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Passive vs. Active Circuitry?

Q: I’m just getting back into the bass and there’s something I’ve always been curious about: the differences (as well as the different kinds) of passive vs. active circuitry. What are the main differences between them, why are there only active and passive circuits, and what does it mean to have either in a bass?

A: Although I am not the most tech-savvy of bassists (and I’m sure many of you will comment back on this to add to what I say here) I think I can answer your question.

Essentially, an ‘active’ bass just has the addition of an on-board pre-amp to give the user further tonal control. Active pre-amps require one (or two) 9-volt batteries although Alembic (who I believe came up with the concept for Phil Lesh of the Grateful Dead) has given the option of additional cables to power the on-board pre-amp.

Passive controls (by definition, a pre-amp is powered, therefore you would not speak of a passive pre-amp) are generally limited to volume control and tone shaping (“tone” knob). While you can shape the tone a bit, there is not nearly the flexibility as with an active pre-amp.

The pros and cons all boil down to personal preference. Personally, I like to have pre-amps available to me but I’ve also added active/passive switches to all of my basses so I have the option of playing the bass passive OR active (the most flexible way to go, I think). Many pre-amps color the sound naturally even before you boost or cut a frequency. For this reason, many players (especially traditionalists) feel that the passive electronics deliver a more organic sound. This is true, I’d say. Many pre-amps do give the user a more “hi-fi” sound, which is desirable by some. Personally, I prefer an organic tone, but sometimes you just need to boost one frequency or another to help compensate for a particular room or to help you cut through a larger ensemble without necessarily just getting louder.

Most active pre-amps will offer a boost/cut knob for 2-4 frequencies. Most will have a volume control and a pickup pan. In addition, to those two knobs, the most common configurations are:

2-band EQ = Bass – Treble

3-band EQ = Bass – Mid – Treble

4-band EQ = Bass – Low mid – High Mid – Treble

I personally find that I’ll use low and high mids the most for shaping my tone to fit a band or stage. Therefore, I tend to go 4-band EQ (often using a “stacked” knob for my mids (meaning there are two knobs affixed to one knob space stacked on top of each other)

I hate to have to rely upon batteries, which is another reason to have a passive switch if you go the pre-amp route. There is nothing worse than your sound crapping out on you in the middle of a gig because your 9-volt died on you (has happened to me once, and I’ve been very careful to make sure it doesn’t happen again).

Now, if my battery dies or starts to sound bad, I can just flip my switch and finish the set passively.

In short, if it sounds good to you, it’s right for you. Just make sure that you explore the tonal possibilities and explore the quality of the sound coming from the instrument with or without a pre-amp and use your own judgement as to what will work best for what you’re doing musically.

If you’re slinging a P-bass in a country or blues band, I wouldn’t bother messing with active circuitry. However, if you’re playing many different styles of music and want one or two basses that can cover it all, a nice active pre-amp can certainly help with that!

Photo credit: Brett Sherman

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Share your thoughts

Paul Vienneau

Damien,
Very good points about passive vs active systems.
I’ve been pretty hard core into passive because of the warm and woody tone it gives me. I’ve been playing for just over 30 years, so I’ve had the time to form opinions on this.
When I was very sick in 1991 some local musicians took donations and bought me a Yamaha John Patitucci model 6-string bass, with active electronics. I’ve used it for specific recording sessions over the years, and on a few tours with a reggae/ska/soul band. In general though, it’s just been here waiting for me.
A number of months back I began playing with a country artist with whom I recorded a CD as a session player awhile back.
I have played my passive Furlanetto 6-string on almost everything since I bought it 18 years ago. The Yamaha was the perfect bass to fill this country band. Just as there are different styles of blues band (Johnny B Gayden played active bass with Albert Collins, wonderfully), there is a huge segment of country music where an active or brighter toned bass is ideal.

I guess my point is that at times something might be more appropriate, but generalizing about where passive/active fits isn’t effective.

I love your playing and have enjoyed your lessons on http://www.playbassnow.com. I just wanted to offer my opinion too about passive vs active.

Oh! I bought a Fender Jaguar bass a couple weeks ago. It comes with an active/passive switch. It sounds so good in passive mode, fingers and slapping. The active controls are pretty cool too.
All the best,
Paul Vienneau

Tim

Tim

Thank you SO MUCH for answering this question! Now all I need to do is go to school for electrical engineering so I can really understand how it all breaks down and works. haha

Justin Killings

Justin Killings

I’ve also found that a combo of active/passive circuits works good if you play fretless, or if you use sound effects.

