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Re: RMItaly BLA600


 

Jim, I now remember you writing about this a few years ago. To me this is a serious design flaw. It shoulda went back to the drawing board. Thanks for writing that again.

So, do you know if the Icom 746 has this spike?

Bob W4JFA?

On Sat, Sep 14, 2024, 10:34 AM Jim VE7RF via <jim.thom=[email protected]> wrote:
The 706mk2 puts out a 150 watt spike, regardless of where you set the PO.? ?The issue with ALC is..... it's closing the barn door after the horse has bolted....too late to catch a spike.? ?ALC sorta works ok on xcvrs with no spike....and only works correctly? if the ALC? time constant in the amp matches the ALC time constant in the xcvr.....which never happens.?

One cure for the spike problem is to use a 9 vdc battery and a 500k? pot.? 9 vdc applied to the extreme ends of the 500 k pot.? ? Negative voltage comes off the wiper....and is fed back to the xcvr's? ALC input.? (positive end of
pot / battery goes to the chassis of the xcvr).?
?
Set the pot? for whatever PO? on SSB? you desire.....and it won't budge.? It can't.? The ALC voltage has now been derived from the pot.....and is fixed....and is always sitting there at the XCVR's ALC input.? ?Scream all you want, and all you will get is say 20.5 watts pep out, that's it....and no spikes.?

The 706MK2 with it's 150 watt spike will smoke every SS amp made.? ?Buddy's? Icom? 775DSP was worse.? ?200 watt spike regardless of where the PO was set at.? ?200 watt spike into his tube amp was not good.? 200 watt spike every time he tripped the VOX on ssb.? ?Same deal on the 706 xcvr, 150 watt spike every time you trip the vox on SSB.?

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