I'm undergoing my first electronics project atm and I've just started breadboarding a bit of an overdrive. I wanted it to be a bit of a overdrive, pre-amp and D.I project. just realised though that I'm not sure what impedance or signal level my bass is pushing out with which to design/build a D.I etc
I have an active bass (ibanez SR500) does anybody have any idea what impedance and signal level i'm pushing out??
Cheers.
I have an active bass (ibanez SR500) does anybody have any idea what impedance and signal level i'm pushing out??
Cheers.
An active bass is more of a line signal than anything else, 50K should be fine for an input impedance - with 500K and up for a passive bass.
Signal level varies depending how you play, but you could easily hit over 1V RMS.
Signal level varies depending how you play, but you could easily hit over 1V RMS.
Measure it. I have three dozen basses, active and passive, of all different levels. The one thing you can be assured of is: there is no standard.jenks said:
No. Some are no different in level (EQ flat) from the passive equivalent.Nigel Goodwin said:
There are good reasons why this might be so.
You need to measure again. Some of my basses hit 12dB or better than that on peaks with slapping or plectrum work.Nigel Goodwin said:
if you're just looking to boost the signal, a simple preamp using a TL062/72/82 and a max gain of 10 would suffice.
in the circuit below, the second half of the op amp splits the 9V battery and provides an active ground. the other half is a noninverting preamp with a gain of 0-11. using a TL062 will give a nice clean signal and low current draw from the battery. and the whole thing fits on a pc board smaller than the battery.
you may want to add a couple of 220uf caps between the supply rails and ground.
in the circuit below, the second half of the op amp splits the 9V battery and provides an active ground. the other half is a noninverting preamp with a gain of 0-11. using a TL062 will give a nice clean signal and low current draw from the battery. and the whole thing fits on a pc board smaller than the battery.
you may want to add a couple of 220uf caps between the supply rails and ground.
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At the moment I'm building a device which has a TS-9 circuit inside which I've just breadboarded and I'm gonna test it soon.
But, I wanted two outputs: one with the impedance and level modified for input to a desk, so that's pretty much a D.I. and the other just line-level jack to put the device in line with rest of my pedals.
So it looks like I should measure the impedance and the average level that my bass outputs before building the D.I then...
But, I wanted two outputs: one with the impedance and level modified for input to a desk, so that's pretty much a D.I. and the other just line-level jack to put the device in line with rest of my pedals.
So it looks like I should measure the impedance and the average level that my bass outputs before building the D.I then...
Previous post is correct. You can simply measure the resistance of the bass output and consider that the characteristic impedence of the pickups since the paralllel capacitance and series inductance of the PUs is nominal. Seymour D has detailed specs in his catalogue. Just remember that everything changes when you play with the volume pot and tone control. Now for the controversial IMHO part. A bass with good single coil pickup wants to look into a valve stage. They don't like transistors, and will lose all of there character (Balls, Timbre, ability to sing). So if I want overdrive, I'd get one of those Mesa foot pedal boxes with a 12ax7, or put a switch in the cathode section of the first stage of the Amp, so I can change the gain of the first stage,which will overdrive the second stage. I once had a dual channel Alembic preamp that I would cascade, that is daisy chain the A and B channel. Very sweet.
Test my tube vs x-sistor theory for youself. Plug something like a '62 jazz bass into your favorite tube head (SVT, Mesa Boogie 400, Sunn Model T, whatever). Notice the grinding growl when you crank it up. And yet it sings like a Stratavarius when you back off. Now plug it into whatever transistor head you want (GK, Trace Elliot, New Fender). Now everything is compressed and tone has flown the coup. Every thing sounds like it's been processed by a computer chip (Line-6 ?). Flea cries out "But my GK has all this PUNCH!" Well so does Mike Tyson, but that doesn't get him the job as first cellist with the Chicago Symphony does it?
Well I've tried my best to start a flame war. Don't let me down!
Test my tube vs x-sistor theory for youself. Plug something like a '62 jazz bass into your favorite tube head (SVT, Mesa Boogie 400, Sunn Model T, whatever). Notice the grinding growl when you crank it up. And yet it sings like a Stratavarius when you back off. Now plug it into whatever transistor head you want (GK, Trace Elliot, New Fender). Now everything is compressed and tone has flown the coup. Every thing sounds like it's been processed by a computer chip (Line-6 ?). Flea cries out "But my GK has all this PUNCH!" Well so does Mike Tyson, but that doesn't get him the job as first cellist with the Chicago Symphony does it?
