You will probably find that in the HRD, just like in my BDRI, the power tube keys and the gap between pins on the preamp tubes are all on the front grille side as opposed to the back panel side of the chassis. You'll see what I mean when you look at the sockets. The first time or two I swapped tubes I looked up at them with a flashlight. Now I do it all by feel with no problem.
I didn't touch the power tubes, but indeed the gap between the pins on the preamp tubes on my HRD are all on the front side.
As for the tube swap, it was my intention to accomplish this without
removing the back cover. Not a problem for V1 and V2 but swapping the PI tube with the cover on proved impossible - maybe possible for someone with small hands
- so I had no choice but to remove the cover and expose the evil capacitors.
For the benefit of those who, like myself, have little to no experience with the inside of a tube amp, I recommend the advice given to help me with my first tube swap and also some things that I learned during the process. The following applies to a HRD. It's very possible that some things will not apply to other tube amps.
- 1. Make sure the amp is turned OFF and UNPLUGGED.
- 2. Place the amp on its side on a sturdy work bench.
- 3. Remove the 6 screws securing the back panel. There is no need to do like I did and remove the 2 screws holding metal grill for the power tubes.
- 4. DO NOT touch anything on or even near the exposed PCB. ... Don't even look there. ... Look Away!
- 5. Carefully and slowly remove the preamp tube stabilizer. It should slide off with a little wiggling and jiggling.
- 6. Grab the tube firmly and coax it out slowly, gently, with an easy and smooth rocking motion. Do not twist.
- 7. Use a flashlight to verify the orientation of the gap between the holes in the socket.
- 8. Grab the replacement tube and orient it so the gap between the pins on the tube match the gap between the holes in the socket.
- 9. Slowly bring the tube towards the socket without changing the orientation and wiggle slightly until you feel the pins going into the holes in the socket, then insert and ensure that the tube is seated correctly.
So thanks everyone for the great advice on the tube swap. As to the results of the swap and how the amp sounds, I'll give it a test run and post an update to my original thread.