[Amps] Options for the AL-1200

[MIKE DURKIN]

> Re tube changes for the AL-1200:
>  
> 1.) See N9ADG's website. About four years ago, several hams put the GS-35b into their 
>      AL-1200's. This seems to work ok except that the cooling is below minimums and a 
>      bigger (noisier) blower is required along with a different filament transformer and bias 
>      circuit;
>  
> 2.) Another workable option is to put in an 8877. You will need a filament transformer 
>      change, socket, and chimney, and you will need the timer and grid current trip curcuit to 
>      protect the 8877. You might need to tweak the tuning/ and or components of the tuned 
>      input circuit;
>  
> 3.) IMHO, swapping to a pair of 3-500's is a great option although they need more drive than 
>      the 3CX1200A7. However, you will retain the "quick on" feature of the amp and the tubes 
>      are cheap! You will need a new filament transformer, sockets, chimneys, and 
>      suppressors;

Honestly i didnt think the cost of a pair of 3-500Z's was cheap copmpared to a single GS-35B. I dont know what is in a AL1200 but i did not replace the 3-500Z's in my Yokagawa PL960( its a THP HL-2K) but instead did some sheet metal work and installed a GS-35B.
Mike
KC7NOA