Do I have to brand match preamp and amp?

Congratulations! Great decision. You will love that preamp for years to come. Feel free to PM me with any questions or whatnot.

Dave

Thanks @dlcockrum ! Now the wait begins. Hopefully the seller ships it tomorrow.

I am still a little skittish because of its age, but even Gary at Ayre thought it was a good gamble

The only thing you have to match is the output impedence of the pre-amp with the input impedence of the power amp. The input impedence of the power amp needs to be at least ten times the output impedence of the pre-amp. The ratio can be higher, e.g. 11:1 or 15:1, but not lower e.g. 8-1, otherwise signal loss and noise may be present.

For example, a pre-amp with an output impedence of 1k ohms needs a pre-amp with an input impedence of at least 10k ohms

The only thing you have to match is the output impedence of the pre-amp with the input impedence of the power amp.

Since he is matching an Ayre preamp with an Ayre amp, I don't think there should be any impedance mismatch.

Another K-5xe MP preamp just posted today, at an even lower price.

https://www.audiogon.com/listings/lis8fb1d-ayre-acoustics-k-5xe-mp-excellent-condition-solid-state

Next thing you know there will be a thread titled "Why so many Ayre K-5xe MP preamps for sale?".

Of course. That’s what happens every single time I buy something