Postby surfnorthwest » 03 Feb 2018, 04:12
V4 - Phase inverter, you will want a balanced tube for this socket. It is used by both channels.
V3 - Effects Loop Buffer Tube, any 12AX7 tube can go hear. It is used by both channels.
V5 - Cathode Follower, DO NOT USE Tung-Sol 12AX7s, SOVTEK 12AX7LPS or Mullard Reissue 12AX7 tubes in this spot they will fry and you will be out a tube. A lot of people say you SHOULD NOT use any Russian tubes in this slot at all. Cathode followers as I noticed in the 6505+/5150II schematic recieve the signal backwards from all the other tubes (with the exception the EFX Buffer Tube) and experience much higher volts than the other tubes causeing them to fry. Most people Recommend a JJ ECC83S or a Chinese 12AX7. It is used only in the Lead Channel
V2 - Gain Stage. It is used only in the Lead Channel
V1 - Shared channel Gain stage. This socket has importance to the note of extra lettter designations. It is the first tube your guitar signal will hit, so you should get a quiet tube that has been tested to not be microphonic. V1a is the first tube half hit, it is a gain stage used by both the rythym and lead channel. V1b is only used by the lead channel as a gain stage along with V1a. This tube, because it is first, is arguably the most important tube. A lot of people recommend a lower gain tube that is very quiet. Using a cleaner tube like a 12AU7, 12AT7, 12AY7 or 5751 tube here should help clean up your rythym channel.
V6 - Gain stage for the Rythym Channel. I'm not sure but I believe it to be most responsible for the crunch settings increase in gain. Trying a Low gain tube like mentioned above will help clean up the rythym channel, and using a high gain tube should help increase the amount gain added by the crunch switch.
My Gear
Surf's Jukebox
'When I Don't Have Anything Interesting to Play, I just Play Fast' But then who wants to hear 64 bars full of 32nd-notes except the douche-bag blowing them from the stage.