Can't wrap my head around active vs. passive basses

[toughluck]

I started playing regularly and seriously only last year and I played an already fairly modern passive P+J bass (budget brand, early noughties), so I don't have experience with older guitars.

I think these two statements are true:
• Fully passive instruments have comparably low outputs (though significantly higher than they used to have half a century ago). So putting a phantom or battery-powered preamp in the guitar itself makes perfect sense. The signal is hotter, it has more headroom, interference induced noise has less effect on the signal.
• Bass amps used to have two inputs, one for passive instruments, and the other for active ones. The active input simply padded the signal before the onboard preamp. You could achieve the same result by plugging your active instrument in the passive input and turning down gain. The only time when you needed to use the active input was if your bass runs so hot that it overdrives the preamp even with the gain turned way down.

So far, so good. But I bought an active guitar last year and I was surprised by one thing: the volume in passive and active modes is exactly the same. I read that this is common with all modern active guitars. I can tell for a fact that the preamp is in use because active mode won't work if the battery is close to being dead, and tone controls only work in active mode. When tone controls are in the center position, it's impossible to hear the difference between active and passive mode.

Active signal is not hotter than passive. It's possible that the noise floor is lower and you get higher SNR in active mode, but interference induced noise is additive. It doesn't care how much (or how little) noise there was previously. If there's enough interference, it will cause noise.

What gives? The only two advantages I see running the bass in active mode is 1) tone control; 2) impedance matching with badly designed amp input stages. Theoretically, there might be a third advantage that when used in a noise-controlled studio, your bass will have a slightly lower noise floor, but I'm grasping for straws.

What am I missing?

 

[Aloe]

3. less treble loss over long cables
4. sparklier sound if run directly to a passive DI

don't be obsessed by any of those, just play your bass the way it sounds better to you.

the active/passive switch on the amp might be just a gain pad, but might be more. on Phil Jones amps it switches the input impedance as well, so passive basses to active input sound very dark, active in active sound almost the same but with less noise.

 

[ardgedee]

The only two advantages I see running the bass in active mode is 1) tone control; 2) impedance matching with badly designed amp input stages.

Those seem like pretty big advantages if they fulfill a need.

I mean, there's only one advantage to having strings on a bass, and that's because they vibrate when plucked. You don't need a lot of reasons if the one reason you have is good enough.

 

[toughluck]

3. less treble loss over long cables
4. sparklier sound if run directly to a passive DI

I haven't considered that, those are pretty good points. They don't apply to me, but I see the appeal for others.

don't be obsessed by any of those, just play your bass the way it sounds better to you.

the active/passive switch on the amp might be just a gain pad, but might be more. on Phil Jones amps it switches the input impedance as well, so passive basses to active input sound very dark, active in active sound almost the same but with less noise.

I think I'm fussing a bit too much over them. I usually play wireless, so maybe if I played on a cable, I would have noticed other issues, but then again, all my amps only have a single input, so I have no comparison. But it doesn't appear that any of them have any weird input impedance tricks, that's actually what prompted this question more than anything else.

Those seem like pretty big advantages if they fulfill a need.

I mean, there's only one advantage to having strings on a bass, and that's because they vibrate when plucked. You don't need a lot of reasons if the one reason you have is good enough.

I chuckled.

It's a fair point, but that would mean that if you don't need either, you're better off with a less expensive passive guitar if it comes with better pickups. But above a certain price point, all I see are active guitars.

Tone control on the guitar is a good thing if you like to annoy the sound guy running the FOH mix among other things. But too much of a good thing is counterproductive if you dial in completely different contours on the guitar and on the amp, though that might achieve exactly the sound that you're looking for.

 

[ctmullins]

Many current active preamps are unity gain, and have been for years. The idea that “active is hotter than passive” must have come from cheap factory preamps, and/or clueless players who habitually dime all the knobs.

Edit: or perhaps players who regularly use their passive tone control. I almost never use mine, but if/when I do I am immediately reminded of its subtractive nature.

