Re: {Collins} Step-start for 30L-1 - Good idea?



Received a private email on this topic...

"I have no idea whether (12A with the Ameritron) is an effective limit or not. I also looked at the Harbach product and did not see that it was listed for the 30L-1, just the SB-220-221.".

Harbach has some lower-power modules for the SB-200/201 and also some "universal" modules that are supposed to be useable with anything; see:

http://harbachelectronics.com/shop/misc/ss-100-universal-soft-start-module/
http://harbachelectronics.com/shop/misc/ss-100-240-universal-soft-start-module-copy/
http://harbachelectronics.com/shop/heathkit-sb-200-sb-201/ss-201-soft-start-module/
http://harbachelectronics.com/shop/heathkit-sb-200-sb-201/ss-201-240-soft-start-module/

But, I just looked over the schematic for the 30L-1 and I don't see a clean way to install this module without an unusual amount of rewiring.  The step-start module needs to go on the cold side of the on-off switch.  On the 30L-1, when wired for 120 volts, the input splits off with one leg going to each side of the on-off switch (DPST), then the cold side of the switch wires individually and separately to each primary winding of the power transformer.  Both the connections from the switch to the power transformer need to be broken, the two sides of the switch jumpered together, and the legs of the primaries jumpered together, then the step-start module inserted.  Not difficult, but more modification than normal, and I'm not sure yet what that would do to the ability to rewire the amp for 220.

Someone else suggested just installing a switched AC source and leaving the amp's power switch on all the time, which is certainly a reasonable alternative and is what I do for my KWM-2A.

Rick WA1RKT



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