Thanks for that jonstatt.
The output tubes, CHP, are Chinese made black-Plate, and with a 4 rating will probably get some smooth distortion fairly early. I bet it sounds sweet. I have a pair of the CHP waiting to try in my HRDlx. I have tried a HRDlx III with the CHP output tubes and I really liked the sound. As for the preamp and PI tubes, I haven't seen any AT7 installed from the factory, but I believe that those are also Chinese made, and for the ECC83, the "S" would indicate Slovakian made, from the JJ factory, but I haven't seen these except for the picture, which definitely looks like a JJ. The "ECC83" is the European designation for a "12AX7", basically the same tube.
Are you sure that position 1 has the AT7? Usually an AT7 (lower gain than an AX7) would be better in position 3, but might work in position 1 as well. You count the positions from right to left looking at the back of the amp, so the rightmost tube is position 1, and count towards the left.
Seems like a very cool tube lineup, that makes for some great sounds.