Cave Dweller for keyboard?

[fatpants]

I've made a Cave Dweller and I like it A LOT!!! With low subtle settings it can sound really expensive (which is what I use it for). The thing is - my keyboard player loves it too and I want to make him one (as a surprise birthday present). So my question would be - should I change the input impedance of the pedal? Is the keyboards lower output impedance going to make any problem or different pedal behavior?
Because he tried a Morley wah pedal and he gets a really distorted sound out of it?
Thanks

[midwayfair]

You could try putting yours in front of his keyboard and seeing what happens. I don't think anyone here's going to be able to tell you anything except as it relates to a line-level signal.

I would guess that it's not going to be able to handle the input level and that much more than just changing the input impedance is needed. There are other, admittedly more complicated, delays that will be better at handling line-level signals.

[fatpants]

Hey 
Thanks again for answering so quickly, we tried it in bedroom levels and it's fine but I don't know how it's going to behave on gig levels. So I guess I'll have to wait for a gig to find out. What other delays would be ok for this? Maybe I'll give it a shot.

[RobA]

By bedroom levels do you mean that you had the amp turned down, or did you have the keyboard volume reduced too? It's the output level of the keyboard that's going to be the issue. Line level is a higher voltage than guitar and the Cave Dweller doesn't have a ton of headroom to start with.

[nieradka]

I used a cavedweller with a theremin which is also a line level instrument (into a pa amp) and it was a non-issue. It was a the dub edition, and I did add some diodes to clamp the volume when it goes into runaway oscillation, but i assume that would happen regardless of the input signal. There isnt any op-amp or clipping stage to overload. Actually, I find most non-overdrive/fuzz/distortion pedals work fine enough (at least for most settings) even when they really shouldnt, the biggest issue is changing any highpass and lowpass filters to accomodate the larger range. 

If it is an issue, I suppose you could always build a very simple pedal to attenuate the keyboards signal down to guitar levels before  going into any pedals.

[RobA]

I found that they now have a more informative spec sheet for the PT2399 than the one I have. The new one specs the AC characteristics with a 500mVRMS input. So, a -10dBV line level output should be within spec for the circuit. A "professional" +4dBu level signal might not work though. I'd guess that it probably won't with out some attenuation up front as that equates to about 1.2VRMS.

The Theremin manual specs it at 500mVRMS too. So, it makes sense that it should work there.

There are plenty of op-amps inside the PT2399 to overdrive, so I think it wouldn't be too hard to find a way to get it to clip  , especially at the 5V Vcc level that it's spec'd for.

Here's a link to the PT2399 reference,
http://www.princeton.com.tw/Portals/0/Product/PT2399_1.pdf

[fatpants]

Thanks everyone.
We tried it in a room through a sound card and on recording monitors, but the keyboard signal was up all the way and no problems. I just noticed that when you turn down the level knob it is like it's turned to 30% (you can't turn it down as much as I can on my guitar) but that's not an issue because he uses it pretty radically anyway. I also finally tried my Cave Dweller on gig levels and it has a his only on repeats   (I guess it's the pt2339 so I'll buy another one and try it. Awesome pedal!

[jimilee]

Really live mine for bass, I really need to have a second one on my board.