This article discusses improving PSRR in cascode circuits and may be useful.
Jaap,
How much gain are you looking to get out of the cascode? Like a pentode, the Norton equivalent circuit applies and the gm of the ECC40 is on the low side.
FWIW, you might do better CCS loading the ECC40. That way, you would get a voltage gain close to the tube's mu of 32.
How much gain are you looking to get out of the cascode? Like a pentode, the Norton equivalent circuit applies and the gm of the ECC40 is on the low side.
FWIW, you might do better CCS loading the ECC40. That way, you would get a voltage gain close to the tube's mu of 32.
thanx
I am trying to copy the schematic of Alan Wright who used a cascoded ecc88 and nowadays uses a 6H30 cascode to drive a PP 300B. I like to try a ecc40 in this same way but perhaps I will use a KT88, KT66 807 or 12E1 as a power tube. And the 6B4g is also on the list.
I intend to use a Pimm ccs followed by a gastube to feed the cascode. To enhance PSRR a superregulator could be used but these things are a bit expensive. Perhaps I use a simple mosfet regulator.
I have a 2A3 se amp with a ecc40 as a beta-follower (schematic from manfred Huber). This is two half ecc40's on top of each other with a current diode in between. It sounds good.
So these are the plans. I hope some genius can tell me how a cascoded ECC40 have to be done with a B+ in the range of 340-380 volts.
I am trying to copy the schematic of Alan Wright who used a cascoded ecc88 and nowadays uses a 6H30 cascode to drive a PP 300B. I like to try a ecc40 in this same way but perhaps I will use a KT88, KT66 807 or 12E1 as a power tube. And the 6B4g is also on the list.
I intend to use a Pimm ccs followed by a gastube to feed the cascode. To enhance PSRR a superregulator could be used but these things are a bit expensive. Perhaps I use a simple mosfet regulator.
I have a 2A3 se amp with a ecc40 as a beta-follower (schematic from manfred Huber). This is two half ecc40's on top of each other with a current diode in between. It sounds good.
So these are the plans. I hope some genius can tell me how a cascoded ECC40 have to be done with a B+ in the range of 340-380 volts.
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