Next best upgrade

[Oldlistener50]

My current setup, which (to me) sounds great:
Pro-Ject turntable
Bottlehead Seduction preamp with the c4s upgrade
G-Snake interconnects
Yamaha RX-V659 home theater amp (that I run in Pure Direct mode)
Grado SR-80 headphones

If I were to spend a grand, what would be the best upgrade?  Ditch the Yamaha for some S.E.X.?  Or something else?

[Doc B.]

If you have no plans to run speakers I'd say stretch a bit and go for Mainline if your budget can go over $1000 a bit. Otherwise yes, I think S.E.X. would be a nice step up.

[Oldlistener50]

Doc, yes I can go for the Mainline, I have been away for a while (hangs head in shame LOL) and haven't been keeping up.  If it will work well with the Grados I currently have, and those that I might upgrade to later on, it sounds like the way to go.  Thanks for the feedback. 

[Doc B.]

Yeh I think it might actually be a little better choice with the Grados, in part because the power supply is very well regulated and thus very quiet. The S.E.X. would probably be fine on the lower impedance settings too, but the mainline on the 32 ohm (low impedance) setting will be more quiet than the S.E.X. in the 32 ohm configuration.