I ran into an issue with "fizzy" sounding Kliche builds when I used TL072's from Tayda. Their TL072CP opamps are apparently factory seconds. I've run into three bad batches of TL072 dual opamps from Tayda. A client alerted me to the issue and when I got it back, I could hear the "fizziness" (buzz) he was talking about. Because I socket all my chips, I thought to try swapping out the TL072s on whim because it was a quick test. I grabbed a pair TL072s from my stock and "fizziness" went completely away. Then I thought to myself, why would a good old jellybean opamp like a TL072 be bad? I looked more carefully at the chip IDs and date codes.
As it turned out, the TL072s I swapped out with are TL072IP - but the bad ones were TL072CP with a date code of 18MDSHY. So I started going thru my stock of TL072 chips. I found that I had a few TL072IPs and most were TL072CPs. The CPs had a date code of "18MDSHY". I checked all 42 of them I had and they ALL exhibited that fizzy buzz noise in the Kliche Build. I also found two other date codes for TL072CPs that exhibited that same fizzy buzz - "14AP8NM" and "07A5L8QM". I looked up from where I got all my TL072CP chips they came from Tayda. I found the TL072IPs I had were from Mouser and all 13 of those I had tested good in the Kliche.
So I looked at StompBoxParts and found they offered TL072IP dual opamps and I ordered 50 of them. When they arrived three days later, I tested every one and they're all good.
So, for me, lesson learned and I do not buy active components from Tayda anymore. With some luck, you may find your fix as easy as swapping out the TL072CPs for some some known good TL072 chips.
However, if that does not solve the 'buzz' you are experiencing, I would check the chargepump. Some charge pumps have an operating frequency of only about 10K Hz - which is in the audio range and will bleed into the signal path. What chargepump are you using? The charge pumps with 25K to 40K Hz operating frequencies have an ID suffix that starts with an "S". If your chargepump does not have an "S" in the suffix, get one that does.
And as always, checking datasheets for operating conditions is always a plus.
Good luck!