#1
first things first, i know there have been threads before but they'll all well and truly OLD

I was just thinking about making an active pickup.
Are the magnets in active pickups different from standard pickups?
i know they use a lot less windings of wire and are then amplified by a preamp.
What if i unwound a pickup and then rewound it to a low impedance (say 1k maybe?) and then used an external preamp circuit would it then be an active pickup (for all intents and purposes) or would i still need to do something else to it?

anyone else got ideas? :P
#3
why dont you just add a preamp to some normal pickups?
Quote by Scowmoo




You deserved this, Matt.
#4
I have done this before using a a 9V battery, a single FET, a few resistors and 2 capacitors to create a common drain circuit.

It's very easy to design and has the advantage of lowering the output impedance so that cable and amplifier input impedance does not effect your sound (and increasing the input impedance as seen from your pickups), while adding virtually zero coloring of the sound. I don't have any circuit diagram around, but you can easily design your own!

see http://en.wikipedia.org/wiki/Common_drain to get started.

/Mike
Last edited by swedishwings at Sep 13, 2009,
#5
Quote by metal-matt
why dont you just add a preamp to some normal pickups?


because the normal pickups + a preamp would still have the higher impedance?

I'm trying to work out some way of getting an active pickup tone without having to pay out for them the proper way :P
#6
Quote by Bigsteve92
because the normal pickups + a preamp would still have the higher impedance?

I'm trying to work out some way of getting an active pickup tone without having to pay out for them the proper way :P


um, do you mean 'active pickup LACK OF tone'?

IMHO active pickups don't sound good, and just don't transmit all the nuances that we know and love as guitar tone, but that's just an opinion.

now Les Paul was a big fan of the idea of low impedance p/u's, so maybe there is something to it... but I would bet money les never EVER used EMG's - suggesting he wasn't a big fan.

They do have high output... but
You can get a great high output sound using passive pickups and any of several online schematics/diagrams to create an active preamp and this would seem a bit more practical to me... but then that's my opinion too.

http://freestompboxes.org/viewtopic.php?f=13&t=431

just in case you change your mind.

they do get rid of picking noise... but then a compressor right aft the gtr will do that too... and IMO is the right tool for the job.
#7
^Way to add a completely non-contributing post. Everyone appreciates it.

TS, I know EMG's are bar magnets, and fairly certain Blackouts are as well, not poles that lots of passives had. Although I'm fairly certain you could still use pole magnets.
Everything sounds great in what you described, just don't forget the battery!
#8
If you have some bar-magnet pickups laying around, you could use those instead of the standard ones with slugs. Might give you a bit more "even" tone.
R.I.P. Les Paul, 1915-2009

A man chooses, a slave obeys.
#9
just thinking, if you were preamp-ing low output p/u's, isnt it the same as amping up a low volume/quality signal?

i mean, you might get the same output on paper but the tonal qualitys might not be the same.

i think what im trying to say is that, you might be just be making a bad tone louder.
but you could prove me wrong, and i hope you do, because all the active pups out there are lame (imo) and i think that puting new designs out there might help that
Quote by Scowmoo




You deserved this, Matt.
#10
Les pauls low impedance pickups were designed to direct interface with mixing boards. They would drive a long cable with no signal loss, had a wider freq spectrum(hi-fi), lower hum etc. For the style les paul played they worked great. But in the era gibson tried to market these pickups, late 60s early 70s, people werent looking for clean tones. So they dropped off the planet for the most part.

Not really a reason regular slug pole pieces wouldnt work in some custom wound low impedance pickups to make into "actives". Its just the conventional thing to use ceramic bar magnets. I looked into this same idea a little while back. Its on my project/experiment list. But I try not to get involved in to many projects at once or none get finished.

Les paul made alot of the innovations he did due to the fact he didnt follow conventional wisdom. Where would we be if had stayed in the box and played it safe like many designers do. TS its a good thing to try worst that happens is it doesnt work. Its worth a try let us know how it does. Im sure when EMG was experimenting others told em it was crazy and would never amount to anything.
#11
Quote by bv310
If you have some bar-magnet pickups laying around, you could use those instead of the standard ones with slugs. Might give you a bit more "even" tone.

bar magnet pickups?
you mean like an SD hot rail type thing?

Quote by metal-matt
just thinking, if you were preamp-ing low output p/u's, isnt it the same as amping up a low volume/quality signal?

i mean, you might get the same output on paper but the tonal qualitys might not be the same.

i think what im trying to say is that, you might be just be making a bad tone louder.
but you could prove me wrong, and i hope you do, because all the active pups out there are lame (imo) and i think that puting new designs out there might help that


well at the end of the day when i get round to this all i'm losing is pickup (which i'll have paid less than 10GBP for) and I'll just put the preamp into another guitar :P

edit: anyone got a pickup they wanna donate for this? (worth an ask :P)
Last edited by Bigsteve92 at Sep 13, 2009,
#12
Quote by Bigsteve92
first things first, i know there have been threads before but they'll all well and truly OLD


just because the thread is OLD doesnt mean any of the info in it is any less useful or accurate. in some cases it may be more useful and more accurate.
#13
Quote by noisefarmer
just because the thread is OLD doesnt mean any of the info in it is any less useful or accurate. in some cases it may be more useful and more accurate.


