K, maybe not 50w... but how 'bout 38w?
Wyetech's new Ruby does just that via a "serial - parallel single ended configuration". Unique and innovative. Check this out:
"300B OUTPUT STAGE
All 4 output tubes also operate in pure class "A1" single ended self-biased isolated circuitry and transformer coupled output.
The 300B gain stage circuitry is exclusive, ground-breaking and unique, being only one of its kind ever to be implemented in a tube output stage.
Simply stated it is a serial - parallel single ended configuration that results in increasing the 300B stage gain by a factor of four, unprecedented and unique.
Two legs of two series connected 300B's are used in parallel by tying the top plates of each leg to drive the primary of the output transformer. The two bottom tubes of each leg is referenced to ground while the top tubes have floating biasing and signal drive.
The current in each leg is monitored for proper operation. If the current goes above or below the designated operational range it will turn on it's corresponding RED LED to tell you it's time to change this pair of tubes.
One of the advantages of this circuit is that it decreases the high voltage supply current by one half, thereby reducing the current requirements for the chokes in the power supply.
Of course, in order to accomplish this you must double the high voltage to this stage. This would be a stumbling block for most designers who tend to shy away from such high lethal voltages necessary here, similar to 211 transmitting tube requirements,
The drive for perfection makes this a necessary measure, since we are using only pure capacitors and inductors [ Chokes ] to filter the dual high voltage power supplies.
Even with this added benefit it still took a large chassis with each monoblock measuring 16.5" x 24" to hold and accommodate the parts needed to implement this revolutionary and innovative circuitry.
Because each leg of both tubes have the same current flowing through them they each have equal bias voltage applied which ensures the tubes are working together in harmony to produce the best possible operating conditions and life expectancy for each pair."
See more at Wyetech's site.
I'm ordering a pair.
Wyetech's new Ruby does just that via a "serial - parallel single ended configuration". Unique and innovative. Check this out:
"300B OUTPUT STAGE
All 4 output tubes also operate in pure class "A1" single ended self-biased isolated circuitry and transformer coupled output.
The 300B gain stage circuitry is exclusive, ground-breaking and unique, being only one of its kind ever to be implemented in a tube output stage.
Simply stated it is a serial - parallel single ended configuration that results in increasing the 300B stage gain by a factor of four, unprecedented and unique.
Two legs of two series connected 300B's are used in parallel by tying the top plates of each leg to drive the primary of the output transformer. The two bottom tubes of each leg is referenced to ground while the top tubes have floating biasing and signal drive.
The current in each leg is monitored for proper operation. If the current goes above or below the designated operational range it will turn on it's corresponding RED LED to tell you it's time to change this pair of tubes.
One of the advantages of this circuit is that it decreases the high voltage supply current by one half, thereby reducing the current requirements for the chokes in the power supply.
Of course, in order to accomplish this you must double the high voltage to this stage. This would be a stumbling block for most designers who tend to shy away from such high lethal voltages necessary here, similar to 211 transmitting tube requirements,
The drive for perfection makes this a necessary measure, since we are using only pure capacitors and inductors [ Chokes ] to filter the dual high voltage power supplies.
Even with this added benefit it still took a large chassis with each monoblock measuring 16.5" x 24" to hold and accommodate the parts needed to implement this revolutionary and innovative circuitry.
Because each leg of both tubes have the same current flowing through them they each have equal bias voltage applied which ensures the tubes are working together in harmony to produce the best possible operating conditions and life expectancy for each pair."
See more at Wyetech's site.
I'm ordering a pair.