Big fan of Tannoys here! They sound pretty great with any decent amp that’s not on the dry, bright, or analytical side of things. I’ve even heard them sound good from the old PS Audio class D amps of the 2000s, so I’d bet your much more modern NAD sounds pretty nice there (I like NAD gear too). I play loud and I like a lot of power. Yes, I can shamefully admit I’ve once even hit hard clipping given 60 Watts/ch tubes into 93dB / Watt Tannoys before! Hence my focus on push-pull amps of KT88-types. So consider that context when I describe my amp experiences.
I’ve ran Rogue tube amps for the vast majority of my 12+ years with Tannoy speakers. Started with the basic Atlas (non-Magnum) and went all the way up to the Apollo Dark monos. Great value for money with Rogue, and great service/support. They’re really great sounding amps with Tannoys, especially as you roll in NOS small tubes to match your needs. I never liked their use of 12AU7 driver tubes much, so I sub in 12BH7 and get better sound. The only downside of Rogue amps with Tannoys is they tend to have a very high gain, so this places a higher burden on your preamp to have a very low noise floor in order to not be audible from the high sensitivity Tannoys. You could always pick up a used Stereo 100 just to play with and see how you like Rogue - it should sound great, especially after some NOS tube rolls. And the older Zeus is a killer deal used (usually under 4K), and is basically the same as the Apollo monos (sans dark upgrades) - if you can handle its 200 lbs!
I’ve recently moved on from Rogue though - to VAC Signature 200iQ monos, which I like even better than the Rogue monos, good as they were. A used VAC 170iQ stereo amp would be well in your price range. Or maybe a used 300.1 Phi for close to your price - if you get lucky. VAC amps have always sounded great with Tannoys! Definitely look into them.
But also - for your budget, consider going for an upgrade of Tannoys - it’s fun to climb up their lines, past or present. You can almost get Churchills for that money, which are truly end-game speakers.
I’ve ran Rogue tube amps for the vast majority of my 12+ years with Tannoy speakers. Started with the basic Atlas (non-Magnum) and went all the way up to the Apollo Dark monos. Great value for money with Rogue, and great service/support. They’re really great sounding amps with Tannoys, especially as you roll in NOS small tubes to match your needs. I never liked their use of 12AU7 driver tubes much, so I sub in 12BH7 and get better sound. The only downside of Rogue amps with Tannoys is they tend to have a very high gain, so this places a higher burden on your preamp to have a very low noise floor in order to not be audible from the high sensitivity Tannoys. You could always pick up a used Stereo 100 just to play with and see how you like Rogue - it should sound great, especially after some NOS tube rolls. And the older Zeus is a killer deal used (usually under 4K), and is basically the same as the Apollo monos (sans dark upgrades) - if you can handle its 200 lbs!
I’ve recently moved on from Rogue though - to VAC Signature 200iQ monos, which I like even better than the Rogue monos, good as they were. A used VAC 170iQ stereo amp would be well in your price range. Or maybe a used 300.1 Phi for close to your price - if you get lucky. VAC amps have always sounded great with Tannoys! Definitely look into them.
But also - for your budget, consider going for an upgrade of Tannoys - it’s fun to climb up their lines, past or present. You can almost get Churchills for that money, which are truly end-game speakers.