First of all, I'm perfectly aware that this is a bad idea and that it might be impossible to get it to work but then again the preamp was just lying in a drawer so I figured it was worth a try. Here's the deal:
I have an Ergo sixstring EUB that came with pretty lousy stock piezo pickup elements mounted under the bridge. I used a Fishman BII that made things a bit better but felt that the sound was lacking... well, something. Swapped the stock piezos for an artec sixstring bass piezo and made a new wooden bridge that fit. Massive improvement but for some odd reason bowing the A-string produced very low output compared to other strings, finger playing was even across all strings. Then it hit me: I did have an old Ibanez EQB-3B that I didn't use, bass/treble/sweep mid volume and BALANCE. So, ordered a JourneyTek Passive 3-piezo EP001K (made for guitar but cheap and with three separate piezo elements) and glued to the bridge. Soldered everything together, plugged in and... well, it works. Sort of. The journeytek doesn't seem to like low notes (ie E & B-string) but the main problem is that setting blend to anything that is not 100% on either pickup causes signal to go weak and produce significantly lower output. Could this be solved by swapping the blend pot to another value or do I need some kind of buffer(s)?
Found attached schematic in another thread and it's the exact preamp I have but I realize that piezos have totally different impedance than regular pickups (yes, the preamp used active pickups earlier). Any suggestions or tips?
I have an Ergo sixstring EUB that came with pretty lousy stock piezo pickup elements mounted under the bridge. I used a Fishman BII that made things a bit better but felt that the sound was lacking... well, something. Swapped the stock piezos for an artec sixstring bass piezo and made a new wooden bridge that fit. Massive improvement but for some odd reason bowing the A-string produced very low output compared to other strings, finger playing was even across all strings. Then it hit me: I did have an old Ibanez EQB-3B that I didn't use, bass/treble/sweep mid volume and BALANCE. So, ordered a JourneyTek Passive 3-piezo EP001K (made for guitar but cheap and with three separate piezo elements) and glued to the bridge. Soldered everything together, plugged in and... well, it works. Sort of. The journeytek doesn't seem to like low notes (ie E & B-string) but the main problem is that setting blend to anything that is not 100% on either pickup causes signal to go weak and produce significantly lower output. Could this be solved by swapping the blend pot to another value or do I need some kind of buffer(s)?
Found attached schematic in another thread and it's the exact preamp I have but I realize that piezos have totally different impedance than regular pickups (yes, the preamp used active pickups earlier). Any suggestions or tips?
