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Active circuit, passive pickups?

K

kyleaubu

Mar 5, 2013
34
0
Fallon, NV
#1
Ok so Im very new to the world of understanding the electronic side of my instruments. So I looked up the specs on all my guitars. These are the specs for my Spector Korean Pro Classic 4.

ELECTRONICS
TONE CIRCUIT: Spector® TonePump Jr. Tone Circuit™
CIRCUIT TYPE: Active - 2-Band
CIRCUIT VOLTAGE: 9-Volt
BRIDGE PICKUP: SSD™ Humbucking Pickup
NECK PICKUPS: SSD™ Humbucking Pickup
PICKUP TYPE: Passive

How is it that its an active circuit but passive pickups? I was under the impression that active was active and passive was passive. I just plain dont understand lol. I tried doing a search but couldnt come up with anything. I figured I could get the answer Im looking for much quicker this way.
 
#5
Some pickups can require power to function i.e. active pickups.

Some don't require power to function i.e. passive.

ALL preamps are active.

A bass w/ passive pickups and an active preamp can run in both active and passive modes.

The problem you are having is that you are trying to see the pickups and the preamp as one unit. They are not.
 
#9
Hello,

I can across your thread because I had the same question, however I have found this link that explains it in detail.
This is quoted from the site:

What's the difference between "active pickups" and "active EQ" or "active electronics"? Most active instruments have passive pickups and an active preamp in the control cavity. When people talk about active EQ or electronics onboard, they are talking about that preamp. Active pickups are ones where the preamp is built into the pickup housing itself. The pickups are still passive at their core, but they have been wound and specially designed for optimal use with a preamp right there in the pickup body. The preamp inside an active pickup may be designed to do any of the functions of an external preamp: buffering, boost, or even EQ control. Active pickups may be combined with another preamp in the control cavity, but they don't need one. On the one hand, adding more preamps together can give you the hottest/highest output levels if that's what you want; but on the other hand, every pre-amplification stage will color, compress, and distort the signal slightly--some people like that sound, others hate it. Again though, the majority of the time, just because an instrument is "active" does not mean it has active pickups.

Can you more knowing folks confirm if this explanation correct?

Hope this helps

John
 
#10
kyleaubu said:
I feel like I need to go take some sort of class for this... Lol. I think I'm getting it.
Click to expand...

You were caught up in a common misconception so it can be hard to search for the right answer since the wrong one is so common. It seems like most people here think that active basses have active pickups until someone sets them straight. An active bass is one that has some element in its internal signal chain that requires an electrical power source to function. An active bass can have active pickups or a preamp or both. Most active basses have an on board battery but some are powered with an external battery or power supply. Some passive basses have a battery on board to power an LED fret marker system, we do not consider them to be active basses. So the presence or absence of a battery is not a certain indicator that the bass is active or passive.

Doley50 said:
What's the difference between "active pickups" and "active EQ" or "active electronics"? Most active instruments have passive pickups and an active preamp in the control cavity. When people talk about active EQ or electronics onboard, they are talking about that preamp. Active pickups are ones where the preamp is built into the pickup housing itself. The pickups are still passive at their core, but they have been wound and specially designed for optimal use with a preamp right there in the pickup body. The preamp inside an active pickup may be designed to do any of the functions of an external preamp: buffering, boost, or even EQ control. Active pickups may be combined with another preamp in the control cavity, but they don't need one. ... Again though, the majority of the time, just because an instrument is "active" does not mean it has active pickups.

Can you more knowing folks confirm if this explanation correct?
Click to expand...

It is mostly fine, I snipped out the part that is more opinion than fact in the quote above. Truth be told no electric bass is truly passive unless you always play it unplugged. As soon as you plug your passive bass into your stage or house amplifier it becomes part of an active system. As long as they are well designed the active parts of the system do not significantly color or compress the sound beyond the limits the musician intentionally dials in by adjusting the EQ, gain, compression, etc, etc, etc controls on the electronics. There is no fundamental difference between the active electronics inside a bass and those inside the rest of the amplification system so there is no need to apologize for them as the author of the above did in the part I snipped.

The "sound" of an active bass that some people "hate" comes from the fact that most active basses load the pickups differently from the way that the pickups in a passive bass are loaded. So they do tend to sound a bit different. People who strive to get the sound that some passive bass had on some old recording will not be happy with most active basses. But it certainly is possible to recreate that passive sound on an active bass with the right internal circuitry. A few basses do that right from the factory and there are aftermarket preamps that can do that too. The active/passive sound difference is an implementation issue, not a fundamental failing of active basses.

Ken
 
#11
I agree that the bit you snipped could have been worded a little more clearly or even-handedly, but (a) notice it does not say anything about onboard preamps versus rack or head preamps, and (b) it is an absolute FACT that no preamp is perfectly transparent, and that the more preamps you stack up, the more coloration occurs. For evidence, just look up the phrase "wire with gain" to see that it is understood by audio engineers to be a mythical goal. Whether the coloration is audible, with one preamp or several, is of course totally subjective and dependent on the listening rig and the context. Also, people regularly complain about their active bass sounding "too compressed" compared to their passives; it is not universal, or even majority, but it is a common complaint.
 
#12
As far as my knowledge goes, active pickups tend to have fewer windings and therefore are lower impedance. This means that there is less magnetic pull on the string, and if it was left passive there would not be enough energy to drive the signal along the instrument cable. So builders like EMG and Seymour Duncan put very small op-amp circuits into the pickup housing itself, driving the signal to a much hotter output before it gets to the output jack. You can use an onboard EQ-preamp with these or not. If you don't use an onboard EQ you'll still require a battery but would wind up with passive controls like Vol-Vol-Tone instead of onboard bass and treble boost and cut. Active pickups sound great on fretless basses IMO. Passive pickups are much better on fretted, because they are warmer (generally speaking), and you can shape their tone with an onboard preamp if you wish.
 
#18
Good discussion here. I have a bass with active electronics I'm thinking about swapping out the preamp. I wasn't sure if I could continue using the same pickups, as they are attached to an active preamp. Now that I say it, it sounds dumb. However, I'm not technical enough to determine if the problem is with the pickups or the active pre.

I guess I'm psyching myself up because I've been eyeing the Sandowsky preamp lately lol. It looks very nice. My current active electronics have a tone knob that is stacked, and the knobs are pretty tall. I like the Sadowsky has a stacked knob but it's very low profile.
 
#19
alaskaleftybass said:
I guess I'm psyching myself up because I've been eyeing the Sandowsky preamp lately lol. It looks very nice. My current active electronics have a tone knob that is stacked, and the knobs are pretty tall. I like the Sadowsky has a stacked knob but it's very low profile.
Click to expand...

Why not just look into getting knobs like that then? I'm not a fan of most stacked pots for the same reason BTW.
 
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