Fishman Model G acoustic preamplifier [Schematic]
- dylan159
- Resistor Ronker
Information
I've traced this little clip-on piezo preamplifier for fun. Seems like a simple yet nice design (aside from those ridiculous electrolytic coupling capacitors a bit everywhere and the wimpy decoupling, which should be fine for battery power). I haven't seen many acoustic guitar preamp schematics around, hope this gives a nice starting point to diy builders.
Basically 10M JFET input buffer into inverting amplifier into active baxandall.
Basically 10M JFET input buffer into inverting amplifier into active baxandall.
Personal blog/archive: https://bentfishbowl.wixsite.com/electronics
Find me at https://discord.gg/bMuhX4TkZM Audio Electronics discord server.
Find me at https://discord.gg/bMuhX4TkZM Audio Electronics discord server.
- Ichabod_Crane
- Resistor Ronker
Thank you!
What is the opamp? I found an image of that preamp, but it's not so clear, it seems to me a LFxxx.
What is the opamp? I found an image of that preamp, but it's not so clear, it seems to me a LFxxx.
- dylan159
- Resistor Ronker
Information
LF353. I didn't manage to make the schem neater but it's there!
Personal blog/archive: https://bentfishbowl.wixsite.com/electronics
Find me at https://discord.gg/bMuhX4TkZM Audio Electronics discord server.
Find me at https://discord.gg/bMuhX4TkZM Audio Electronics discord server.
- dylan159
- Resistor Ronker
Information
Exactly the same! Same random mix of metal film and carbon film (actually in different positions than mine), and mind has no greenies and the op amp is one of those pretty old ones with the silver band.karul wrote:inside
https://reverb.com/au/item/3950739-vint ... sys-prefix
Personal blog/archive: https://bentfishbowl.wixsite.com/electronics
Find me at https://discord.gg/bMuhX4TkZM Audio Electronics discord server.
Find me at https://discord.gg/bMuhX4TkZM Audio Electronics discord server.
- Ben N
- Cap Cooler
Thanks, this looks really handy.
Anybody have any thoughts on whether the first opamp might double as a mixer for a (buffered or unbuffered) mag pickup input by way of a suitable (10k-20k?) mixing resistor to the (-) input?
Anybody have any thoughts on whether the first opamp might double as a mixer for a (buffered or unbuffered) mag pickup input by way of a suitable (10k-20k?) mixing resistor to the (-) input?
- Yazoo55
- Breadboard Brother
- dylan159
- Resistor Ronker
Information
Sure, I'll upload some as soon as i can in a few days if you're interested.Yazoo55 wrote:This is another picture I found online without the greenies.
Just a query - the capacitor on the power/voltage divider to give the reference voltage is bigger, maybe 100uF(?) from what I can make out.
Any chance you could upload a picture of the copper side of the board please?
It seems to me that their philosophy for populating the board is "whatever they had around"
Personal blog/archive: https://bentfishbowl.wixsite.com/electronics
Find me at https://discord.gg/bMuhX4TkZM Audio Electronics discord server.
Find me at https://discord.gg/bMuhX4TkZM Audio Electronics discord server.