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Why Are Active Pickups Always Covered?


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I think that all the active pickup companies are trying to keep their exact construction methods a secret.

(Actually I was serious there... it wouldn't be the first time something was done that way). Plus, I mean, they don't want the little preamp bits wobbling around, and there's not nearly as much wire as a passive pickup and the magnets are different, so they'd look very different.

Edited by jnewman
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Actually, it depends on your definition of "active". Seymour Duncan, Bartolini, and EMG use fully epoxy potted designs to both reduce feedback and hide their designs, but it's more to reduce feedback and reduce the workload on the internal preamps. An active pickup can feed back on itself very easily if the preamp is located on the pickup and the potting will keep that from happening. It also helps reduce the amount of outside noise that's picked up and amplified by the preamp.

There are plenty of ways to make regular passive pickups into active pickups. Several companies sell active electronics and preamp kits that'll do the passive conversion and we see a lot of these with basses especially.

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...active pickups and active PREAMPS are two different things. Retrofitting an active preamp to a guitar with passive pickups does not make the pickups active. EMGs, as crafty noted, have preamp components built into the pickup itself. The pickups are much lower output and have fewer windings than passive pickups.

As far as I can tell, all Carvin pickups are PASSIVE. The only active components they offer are preamps.

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...active pickups and active PREAMPS are two different things. Retrofitting an active preamp to a guitar with passive pickups does not make the pickups active. EMGs, as crafty noted, have preamp components built into the pickup itself. The pickups are much lower output and have fewer windings than passive pickups.

Hmmm...I'd have to disagree with you on the semantics there, Primal. True, most "active" pickups that don't need anything except a power source usually have weaker magnets and a lower output to the preamp, but that doesn't necessarily mean that the windings are that much different. Also, if I took a regular PAF, glued a preamp to the bottom of it, and encased the whole thing in epoxy, does that make it an "active" pickup too? Are EMGs "extra-active" if you put a PA-2 or Afterburner on the system?

Anyway, it's a silly argument. Active is active, passive is passive, it just depends on what's coming out of the output jack...

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...active pickups and active PREAMPS are two different things. Retrofitting an active preamp to a guitar with passive pickups does not make the pickups active. EMGs, as crafty noted, have preamp components built into the pickup itself. The pickups are much lower output and have fewer windings than passive pickups.

Hmmm...I'd have to disagree with you on the semantics there, Primal. True, most "active" pickups that don't need anything except a power source usually have weaker magnets and a lower output to the preamp, but that doesn't necessarily mean that the windings are that much different. Also, if I took a regular PAF, glued a preamp to the bottom of it, and encased the whole thing in epoxy, does that make it an "active" pickup too? Are EMGs "extra-active" if you put a PA-2 or Afterburner on the system?

Anyway, it's a silly argument. Active is active, passive is passive, it just depends on what's coming out of the output jack...

Actually Primal is correct. EMGs are quite different than passives with an active preamp in the control cavity. The EMGs have much fewer windings and are made differently than "normal" pickups. You might get close, but it's not going to be the same sound because the pickups will react to the strings differently.

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The gain staging of an EMG-style active is quite different than a passive w/ preamp. Their "base" output levels are much different as mentioned by Primal. Also, due to the number of windings and other core construction issues, EMGs will pick up and transmit a much wider spectrum of frequencies. It's this frequency spectrum, moreso than just the output levels, that sometimes gives EMG the (false, IMO) reputation of being sterile. This frequency range, plus the different string-to-pickup interaction mentioned by Godin, sets EMGs apart.

comparing EMGs to typical passives:

- base (non-preamped) output level -> very much lower on EMG = different gain staging

- magnetic pull -> much lower on EMG = different string interaction

- coil windings -> far fewer on EMG (diff. wire, too? Dunno) = much increased range of frequencies that can be reproduced

There's definitely a lot more setting them apart than the preamp. If anything, the preamp is the LEAST relevant similarity, though of course it's a vital component to EMGs because it enables the different construction to "work" properly.

Greg

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You guys are completely missing my point. The coils on EMGs are no different than what you'll find on most passive pickups, except for fewer, though not substantially fewer windings. They use blades and polepieces just like everyone else. The difference with EMG is how they interact with their preamps. The preamps take the output from each coil and use their "modeling" (read: summing amplifiers) to artificially shape the tone of the pickup. The "sterility" of EMGs comes from the fact that they are all designed to sum the output of their coils in the same manner from guitar to guitar.

I really don't see a difference in using outboard preamps that will allow you to accomplish the same with passive pickups.

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I'm quite sure that someone is missing a point. I'm not so sure it's me. :D I definitely understanding what you're saying about the similarities. My post was meant to illustrate that there are key differences that make all the... er.. difference! in the world. You won't convince me that your scale for measuring the differences is the "right" one, and if my above post didn't convince you to see things by a different scale, then there's not much more I can do. :D

I just don't buy it when it's claimed that somebody who disagrees or has a different perspective is "missing a point," because that would mean that only agreement demonstrates that the point has been understood. And that's not the way it should work. I see your point, I just don't agree. I think the differences are more important than the similarities, and I feel that an EMG active pickup is NOT the same as a passive pickup with a preamp. For the reasons already listed.

Greg

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EMGs have much lower output coils. this is then amplified beyond the point where passive pickups are. they do this for a few reasons, one of the bigger ones being less noise. i took one apart, it looked like it only had about half the normal number of windings.

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EMGs have much lower output coils. this is then amplified beyond the point where passive pickups are. they do this for a few reasons, one of the bigger ones being less noise. i took one apart, it looked like it only had about half the normal number of windings.

How did you get it disassembled?

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I know a lot of people who'd like to know more about this tubab0y...there have been a few threads here alone over the years. Most of what people say about the EMG's is speculation as it is difficult to get inside and take readings and circuit components.

I had guessed that perhaps they used conventional windings and bobbins for ease of manufacture and predictable tone outcomes but less magnet strength and preamps to compensate for that perhaps...pure speculation of course...

Epoxy moulding serves a lot of purposes as mentioned, but it is a way of making a solid "product" without outlaying enormous costs in having specific parts made...I suspect the bobbins are, or were originally, standard components when the company started up...

As I say...pics and any readings from within these things could help with the speculation...or fuel the debate further...

pete

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Yeah, I've taken pains to refer to "EMG active pickups" in this thread, because EMG's covered epoxied pickups are certainly not the only ones. Often, though, if it's an otherwise passive pickup that goes through a preamp and active EQ, they'll say "active electronics" instead of "active pickups". I'm not sure which category the MM pickup fits into, but I've always thought of it as an active pickup, too.

In short, all the points I've made above have always referred to the EMG pickups in specific. Otherwise, it just becomes a debate in semantics.

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