Shorting plugs

The Shorting Plugs, just prevent stray noise pick up from the un-used inputs.
These would be most effective for low level inputs such as Mic or Phono ( Moving Coil or Moving Magnet ) inputs, which see a substantial voltage gain at these inputs.

Actually, the unused inputs are typically left 'Open" not connected, at the selector switch, and the argument is that the signal will 'Jump Across' the open contacts, and polute the active input.

SOME amplifiers are designed that all unused inputs are automatically grounded thru an appropriate resistor ( Typically 10K or 100K )

The digital Output is designed to ideally feed 75 Ohms cables and a 75 Ohms impedance ( or 50 Ohms, depending on the design ). Hence this is the ideal load for it. It would be happiest into a 75 Ohms.

Worth trying then on digital ?

....And loads of 100k on analogue outputs?

Manek

As they say .... : Your Milage May Vary " ...

No harm done though !

P.S.
Why 100K ? The shorting plug will not load any external device ( unlike a built in loading resistor ). Go with the low value ( eg 2 K ) for lowest noise.

Manek schrieb:

Hi How many of you are using shorting plugs on your rca inputs ? Was reading article on plugs with 2k resistors soldered onto rca plugs for analogue inputs. How would this help ? and 75 ohm resistor on a digital output ! Wouldn't this destroy the circuit ? Manek

Manek,
Cardas provides RCA shorting plugs where the analog inputs are shorted to ground by connecting the center pin to the outer metal ring of the RCA jack.
So, I'm wondering why Amp_Nut is recommending 100K???

I have left my analog inputs floating for the last 6+ years & I do not feel that I'm missing anything. FWIW.

Bombaywalla said :

So, I'm wondering why Amp_Nut is recommending 100K???

Actually, Amp_Nut said :

Go with the low value ( eg 2 K ) for lowest noise.

Amp_Nut schrieb:

Go with the low value ( eg 2 K ) for lowest noise.

yes, Amp_Nut, I now see that! I must have not registered it when I read your post.

I think that we agree to leave the analog outputs un-touched, correct?
And, the unused digital o/p connected to 75-Ohms to give max load xfer of rail-rail digital output so as to reduce square wave harmonics spewing everywhere, correct?


So, my question is: why not simply short the analog inputs to ground like the Cardas plugs?

bombaywalla said :

So, my question is: why not simply short the analog inputs to ground like the Cardas plugs?

Yes, Sir ! I agree with you.

However, since Maneck was quoting someone's earlier advice of 2K Ohms, I stayed with that figure....

Amp_Nut schrieb:

bombaywalla said : So, my question is: why not simply short the analog inputs to ground like the Cardas plugs? Yes, Sir ! I agree with you. However, since Maneck was quoting someone's earlier advice of 2K Ohms, I stayed with that figure.... 8)

Ach! OK. Thanks!