1.9v ac on input of sb220 when keyed. Why? Is this normal?

I have both and sb220 and the newer HL 2200 they both have about 2 volt AC on their input when they're keyed up if you put a meter across the input coax to me that seems kind of strange.
I'm concerned that this amplifier ruined the SWR sensing diodes when I hooked an Icom 706 Mark II G up to it.

 

Are you measuring this with a 10 Meg Ohm input DMM?

Try this again with 1 K or 10 K resistor to ground, effectively across the DMM test leads.

 

fluke 16 and some other high-dollar Chinese multimeter I'm pretty sure that they're both true RMS reading meters

 

Heres what i found

 

More than likely you're seeing stray AC; I don't think the SWR detect circuits are going to be affected in a 706 series radio ... try the resistors, if the voltage is a mere fraction, its just 'stray' AC ... hold one of your meter leads up near a lightbulb - same effect.

 

Here's the other
I tried the lightbulb trick and I got 0.1 when I did that
I'll look for a 1K or 10K resistor and try that also I just know that I don't see any voltage across the input in my solid-state amplifier so that's why I was kind of concerned

 

I should ask - was this with antenna connected? I see about 20 or 30 mV AC using a scope connected to my 2 meter vertical, which is not DC grounded. After the first rain falls that value decreases by quite a bit ... I think I'm seeing stray AC on that antenna from the buried utilities in the alley.

If I do the same thing with a DMM in the car on a 2 m mobile antenna, underneath power lines I can see 2 or 3 V AC.

 

.076vac with 10k ohm across leads

 

Ahh ... more like it. All the characteristics of "stray" AC line voltage. Those amps are not terribly well-shielded inside - did you have an antenna of some type connected too?

 

Yep into my tuner then my 300 foot loop