eBay

Here is a lot of 5 Vishay (formerly Sprague) .1 @ 400V Orange drop caps for guitar amp tone stacks or coupling caps or for similar audiophile applications. Lead spacing looks to be 5/8" o.c, (actually .62").

There are as many opinions about capacitors as there are...well, you know....The only way I have found to try to correlate is measuing Q on my Philips 6303 lab grade RLC tester. This a relatively Hi-Q cap coming in around 290. for reference a Mullard mustard .022/400 comes in around 300, a Blue Ajax .022/400 comes in at ~330, and a mullard mustard .1/400 comes in a 330. I haven't done exhaustive testing and say M150's, Mojo Dijon's, Sozo's, PIO's, PolyProp's, etc. JFYI.

Be curious to hear what these sound like.

BTW, there are so many incarnations of "orange drops" you can't generalize. They are not even all MKT. You have to look at the specific number and go to the spec sheet. Very time consuming, but worth while.