Sid

Sid

My thanks for not taking the “Active/passive is the only way to go route”. Very informative article. I think the one phrase that sums it up is “if it sounds good to you, it’s right for you”. Excellent advice.

    Jeff

    Jeff

    I’ve owned many of both “kinds” and I always make my way home to an old Fender Jazz bass. The “passive” bass has so many different sounds it’s hard to imagine needing anything else – it works for jazz, funk, country, rock, fusion. For me it’s more bout the hands than it is the electronic. One of the things I hear over and over is that even if I’m playing a $50 piece of junk it still sounds pretty much the same as my 63 jazz…or Fodera . . . or Carvin…or Shecter….

      steve

      steve

      I’ve had a p bass for 20 years and it’s what I always go back to. They were user friendly long before the term was coined.

waypoint

waypoint

Very good article! I, too, like the fact that you didn’t take one stance or another. Everyone has preferences. It really does depend on what style you play and what you want. I have a late-90’s Peavey with passive EMG’s that is great for pop/slap and has a real punchy sound. I can play harder on it. I also have a Switch Innvo-IV with actives that are really hot. (I don’t play all the time so it picks up everything) I like it because of the brighter, more modern sound. Just depends on where I’m at and what I’m playing.

Zulu

Zulu

I agree with having the option of a passive/active switch. I have a Ken Smith bass that gives me that option as well as switching between series/parallel path. I always thought having the most options was the way to go. However, the biggest issue with varying between active and passive for me has always been the input signal strength. It’s a good idea to have a way of balancing your input signal, especially among multiple basses that ate active and passive. Otherwise, you can spend a bunch of time turning nobs in the middle of a set.

Mike

Mike

I have been playing bass off and on for close to 20 years and I have found that I really like active circuitry. It really adds extra punch to my sound even if I set the controls flat. I’m also a finger player and using active pickups helps beef up the sound. I find the sound of a pick is just too harsh for my liking.

Uwe Forschner

Uwe Forschner

Hi to all you bass players around the world! Now celebrated my 36 aniversary of gigging, so over this long time I had several bass guitars. First some passive, like a Tokai Jazz and a Fender 1964 Precision. Then there was a real expensive I wanted real badly: A Lado, a high-class – model. Active circuit, some out-of-phase, serial and parallel – switches – and a knob, who gave you at last nine (9!!)different sound presets – and none of them worked for me. It sure was not the amps fault as I played a GK 400 MB this time. So the bass had to go. It was just too complicated.

A long time there were only passive basses, then in 1990 I found me a beautyfull Warwick Streamer Stage, active. You can swich off the preamp, but I just do it quite seldom.

Later there was a MM SR5 to follow, well known 3-band-eq, than a custom built Haeussel Bass. This one has a quite difficult active circuit, but set flat it sounds absolutely amazing. And you can switch it off.

So I have a lots of different bass guitars, actives and passives. I love them all, avery bass has its sides I love.

Don’t make a dogma of this! It does not matter if active or passive. But in case of active circuit: K.I.S.S. – keep it super simple! Not too much knobs. I love basses, that work, just plug and play.

Cheers

Uwe

John Shaughnessy

I converted all of my basses to active a couple years ago, for a reasons that haven’t yet been covered:

1) An active signal output is generally “buffered” – without getting super technical, this basically means that the signal coming out is strong and free of distortion or interference from other components. This means you can use long cable runs, plug straight into a mixer or recording desk without a DI, etc.

2) the other thing is that true active pickups (as opposed to a passive PU with a preamp attached) are exceptionally quiet and are great at rejecting interference from computer monitors, lights, dirty power etc.

I do a lot of recording and really hate spending hours trying to “denoise” a passive bass. And if you’ve ever done a gig in a bar where you’re in the same circuit as a neon sign or ice machine, active PUs are your best friend.

I don’t much care about the tone shaping capabilities of preamps, as you can do that from your amp anyway. In fact, my main active bass has NO tone controls at all, and the others are wired with a single passive tone knob. This configuration is like passive, but better.

The only downside is changing the batteries…