 

[brianrost]

Just use your ears. I don’t care if the bass is passive or active, I care that it sounds good. I’ve owned both and only a couple of active basses had a passive bypass. Some of the active basses did not have mutliband EQs, the active part was gain only. There are passive basses with bass and treble EQ…G&L for example.

The lack of a passive bypass means only one thing to me…check your battery voltage regularly and always bring a spare.

 

[el murdoque]

It's about impedance. I'm too stupid to properly understand it myself, but one has a very high impedance output and the other has a very low impedance output. One has those problems that signal degrades while traveling through a cable, especially when the cable is long. (The passive bass)
The other can drive long cables no problem. (the active bass).

 

[MCS4]

The issue is that passive pickups vary widely in terms of output, and passive pickups are used in most basses with active preamps, so you really can't generalize too much. Add to this the fact that active preamps often have an internal trim pot that can be used to adjust the output gain, and you get a situation where there is no real point trying to predict whether a bass is going to be hot or not based upon passive vs. active.

Setting this aside, there are lots of threads about the potential benefits of active vs. passive, and they rarely have much to do with raw output.

 

[Aloe]

I usually play wireless

ah, yeah, wireless is a buffer, so basically if you have that covered, that's either a question of 'would you like tone controls on your bass' (for example, not to tweak knobs on the amp, that's set up for another bass) and 'how it sounds better to you'.

so, basically, a wireless buffers your signal, just like an active bass. thus dealing with impedance issues and stuff.

 

[mambo4]

1) tone control; 2) impedance

What am I missing?

nothing. That is the sum of what active instruments get you.
Maybe signal buffering too (tone unaffected by downstream circuitry)
if that doesn't fall under impedance matching.

 

[Jeff Hughes]

Passive=original NES controller
Active=turbo NES controller

Someone once described active versus passive as the active was faster to grab the disruption in the magnetic fields whereas the passive was slower. To me the extra juice always made active basses more effortless to play while producing frequencies that could stand out in a busier and more crowded stage or recording mix. I never liked messing with the batteries though.

A passive bass plugged into an eq pedal or preamp helps you control the gain and boost of select frequencies whereas an active bass has that baked in and controllable by onboard knobs.

Volume is a funky thing given the harmonics can change our perceptions.

 

[Altitude]

The impedance matching thing is academically true but probably overthought. Generally we think a guitar cable can be 20 feet long before any loss of high end becomes perceptible in a passive pickup situation. Not sure how many of us use cables longer than 20 feet between bass and amp.

 

[Wesley R]

Unless your bringing in a living wage, play what you want and can afford. If making big coin, play what your told.

One might a close friend and I were drinking a little too much. Around three in the morning he looks at me and in a very somber tone of voice says "I've been chasing the tone on my head for a long time." " I am further away now then ever before." Two days later most of his set is up for sale, and were driving all over looking for gear close to his early set ups.

 

[Boundary Effect]

Add this to the discussion. The first amplification stage, the input stage, can be critical for quality when a moderately high-impedance low-output transducer (pickup) is in use. This is why cable quality and length is noted because it becomes a component of the transducer/input stage circuit. If one uses effects pedals, the first effect pedal's input circuitry essentially becomes that first stage. In that case, an active bass output could be a better choice. If one does not use pedals and wants the full tube experience from their V4b or any well designed bass amp, a passive signal into the front-end of that amp might be the way to go. The tech certainly has improved in the last forty/fifty years. I recall how noisy a 1977 MXR Phase 90 was on my Rhodes piano.

 

[DonaldR]

Avantage #1: As already said, the active buffer really close to the passive pickups. The volume and the tone pots are just after the buffer instead of between the pickup, a long cable and a buffer (pedals or amps). It's a more consistent sound and less dependent of the input impedance of the next device.

Advantage #2: I can use only my bass plus a cable and plug it in almost anything. It can be an amp, a passive/active DI, a channel strip or a mixer input.

