[AMPS] Blown TL922A... What to do?

Steve Thompson rfamps@ic24.net
Wed, 13 Sep 2000 07:43:03 +0100

-----Original Message-----
From: measures <2@vc.net>
To: AMPS <amps@contesting.com>
Date: 13 September 2000 02:36
Subject: RE: [AMPS] Blown TL922A... What to do?

>>     I like the idea of modeling the circuit. However,
>>much of the circuit is not considered. People often don't realize that
>>that there are additional inductances due to the current paths thru the
>>chassis and often these impedances are in both the input and
>>output circuits.  I have seen many amplifiers that have very long paths
>>from the anode (PLATE) thru the coupling capacitor, PI input capacitor, to
>chassis and
>>back to the grid and cathode circuit. Sometimes this path is a foot in
>>length or more
>>. This single loop amounts to nearly a uH of inductance with
>>who knows what other impedances tied to it and signals sharing the path.
>>    My electronics instructor used to say often the problems with a
>>is the component you can't see. Especially with RF circuits.
>Amen to that, Bill.  Who would ever have guessed that there is a
>Z-step-up L-network hidden inside the Tune-C in a 922?

C'mon, Rich, make with some details. Where's the L, where's the C, what are
their values, and do they predict the required voltage step up?


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