Looking for information on who repairs NAT Audio Preamps and Amps

According to NAT's website:

Mike Powell Audio has become an authorized Service Point for NAT AUDIO products in USA.

 

Mike Powell Audio-Atlanta, GA
America Sales and Authorized Warranty Service
Phone: 404 764-6233
For more information, please visit the following link http://mikepowellaudio.com/

Try googling your local area for electronics Techs/repair facilities, there is rarely anything in any audio equipment that the majority of good techs can't deal with. this is not rocket science after all. Only a few software issues. etc. would demand going to the manufacturer ( after warranty of course).