A look inside a Lane Poor MM5.

[belwar]

Well here is a rare oportunity for some of you.. I decided to hack apart my Lane Poor MM5 (which by assumption is near identical to the MM4). I photographed everything as I went, and I have the high res photos if anyone really wants one.

I haven't taken measurements of the bobbins yet, that will be the next time I get bored... Anyway here goes. I used a large belt sander with a 60 grit belt to grind through the layers. Very tough to do as the magnets stick to the metal platten.


Picture 1: Here is the outside of the pickup, the MM4 is in a musicman style case, but the MM5 is put in the soapbar style casing.



Picture 2: This picture is the first layer when you sand through the top. The whole pickup is encased in thin brass shielding soldered to ground.



Picture 3: Bottom view of the pickup (serial number removed).



Picture 4: Here is a side view. What you can see is that the "shell" or case of the pickup is harder. The inside is more silicon like, while the outside is cured very hard. Two completely different materials. The outside sands very easy, but the inside is very gummy.



Picture 5: Bottom view of the pickup, again more shielding..



Picture 6: I've slowly picked away all of the silicon from the foil, and now you can see the ground wire soldered to the foil, You can also see that the foil is tightly held together with solder. Very nice looking.



continued....

[belwar]

Picture 7: I've removed the foil from the bottom of the pickup. Immediately you can see there are two distinct bobbins. The bobbins are made from single side copper clad circuit board. There are two small pieces of circuitboard glued to the bottom of the two bobbins to hold it together for assembly. Its wired like a standard humbucker. End to end connected, start 1 is hot lead and start 2 is ground. Like me, you are probably gathering by now that it is NOT a side

winder.



Picture 8: There is a small little brass insert thingy that holds the two wires in place.



Picture 9: Top of the pickup, foil removed



Picture 10: THE MONEY SHOT. I've sanded through the copper on the top of the bobbin, and now you can see the inside of the pickup. It's a standard humbucker, no poles, wire wound directly around ceramic magnets. Sloppy bobbins.



Picture 11: The underside, sanded slightly more. Note that part of the copper on the circuit board is removed. This creates an area where the leads can be soldered. There are no holes in the bobbin. The wires are brought around the edge of the bobbin.



Picture 12: Closeup.



Picture 13: Closeup 2

[belwar]

... and lastly

Picture 14: Side view of bobbin.

[David Schwab]

Interesting, and kind of what I expected.

What was the DC resistance reading on this one?

[David King]

Well after all that speculation don't we all feel a bit silly? I know I do.

These are very smart from a production standpoint but I find the copper cladding and the brass foil a bit redundant. I'll bet Lane was hoping to get by with just the copper but needed to add the brass when the noise still hadn't abated completely.

What are the dims on those magnets? are the super powerful or just ho-hum i.e. C5/C8 or maybe C2?


I take it the wire is plain old 42 single SPN?

[jonson]

not too far removed from Kents potted pickups other than coils wound on mags and Kent wrapped in ali foil.

[David Schwab]

Well after all that speculation don't we all feel a bit silly? I know I do.

I'd like to see one of the side winders... but this is what I expected of the humbuckers, and said so back in one of the original threads on LP pickups.

So I get a cigar!

Seriously though, this is what they sounded like to me. Low inductance, low turns pickups. My first prototypes from 4 years ago were made like this. That led me to the old forum where I was trying to find out why they were so low output! Of course they were also lo-z.

[Possum]

....

Where are the alien bodies now that we know how the craft operates :-) What is the deal with these pickups, did some famous bass player use them or something, I've never heard of these before. This is like watching a CT scan.....

[Joe Gwinn]

Well here is a rare opportunity for some of you.. I decided to hack apart my Lane Poor MM5 (which by assumption is near identical to the MM4). I photographed everything as I went, and I have the high res photos if anyone really wants one. ......

Picture 4: Here is a side view. What you can see is that the "shell" or case of the pickup is harder. The inside is more silicon [rubber?] like, while the outside is cured very hard. Two completely different materials. The outside sands very easy, but the inside is very gummy.

Someone knew what he was doing. The soft potting is required so that the unit won't over time tear itself apart from the effect of temperature variation on mismatched temperature coefficients of linear expansion.

The potting material may be a silicon rubber or a urethane. The easiest way to tell is to burn some. If silicon, the ash will literally be sand. Urethane will burn completely, leaving little or no ash, unless there was a filler of some kind. One can also usually tell from the smell of the smoke, if one has samples with which to compare.

The shell is likely an epoxy or a polyester, unless LP had them injection molded. If the shell material melts when touched by a soldering iron, the shell is injection molded. If not, it's probably cast epoxy or polyester. Again, the smell of the smoke will tell.

[David King]

Interesting set of tests Joe. Thanks for that. Polyester almost never looses it's styrene smell even decades after it is cast. For that reason, I'm pretty sure that the outer potting is epoxy or polyurethane. I know the Lane cured the pickups in an oven (twice if that article is accurate) and that would lead me to believe that both the inner and outer matrixes were epoxy based.

David, good point, I'd missed that this particular pu was an HB.

[Sheldon Dingwall]

Someone knew what he was doing. The soft potting is required so that the unit won't over time tear itself apart from the effect of temperature variation on mismatched temperature coefficients of linear expansion.

The potting material may be a silicon rubber or a urethane. The easiest way to tell is to burn some. If silicon, the ash will literally be sand. Urethane will burn completely, leaving little or no ash, unless there was a filler of some kind. One can also usually tell from the smell of the smoke, if one has samples with which to compare.

The shell is likely an epoxy or a polyester, unless LP had them injection molded. If the shell material melts when touched by a soldering iron, the shell is injection molded. If not, it's probably cast epoxy or polyester. Again, the smell of the smoke will tell.

I'd really like to know what the inner compound is. The outside IIRC was epoxy.

Joe, do you mean silicone rubber (I've never heard of silicon rubber)? If that's the case, how would you tell?

I'm still looking for an RTV potting compound.

[David Schwab]

Polyester almost never looses it's styrene smell even decades after it is cast.

This is true! I broke open a non working Bill Lawrence pickup once that had to be 20+ years old, and I could smell the polyester resin.

I'd like to know what's in the pickups too. I use potting epoxy... don't know if that's different from normal epoxy. It cures hard.

[David King]

I'd really like to know what the inner compound is. The outside IIRC was epoxy.

Joe, do you mean silicone rubber (I've never heard of silicon rubber)? If that's the case, how would you tell?

I'm still looking for an RTV potting compound.

It could be Devcon Flexane
ITW Devcon | Two of the most recognized brands in all of industry; Devcon® and Permatex®.
though I don't see a need to heat cure that. There's probably a gummy-setting epoxy out there that works as well for less $$. Maybe Lane just shorted the hardener ratio?
I found this place Hexion.com - Epoxy Elastomer Modified Resins - EPON
I also saw a couple of patents regarding elastomer epoxies. Add a hundred parts Bisphenol A to the mix and go.

Any of the two part silicon RTV casting resins would accomplish this as well.
John Greer- Silicone Mold Making Rubber, RTV Molding Rubber

There's also a latex option from JGreer too.

[David Schwab]

He might just bake it to make it cure faster?

[Possum]

...

OK I googled Lane Poor, now I know. They are cool because you can't get them anymore Another myth busted.

You might look into jewelry supply websites and look for injection mold making materials. There are all kinds from RTV to stuff that bakes at around 300 degrees. I think he must have had injection covers made, would be a pain in the butt to do a double molding affair. The filler though looks odd, like sandy, maybe just an artifact of how Belwar sanded them?