Klas Strandberg wrote:
> But the
>
>>connection point on the circuit board for cold was one point, so the
>>cold is in common between the two channels. I did not connect the
>>shielding of the cable to the ground.
>
>
> Instead of connecting the cold wires to handle ground, put a 10 mfd in
> series with a 200 Ohms resistor on each wire, and then to ground. Then your
> HHB will see 200 Ohms impedance both on pin 2 and 3.
So I do need to modify the circuit board. Is this the way you do it with
the XLR version? It's going to be fun stuffing the extra components in
that space.
> If the shield should be connected to "handle ground" or "HHB ground" is
> unclear. It's probably the same. The most common with a high-output mic is
> that you connect on both sides.
> In order to avoid hum, one must also investigate the option to connect pin 1
> of the XLR to the chassis ground pin of the XLR. Sometimes this makes a big
> difference, but mostly none at all.
The shield is connected to HHb ground in my case, and all the
interconnects to the XLR's case to shield are in place.
As I noted, by not connecting it to the handle ground, and thus tying
the signal cold to shield ground I avoid any conflict if I fail to turn
off the phantom power on the Portadisc. Otherwise I'd short one side of
the phantom power, the Portadisc can handle that, but I'm sure it's a
battery drain.
All my other mic systems are designed for both phantom powering and
balanced XLR, so all have the shield going all the way to them. Except
the SASS/MKH110 setup, where doing that allowed the two mics to
interact. That one is also not phantom powered, but a internal 9 volt
rechargable. The MKH110's were designed for 8 volts, positive ground.
> The basic reason why you have a risk for hum with a Telinga (when mains
> connected) is that I have saved weight and price on not having enough
> shielding of the handle PC board. As you say, it works just fine when you
> use it as intended - outside on battery equipment.
And I'd rather have the saved weight. The lighter it is the longer I can
hold it up. It's wonderfully easy to use. Don't add weight.
I've not been able to induce much hum holding the handle near known AC
sources. It's got to be a pretty strong source to do anything.
Walt
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