I meant that as a defense from the 'use the search button' messages
And I have looked at the other threads about this and thats why I posted this one
( i stumbled across one by chance )
#14
Quote by Bigsteve92
first things first, i know there have been threads before but they'll all well and truly OLD
Cool that you searched, man. Repeats of recent threads are annoying as fuck. A new thread on a topic that might have been covered ages ago is no probs, though.

Quote by Bigsteve92
I was just thinking about making an active pickup.
hmmm. there's a lot to it.
you'll need to learn a good bit in order to do a good job of this.

Quote by Bigsteve92
Are the magnets in active pickups different from standard pickups?
I'm pretty sure the magnets on EMGs are much weaker than on most passives. And they want you to put their pickups closer to the strings.

Quote by Bigsteve92
i know they use a lot less windings of wire and are then amplified by a preamp.
EMG uses less windings, but I can't say for sure this is true for other actives.

Quote by Bigsteve92
and are then amplified by a preamp
Yeah, that's where much of the magic is.

Quote by Bigsteve92
What if i unwound a pickup and then rewound it to a low impedance (say 1k maybe?)
That will give you a coil with less inductance. It will naturally be bright. But you will lose a lot of output. You might be well off to use a different (shorter) bobbin so all the windings are closer to the strings. Some experimentation would be in order.

Quote by Bigsteve92
and then used an external preamp circuit would it then be an active pickup (for all intents and purposes)
one of the most important features of an active is the preamp being internal to the pickup housing. The wires from the coils to the preamp are short. This gives hum and noise little opportunity to enter the system. If the preamp is farther away, you allow more hum and noise to enter the system. Since you need to amplify the signal a lot because you're using fewer windings, you are also amplifying any hum or noise that gets in.

Putting the preamp close to the pickup will be very important to you.
Meadows
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I wont be like those jerks who dedicate their beliefs to logic and reaosn.
#15
Ah, that's why they go to the effort of getting the preamp inside the housing.
Would i be right in assuming that I'd have room to put it underneath the pickup in a standard route if i used a shorter bobbin and put it closer to the strings?
#16
I've looked in to this, and haven't gotten around to ordering parts/doing the project quite yet.

The magnets are no different, and you could indeed just rewind a standard pickup and add a powered preamp circuit to it. From what I found on the internet, the EMG 81 is wound with 42AWG wire and has 81 coils/wraps. So these coils aren't just underwound, they are underwound to the point that you feel like it wouldn't even make a sound.

After it's put together, you would want to pot the pickup in epoxy, just to further discourage any possible noise.

If you have any questions, shoot me a PM.

Have a sizzlin' day,
AJ
Quote by conor1148
who cares if they're drawn,


boobies



Gear:
Peavey Supreme 100W head
Crate 4x12 cab
Epiphone Les Paul Standard+
Modded Johnson Stratocaster
#17
hey, thnking of experimenting with pickups, if you made a electromagnet about the same size as the magnet that you would use on a pickup, then added some way of makeing it more/less magnetic, wouldent that give you something interesting to play with? has it been done before?

i would think that then you should be able to adjust the "heat" of a pickup, so maybe you would have a high output pickup that would be adjusted to a middle, or low output pickup....

if it hasnt been done before i call dibs...
Quote by Scowmoo




You deserved this, Matt.
#18
Quote by Emoishboy
From what I found on the internet, the EMG 81 is wound with 42AWG wire and has 81 coils/wraps.
I believe this to be false.

Quote by metal-matt
hey, thnking of experimenting with pickups, if you made a electromagnet about the same size as the magnet that you would use on a pickup, then added some way of makeing it more/less magnetic, wouldent that give you something interesting to play with? has it been done before?

i would think that then you should be able to adjust the "heat" of a pickup, so maybe you would have a high output pickup that would be adjusted to a middle, or low output pickup....

if it hasnt been done before i call dibs...
You can have it. Do. Not. Want.

Electromagnets require a strong current.
Run that from a battery and it would die quickly.
Run it from a power supply and the filtering had better be damned good, or you'll couple any ripple right into the pickup coil.
Meadows
Quote by Jackal58
I release my inner liberal every morning when I take a shit.
Quote by SK8RDUDE411
I wont be like those jerks who dedicate their beliefs to logic and reaosn.
#19
ahh so there is resons why people dont do it...

but i think i will have to try it at some point, experimentation is allways good dont you think?


and i did think that the windings on EMG's wernt the same as there name, because i dont think that it would be enouf winds, and the differance between 4 winds (81-85) wouldent have much tonal change...
Quote by Scowmoo




You deserved this, Matt.