ECC40 cascode

Jaap · 27th December 2006, 07:13 PM

I would like to try a cascoded ECC40 as a driver for an amp. But I lack the knowledge to design one. Does anybody have a schematic or give me a clue ?
regards,
Jaap

ray_moth · 27th December 2006, 08:58 PM

This article discusses improving PSRR in cascode circuits and may be useful.

Eli Duttman · 27th December 2006, 11:06 PM

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.

Jaap · 28th December 2006, 09:00 AM

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.

27th December 2006, 07:13 PM	#1
Jaap diyAudio Member Join Date: Dec 2002 Location: Netherlands	ECC40 cascode I would like to try a cascoded ECC40 as a driver for an amp. But I lack the knowledge to design one. Does anybody have a schematic or give me a clue ? regards, Jaap

27th December 2006, 11:06 PM	#3
Eli Duttman diyAudio Member Join Date: Apr 2004 Location: Plainsboro, NJ	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. __________________ Eli D.

28th December 2006, 09:00 AM	#4
Jaap diyAudio Member Join Date: Dec 2002 Location: Netherlands	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.

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27th December 2006, 08:58 PM	#2
ray_moth diyAudio Moderator Emeritus Join Date: Jan 2004 Location: Jakarta	This article discusses improving PSRR in cascode circuits and may be useful.

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