I have built this op-amp circuit below to be able to adjust the input volume at the beginning of my effect chain to pedals without needing to turn the volume knob down on my guitar that causes trebles being lost. I was recommended this circuit instead, as it was said to preserve the trebles on the volume reduction that is important for me.
It seems to work as should, the volume recudction seems to preserve the trebles, but there is one little problem: the signal contains a low frequency element, that must be arising from the picking (I guess), that is lower than the fundamental of notes I am picking. When the op-amp is not in the chain and I reduce the volume on my guitar to send the signal at the proper voltage to my pedals, I can hear the low frequencies are boosted a bit, but that popping sound is not very noticeable at the end of the chain. I mean in mixes it doesn't stand out. But when the op-amp is inserted into the chain to reduce volume instead of the knob on the guitar, even if the low frequencies seems to be more silent than trebles, that popping is much more noticeable.
Moreover, if I install a treble bleed mod on my guitar's volume pot (500K pot in guitar, 1nf capacitor with a 200K resistor soldered between its leads, capacitor leads soldered on the wiper/pickup lug) and turn the volume down on the volume knob instead of using the op-amp, the low frequencies got reduced much more significantly, and that popping sound is not noticeable at all. I guess this is because of some more effective bypassing of trebles occurs this way.
Do you have any idea how to prevent the op-amp enhancing that popping sound? What should I modify on the circuit for that?
Here are samples to hear what I mean when I write popping sound:
https://drive.google.com/file/d/112gXtM ... sp=sharing
https://drive.google.com/file/d/1wntMGu ... sp=sharing
https://drive.google.com/file/d/1pixT4K ... sp=sharing
Here is the schematic of my op-amp:
It seems to work as should, the volume recudction seems to preserve the trebles, but there is one little problem: the signal contains a low frequency element, that must be arising from the picking (I guess), that is lower than the fundamental of notes I am picking. When the op-amp is not in the chain and I reduce the volume on my guitar to send the signal at the proper voltage to my pedals, I can hear the low frequencies are boosted a bit, but that popping sound is not very noticeable at the end of the chain. I mean in mixes it doesn't stand out. But when the op-amp is inserted into the chain to reduce volume instead of the knob on the guitar, even if the low frequencies seems to be more silent than trebles, that popping is much more noticeable.
Moreover, if I install a treble bleed mod on my guitar's volume pot (500K pot in guitar, 1nf capacitor with a 200K resistor soldered between its leads, capacitor leads soldered on the wiper/pickup lug) and turn the volume down on the volume knob instead of using the op-amp, the low frequencies got reduced much more significantly, and that popping sound is not noticeable at all. I guess this is because of some more effective bypassing of trebles occurs this way.
Do you have any idea how to prevent the op-amp enhancing that popping sound? What should I modify on the circuit for that?
Here are samples to hear what I mean when I write popping sound:
https://drive.google.com/file/d/112gXtM ... sp=sharing
https://drive.google.com/file/d/1wntMGu ... sp=sharing
https://drive.google.com/file/d/1pixT4K ... sp=sharing
Here is the schematic of my op-amp:
