On Sep 21, 2005, at 6:28 AM, Patrick Egloff wrote:
> Hi Robert,
>
> I'm not very aware about this type of setup, but the 4CX1500B has a 1W
> max
> grid dissipation, so you could quickly burn it when exiting it too
> much.
In super-cathode driven config, there is never any grid-I or grid-diss.
because the grid-cathode potential is always zero.
> On the other hand, the 4CX250B has only 2W grid dissipation, so it
> would be
> interesting to know with how much power you drove this tube in your
> super
> cathode driven mode amplifier ?
>
> I'm about to build an amp with a 4CX1500B for 2m but in "normal"
> setup...
> Lucky man you're to have several new tubes !! I've to dismantle my
> home made
> HF amplifier to have a tube for my new project ! hi hi
>
> 73 and greetings from Corsica , Patrick TK5EP
>
> 2005/9/21, robert briggs <vk3zl@bigpond.com>:
>>
>> This one may have been asked before.Over the past few years I have
>> constructed a few amplifiers using pairs of 4CX250/350B tubes in Super
>> Cathode Driven Mode,The Screen Grid grounded and the Control Grid
>> tied to
>> the Cathode.The amplifier's have been quite reliable and I havn't
>> worn a
>> tube out yet despite some quite hard use from time to time.
>> I got the idea origionally from an article by Orr and Sayer in QST
>> July
>> 1967.
>> I am wondering if this method could be applied to the 4CX1500B.I have
>> a
>> few new tube's and a socket or two but can't be bothered with Grid
>> Bias and
>> Screen voltages and all the extra circutry involved.
>> I would be interested in some good technical opinion's.
>> Regards all from Bob VK3ZL..
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>>
>
>
>
> --
> TK5EP
> Patrick Egloff
> http://tk5ep.free.fr
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>
>
Richard L. Measures, AG6K, 805.386.3734. www.somis.org
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