i think the problem is that whenever i touch the sensor on the string that it muted the string any ideas what i should do?

and are you supposed to touch the output transformer/coil on the string?
 
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