Seeking Info & Opinions Re: Electromuse Eye-Beam Pickup (for Lap Steel)

[rjb]

So, I've got this no-name, junk-store lap steel that I want to fix up just to play "Sleepwalk."

The pickup is marked "EYE-BEAM Electromuse STRING PICKUP CHICAGO USA".



Here's what I've found out about Electromuse via the interweb:

1. What Wikipedia says. Electromuse - Wikipedia, the free encyclopedia

2. A bazillion Electromuse "canoe paddle" student lap steels were built in the '40s and '50s.
Here's one. http://www.krazykatmusic.com/wp-cont...ap-Steel-1.jpg

3. My instrument appears to be some "store-brand stencil." It has the same control plate and 12 ft pigtail as the "canoe paddles", but the same body shape and red, white, and blue fretboard as this "Bronson". Zorko's Guitars

4. The pickups are low output. On one Steel Guitar forum, an old timer reminisces about the canoe paddles coming with "pure iron strings" to increase output, and having to oil the strings to keep the rust down enough to avoid tetanus....



Here's what I've found out by examination and disassembly of my instrument:

1. The wiring is standard-issue "one pickup with volume and tone"- except the volume pot is only 20Kohm. The tone circuit is 150K pot with .05uF cap.

2. The Eye-Beam pickup is slightly weird- basically a blade pickup turned sideways. The core is a piece of steel I-channel (AKA H-channel), magnetized across the bar so one flange is North and the other flange is South; the two "toaster slots" in the cover align with the flanges.

3. The core is badly rusted and pitted. The cloth tape wrapped around the core split along a flange, and a bunch of inner coil turns severed.

4. I'm not sure of the coil wire guage, but there wasn't a whole lot of wire in the coil.



Here's how I contemplate rebuilding the pickup:

1. Either clean up the original core or find a bright, shiny, new piece of I-channel. Also, file the ends smooth and round.

2. Wrap the core with cloth tape, then soak the tape in nail polish.

3. Wind as much 42AWG as physically possible onto the core.

4. Magnetize the core with a pair of the strongest Neos I can get my hands on.

5. And so on.



Here are some questions:

1. Where can one find new steel H-channel, 1" wide with ~3/8" flanges?

2. In theory, does the Eye-Beam pickup work? Or is it like the hummingbird that can hover because it doesn't know physics?

3. In practice, do these pickups have any redeeming values? Might I be able to get "reasonable" level from a rebuilt pickup? Would I be better off replacing the Eye-Beam with something else? If so, what would be a good example of "something else"?



Thanks,
-rb

[Bruce Johnson]

For the steel H-channel, you can probably clean it up and re-use it. Basically, scrape off the worst of the rust, file the surfaces relatively smooth, polish the ends of the blades that will show, and get it nickel plated.

If you really need a new one, it's probably easiest to machine a replacement from a small bar of 1018 steel. It may take some searching to find some mild steel H-channel in that small size. I've never really looked.

[rjb]

Brain spin- "thinking" ahead.

I am under no delusion that this lap steel is a valuable antique, and have no qualms about modifying its mojo.

Considering that all I currently have, pickup-wise, is a chunk of rusty steel and a spool of wire, I may be getting ahead of myself here, but does anyone have an opinion whether any of these might be worth trying?

1. Attach 6 little NEO magnets (say, 1/4" x 1/4" x 1/8" thick) to each flange of the Eye-Beam's "I-Beam". Maybe could shift NEOs around to adjust relative string output.

2. Install a "Stratoblaster" type JFET buffer. Should its input impedance be modified to ~200K-500K?

3. Replace the Eye-Beam with a ready-made dual-rail humbucker. Would need to remove cover and space rails to fit Eye-Beam cover. Also would need new pots- may as well get with push-pull switch for serial/parallel wiring.

Opinions welcome.

Thanks,
-rb

[rjb]

D'oh

3. Replace the Eye-Beam with a ready-made dual-rail humbucker.

Assuming I want to keep the cover, this won't work- even with magnet rails. The cover slots are too close to the sides to wrap a coil around the rails.

[rjb]

For the steel H-channel,...

I'll probably clean it up, as you suggest. Machining a new part may be easy for YOU, but....

Still, I keep thinking that I've seen that H-channel before, in a different context. Did it use to commonly be used to support desk & workbench tops, or shelving or something like that?

