Cave Dweller 2015 high amount of PT2399 noise

[iefes]

Hey all,

several years ago I built the old version of the Cave Dweller and really liked it. I decided to try the newer version but the hiss that comes with the repeats even on delay-time settings around noon makes it kinda unusable for me. I mean, I know that the PT2399 introduces a lot of noise because of the analog-digital-analog conversion especially at higher delay settings but it's just too much in this case. I tried tons of different PT2399 ICs I had laying around and also pulled the PT out of my very good sounding Multiplex Jr build but it was always about the same amount of noise accompanying the repeats. I tried increasing R9 to 1k5 to cut more of the higher frequencies and it helped a little bit but it's still not really usable for me.

So, do you guys have any suggestions what I could try to cut more of the noise? I know we don't have the possibility of "quasi-companding" here as we don't have a dedicated output-buffer but couldn't we achieve something similar with the built-in opamp? Like reducing the gain on the input-buffer and increasing the gain on the output-buffer after heavier filtering of the delay repeats? Something like this?
Any ideas would be nice. I assume I can't expect a sound like from the Multiplex or the Deep Blue or whatever but at least it should be usable also when the delay pot is set around noon.

Ah, and one more thing I was wondering about: Why isn't the Mix-pot set up like usual as a voltage divider between the dry and the wet signal? This way we could get 100% wet signal and 0% wet signal and all in between. But as it is it just allows for 50/50 as a maximum.

Thanks a lot in advance! And thanks for the great work all you guys here are doing for the DIY-community :-)

cheers, iefes