As i happen to have an OMNI VI+, i would sure appreciate a point in the
correct direction for a replacement to the noisy amp relay.
Thank - you.
On Sun, 2007-12-09 at 20:07 -0500, Paul Christensen wrote:
> > The Omni VI/VI+ used a reed relay for T/R switching, even tho they may
> > have
> > used diodes in the circuit. Remember all the complaints about how some
> > folks could hear their relay and others couldn't? :-)
> The mechanical mounting of a T/R relay has a profound effect on acoustical
> noise. To reduce noise of any relay in a T/R circuit, the idea is to reduce
> the effects of the PCB or chassis functioning as an acoustical sound board
> (e.g., like that found on a piano or violin).
> Even on the Omni Six series, the noise of the T/R reed relay varied from
> nearly zero to annoying,
> depending on how the relay was inserted during manufacturing. The distance
> of the reed relay's body from the PCB generally established the level of
> By contrast, the Omni Six's open-frame amp relay is quite loud. There are
> other noiseless solutions for that, including the bypassing of the amp relay
> with a high-voltage, high-current MOSFET switch, capable of silently
> switching nearly any AC or DC amp key line.
> The idea propagated by others that a "Y" adapter used on the Omni Six's
> TXOUT/TX EN line through a steering diode to the amp is a bad one and leads
> to hot-switching on some amps without such timing protection. I know it
> works for some folks, but they're lucky in that the amp senses the hot
> switching -- until the protection circuit fails. Those two amp sequencing
> jacks are meant ONLY for amps that accommodate a bi-directional handshake.
> Paul, W9AC
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