TUBE FUNCTION AND LOCATION CHART
Preamp tube locations are indicated by tube type on the rear panel of the chassis. Tube types are factory
selected for superior performance, consistent tone quality and reliability. While substituting other brands may
not cause damage to the amplifier this may affect amplifier performance in unpredictable ways. 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. 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).
12AX7WB Sovtek
12AX7A Tung-Sol
Use in place of WB for more aggressive top end and increased mid gain.
12AX7 China Selected Use in place of WB if more overall gain is required.
V2
Gain Stage 2 for Lead channel.
12AX7 China
Gain Stage 3 for Lead and Rhythm channels. Active when either Gain Switch is set
to HI.
V3
Gain Stage 4 for Lead and Rhythm channels.
12AX7 China
Tone Control Driver for Lead and Rhythm channels.
V4
Gain Stage 2 for Clean channel.
12AX7 China
Gain Stage 2 for Rhythm channel.
V5
Phase
Inverter
12AX7 China
V6
Power stage buffer/driver.
USE ONLY 12AT7.
12AT7 China
NOT INTERCHANGEABLE WITH ANY OTHER TUBE TYPES!
V7 – V10
Power Tubes
MUST USE ONLY KT88 or 6550.
KT88 Sovtek
NOT INTERCHANGEABLE WITH ANY OTHER TUBE TYPES!
KT88 EH
KT88 Svetlana
6550 Sovtek
6550 Svetlana
