I don't know what you built, but I'll use the Rebote 2.5 as an example, since I just installed this mod on one the other day.
The build document from Tonepad shows a 15k resistor coming off the "Repeats" wiper, and notes that reducing it to 10k would be useful for runaway feedback. I compromised and replaced the 15k with a 6k8 and 4k7 (in that order), and used a 3-position on-off-on toggle to run either a 22nf or 39nf to ground from the resistor junction for either no rolloff or one of two different rolloffs. In the rolloff settings, you can dime the Repeats control and it will certainly linger, but it won't get that increasing buildup of loud noise.
I've actually been doing a mod very similar to that for over 30 years, since back when I was using table-top analog delay boxes. Rolling off some treble from subsequent repeats has a nice way of making repeats move a little more into the background so that you get the ambience effect but without distracting and cluttering up your sound. It also has a nice way of moving delays closer to the reverb end of the spectrum, becoming more of a "wash", and less in your face. Worth doing even if you aren't trying to tame runaway feedback.