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12b4a phase splitter! The best?

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Hello everibody
I am working in my latest amp and testing phase splitters to find up the best sounding one!
The output is EL34 ultralinear PP and tested 12At7,12Au7,12aX7 as phase splitters, but i found in my old box 2 12B4A tubes, and connected them with 9K resistor cathod to ground,9K plate to B 300V and grid to previous tube plate (12At7) with 100V plate voltage! And i found i have the best sound i ever had!
Does someone tested this tube (12B4A) as phase splitter?
If not TEST IT because it sounds raelly NICE!
Best Regards!
 
hey-Hey!!!,
Running a pair as LTP in a linestage. B+ near 500, 20k plate loads, CCS tail and plate voltage ~125. Very nice performance and balanced output to drive a Rane crossover. tried also triode-strapped EL86 with similar results, slight edge to the 12B4. Quite sensitive to vibration picked up from the top plate from the power supply Iron. Going to fix it with a separate plate for the amplifier section and some damper rings like herbies tube dampers.
cheers,
Douglas
 
That makes sense as with a concertina (split load) you want a tube with low mu (there is no gain with this stage anyway) and high transconductance. The 12AT7 and 12AX7 would be eliminated right away as unsuitable given the requirements. If you like the 12B4 then try the 6S4. Even better try the 6EM7 with the high mu as the voltage amp and the low mu as the phase splitter.
 
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