[sdiy] Hand-matching capacitors for filter stages

[Tom Wiltshire]

It seems to me that some people spend quite a lot of time matching  
transistors for a fairly marginal benefit, given the quality of  
modern transistors. You may be a dedicated transistor-matcher and  
disagree with me. Fair enough - I admire your dedication.

However, capacitors are a different story. I often use polystyrene  
capacitors for filters, since these are widely regarded as the best,  
and breadboard experiments I've done do tend to support this. What  
I'm wondering is how much of this improvement is due to the material  
(e.g. polystyrene) and how much of it is down to the fact that the  
expensive capacitors are 1% tolerance rather than 5%, 10%, or worse.  
Improving the matching between filter stages is important for the  
filter response and sound of the filter, and given that l use 1%  
metal film resistors in these circuits, the capacitor component  
tolerance has to be one of the largest variations between stages.

So the question is - does anyone match capacitors for filters? Could  
I get some cheaper-but-still-quite-decent capacitors (like a 5%  
polypropylene film cap, WIMA FKP2 for example) and then hand match  
them to get 1% tolerance (or even better)? Does anyone have any  
experience to share?

Thanks,
Tom