Belongs to this SE DIY amp. DIY Tube Amplifier Kit 6L6 + 6N8P Single Ended Tube Power Amplifier Kit | eBay I've not seen a thread about this one, but one similar (An EL34 amp)
My question is the function of the two diodes in series after the choke. What/why are they there? Are they zeners or something? They are labeled as 47 V in the parts list.
My first foray into the valve world, thought I would start with something simple and cheap.
Thanks!
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Yes, those are Zener diodes, to drop some DC voltage. That's why their cathodes are connected
to a more positive voltage. They set the 6p3p screen voltage to be a specific amount below the
plate voltage.
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Hi Ray, What do you call that type of driver tube arrangement? I know i have seen it before but the name i can't recall. And what is your opinion of this overall circuit.. ? I am always looking to try different SE circuits and i am not very familiar with this one. Regards, 808.
Its called a Cascode, consists of a common-emitter stage (lower tride) feeding into a common-base stage (upper triode), combined they work similar to a pentode, high gain, low Cag, high bandwidth ... etc
digital desire,
Your amp schematic is essentially this commercial amplifier:
Lowther Club Jazz 6L6 Amplifier
It not only uses the cascode input stage, it uses schade negative feedback from the output stage plate back to the top plate of the input stage, and global feedback from the output transformer secondary back to the bottom tube cathode of the input stage.
Your amp schematic is essentially this commercial amplifier:
Lowther Club Jazz 6L6 Amplifier
It not only uses the cascode input stage, it uses schade negative feedback from the output stage plate back to the top plate of the input stage, and global feedback from the output transformer secondary back to the bottom tube cathode of the input stage.
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