Well I've tried my best to start a flame war. Don't let me down!
Typically bass pups have between 4 and 16H of L Capacitance is between 200 and 300pF. At least the ones I measured.makinson1 said:
Best dats, but still not much.makinson1 said:
Bollocks.makinson1 said:
Bollocks! Well, I'm prejudiced. I think tubes sound better than solid state devices. I think black vinyl sounds better than CDs. I think mag tape sounds better than a hard disk. So there. Bollocks? Is that a Britishism? Something like ********? Is there a translator out there that can translate that into American?
makinson1 said:
Well you have two of them, and they hurt a LOT if kicked! 😀
Bear in mind the OP has an active bass, not a passive one, so no need (or use) for a high impedance input as you would need for a passive bass. Most amps though have sockets for both, so it might be an idea to add both?.
Valve amps have their uses, but it's mainly personal choice, and a decent transistor amp would be my choice for bass, as I like a clean sound, not the distortion and colouration of a valve amp.
Nigel Goodwin said:
Either amp should be able to be adjusted for the amount of drive (distortion). It's just that when solid state amps are overdriven they clip the signal like a limiter rather than a compressor. I don't know if that simile works for you.
So? They are your preferences and very far from universal.makinson1 said:
As I used it, "bollocks" means BS in yankspeak.
Correct. Sorry to the OP, but when I said 'measure' earlier, I simply meant level. Some basses like Spectors with the Tonepump put out a very high level that often causes problems with some amps and pedals/FX, and some are unity gain.Nigel Goodwin said:
Best bet is to record your bass into a soundcard, just playing normally (for you), then play as aggressively as you ever do. Check the peak levels as well as the averages. The volume envelope will allow you to experiment with the topology to set levels of say where clipping diode networks start to take effect, so you can optimise it more easily than just by ear. I often build MI amps using a number of recorded solo instrument pieces straight into the instrument input (via a pad). This way I get absolute consistency when experimenting as you (or anyone else) never play the same piece the same way at the same level twice in a row. When you feel you are close, play into it and experiment with ranges of settings more.
John Broskie (www.tubecad.com) had an excellent variable clipping network design a couple of years back. It can be made to work very well. You'll need to dig around to find it.
Bass O/P Z will be lowish but it will depend if there is a vol control at the output as some are configured, or if there is a buffer after it. Both are common. It should not present an issue for you.
True, and I've heard all sorts of players get great tone from greater and lesser basses and cabs. I want to hear what I'm playing, and not have it hacked by 12AX7's. Blech.Nigel Goodwin said:
That is far from the truth. In some simple ccts, it is the case, but there are lots of ways to do it differently.makinson1 said:
Yep. By varying the gain driving it, the clipper supply voltages and perhaps even the network values, a neat sounding variable clipper can be made. I've used it on some tube (clean sounding) ccts with success when experimentingteemuk said:
actually there are some SS amps out there that will compress. it's actually done to keep the amp from clipping. another series of SS amps has a soft clip circuit in ithe preamp that has a characteristic very similar to a tube output stage (not in pro audio.... it was NAD consumer audio). which gives a rounded clipping and keeps the amp itself from clipping. i have designed a tube preamp that gives a nice tube sound, through a SS amp (as have a lot of others), but mine uses submini tubes and will fit inside a guitar.
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Ditto. When was the last time a high-end audio company advertised " Our tube amp is so good it sounds like transistors" ? Just check out any of the onliine reviews of amps like the Manley's, Audio Research Corp, VTL, BAT. As for tape being dead, you'd be astonished to learn how many of the top recording studios still use 24-track tape to track to before they dump it to the Apple hard drives and ProTools. Why do all of the top mastering studios use 2-track Ampex ATR machines? http://www.atrservice.com/
makinson1 said:
Nothing wrong with hitting below the belt, I teach martial arts (Ju Jitsu), hitting (or kicking) below the belt is a favoured technique
He's got a lot to be blamed for, that Marquis of Queensbury!.
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