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EMG ressurection

1/9/2005 7:32 PM
mr coffee	EMG ressurection Hi all, I just bought an old L2 steinberger only to find that one of the pickups is half-dead. As I understand it, the pickup is basically the EMG P-bass design in a mini-humbucker size housing. One of the coils or the electronics for one of the coils is apparently bad, as the D and G string sound fine, the A is much weaker, and the E is non-existent. The new ones are apparently not the same, and I was wondering if anyone had ever tried to dissect one of these guys and repair it? Anyone even know if they use an op amp, in-amp or discrete design, whether the coils are potted in epoxy along with the electronics, or whether they are potted first in something less stressful (and more likely to be repairable) like RTV silicone rubber? I'm pretty handy with electronics so if I could get to the coils without ruining them and had a general idea, I could easily enough reconstruct a suitable preamp and adjust the gain until it balance with the other pickup. Any suggestions or thoughts would be much appreciated. Bart

1/9/2005 7:32 PM

mr coffee

EMG ressurection

Hi all,

I just bought an old L2 steinberger only to find that one of the pickups is half-dead. As I understand it, the pickup is basically the EMG P-bass design in a mini-humbucker size housing. One of the coils or the electronics for one of the coils is apparently bad, as the D and G string sound fine, the A is much weaker, and the E is non-existent.

The new ones are apparently not the same, and I was wondering if anyone had ever tried to dissect one of these guys and repair it? Anyone even know if they use an op amp, in-amp or discrete design, whether the coils are potted in epoxy along with the electronics, or whether they are potted first in something less stressful (and more likely to be repairable) like RTV silicone rubber?

I'm pretty handy with electronics so if I could get to the coils without ruining them and had a general idea, I could easily enough reconstruct a suitable preamp and adjust the gain until it balance with the other pickup.

Any suggestions or thoughts would be much appreciated.

Bart

1/10/2005 7:53 AM
MKB	You may have a distant possibility to disassemble the pickup, but you have to be extremely careful and realize that you may destroy it in the process. Some potting epoxies will soften when heated, so you can take a heat gun, chisel, and dental picks, carefully heat the epoxy with the heat gun, and remove\pick out the potting. I used to do this with potted electronics at work (evaluating field failures), and was successful removing the coils from a Gibson super-humbucking without breaking the winds. If you are successful removing the components, they could possibly be repaired and reassembled. You could purchase a small amount of potting epoxy from Mouser or Digi-Key, and repot the pickup. You may want to consider this as a last-ditch effort, as you run a high possibility of destroying the pickup.

1/10/2005 7:53 AM

MKB

You may have a distant possibility to disassemble the pickup, but you have to be extremely careful and realize that you may destroy it in the process. Some potting epoxies will soften when heated, so you can take a heat gun, chisel, and dental picks, carefully heat the epoxy with the heat gun, and remove\pick out the potting. I used to do this with potted electronics at work (evaluating field failures), and was successful removing the coils from a Gibson super-humbucking without breaking the winds.

If you are successful removing the components, they could possibly be repaired and reassembled. You could purchase a small amount of potting epoxy from Mouser or Digi-Key, and repot the pickup.

You may want to consider this as a last-ditch effort, as you run a high possibility of destroying the pickup.

1/10/2005 4:41 PM
mr coffee	Hi MKB, Thanks for your reply. Anything you can share about your technique for removing the epoxy without destroying the coils? If you would consider a 5 minute phone call consult so I am a bit more confident as I take it on (what do I have to lose? ... the pickup doesn't output from the E and A string coil), I would be VERY appreciative and would attempt to repay your efforts in some manner. If you would be willing, send me your phone # and convenient times and I'll be more than delighted to call you on my nickel-dime-quarter, ... whatever the metaphor is these days... for a consult. I am not too concerned about destroying the electronics - I can replace that easily. Probably have comparable or better noise characteristics, especially if it turns out to use a 25-year old op amp in there! Magnet structures and windings are MUCH harder to duplicate. And all the people I talk to say the old EMG-SSs sound MUCH, MUCH better than the current EMG-HB that EMG tries to steer Steinberger replacement-seekers to now. The pickup I have is circa 1980 according to Gibson, who now posess the production logs for Steinbergers. It has that damn tan-brown epoxy EMG apparently experimented with back then which hardened faster than the black used before and since (think "save production costs and speed up production"), but which they abandoned a year or so later (although EMG denies THAT affected reliablity ... yeah, uh-huh, sure, [eye-roll]... that way EMG doesn't have to assume responsiblity for replacing all the flaky pickups they made back then based on some bean-counter's dumb-ass idea [knowing grin]). Looking forward (hopefully) to hearing from you. Thanks, Bart

1/10/2005 4:41 PM

mr coffee

Hi MKB,

Thanks for your reply.

Anything you can share about your technique for removing the epoxy without destroying the coils?

If you would consider a 5 minute phone call consult so I am a bit more confident as I take it on (what do I have to lose? ... the pickup doesn't output from the E and A string coil), I would be VERY appreciative and would attempt to repay your efforts in some manner. If you would be willing, send me your phone # and convenient times and I'll be more than delighted to call you on my nickel-dime-quarter, ... whatever the metaphor is these days... for a consult.

I am not too concerned about destroying the electronics - I can replace that easily. Probably have comparable or better noise characteristics, especially if it turns out to use a 25-year old op amp in there!

Magnet structures and windings are MUCH harder to duplicate. And all the people I talk to say the old EMG-SSs sound MUCH, MUCH better than the current EMG-HB that EMG tries to steer Steinberger replacement-seekers to now.

