How long is it taking to receive a preamp?

These guys have some in stock, buy one, no waiting. Some are less than $10-20K

https://upscaleaudio.com/collections/preamplifiers

Demand is high and parts are scarce.  It always depends on the brand and how lucky/unlucky you are but know transformers and semiconductors have been miserable to source.  

So how is payment being handled for delays?

my dealer dont accept cc.  Wants a wire of 50%. Paying $10k cash and uncertain delay.

Any body buying a preamp? High end hifi sales really bad?

Actually the industry is doing well from everyone I've talked to. But one thing that has made things tricky is supply side shortages. Shipping, especially from overseas, is delayed as shipyards and the like are short on employees as are the airlines.