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Should the sound level in Triode mode be lower than in Tetrode

I've just got Manley Lab Series 100 vacuum tube monoblocks. And I am a bit confused what to expect from TRIODE / TETRODE modes. The user manual says that: 

"...When the switch is in the upper position, the amplifier is in TRIODE mode which will produce half the power of TETRODE operation."

In the same user manual under the Specifications section I find that the Output Power for: 


TETRODE: 135Watts (@1.5% THD 5 ohm load)

TRIODE: 65 Watts (@1.5% THD 5 ohm load)

I have been running a number of db level measuring tests by switching from TRIODE to TETRODE mode keeping the volume knob unchanged. But it appears that the sound volume remains exactly the same in both TRIODE and TETRODE modes. Shouldn't I expect the sound level in TRIODE mode to be half of what in TETRODE mode?  

esputnix

Showing 2 responses by ghdprentice

ghdprentice
7,646 posts
 
@imhififan 
+1 Well put.
ghdprentice
7,646 posts
 
My Audio Research Reference 160s is the same way. While the wattage is halved in Triode mode the difference is barely discernible. Careful listening is likely to reveal a bit more slam in Tetrode mode and a bit more warmth in Triode mode. Most of the time you are not using the max wattage. Also, I suspect since the same transformers are used in either mode the current available Is similar. So, keep listening… the difference is really subtle. 
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