This post is a thought experiment biased to a guitar application and based on finding an interesting use for a low power radiogram stereo amp. As such, this post is not relating to 'hi-fi', and not relating to 'parallel output tube SE'.
The radiogram has a stereo set of 6BQ5 SE low power amplifiers.
The first thought is to drive both SE amp output stages with the same signal, and parallel the OT output windings, and use a common speaker of half the 'per amplifier' impedance.
Consequences should be that speaker impedance can be halved (this may be advantageous if original speakers were 15 ohm), and may end up getting some more dB. Harder on the power supply.
The second thought is to drive each SE amp output stage with opposite phase (eg. via a previous PI stage), and parallel the OT output windings but in opposite phase connection, and use a common speaker again of half the 'per amplifier' impedance.
Consequences would be same as for first thought, but maybe not so nice an output, as even order harmonics may cancel. Easier on the power supply.
The third thought is the same as the second, but move the bias colder in both output stages. The concept is that this would bend the loadline of the conducting tube for larger signal levels, or would it?
The radiogram has a stereo set of 6BQ5 SE low power amplifiers.
The first thought is to drive both SE amp output stages with the same signal, and parallel the OT output windings, and use a common speaker of half the 'per amplifier' impedance.
Consequences should be that speaker impedance can be halved (this may be advantageous if original speakers were 15 ohm), and may end up getting some more dB. Harder on the power supply.
The second thought is to drive each SE amp output stage with opposite phase (eg. via a previous PI stage), and parallel the OT output windings but in opposite phase connection, and use a common speaker again of half the 'per amplifier' impedance.
Consequences would be same as for first thought, but maybe not so nice an output, as even order harmonics may cancel. Easier on the power supply.
The third thought is the same as the second, but move the bias colder in both output stages. The concept is that this would bend the loadline of the conducting tube for larger signal levels, or would it?
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