[HBR] Another Receiver Project

[waltah at earthlink.net]

I'm going to use a KVG XF-9 (no letters after) crystal filter in this 
project; I have a guesstimate of the impedance from the circuit in 
the donor set but I wonder if anyone has a spec sheet or long 
memory?  

All the (later) letter models seem to be 500 ohm but this is from a 
vaccum tube set and I'm guessing 50k input and output.   Anyone 
know for sure?  

Thanks!

Walt
KJ4KV