The pickup I have is circa 1980 according to Gibson, who now posess the production logs for Steinbergers. It has that damn tan-brown epoxy EMG apparently experimented with back then which hardened faster than the black used before and since (think "save production costs and speed up production"), but which they abandoned a year or so later (although EMG denies THAT affected reliablity ... yeah, uh-huh, sure, [eye-roll]... that way EMG doesn't have to assume responsiblity for replacing all the flaky pickups they made back then based on some bean-counter's dumb-ass idea [knowing grin]).

Looking forward (hopefully) to hearing from you.

Thanks,
Bart

1/10/2005 9:42 AM
Sheldon Dingwall	You'll destroy pretty much everything trying to get the epoxy off. This is a common problem and IME EMG has been very resposive. Give them a call.

1/10/2005 5:42 PM
mr coffee	Shelton, Thanks for reply. With regards to "destroying the pickup", I haven't got much to lose here, do I? I mean, considering that the pickup is, as it currently is, with one coil(or one half of the preamp) dysfunctional, for all practical purposes, basically worthless, right? When you say this is a "common problem," are you refering to EMG pickups commonly going bad in general, or what? I have been led to believe that EMG pickups are supposed to be pretty reliable (though I have heard others say EMG pickups' dying is fairly common, and that EMG potting techniques are far from state of the art... (that EMG and other "potted pickup" manufacturers need to learn to pot coils and elctronics assemblies in RTV silicone separately first, to lessen the mechanical stresses caused by the potting process, etc.). I know from my own electronics background, that many IC manufacturers learned this lesson back in the late '70s with epoxy DIP packages, and now routinely cover IC chips and chip-to-lead-frame wires with RTV-like silicone resin prior to potting the whole deal in epoxy. Admittedly, lead-frame to chip connection wires are a little more delicate than pickup wire, or at least more delicate than the really, really, fine gauge wire used in some pickup windings. I had been under the impression that EMG pickups were supposed to be long-lived, i.e., when I called Tech support about specs because I was considering buying another out-of-production model I found on the 'net, and then expressing my reluctance to buy it to the tech when I found out it was 20 years old, the tech gave me this spiel about EMG pickups having a "very long life" because the electronic components inside it were under so little stress electronically that an older pickup was supposed to be really reliable since it had made it through the "infant-mortality" part of the bathtub curve and should therefore be "at least as reliable as a new one, and have many, many years of life left in it." Don't get me wrong, I am (mostly) a fan of EMG pickups, both for bass and guitar. I have them on half of the guitars I own. They are quiet and sound great when functioning properly IMHO. But when you say "IME EMG is very responsive," you lose me. Do you mean to say that they will make me a "custom pickup" with the same magnet structure, windings and phase as the original EMG-SS "for only $250", or something like that, or what? Please elaborate. Bart

1/10/2005 5:42 PM

mr coffee

Shelton,

Thanks for reply.

With regards to "destroying the pickup", I haven't got much to lose here, do I? I mean, considering that the pickup is, as it currently is, with one coil(or one half of the preamp) dysfunctional, for all practical purposes, basically worthless, right?

When you say this is a "common problem," are you refering to EMG pickups commonly going bad in general, or what?

I have been led to believe that EMG pickups are supposed to be pretty reliable (though I have heard others say EMG pickups' dying is fairly common, and that EMG potting techniques are far from state of the art... (that EMG and other "potted pickup" manufacturers need to learn to pot coils and elctronics assemblies in RTV silicone separately first, to lessen the mechanical stresses caused by the potting process, etc.).

I know from my own electronics background, that many IC manufacturers learned this lesson back in the late '70s with epoxy DIP packages, and now routinely cover IC chips and chip-to-lead-frame wires with RTV-like silicone resin prior to potting the whole deal in epoxy. Admittedly, lead-frame to chip connection wires are a little more delicate than pickup wire, or at least more delicate than the really, really, fine gauge wire used in some pickup windings.

I had been under the impression that EMG pickups were supposed to be long-lived, i.e., when I called Tech support about specs because I was considering buying another out-of-production model I found on the 'net, and then expressing my reluctance to buy it to the tech when I found out it was 20 years old, the tech gave me this spiel about EMG pickups having a "very long life" because the electronic components inside it were under so little stress electronically that an older pickup was supposed to be really reliable since it had made it through the "infant-mortality" part of the bathtub curve and should therefore be "at least as reliable as a new one, and have many, many years of life left in it."

Don't get me wrong, I am (mostly) a fan of EMG pickups, both for bass and guitar. I have them on half of the guitars I own. They are quiet and sound great when functioning properly IMHO.

But when you say "IME EMG is very responsive," you lose me. Do you mean to say that they will make me a "custom pickup" with the same magnet structure, windings and phase as the original EMG-SS "for only $250", or something like that, or what?

Please elaborate.

Bart

1/11/2005 2:54 PM
Sheldon Dingwall	Bart, The pickups that EMG made for Steinberger had a tendency for the bass coil (I think) cutting out. I contacted them a couple of times with this problem and they sent out a replacement even though the warantee period had long since expired. This was a few years ago so they may have a tighter policy now YMMV. It doesn't cost much to give them a call though.

1/11/2005 6:46 PM
MR COFFEE	Sheldon, Thanks for the clarification. I'm still a bit confused though - I'm under the impression they don't make a pickup using the same magnetic design as the pickups made for the early Steinbergers. Everthing I've read indicates the EMG-HB is different and is available in only one phase. So how did EMG send out a "replacement"? Thanks, Bart

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