I aquired some 6CW7's recently and was wondering
how they compare in a cascode circuit to say a 6DJ8?. Has
anyone had any experiences with the type?.

Mark Harriss

Mark Harriss wrote:

I aquired some 6CW7's recently and was wondering
how they compare in a cascode circuit to say a 6DJ8?. Has
anyone had any experiences with the type?.

Mark Harriss

These are usable, but have an entirely different pin out to a
6DJ8 or other standard twin triode, and so that makes them
incompatible with other tubes which might be plugged in.
They were meant for cascode of grounded grid applications.
There is nothing magical about the sound.

Patrick Turner

These are usable, but have an entirely different pin out to a
6DJ8 or other standard twin triode, and so that makes them
incompatible with other tubes which might be plugged in.
They were meant for cascode of grounded grid applications.
There is nothing magical about the sound.



G'day Pat,
I've read that cascode valves are
specifically made for the job and wondered what makes
the difference to their operation. I notice an internal
shield plate but apart from that I can't see any real
difference to a regular dual triode. Apart from the
pinout it looks similar to a 6DJ8 though the mutual
conductance is about half.

Mark Harriss

"Mark Harriss" wrote in message
...

These are usable, but have an entirely different pin out to a
6DJ8 or other standard twin triode, and so that makes them
incompatible with other tubes which might be plugged in.
They were meant for cascode of grounded grid applications.
There is nothing magical about the sound.



G'day Pat,
I've read that cascode valves are
specifically made for the job and wondered what makes
the difference to their operation. I notice an internal
shield plate but apart from that I can't see any real
difference to a regular dual triode. Apart from the
pinout it looks similar to a 6DJ8 though the mutual
conductance is about half.

Mark Harriss
You hit the nail on the head, tubes designed for grounded grid operation
typically have low mutual conductance.

Jimmy wrote:

You hit the nail on the head, tubes designed for grounded grid operation
typically have low mutual conductance.

Thanks for the information Jimmy.

Mark Harriss wrote:

These are usable, but have an entirely different pin out to a
6DJ8 or other standard twin triode, and so that makes them
incompatible with other tubes which might be plugged in.
They were meant for cascode of grounded grid applications.
There is nothing magical about the sound.

G'day Pat,
I've read that cascode valves are
specifically made for the job and wondered what makes
the difference to their operation. I notice an internal
shield plate but apart from that I can't see any real
difference to a regular dual triode. Apart from the
pinout it looks similar to a 6DJ8 though the mutual
conductance is about half.

The tube is set up for low capacitance.
Unless set up optimally, cascode/grounded grid circuits can
have parasitic oscillations with are a pita at 200 MHz.
I see nothing preventing their use at AF.

If you can accept the pin out restrictions, then go for it.

Patrick Turner.



Mark Harriss