Remaking The Horseshoe Bass Bobbin

[Moonie Man]

For your reference: Here is the specification of the coil wire which I use.http://www.mwswire.com/awgsearch2.asp

[johnallg]

Time to let copper fly!

[jps]

Time for a true, hand made scatterwound bobbin to be made!

[Moonie Man]

My old Lap Steel bobbin with Horseshoe has still been installed in my Bass.
Although it is I played repeated and sound is checked, and that sound is overdriving in sometimes but there is brilliance and clarity in it sometimes too.


I think that the direct cause of higher output(when I picking strongly) is not the value of 7.237K ohms DCR of a coil.
Supposing if a strings is set at a suitable interval in the magnetic field, I think that DCR value is probably no problem to use and match combination to Toaster-Top at front.

However, if in the coil wounded more mostly, it will be high frequency response is spoiled and more output be gain like indication of Geir, Sean and CJ.
Actually, the sound of my old Lap Steel bobbin is thick and bold but it is a good sound pleasing to me..
I will revision a target acquisition value of DCR to the wide range of 6K to 7K+ ohms upward roughly for the coil winding. Probably, in a value lower than 6K, an output will be too low to use with Toaster-Top though it is excellent in the high frequency response.


Now, the subject of a present stage is - What rotation numbers of winding turns to desired DCR value?
Since I am the first experience, I would like to advance things to safety this time, although precious suggestion was obtained from several experienced members also with this thread here. Once it turns off and cut the wire, that is because it will be troublesome.
I would like to try the number of times of exceeding 8,000 turns of winding further on that for the first. (Although there is probably an objection .... )

[johnallg]

It is easier to overwind and then take some wire off than to wish you added more turns.

[cjj]

You can calculate the approximate amount of wire you will need. 42 gauge wire has a DC resistance of 5470 ohms/km, so to get 7500 ohms, you will need 7500/5470=1.3711km of wire.

Now, take a piece of the wire and wrap one turn around your bobbin, then measure that length. The number of turns will be given by 1.3711km/length_measured.

Of course, as you wind more wire onto the coil, the length per turn will increase due to the increasing size, so you will not actually need as many turns as calculated. This is OK, as John said, it's easier to overwind and then take some wire off, measuring the resistance every few turns (or measuring the length of the outer turns and calculating the resistance per turn and then how many turns to remove).

If you keep track of how much you remove, you will know the number of turns left on the coil and will be able to reliably make more coils with the same resistance...

[teeder]

[weemac]

ResistanceisFutile.jpg

Shhhh!

emac.

[Moonie Man]

CJ, Thank you for your polite advice.
But my project is under stagnation now.
I tried the trial winding - As a result, the arrangement of the winding machine got to know that it was delicate and difficult.
It is adjustment of rotation speed, a wire guide, hand tensioning, and a spool, etc. so, in order to find out these best relations, it is still likely to take a little time.

I forgot for there to be my work!

[Moonie Man]

The perimeter of the center section my bobbin is about 124 mm.
I go to sleep in preparation for tomorrow's work.
Good night.

[Seans]

What resistance do you get on 10 winds.

[Moonie Man]

Surely, the perimeter of the center section my bobbin was 119.7 mm.
According to calculation of CJ's, when 6.8k ohms is set as a target of my bobbin, it is:
6800/5470 = 1.243144 km.
1243144 mm/119.7 mm = 10385.

[Moonie Man]

What resistance do you get on 10 winds.

Sean, it was 10.8 ohms. (if correct)

[Seans]

So that works out at 8,640 ohm for 8000 winds, taking into account the bobbin size at the start and will increase more, I reckon a very approx finish at 8000 winds of 9K. Does this compute with the other calculations.

[Moonie Man]

Sean, You are right. But the problem is deferment just for a moment.

For the time being, I will begin adjustment of my winder.


Session One: Stopped@243 - The wire has gone out on the edge of wire spool.
Session Two: Stopped@26 - When I tried to take a coffee cup single hand, the wire went out.
Session Three: Stopped@774 - I have kicked away the wire spool accidentally.

However, the modified Walking Step Counter was small about $1.30, it was work without something to say with sufficient reliability.
I thought that wire guide of winder was the most important.


At the beginning of the trial winding, I substituted the bobbin of the spare for this but it was not able to tune finely and not perfect.
From such a thing, I newly have to manufacture a Wire Guide after this.

I tend a little now not to sleep well...