Thanks, Bruce
-rb

[jason lollar]

i would like to see some photos of that -Either the core is magnetized or the magnet is somewhere outside of the coil- if the core is magnetised its probably not typical steel, i would clean it up and nickel plate it if you have the stuff to do so in shop or wrap it with some tape top keep corrosion at bay, remag it and put about 5000 to 7000 turns of whatever wire gauge will fit and try that before you start thinking about making something to fit.

[rjb]

i would like to see some photos of that

Oops. I kinda assumed you would be the world expert on these things. I should have had the presence of mind to take some pix before tearing everything down, but I think the heat wave boiled my brain. I've attached some mockups & re-enactments, and will try to describe it the best I can.

Either the core is magnetized...

Yes, the core is magnetized across the bar; one flange is North (marked with a red paint dot) and the other flange is South.

i would clean it up and nickel plate it if you have the stuff to do so in shop

Har. I'm a shade tree mechanic without a shade tree. I'm lucky to get to use the potting table next to the back porch....

or wrap it with some tape to keep corrosion at bay

I do plan to wrap it in tape to protect the coil wire, but it was originally wrapped in tape & it corroded- over how many years, I don't know.
Would painting it with nail polish, or maybe metal primer & Rust-oleum, work?

remag it and put about 5000 to 7000 turns of whatever wire gauge will fit

I don't think I could get that many turns- not, at least, without adding some temporary "flange extenders". I'll see what I can do.

But I might start out trying fewer turns.
The original coil didn't use a lot of wire- wound mostly in the middle, not much on the sides.
Almost looked like it was hand wrapped vs hand wound.

I wasn't able to measure the coil DCR, but tried working backward
using a rule of thumb mentioned by forum member "bbsailor" that says
"the load on a pickup should be about 40 times its DCR..."

Load = 20K ohm (Volume Pot)
Coil DCR = 20Kohm/40 = 500 ohm
42AWG = 1659 ohm / 1000 ft (typical)
Coil wire length = 500ohm / (1659ohm/1000 ft) = 301 ft
Measured Length of 10 turns = 4 ft, 1 in = 4.083 ft
#Turns of 42AWG: 301 ft / (4.083 ft / 10 turns) = 737 turns

Since I actually measured 21 Kohm for the Volume Pot, I figured I could bump that up a bit:
21 Kohm load -> 525 ohm coil DCR -> 775 turns 42AWG
Or maybe, say, 800-1000 turns for a "hot" pickup!

Then I thought I'd try hanging little Neo magnets on the flanges. Not exactly traditional, but my hope is it would boost the output.
Does anyone have any thoughts on this?

Thanks,
-rb
-----------





Here's a rundown on the attached pics.

1) Front of control plate and pickup cover; note position of "toaster slots".

2) Back of control plate. Pickup cover is held to plate by 4 tabs that engage 4 slots, then are twisted 90 degrees. Harness pics can be found elsewhere on the interweb. Pickup leads are bare wire for start and blue for finish.

3) Inside of the pickup. You've really got to use your imagination here.
Pretend H-channel is very rough cut; the ends look like they were chewed off by a beaver. A layer of black cloth tape bulges out the "toaster slots", pressed by the channel flanges. The channel is wedged in place by two short pieces (only one is shown) of flattened rubber tubing (or wire insulation?), one on either side. As mentioned before, the channel is magnetized across its width. It is covered with a layer of white cloth tape, then (sparsely) wound lengthwise with red magnet wire, then wrapped with more white cloth tape.

4) A family portrait of some of the pickup components. The magnet wire and white cloth tape send their regards.

5) End view showing the non-symmetrical shape of the H-channel flanges. The H-channel is about 15/16" tall; web about 1/8"; total flange length about 3/8". It was cut to about 2-3/8" long.

6) A re-enactment showing how the start wire is attached. Some red-insulated solid steel wire plays the part of the magnet wire.

Later,
-rb

[David Schwab]

I should have had the presence of mind to take some pix before tearing everything down, but I think the heat wave boiled my brain.

I always take photos of pickups before I take them apart. That way you have a record of the pickup. Especially something rare like this.

One way you could have estimated how much wire was on the coil was by weighing it on a digital scale before, and after removing the wire.

[rjb]

I always take photos of pickups before I take them apart. That way you have a record of the pickup.

I intended to take photos for just that reason, but got lost in the heat of the moment. Or something.

