6U8 voltage amplifier and phase splitter in one tube

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Mars

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Hi All

I am working on my amp building manual, and it needed a chapter on the 6U8 pre-amplifier and phase splitter. The idea is to explore the details of point to point wiring the 6U8 into a serviceable pre-amp for a push-pull amplifier. The 6U8 (also known as the ECF82)  is similar to the 6AN8, except the pinout on the tube base is different, and readily available from tube suppliers.

The idea to use a single tube as both voltage amplifier and phase splitter is attractive, and the high gain and low distortion of the pentode section makes it more attractive than the dual triode cousins. Dynaco use these types of tube even in their Mark III 60 watt monoblocks.

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See the minor differences below between a 6U8 and a 6AN8:

6U8
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6u8_057r.jpg


6AN8
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6an8.jpg
 
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