Dan Armstrong Replica Part 6

Well, let’s wrap this up. 

Har har har.

As noted in my last entry, I am making the pickup for this guitar. My reasoning is that the original pickup is very distinct in appearance, so I would have to build the outside anyway, and I’ve always wanted to try my hand at winding pickups (hence building the winder), so why not?

Once you have all the machinery and parts in place, the actual process is fairly straightforward.

Barring catastrophic failures that make you start all over again.

I wound each bobbin with the AWG42 copper wire. The first bobbin has 5,200 wraps, and the second, due to a brain fart, has 5,500.

This is hardly a problem, and in fact a new trend in pickup winding is intentionally mismatching coils.

So for once in my life I’m trendy. And I didn’t even have to get a haircut.

The bobbin on the right is not as even as the one on the left, but for my 2nd-ever bobbin I think its okay.

The original Armstrong pickups had 9.5k (kilohms) of resistance. Mine ended up at 8.5k, which is not really close, but close enough for a first try. And many classic pickups, including the revered Gibson PAF, are 8.5k. So like I said, close enough.

Which normally only counts in horse shoes and Cruise missiles, but I digress.

You can sort of see the ends of the wire, which are taped to the bobbin. Each end gets a larger wire soldered to it because it’s much easier to work with.

If you break the starting wire of the AWG42 (the end at the beginning (!) of the wind) you have to start all over again.

But hey, no pressure, right?

I managed to do that without ruining either coil.

The coils need a baseplate to sit on. So I made one from a piece of brass, making sure the coils were spaced correctly for the Dan Armstrong (slightly wider than a normal humbucker, which is another reason I had to do it myself.

DIM, if you will.

The green wires are the ‘start ends’ of each coil, and the red ones the ‘finish ends.’

Green for start and red for stop. Talk about dim…

Beneath each coil are small magnets that touch the steel blade ‘polepiece.’ The wire, magnets and polepiece work together to ‘hear’ the strings.

Here’s a picture of a standard humbucker that will give you a clearer view, though its design is slightly different.

On my pickup, the magnets are about the same size as the ‘shim’ in the above photo. The blade polepiece protrudes from the bottom, so there is no need for a spacer (or shim).

Two magnets are  placed on each polepiece, so there are four magnets under the coils. I secured the coils to the baseplate with bobbin mounting screws as shown in the photo.

My pickup has a large piece of brass sticking up on one end, but that’s a design consideration.

I linked the end wires of each coil, and made the start wires signal and ground. The below photo shows the red wires soldered, but the green ones were later soldered to the silver and white wire in the lower left corner.

Although the windings on a pickup seem very tight, they can and do vibrate, especially if the guitar in question is being played at high volume.

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This vibration manifests itself in what is called microphonic feedback, which is that high, piercing and uncontrollable screech you hear when, for example, a microphone feeds back.

It’s nasty and its harmful and I can’t stand it.

Wait, are we talking about pickups or the CCP?

Luckily for pickups, there is a solution, and it’s called wax potting. By dipping the pickup into melted paraffin, the coils no longer have the room to vibrate since that space is now taken up by wax.

That means you can play louder than Jesus and the bad sounds are totally your fault. 

I potted the pickup using tea candle wax. I fashioned a double boiler using a small pan and a glass container. You have to do this because wax is very flammable.

150 degrees is the correct temperature, which I ensured with a meat thermometer. Which I bought in the same place as the small pan and the tea candles.

Yau Ma Tei rules.

I dipped the pickup into the now-liquid wax, occasionally moving it around to dislodge any air bubbles. There were, which let me know the wax was displacing the air like it was supposed to be doing. 

I was still nervous since I’ve never done it before.

After ten minutes, I took it out and wiped off the excess while it was still warm. It’s much easier to do that way. 

I hoped that the wax might also protect the tiny start end wires, because if they break…

I was very nervous this whole time because I had to do a lot of things that were potentially harmful to those two little strands of wire, but luckily they never broke.

Now that I had the bottom of the pickup taken care of, I needed to do the top. 

One of the things I’ve really had to think through is how to replicate the Dan Armstrong pickup housing.  The originals were cast resin, and that’s a little too far for me to go.

I made a casing from brown plastic that closely matches the original Dan Armstrong color.

