[Elecraft] Heil HC-4 with K2 . . .

[Ron D' Eau Claire]

Steve, G4MJW, wrote:
> Tom/N�SS suggested increasing the value of R14 from 1K to 10K. This has
> increased the gain nicely and it's now just high enough for the
> VOX to work
> with a normal voice. BUT there is now too much gain for the Balanced
> Modulator. So I have increased the value of R2 from 5.6K to 10K and the
> reduction is sufficient to produce nice sounding SSB as before. That's OK
> for the HC-4. Now no need for any additional pre-amplification.

R14 (on the SSB adapter) is at the Input to the Speech Compressor and R2 is
between the Speech Compressor and the Balanced Modulator.

Are you saying that increasing R14 to 10k drove the Speech Compressor so
hard it was unable to maintain the proper level to the Balanced Modulator?

I am curious about how sensitive that Speech Compressor is. I have read of a
number of ops using an outboard preamp ahead of it!

There were some ops who swapped R2 and R14 a while back in order to get more
gain. That did raise some concerns about over-driving the Balanced Modulator
because of the swap reduced the value of R14 from 5.6 k to 1 k. But this is
the first I've heard of being able to over drive the Speech Compressor by
simply changing the value of R14 (If I understand you correctly).

Ron AC7AC
K2 # 1289