TUBE FUNCTION AND LOCATION CHART
Tube types are factory selected for superior performance, consistent tone quality and reliability. For best
performance, replace only with factory recommended tubes.
Warning! Substituting other tube types is not recommended.
Each 12AX7 has two sections/functions. Section A is shown first, Section B is second. Factory recommended
tubes are listed under each location. A recommended alternate is listed below the factory installed brand.
Numbering sequence is right to left looking at back of amp starting with the row closest to
front
panel of amp.
V1 (shielded tube)
Input Gain Stage 1 (Parallel Triodes).
12AX7 Tung-Sol
12AX7WB Sovtek
Use in place of Tung-Sol for less mid saturation and deeper low end.
V2
Gain Stage 2 for LEAD channel.
12AX7A/7025 China
Gain Stage 2 for RHYTHM channel.
V3
Gain
Stage
3.
12AX7A/7025 China
Tone Control Driver for LEAD and RHYTHM channels.
V4
Gain stage 4 for LEAD and RHYTHM channel in MORE mode only.
12AX7A/7025 China
Tone Control Driver for CLEAN channel.
V5 (shielded tube)
Gain stage 3 for CLEAN channel.
12AX7A/7025 China
Gain stage 2 for CLEAN channel.
V6
Phase Inverter for power amp.
12AX7A/7025 China
V7 – V8
Power Tubes.
KT88 Sovtek
KT88 EH
USE ONLY KT88 or 6550. NOT INTERCHANGEABLE WITH ANY OTHER TUBE TYPES!
V9
Rectifier
tube.
5U4G EH
USE ONLY 5U4 OR EQUIVALENT. NOT INTERCHANGEABLE WITH ANY OTHER TUBE TYPES!
DO NOT USE SOLID STATE RECTIFIER TUBE SUBSTITUTES!