Especially something rare like this.

I don't think these pickups are all that rare; you see Electromuse "canoe paddles" on eBay all the time.
Of course, people want more for an old student lap steel than I'd like to pay ....

One way you could have estimated how much wire was on the coil was by weighing it on a digital scale before, and after removing the wire.

Or I could have weighed the wad of wire directly, after removing it from the core. If I had a digital scale.

Oh well, no use crying over spilled wire.
-rb

[David Schwab]

I intended to take photos for just that reason, but got lost in the heat of the moment. Or something.

That happens to me when I'm on vacation!

I don't think these pickups are all that rare; you see Electromuse "canoe paddles" on eBay all the time.
Of course, people want more for an old student lap steel than I'd like to pay ....

That's the point. I never even heard of one, let alone saw the inside of the pickup. So even if they are out there, the gut shots sure aren't!

Or I could have weighed the wad of wire directly, after removing it from the core. If I had a digital scale.

You want to weigh it on the bobbin, so you can then wind the bobbin to the same weight. I did that recently with a '76 Thunderbird bass pickup.

[big_teee]

"You want to weigh it on the bobbin, so you can then wind the bobbin to the same weight. I did that recently with a '76 Thunderbird bass pickup."
Did you charge the guy by the ounce, or by the pound???
T

[jason lollar]

ive rewound many many lap steels- never seen that pickup or anything remotely like it. Some really old pickups didnt have much wire on them but the amps they used then had a different input than later models so it didnt take much to drive the amp. Also some of those old pickups just never sounded that good anyway
You would need to charge up that magnet and see how much magnetism you have availible and use some 44 gauge wire or smaller if you have it or make something entirely new to fit in the cover

[rjb]

ive rewound many many lap steels- never seen that pickup or anything remotely like it.

Oh, expletive! I really didn't think they were that rare.

Some really old pickups didnt have much wire on them but the amps they used then had a different input than later models so it didnt take much to drive the amp.

I have read passing mention (without attribution) that the Eye-Beam was "one of the first practical pickup designs." Might it have originally been designed to the old 600 ohm radio standard? Now I'm considering winding it to 600 ohms DCR (~884 turns 42 AWG) and using a mic matching transformer at the amp, or running into a mic mixer.

Also some of those old pickups just never sounded that good anyway

Yup.
I've read a few conflicting opinions. One guy said it sounded great on a Spanish guitar, mounted an inch away from the strings. Others say the "canoe paddles" have a clangy somewhat resophonic sound, that lacks sustain and doesn't really sing. But then some blame the large control cavity ("not enough contact between the body and control plate") and/or the plexiglass nut.

You would need to charge up that magnet and see how much magnetism you have availible and use some 44 gauge wire or smaller if you have it or make something entirely new to fit in the cover

Just to make sure I'm not making assumptions or being a blockhead:
Are you saying that in order to make this pickup compatible with modern guitar amps, I would have to get the magnet as saturated as possible, and use a very small wire guage in order to squeeze as many turns as possible into the limited area provided by the I-beam flanges?
And if I did that, would I change to a higher resistance Volume pot to avoid over-loading the pickup?

Might these schemes work instead:

1) Use fewer winds (knowing that the output level, DCR, and impedance would all be lower than a modern pickup) and a matching transformer to compensate.

2) In addition to 1), hang small neo magnets (1/8" x 1/8" x 1/16") on the ends of the flanges to boost the magnetic field and the output level.

Thanks, Jason

-rb

PS- Sorry again for not taking gut shots.

[Sweetfinger]

I used to own an Electromuse with an "Eye Beam". It sounded great, not weak at all. The cheapness of the guitar itself was what sort of dragged the thing down as a utility instrument- especially the "bridge" which contributes to the resonator like quality alluded to in a previous post. Certainly the one great thing about mine WAS the pickup. Did this pickup work or was it dead when you got it? Also, these aren't really all that rare, but aren't "common" either - I have seen maybe 5 of them through the years. I'll add that any "old timer" who had to "oil" their strings to keep them from rusting and uses that fact as some measure of the quality level of an instrument is, in my book, officially a "coot"!

[David Schwab]

"You want to weigh it on the bobbin, so you can then wind the bobbin to the same weight. I did that recently with a '76 Thunderbird bass pickup."
Did you charge the guy by the ounce, or by the pound???
T

By the gram!