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bass guitar signal voltage output
- Thread starter ybassman
- Start date
It doesn't work that way. Voltage is continuously variable, depending on what notes are being played, how hard, etc., and the nominal voltage is going to vary considerably, based on the pickup winding, magnet strength, distance from the strings, etc. You can draw certain conclusions about pickups of particular types, but no one sits around measuring the voltage, and trying to record statistics.
What is your reason for asking?
What is your reason for asking?
LoveThatBass
Supporting Member
I agree here. I have some Active basses that can swing as much as 2+ volts and my Peavey with Active pickups AND preamp as much as 4.7 volts Peak to Peak. I have some alumitone pickups that put out twice the signal level as say a typical Jazz bass pickup and those are all over the place depending on pickup in question.
There is no inherent difference in voltage between active and passive. That's an irrelevant factor.
What does the output of a pickup have to do with the input stage of a subwoofer amp?
Firstly, the concern lies with the preamp, not the power amp. Secondly, you can follow any standard model for designing that preamp.
Its going to vary a lot, but you can get a rough idea of the maximums to design to by looking at preamp design.
Most onboard bass preamps (and stomp boxes) use a 9v battery, which means that any peaks that exceed plus or minus 4.5v would clip the preamp (though it will be slightly less than this in reality, due to the circuit and battery discharge). Some people like to run a two battery preamp design (and can apparently tell the difference) which means that there is possibly the occasional peak that exceeds 4.5v, but that it is not a big factor since most people are happy with a single battery (or a 9v powered stomp box).
Most onboard bass preamps (and stomp boxes) use a 9v battery, which means that any peaks that exceed plus or minus 4.5v would clip the preamp (though it will be slightly less than this in reality, due to the circuit and battery discharge). Some people like to run a two battery preamp design (and can apparently tell the difference) which means that there is possibly the occasional peak that exceeds 4.5v, but that it is not a big factor since most people are happy with a single battery (or a 9v powered stomp box).
I'm trying to design a compressor and I have been researching about the same issue.
the only site that I found on the subject is this:
[Invalid or Expired Link Removed]
the only site that I found on the subject is this:
[Invalid or Expired Link Removed]
Not just that, cause a normal IC, such as TL071 with 9 volts power supply will be able to amplify without clipping up to 7 volts. That's its headroom. (I'm no expert, this is jut common knowledge)
There are ICs called "rail to rail", who can produce signal within power supply and zero volt, but not all ICs are like that.
. . .
Another thing that need be mentioned is that -- if I understand it well -- this does not imply that a pickup signal is nearly +/-3.5 V... (which would become 0-to7V during amplification)...
this implies, sure, that the input signal is within that range, +/- 3.5 volts, or +/- 3 volts...
but what it really implies is that even the output signal is within the range, below the "headroom"... after a reasonable about of gain has happened...
I mean, from this we can only tell the pickup signal's average / maximum / typical maximum level if we know the amount of gain that a preamp performs...
what I believe to know is that an SPB-3 is of the order of 100-200 millivolts, but it is no accident that pickup makers only say "it's hot or high" and don't bind it to a numeric value, cause playing style, strength of picking, string to pickup distance, string gauge all play in this...
just read this very good article by a PRO, Rod Elliott, with measurements of pickup signal levels...
Guitar Output Voltage
Impedance of the input on your amp is critical for a passive bass. The peak voltage may be up to 200mV, but there is not much power behind it. A low impedance input would drop the signal down to almost 0. Active electronics push the signal stronger. An active and a passive bass will push the same voltage at the same volume.
The active circuit may be able to push a louder signal, but it also can source more current.
Learn from best practice used by the big amp manufacturers. A pad switch that drops the signal 15dB first. Then input should have a high impedance buffer. Lots of pedal circuits online will show you what to do for the buffer.
Preamp stage then puts your signal into the range your power amp circuit wants.
Update: Simplest thing to do would be buy a pedal like a Sansamp or the cheap Behringer for the input and preamp of your amp. Just add a power stage to the end of it.
The active circuit may be able to push a louder signal, but it also can source more current.
Learn from best practice used by the big amp manufacturers. A pad switch that drops the signal 15dB first. Then input should have a high impedance buffer. Lots of pedal circuits online will show you what to do for the buffer.
Preamp stage then puts your signal into the range your power amp circuit wants.
Update: Simplest thing to do would be buy a pedal like a Sansamp or the cheap Behringer for the input and preamp of your amp. Just add a power stage to the end of it.
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just a subtle correction:
active circuits do push (amplify) the signal, passive circuits (a potentiometer + a capacitor) don't push it at all...
however, passive basses use preamps, too
only not onboard... as we knowI'd advise against buying a behringer...
if you want a buffer, ask someone to build it for you... they can be on/out board
I've read about a cool onboard buffer here: Onboard Buffer - Nice one Albert and Don
(I'm not sure though what this has to do with the OP
)
Passive basses do push, but weakly. The string vibrating over the magnetic field of the coil generates electricity.
if that's "pushing", sure
I'd however put it like this:
active basses have the preamp in them which amplifies the signal, while passives don't
amplification can be viewed as "pushing"...
generating the signal should be seen as act no. 1. / "box" no. 1 in the process flow diagram, only after which can we talk about a signal... so it should be separated from doing anything to the signal
but you can use any terms in any combination, of course
the only point is understanding what we talk about
I just came across this thread from Goggle researching this very thing, for the purpose of mounting a "frankenstein style" meter on a "steampunk bass," along with antiquey rheostats (potentiometers) for volume/tone, and a huge can capacitor.
I gather that it will have to be a millivolt meter.
I haven't found anything about amperage yet, but I'm guessing that'll be milliamps, as well. Microamps?
The signal is an AC signal, so you have some circuitry to figure out.
If you are building an active bass, I would suggest a microamp meter on the battery. That should work.
If you are building an active bass, I would suggest a microamp meter on the battery. That should work.
I like the way you think. Man, there's some crazy, very well done, steampunk basses folk have built. Hope your project progresses well.
A bit of DIY is in order . I am in the middle of redesigning my 18v class D amp for battery use . I am using a TL071 as a non inverting amp/buffer . 10M input impedance and adjustable gain from 0-16dB . The gain control will be the only control on the amp . Volume and tone from the bass . It seems to cope with every bass I have played through it . Dime the volume on the bass and adjust the gain just short of clipping when playing hard .
Changing values of feedback components would allow more gain if needed .
Changing values of feedback components would allow more gain if needed .
