Doepfer

Hi list,
I have a slight concern, doepfer have 2 modules that use 
discontinued chips. The a-111 hi-end VCO and the new A-109 signal 
processor both use curtis chips no longer made. What if these chips 
fail in a year or 2, we're gonna have serious difficulty getting 
them repaired. I'm sure there's a reason for using these chips and 
not new ones (mainly the sound) and I really like the curtis chip 
filter and VCO (love the VCO) but slightly worried I might have a 
dead module on my hands in a few years.
But, a lot of curtis synths are still alive and well so probably not 
a problem really.
Are there any alternative chips that sound and act like a curtis 
chip?
If not, can doepfer get some made or is it too expensive? (question 
for Mr D)
Do these chips ever die or am I talking rubbish and worried about 
nothing?
Just a thought!

>John