Hello, I'm looking for some help with a simple opamp circuit. I play bass and in the end of my pedal chain there is one which has two outputs: a DI (goes to front of house) and an unbalanced output (goes to stage amplifier). This DI is already too hot for some mixers, but the unbalanced output has not enough gain to fully drive the stage amplifier. Being just one gain control to both outputs, you see the dilema.
I'm looking for building a device with an opamp to put after the unbalanced output and give some gain before the stage amp. As I'm not any expert, I read this article: https://sound-au.com/dwopa.htm and draw the following circuit from it. Assuming the opamp I'm going to use is capable of that gain, could someone point if this should work, or give some directions?
Some information:
-> Unbalanced output is 2kOhms
-> Stage amp input is 10kOhms (Crown XLS2500)
-> A bass guitar average output is around 100mV so, in my head, 30x gain would give me 3V, which would be more than enough
-> If this gain would be too much, would just tweak R1 until I'm happy
-> I have an isolated PSU which provides +18V 250mA. My idea would be to use a converter module to get +-18V from it
-> Bass signal is already buffered
-> This building must be as small as possible
Which opamp to use is another dilema. Thing is that, where I live, any TI, AD or BB brand opamp to sell will be fake. I just expect the opamp to do what it's meant to: amplify with no coloration, distortion or noise, which I can't expect from these fake ones.
I've found some discrete opamps with good reviews and good price to get over here, like this one: https://www.aliexpress.com/i/3256805273980370.html?gatewayAdapt=bra2glo4itemAdapt
So, my questions are:
1. Am I being too naive expecting it to simple work as I described?
2. If it's okay, should I add something into circuit, expecting a better behaviour?
3. Input/output GND and PSU GND should be wired together as draw in the circuit?
4. Having +-18V is right to assume it won't need a capacitor in the output to block DC?
5. If all of this just doesn't make sense, do you have some other suggestion for my situation?
Thanks for any input
I'm looking for building a device with an opamp to put after the unbalanced output and give some gain before the stage amp. As I'm not any expert, I read this article: https://sound-au.com/dwopa.htm and draw the following circuit from it. Assuming the opamp I'm going to use is capable of that gain, could someone point if this should work, or give some directions?
Some information:
-> Unbalanced output is 2kOhms
-> Stage amp input is 10kOhms (Crown XLS2500)
-> A bass guitar average output is around 100mV so, in my head, 30x gain would give me 3V, which would be more than enough
-> If this gain would be too much, would just tweak R1 until I'm happy
-> I have an isolated PSU which provides +18V 250mA. My idea would be to use a converter module to get +-18V from it
-> Bass signal is already buffered
-> This building must be as small as possible
Which opamp to use is another dilema. Thing is that, where I live, any TI, AD or BB brand opamp to sell will be fake. I just expect the opamp to do what it's meant to: amplify with no coloration, distortion or noise, which I can't expect from these fake ones.
I've found some discrete opamps with good reviews and good price to get over here, like this one: https://www.aliexpress.com/i/3256805273980370.html?gatewayAdapt=bra2glo4itemAdapt
So, my questions are:
1. Am I being too naive expecting it to simple work as I described?
2. If it's okay, should I add something into circuit, expecting a better behaviour?
3. Input/output GND and PSU GND should be wired together as draw in the circuit?
4. Having +-18V is right to assume it won't need a capacitor in the output to block DC?
5. If all of this just doesn't make sense, do you have some other suggestion for my situation?
Thanks for any input
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