CONFIGURATION JUMPERS – MODE OF OPERATION:
The Model 1 has four groups of jumpers intended for setting a mode of operation – Pentode mode (P), Ultralinear mode (UL) and Triode mode (T). Ultralinear mode can only be used with output transformer that have additional terminal for UL operation.
Shorting blocks are inserted vertically so that the desired mode of operation is selected. The pair of pins on the far right side is not used.
NOTE: At any time one of the P, UL or T connections must be used.
CONFIGURATION JUMPERS – GRID BYPASS CAPACITOR:
Jumper J121 (122, 151 and 152) can be used to bypass G2 on the pentode section. The bypass is preferred by some designers, it will result in slightly different sound and we decided to have it included as an option.
In order to engage the bypass, the shorting block should be inserted horizontally shorting two lower pins. The upper pair of pins is not connected anywhere and can be used to hold shorting block if the bypass is not desired.
NOTE: The grid bypass should only be used with Pentode mode of operation. Using it in any other mode will cause damage to the amplifier and/or output transformer!
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