When to use shorting plugs vs caps on unused I/O


#1

Just wondering what is correct on BHK preamp/ amp/ Directstream Sr. Where are shorting plugs best used vs caps? Why?
Thx in advance


#2

On the DS Sr: In general for safety you don’t use shorting plugs on outputs, this is true for the DS Sr. Use caps on the unused outputs if you want.

Shorting plugs are fine on the S/PDIF and AES inputs. If you have a USB cap that’s fine, I’d be wary of a USB shorting plug. The I2S HDMI connectors are electrically very similar to the HDMI spec so anything that works with general HDMI will work on the I2S inputs - in theory it could short the two sides of each differential pair together - there’s nothing to be gained by tying those four shorts to ground or power.


#3

I also use shorting plugs only on my BHK unsued rca inputs. In my DS I use caps on my unsued rca outputs. As far as I know there are usb and hdmi caps available from Audioquest.


#4

Thanks guys, was mainly referring to RCA/XLR vs digital. I guess the other question is whether shorting the unused inputs on the BHK preamp results in an audible difference- will report back.


#5

Shouldn’t really matter so I’d be curious as to what you find.


#6

Well,
After using shorting plugs on the unused BHK preamp inputs(RCA inputs 3-5) and caps over RCA inputs on inputs 1 and 2(I’m using XLR on 1 and 2) there is a definite lowering of the noise floor. Now I will try XLR covers on the unused inputs. I’m running some efficient speakers (93dB) and resting noise is easily discernible. Fun hobby chasing tiny gremlins back into shadow!


#7

Shorting plugs installed in all the unused phono and XLR inputs and I’ve been using the BHK Pre this way for well over a year.
Like you said, lowered back ground noise and the system definitely sounds better this way, more engaging… The unused sockets seem susceptible to channelling RFI… I have done this for years on all my previous equipment, the results are repeatable… I inserted XLR plugs into the BHK inputs with the three connections joined together… Don’t short out an input if you are using the other on the same connection… Eg…If using an input XLR on say input 2 then don’t short the unused phono socket on input 2 and / or vice versa… But I only use one XLR input so all the other unused inputs are shorted… I am not really into the hifi daft stuff but this really does work !