How long is it taking to receive a preamp?

Depends on the dealer and the product. 

For me it is driven by what I have to pay, when I have to pay it and what flexibility I have to cancel.  If it is a product where I pay nothing till it ships, I can cancel anytime prior to production, or is an item that sells quickly, I will take a modest deposit.  If I have to put down a 50% deposit, you put down a 50% deposit.  

If I have to pay for the entire item up front at time of ordering (yes, some companies require this), it is a special order item that I can't cancel, etc... then you will pay a significant deposit or for the whole thing at time of order and terms will be clear if the deposit is refundable which again, is driven by my terms.  

If you cancel and am out $10K or will be bringing in an item that might take me a really long time (years) to sell...that is where sometimes terms are not appealing.    

Most things are special order. 
Wiring money is not helpful.  Full pay and waiting 2-3 mos even with cc is an issue, no recourse for nondelivery.

and this a from a us manuf.

There is a guy on Diyaudio who builds Douglas Self's legendary preamp for about $700.  The most original part of that preamp is that you can select the frequency at which its tone controls operate. I ordered one and cannot wait to get it soon. 
You can always also get a Freya +/s with a Lokius as excellent value but unfortunately with no balance control. 

You have three choices then. 1. Find a different dealer who has better terms on the preamp you selected (may not be possible if manufacturer driven). 2. Buy used if you can find one
3. Select a different preamp with more favorable terms 

I was treated pretty crappy over at the Decweenie forum for asking a question relating to wait time.....quite a rabid following over there.....