DIY active pickup not working

D

douel

New member
Hi there,

I've been playing around with a couple of emg clones and made an 89 clone.
However, it's not working quite as it should be and I've no idea why, and I am hoping someone with more knowledge than myself may be able to offer some expertise.

Before encasing it in resin, I decided to encase it in wax to hold it together to test it (didn't make an RFI shield, but I don't imagine this would be a problem(?))

In humbucking mode it makes horrible noises which can only be described as being engine-like
In single mode it is far quieter than it should be, similar to an active pickup without the battery (however it's silent when I take it out, so I presume that the preamp is working).

I've had similar sounds from actives when the battery is low, but I've checked my batteries and power connections and they all appear fine, and checked for any shorts but I cannot find any of those either.

Anyone out there kind enough to guess what the problem could be?
 
Re: DIY active pickup not working

Welcome to the forum.

Just to confirm, you potted your project low impedance + pre-amp design pickup in molten wax.

Do you have specification data for whatever ICs you employed? Do these specs nominate an acceptable working temperature range?
 
Re: DIY active pickup not working

yes, that's right.
I've just been using the preamps from my previous pickups and therefore don't know any technical details about them.
Are these symptoms of fried circuits? I assumed it wouldn't have caused it any harm because the components would have taken solder heat to install
edit: being an emg clone I believe it to be an LM4250, toleratant up to 125oC
 
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Re: DIY active pickup not working

To what temperature did you heat the potting wax?
 
Re: DIY active pickup not working

No idea, I just cut it into slivers and heated it over some water, it can't have gone near that though.
On closer inspection of the emg 89 I noticed it had significantly more cables coming out of it then mine did and I believe that my problem was that I was not switching the output of the primary coil as I was switching between modes, and instead had them both engaged simultaneously. I'll report back with my findings tomorrow.
 
Re: DIY active pickup not working

Update:
got the humbucker part working now with the additional wires, however the stack is still playing up.
I disconnected the preamp and tested it on another (passive) pickup and it seemed to reduce the volume 10 fold before amplifying it to twice that.
I suspect that the problem may be the way I've hooked the pickup up to the preamp.
Is a stack usually connected to a preamp differently from a traditional humbucker?
 
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