I need to attach the cover to the brass baseplate. In order to do that, I decided to emulate the original Dan Armstrongs’ dual banana plugs on the bottom edge of the pickup:

But in this case, I’m using a pair of machine screws - 

to attach the baseplate, into which I drilled corresponding holes and threaded them with one of the screws:

Near the left edge of the frame, I drilled a hole for the pickup wire to pass through. Didn’t get a photo, but I hope you can follow me.

The baseplate fits into the frame very closely and is secured by the two machine screws:

So now it was time to make the top for this thing. Rather than having new polepieces machined, I wanted to see if I could fake it. I needed to emulate the rails in the top, which I did with 5mm stainless steel that I none too delicately bent to (roughly) a 12″ radius.

I surrounded them with pieces of plastic that I super-glued together. 

I hadn’t yet finished and sanded it in the above photo, which is why it looks like it has some kind of egregious skin condition.

I found the easiest way to make the top (after trying several methods that ended in abject failure and profanity) was by using multiple pieces, rather than trying to cut the rails into a solid piece.

I tested the ‘transparency’ of the top (i.e. would it muffle or otherwise ruin the ‘hearing’ of the pickup) with another guitar, and it didn’t seem to interfere with the sound, so that was one worry nullified.

I glued the top of the pickup cover to the frame and sanded it smooth all the way around. 

Through this whole process, I kept checking to see if the pickup still worked, and it did.  

So now I need to attach the pickup to the guitar. After a lot of thought, I decided to use a modified form of the original pickup attachment method, which was a thumbscrew on the back of the guitar by which the pickup was kept in place:

I had neither the means nor the desire to create such a big recess in the back of the guitar. So I downsized the hardware.

 

You can see the bobbin attachment screws in this photo as well.

I had to be careful with the center screw, because it came very close to the pickup bobbins, and if I broke that copper wire…

But I didn’t.

Well, there’s nothing left to do now but put it on the guitar.

I had already cut out the pickguard. 

Those knobs are very different from the originals:

But considering they cost about US$49.50 less than the originals I could buy, I can live with it. I will get better ones, but for now the ones I have will suffice.

Astute (!) observers will notice that I did away with the toggle switch, since it was a tone circuit that I wasn’t really too interested in (and it made wiring simpler).

I also added a washer to help strengthen the area around the jack since Formica is not very strong.

I’m not the first person to do these modifications:

Wiring the pickguard was very convenient, since all the components (volume, tone and input jack) are close to each other and you don’t have to snake wires through holes.

One thing I did need to do was deepen the hole for the input jack:

This of course made me nervous since messing that up meant ruining a ton of work.

But I didn’t.

The black wire in that photo is attached to the bridge; the strings must be grounded.

You can also see the mistake I made when routing that cavity. To shore up my flagging pride, here’s looking through you, kid:

Yes, that’s through the guitar you’re looking.

I wired the pickup to the pickguard (or more precisely to the volume pot) and assembled the guitar:

Because my pickup is not as tall as the original, I used some foam under the pickup to elevate it; the closer it is to the strings, the louder it is. You can see it in the closeups of the back of the guitar:

You can also see the set screw holding the pickup as well as the shims I needed to add to the neck heel; the action was too high (even for a guitar used for slide playing), so I had to add them.

Recently, I went hiking with friends up Tai Mo Shan, the highest peak in Hong Kong. I found a piece of synthetic stone used for countertops while I was up there.

I have NO idea why it was there, but I took it home, much to the amusement of my hiking companions.

What they didn’t know is that you can use that stuff to make string nuts, which is what I did with it:

I really like the way it looks, and it seems to sound pretty good too. I also like the fact that I found it on a mountain. 

I’m still working on the setup of the guitar, but it’s coming along. I strung it with 12s, which are very heavy, but it’s tuned to open G and I won’t be bending any strings. 

The pickup works (even after all those chances to break it), and I think it sounds pretty good, especially for a first effort.

I can’t believe I’m doing this, but here:

I haven’t spent any decent time playing slide in a few years, so please forgive my lousy playing. Now that I have a dedicated slide guitar, I will get back to it.

I’m still mildly shocked and deeply amused that I managed to pull this one off. It was a lot of fun, a learning experience, and I ended up with (another) nice guitar.