Octave V 70 Class A, Owner'S Manual

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7. TUBES
7.1 Removing the grille
See chapter 3.2.
7.2 Tube layout
Output tubes V1 - V4 KT120 as standard
V1 + V2 left channel
V3 + V4 right channel
Driver tubes V5 ECC 83 (12 AX 7)
V6 + V7 ECC81 (12 AT 7)
The pentode output stage topology of the V 70 Class A makes it possible to use of a variety of
output tubes. Because the specification limits of the tubes are never exceeded in pentode mode,
weaker output tubes may also be considered.
Output tubes can be divided into two broad classes – classic pentode output tubes for medium
power amplifiers and modern, high performance pentodes for power amplifiers up to 60W Class A
output.
Low Power, 25 W: output tubes:
KT 88, 6550
High Power, 50 W: output tubes: KT 120, KT 150
Note:
Some tubes will fit into the sockets but will still not work with the V 70 Class A – such as the EL 509
/ 519, for example. Low Power tubes like 6L6, KT 66 or 5881 are not recommended.