[Ron Ramirez]

Very interesting, and I stand corrected! There was a time when I could not find 110 pF mica caps, and I don't think even Mouser had them at the time. Oh well.

There is a page I was thinking of, where the author, wa2ise (who is a Phorum member) advocates the use of 33 or 47 pF caps in place of the old 100 or 110 pF caps:

Another thing you should address is the small RF filter caps on the audio output of the detector. Have them too big and you can get tangent distortion because they take too long to discharge to allow a full amplitude 5KHz sine wave thru without getting tangent clip. Change the (usually) 100pf caps to around 33 to 47pF.

http://pw2.netcom.com/~wa2ise/radios/feedback.html

I've replaced 110 pF micas with 33 pF micas in some of my own sets since reading this tip a few years back. They did no harm, although I don't have any fancy test equipment to measure the difference.

Perhaps wa2ise will jump in here with some comments of his own.