Hi Rafael,
Not yet. The guy does good quality work at a reasonable price so he's swamped with orders. I also made a couple of changes to the original design. I heard of a couple of very highly regarded preamps using DHTs so I asked Nicholas what he thought of this. He said no problem, my own preamp uses a 45 tube driven by 6922. He adapted his preamp for the use of 6FQ7, electrically similar to 6SN7 and sat down and listened to pure 6SN7 vs 6FQ7 driving a 45. 6SN7 was darker, 45 was fuller sounding, better upper extension and more microdetail.
So now my preamp will be a choke coupled 6SN7 driving a 45 conservatively, the output transformer lowers the gain to 4dB in low gain mode or 8dB in high gain mode, I have 2 pairs of XLR outs and 2 pairs of SE outs , output impedance around 50 ohms with both XLRs used, which is very low.
The other thing is that the remote control unit didn't work out as expected and manual was significantly better sounding, so that's what I chose.
Will let you know how it sounds driving the Spectrons in monoblock mode.
romandoc