Tweak for digital seperates

[JamesB]

Hi dudes,

I've made up terminators for the unused digital outputs in my various DAC/De-jitter/Upsample digital gear and it's made a really nice improvement.

Check out:
http://www.AudioAsylum.com/audio/tweaks/messages/11799.html

For the 75ohm ones I was lazy and brought some pre made ones of the net. For the 110ohm ones I brought some XLRs and 1W resistors from DSE and made them up.

Worth a try as it only costs a few bucks...

-- James :)

[Owen Y]

GOOD tweak! Must try it!

I presume you are talking about BNC plugs wired with 75ohm shunt Rs?

And... you terminate all your unused Balanced XLR output sockets with 110R?.

PS. ARC (Audio Research Corp) used to supply RCA shorting plugs to be used on all unused input RCAs... for minimising noise pickup & keeping sockets clean!

Owen

[Owen Y]

Further thoughts....

One of the issues to consider here with this idea is that your device in question will now have to drive drastically reduced loads, if all these outputs are unswitched/connected. ie. the DAC or whatever has its output load reduced by quotient of the number of live output sockets terminated in this way. eg. 2 outputs => halved load, 3 sockets => one third load, & so on.

The question would be... is the device capable of driving lower impedance loads?

See: http://www.borbelyaudio.com/kit_upgrades_term.asp

If the device doesn't like it, then that would certainly change the sound that you are getting! :eek:

Cheers, Owen

[Callum]

Originally posted by Owen Y
ARC (Audio Research Corp) used to supply RCA shorting plugs to be used on all unused input RCAs... for minimising noise pickup & keeping sockets clean!

I was going to try this tweak with my amp to reduce the background noise from my speakers, but when I talked to Perreaux about it they said all non-selected inputs are shunted to ground via a resistor anyway. Smart. I presume other manufacturers would do the same, so might pay to check with them before needlessly putting shorting plugs on unused inputs. Doesn't keep the sockets clean though.

Oh yeh, the noise I had turned out to be due a particularly poisonous leg of the house wiring. Since resolved.

The digital output termination sounds like its worth a crack. Cheers James.

Callum

[JamesB]

Originally posted by Owen Y
GOOD tweak! Must try it!

I presume you are talking about BNC plugs wired with 75ohm shunt Rs?

And... you terminate all your unused Balanced XLR output sockets with 110R?.

PS. ARC (Audio Research Corp) used to supply RCA shorting plugs to be used on all unused input RCAs... for minimising noise pickup & keeping sockets clean!

Owen

Yeah, I got 75ohm BNC terminators for my SPDIF outputs with BNC. For RCA SPDIF I got RCA>BNC adapters and used the BNC terminators. (These look neater that DIY - but DIY is certainly possible.)

For the unused XLR (AES/EBU) outputs I wired 110ohm worth of 1w resistors between pins 2 and 3.

[JamesB]

Originally posted by Owen Y
Further thoughts....

One of the issues to consider here with this idea is that your device in question will now have to drive drastically reduced loads, if all these outputs are unswitched/connected. ie. the DAC or whatever has its output load reduced by quotient of the number of live output sockets terminated in this way. eg. 2 outputs => halved load, 3 sockets => one third load, & so on.

The question would be... is the device capable of driving lower impedance loads?

See: http://www.borbelyaudio.com/kit_upgrades_term.asp

If the device doesn't like it, then that would certainly change the sound that you are getting! :eek:

Cheers, Owen

Jon Risch talked about this on the AA and said that if there was a problem then it'd certainly be audible. I've had no worries with all my gear so far - that has always been an improvement. YMMV.

[JamesB]

Originally posted by Callum
I was going to try this tweak with my amp to reduce the background noise from my speakers, but when I talked to Perreaux about it they said all non-selected inputs are shunted to ground via a resistor anyway. Smart. I presume other manufacturers would do the same, so might pay to check with them before needlessly putting shorting plugs on unused inputs. Doesn't keep the sockets clean though.

Oh yeh, the noise I had turned out to be due a particularly poisonous leg of the house wiring. Since resolved.

The digital output termination sounds like its worth a crack. Cheers James.

Callum

I think you've got it Callum, but for just in case, to avoid confusion for others reading... This tweak is for DIGITAL outputs. Not analogue. DON'T try it on your pre-amps or other anallogue inputs/outputs unless sanctioned by your manufacturer, bad things are likely to happen!!!!!

-- James :)

[Owen Y]

Originally posted by Callum
I was going to try this tweak with my amp to reduce the background noise from my speakers, but when I talked to Perreaux about it they said all non-selected inputs are shunted to ground via a resistor anyway. Gasp,.... that sounds like Relay-switching on the inputs!

An aside...
I built a Linestage a not so long ago, incorporating the cool idea of having input-switching right at the sockets, utilising Relays, thus... ultra-short signal path avoiding the traditional scheme whereby the rear input wiring is taken all the way up to the front panel Input switching, then to the circuit.

Problem was... I discovered that relays (Omron G5V-2) seriously degrade sonics (dynamics), compared with a good switch.

(Note: I didn't survey any other, possibly better, low signal relays.)
Cheers, Owen

[Callum]

Originally posted by Owen Y
Gasp,.... that sounds like Relay-switching on the inputs!


Judging by the sound the amp itself makes when you change inputs, I'd say you're on the money. Smart. Actually, just checking an old photo I took, they (gasp) are Omron G5V-2s (apologies if posting that is offensive to anyone at Perreaux). Maximum smartness.

If dynamics suffer badly from the use of these , then I'd love to hear my amp without relays on the inputs 'cause I think dynamics are one of it's strong points. Lacking in experience am I perhaps.

Callum

[Craig F]

Originally posted by Callum
If dynamics suffer badly from the use of these , then I'd love to hear my amp without relays

I think you can rest easy Callum. The Gryphons I lust after use relays as well and again, if dynamics suffer then they'd be beyond amazing without relays. All together now, "It's not the technology, it's the implementation that counts".

Cheers,

Craig.

[Callum]

Originally posted by Craig F
I think you can rest easy Callum. The Gryphons I lust after use relays as well and again, if dynamics suffer then they'd be beyond amazing without relays.

Cher. Good to hear.

All together now, "It's not the technology, it's the implementation that counts".


And an Amen to that.

[Owen Y]

Originally posted by Callum
If dynamics suffer badly from the use of these , then I'd love to hear my amp without relays on the inputs 'cause I think dynamics are one of it's strong points.Well it's the TOTAL design package that counts, in the end, and product "voicing". I wouldn't lose sleep. ;)

Owen