Paying with a cashiers check? Need advice!

I wouldn't do it. I would pay the paypal fees but I wouldn't do it. I actually paid once with a cashier's check and the transaction worked really well, but the only reason I did it was that my best friend lived in the same city. I at least knew someone can go and knock on that door if I didn't get my item.

NEVER, NEVER, NEVER PAY WITH A CASHIER'S CHECK!!!

Looking at the listing and the seller does not have feedback for the last 3 years would be a deal breaker. Another thing I noticed is the pre amp only weighs 26 lbs. A McIntosh box probably weighs 20 lbs. The weight should be at least 40/50 lbs. The $2150 price is probably the lowers a c46 has sold for. Quite a few selling around $2400.
It you send him a check and in fact he ships the preamp to you and the glass is broken. You are screwed. I sold McIntosh for years and they have to be packed perfectly to protect the glass. McIntosh has never accepted any item for repair without the correct McIntosh box for the component.All that being said, you might be saving $350 on the deal but is $350 worth al the stress you will have waiting to see if in fact you get the c46 and second it is not damaged and working.
Either use Escrow.com or Pay Pal or walk away. Not worth the stress.

Don't take one. They are not the same as cash or paypal. They van be forged and they can be cancelled; I find they're often used in scams in fact people have ot go out of their way (supposedly) to drive to a bank to cut a check when paypal, venmo are super convenient and at least Paypal is secure. After years of seeing them used in scams in retail stores I ran as well as car dealerships I view them as a red flag. 

PayPal or no deal