Advantage #3L Biggest advantage IMO is that you can boost/cut bass, mid, or treble just a little for certain parts of a song without using external eq pedals or playing with your amp eq. Part's done then move eq back where it was. The Scrambler in the Ampeg SCR-DI is losing a bit of low end when engaged, so I switch the Scrambler on, boost lows on my bass. Turn the Scrambler off then put bass knob where it was.

Advantage #4: The B string seems more defined and balances better with other strings. But this is just my opinion and not backed with scientific data. Might just be the pickups in only two different basses, so my sample is too small to conclude anything.

Passive is a very good and sounds more vintage IMHO. There's no best, only what you prefer.
I would probably put a J-Tone preamp in my Jazz 5 because I prefer active sound. But I play my Yamaha TRBX-505 almost exclusively in passive mode and switch to active mode when I want a more modern/defined sound or for slapping.

 

[ga_edwards]

One advantage active basses have is that you can reduce the volume without affecting the tone. Passive bass volume controls can affect tone.

This comes in handy if you switch between basses (and the active is naturally louder).

 

[FullumMusic]

A lot of the differences are either advantages on paper, but nominally different in real-life, or more preferences than actual advantages.

Like, active basses are hotter than passive basses, except for when they're not. My hottest bass is a passive P, and the lowest output bass i've ever owned was active.

Or, the onboard Pre acts as a buffer which is "better" for the signal before it goes down the cable and into the pedals or amp input. But if your passive basses sound good in the exact same situation, is it really "better"?

Active basses (electronics, not necessarily active pickups) have onboard EQ. That's "better" if you like having an EQ directly on your bass. But also, you could have a pedal pre-amp with an EQ also. And you already have a pre-amp and EQ on your amp. So how many pre-amps and EQs do we need in our signal chain?

Is changing a battery once ever 3-6 months better? Is having to unplug your bass when you're not playing better? Are either really that big a deal? No... except i hate both of them no matter how insignificant they really are.

Neither is better. They're just different. You only need Active Electronics on your bass if you like or want them, or if the bass already has them and you love the way the bass sounds and plays.


Or, look at it this way:
1 - Have you ever been in a musical situation with a passive bass that you couldn't get through without onboard active electronics?
2 - Have you ever been in a musical situation with a passive bass where you thought, "wow, active electronics would have made that so much better!"?

 

[darwin-bass]

• Fully passive instruments have comparably low outputs (though significantly higher than they used to have half a century ago). So putting a phantom or battery-powered preamp in the guitar itself makes perfect sense. The signal is hotter, it has more headroom, interference induced noise has less effect on the signal.

What gives? The only two advantages I see running the bass in active mode is 1) tone control; 2) impedance matching with badly designed amp input stages. Theoretically, there might be a third advantage that when used in a noise-controlled studio, your bass will have a slightly lower noise floor, but I'm grasping for straws.

What am I missing?

Your first statement is simply not universally true. Passive basses, even old ones, are not lower output. And adding a preamp does not automatically mean the bass will be louder. If you boost the bass control, yea, it is louder but with the tone controls at neutral, most of the time the output will be similar to passive.

Most of the advantage is in tone shaping. On-board EQ plus impedance control alters the sound. Badly designed amp input stages? I don't think I've ever seen that.

As for noise, the lower output impedance can reduce noise picked up in the cable but adding active circuitry can add noise so a preamp is not necessarily quieter than a passive bass feeding the same amp.

 

[darwin-bass]

One advantage active basses have is that you can reduce the volume without affecting the tone. Passive bass volume controls can affect tone.

Oooh, I forgot about this. Big advantage to active!

 

[Jefenator]

I never use passive bypass when available on an active bass.
And yet, I never miss having the active circuitry on a good passive bass.
I'll keep trying the "active" input on a new amp when appropriate, but thus far I have preferred the response with the passive input every single time.
These things do not make complete sense. But they don't have to; we are not Vulcans.
At the end of the day, if it sounds good, it is good.