[AMPS] tube compatability

[km1h @ juno.com]

On Thu, 20 Nov 1997 14:52:46 -0700 al511@freenet.uchsc.edu (Robert Neece)
writes:
>
>
>With respect to 3CX800A7's, and the like, Tom, W8JI, writes:
>
>>Be sure to add a grid over-current protection circuit to your amp, if 
>
>>it does not have one, or you will eat up tubes.
>>
>>A fuse is NOT enough, nor is a warning light.  You need something 
>that 
>>quickly knocks the [name your amp] off line if the Ig ever gets over
>>[name your maximum comfort level] mA... even for a brief instant.
>
>Agreed.
>
>My copy of Bill Orr's Radio Handbook shows one version of a grid 
>over-current protection circuit designed, as I recall, by W8ZR.  
>Some years ago, a fellow (might have been ZR) was selling 
>printed-circuit
>boards for his own flavor of circuit.  

W8ZR's was an 8877, that Orr Handbook circuit has also been updated by ZR
( Prez of Miami University) but not published.
The 3CX800 circuit you're thinking of may the one in HRM by K8CC. That
circuit had a complete set of boards available from Radiokit for many
years. The boards are probably still available from FAR Circuits. 

GL   Carl   KM1H



>
>What's the latest wisdom on creating a suitable circuit?  Any source
>of PC boards or other short cuts to getting the job done?
>
>73 de Bob, K0KR
>
>
>
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