bassman Posted January 10, 2005 Report Share Posted January 10, 2005 This bass came out as I expected in all aspects except (I hate to have to say that) in the low end department. It needs an awful lot of preamp boosting to give it enough low end to my taste. The idea was to keep this bass very clean simple, I am probably going to add a jazz neck pickup (stacked coil- quiet). I would like to this but am not sure of the best way to combine it with the current electronics. The current pickup is a fishman matrix natural 1, it has an active 9 volt preamp. The jass pickup will probably be passive. I am not sure if I should or even can (without damaging the fishman preamp) run the jazz pup into the fishman preamp to be boosted in signal as well, or should I just blend the two together with the appropriate blend pot (as there are pots meant just for doing this). The catch is that if I do that I dont want a blend knob on the fron of the bass, i want a very small pot inside that I could preset to the dsired blend and leave i that way. Just rambling out my thoughts at this point, does anyone have any god ideas on this one? Quote Link to comment Share on other sites More sharing options...
frank falbo Posted January 10, 2005 Report Share Posted January 10, 2005 Bartolini makes piezo/magnetic buffers, as well as generic dual buffers for blending whatever you want. The piezo/magnetic buffers are designed for the passive signal from the piezo, though, so I don't know if that's a good idea to use after the fishman pre. I would use an active Jazz pickup (or smaller soapbar) heck, even a P-bass pickup would follow the look of the offset fretboard shape. Anyway if you used an active pickup, preferrably one that could have selectable boost frequencies, you could tailor the sound of the magnetic to compensate for the weaknesses of the piezo, all hardwired without knobs. Then, presumably since both signals are active and low impedance, a simple blend pot would do the job. I mean sure at the center detent, one pickup might be a little louder than the other, but you could even attenuate that internally if you wanted the center point to be your ideal custom blend. If you use a passive magnetic you basically end up having to preamp it to blend it with the piezo anyway. And running it into the piezo's preamp isn't a good idea IMO. Piezo's have a much higher passive impedance, and a passive blend of the two before the preamp would result in a weird phasing point where the impedance of the one started usurping the sound of the other, before you were able to get the desired volume balance between them. The subtext of any blending of two different sources is the impedance. Quote Link to comment Share on other sites More sharing options...
bassman Posted January 10, 2005 Author Report Share Posted January 10, 2005 If the jazz pup were active would I need to wire the blend pot after the signal of the two were boosted or before. There also exist the issue that the fishman preamp is built into the barrel jack/strap button (i do not use is as a strap button though- I recessed it) so it is basically a preassembled jack preamp that I would prefer not to take apart for fear of harming it. Quote Link to comment Share on other sites More sharing options...
frank falbo Posted January 10, 2005 Report Share Posted January 10, 2005 If the Jazz pickup were active, the signal would be compatible with the piezo after the preamp. So the blend would happen after the preap jack. You could always install a second jack and then put the blending hardware in an outboard box. That's what I did for my acoustics. They have mics and piezos and nothing more. Then when they get to the box, they are preamped, and the mic gets phantom power from there too. You could have a combined output and seperate outputs so you could send the piezo to one amp and the magnetic to another, or send them to different channels on the board for seperate processing. If you open the Fishman jack, you'll likely find a small circuit board that is hardwired to the jack pins. You could probably easily desolder it and re-wire it outside the unit into a box, or inside you're electronics cavity. The only thing is the batteries. If the Fishman takes a little watch battery then you still need the 9 volt for the magnetic. You could still ditch both preamps and use the Bartolini magnetic/piezo buffer, but it doesn't have EQ to my knowledge. Whereas the Fishman is probably custom EQ-ing the signal. Quote Link to comment Share on other sites More sharing options...
bassman Posted January 10, 2005 Author Report Share Posted January 10, 2005 I really only want to have one jack. The fishman pre is wired to a 9 volt battery- I have looked inside the casing as I had to solder the pickup leads onto the board. I know that I could desolder the board from the jack and I might have to do just that. I have emailed fishman to see if I can safely run a passive magnetic pickup through their preamp along with the piezo signal, we shall see how long they take to actually get back to me on that. So does the BArtolini pot work by buffering the magnetic signal? and then working like a standard blend knob after that? My impression is that a piezo signal is mcuh weaker than a passive magnetic signal- so this is what makes sense in my mind. I beleive the fishman pre is eqing things- Quote Link to comment Share on other sites More sharing options...
thedoctor Posted January 14, 2005 Report Share Posted January 14, 2005 Frank, will the fishman tolerate 18 volts? It helps the crap out of the bass pre/EQs that I have messed with but none of them were fishman. Quote Link to comment Share on other sites More sharing options...
bassman Posted January 15, 2005 Author Report Share Posted January 15, 2005 The problem has been solved!!!!! The sound coming out of this baby is fat and juicy now! I am so releived to find out that I am just a plain idiot when it comes to electronics, but at least I was able to find out what was wrong with my own mind. Despiteall of the suggestions I got, the real culprit came from a misunderstanding I had about the wiring of the piezo to the preamp. The bottom line, I had a 25k volume pot in there when it should have been a 250 or 500- yes, I pulled a Homer. When I ordered the piezo preamp combo I did not know how it wass wired together, so naturally I ordered a 25k pot to go with the active system. When the time came I just wired everrything up as I saw fit- I did not even consider the fact that I was not able to put the volume pot after the preamp without any major changes to the setup- so I easily put the pot between the piezo and preamp- which is where a 250 or 500 k pot should be. After all of the planning and time I put into this bass it is a bit amusing to run into such an error- and take a week and a half to figure it out. This bass sounds so f%$@ing badass. Quote Link to comment Share on other sites More sharing options...
frank falbo Posted January 15, 2005 Report Share Posted January 15, 2005 It's a good thing you didn't start routing it already. To clear up the last few questions, for anyone else following this: Yes the Bartolini would buffer the magnetic and the piezo together so they would come out the other side at the appropriate impedance and levels. If you just used a pre on the magnetic you would set the level with a trip pot, but the impedance would match the fishman pre output. Then you'd use a blend. I have no idea if the fishman could take 18 volts, it probably doesn't even take 9 volts. A lot of those jack-mounted pres use little watch batteries at 1.5v. I don't know what value pot you used, but I'd suggest 500k or 1meg unless it sounds harsh. But then again, it won't be harsh because the fishman pre should be able to take it in at any pot value, because it can take the signal directly without a pot! The biggest difference will be in the taper. You might notice that a 500k cuts the volume away too quickly, so a 1meg will allow more fade over a longer travel. Quote Link to comment Share on other sites More sharing options...
bassman Posted January 16, 2005 Author Report Share Posted January 16, 2005 I am really glad I didnt start routing... The fishman I have does use a 9 volt. I was not able to find a 1000k locally so I am going to try a 500, I do not want to pay for the shipping of a single pot so I will only orer one if i think it is necessary or when I order some other items i really need. Quote Link to comment Share on other sites More sharing options...
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