Constant sidetone

[Steve and Anne Ray]

The constant sidetone is quite away down in most HW-101, I found I could get
it down even further simply by putting a tube shield on V15.   I also wired
up the sidetone, like the SB100 series where a pot is used to control the
volume.

73,
Steve Ray K4JPN ex K1VKW
HW-101, HW-8, Elecraft K2 1422
HeathKit fan
EM82fp
Warner Robins GA

----- Original Message -----
From: "Mark Graalman WB8JKR" <wb8jkr at JUNO.COM>
Sent: Sunday, September 23, 2001 8:40 AM
Subject: Constant sidetone


>   I've come up with an idea that MIGHT do away with
> the constant sidetone in the HW101 when the rig is in
> the CW mode but the key up. Let me preface this by
> saying that placing a .01 uf cap from the below indicated
> point (C315/R329 junction) will stop the constant tone
>
>   On the schematic the output of V15A is coupled to V15B
> through C315 and R329, the reason the sidetone is always
> heard is because the inter-electrode "C" of V15B couples
> it to the audio amp V14B no amount of cutoff bias to V15B
> will cure the problem. Here's my idea:
>
>  Place another .005 disk cap in series with C315 then at the
> junction of these two caps connect a diode with the anode to
> chassis ground, then connect one end of a 22K resistor from
> the junction of the two capacitors and the diode cathode to the
> CW key jack. When the key is up the diode will be biased "on"
> by the -55 volts at the key terminal thus bypassing the audio
> tone from V15A to ground. When the key is pressed the bias
> is removed from the diode and the audio is allowed to the grid
> of V15B. The 22K resistor allows the key line voltage to bias
> the diode on without placing the rig into the transmit mode.
>
>   Any thoughts? Criticisms?
>
>
>   73, Mark WB8JKR
>
> Novice 3/71, General 8/72, Advanced 6/80, Extra 8/88
> Member Society of Cable Telecommunication Engineers
> Member ARRL, DXCC, WAC, WAS, VUCC 2 meters, GJDXCC, OTC, RCC, QCWA
>

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