R Series V1.0 p 24
3. Check the signal level at other devices in the signal path.
4. One or more tubes may be bad (refer to the tube information, or take your amp to
qualified service personnel).
Tube Care And Replacement
Like a sports car, there's a certain amount of wear and tear to be expected in a high-
performance tube amp. Over time, especially with hard use, tubes may need
replacement. That's why it's a good idea to make note of when you purchased your amp
and whenever you replace tubes. It's no accident that your amp has two common types
of tubes: They're great-sounding and reliable, and it's easy to find replacements. Here
are tube charts to show you which tubes go where.
Chubster 40, R30-112
V1 V2 V3
V4 V5
V7
V6
Location Type
V1
12AX7
V2
12AX7
V3
12AX7
V4
12AX7
V5
12AX7
V6
EL-34
V7
EL-34
Here's a brief description of what each tube does:
V1 Input buffer and tone control driver for Channel 2, and also the first preamp stage of
Channel 1
V2 Tone control follower for Channel 2 and an additional gain stage for Channel 1
V3 Final stages for both channels before the mixer stage
V4 Reverb follower and the mixer stage, provides gain to the reverb pan
V5 Phase inverter driver tube for the power amp section
V6, V7 Power amp tubes--for best operation, they should always be changed in pairs
