J'aimerai également connaitre la fonction de chacun des 3 tubes étage préamp (ex: v1=input normal v2=in top boost, v3 fx loop, etc...)
All Tube Signal Path
The
AC30C2 featured an all tube signal path.
The signal from the "Normal" input jacks was preamplified by one half of V1 (12AX7). The signal from the "Top Boost" inputs was preamplified by the other half of V1. In a slight departure from the original circuit, the value of the plate resistor for the "Normal" channel was 100k rather than 220k. The 100k plate resistor allowed the "Normal" channel to produce more gain. The "Top Boost" channel retained a 220k plate resistor.
The classic "Top Boost" circuit (Bass and Treble controls) was powered by V2 (12AX7). A third 12AX7, labeled V3, served as the phase inverter.
Four EL84 output tubes (V4-V7) created the classic 30 watt Class A, NFB Vox AC-30 output stage.