DYNACO PWRAMP80 Assembly Manual page 33

 R12 provides DC bias current for the positive input.
 R7 and R8 set the power amp's midband gain.
 C4, C9, and R16 civilize the behavior of the protection circuits when the amp is
heavily loaded.
 R9 unmutes the power amplifier when adequate voltage is present.
 C7 and C8 provide power supply bypassing that aids the amplifier's stability.
 R11 and C3 form the Zobel network that helps stabilize the output stage.
 The output of the amplifier goes off the board to the clamp mounted C7 via the
C7LPOS pin. The output of that capacitor returns to the board via C7LNEG.
 That signal passes through the parallel L1-R10 combination that helps assure the
amp's stability in the presence of capacitive loading.
 K3 helps assure the absence of turn-on/turn-off pops and clicks. Assume that the
amp has been off for a while. Now, when the amp is turned on, K3 remains de-
energized until DC voltage is good, AC input is present, and the time delay
expires. During all that time:
o The speaker outputs are disconnected.
o C7 charges to its proper value through R31.
o The amplifier input is muted
 Once RLYDRV goes low (active), the relay coil is driven, and:
o LED D9 lights up.
o K3 connects LEFTOUT to the amplifier output
o The SOUND node rises, removing the muting action on the input.
o The amplifier is ready to reproduce the selected source.
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