[Amps] Tube amps are not a thing of the past

[donroden at hiwaay.net]

I have never liked the 30S-1 grid derived ALC.
The grid voltage is passed through ( essentially ) an audio transformer and
the tube has to draw grid current before the transformer's secondary  
is rectified for an ALC voltage.

Sure, it's RF Frequency independent, but a cathode voltage sample with  
an adjustable ALC control would be better to prevent grid current  
BEFORE it happened.

Don W4DNR

Quoting Gary Schafer <garyschafer at largeriver.net>:

> Hi Jim,
> I think that the 4CX1500 has the same grid as the 4CX1000.
> Somewhere I have seen it written by Eimac that it is ok to draw a small
> amount of grid current during brief tune up.
>
> The Collins 30S-1 (4CX1000) develops ALC from grid current.
>
> 73
> Gary  K4FMX
>
>> -----Original Message-----
>> From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of MU 4CX250B
>> Sent: Monday, June 05, 2017 11:03 AM
>> To: Jim Thomson
>> Cc: amps at contesting.com
>> Subject: Re: [Amps] Tube amps are not a thing of the past
>>
>> I've long wondered what the zero watt rating of the 4cx1000 grid
>> actually means. I've assumed it means the tube is rated for class AB1
>> operation only, and that the rating doesn't reflect the actual
>> physical limitation of the grid structure.  I wonder if anybody has
>> actually cut apart a tube and inspected the grid?
>> 73,
>> Jim w8zr
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DonR