Not sure if this is the correct section.
My set is as below.
Cyrus dad3 cd --> MF m1 dac --> Chinese 6j1 valve buffer --> cyrus pre --> krell
Connection to dac is optical toslink.
In and out of valve buffer is van den hul d102.
Now I wanted to try different cables so I have two pairs of van damme silver plated cables with wbt phono connectors.
When I replace both pairs of vdH, there is a hum on right hand speaker.
I've checked vD cables with dvm and 0 ohm so nothing to indicate a fault. I've also swapped them around and hum is the same, I. E. It does not follow a cable.
Now here is the weird bit.
I replaced the vD cable, right one going from buffer to pre with the vdH or a cheap lead, hum stops.
WTF is going on?
My set is as below.
Cyrus dad3 cd --> MF m1 dac --> Chinese 6j1 valve buffer --> cyrus pre --> krell
Connection to dac is optical toslink.
In and out of valve buffer is van den hul d102.
Now I wanted to try different cables so I have two pairs of van damme silver plated cables with wbt phono connectors.
When I replace both pairs of vdH, there is a hum on right hand speaker.
I've checked vD cables with dvm and 0 ohm so nothing to indicate a fault. I've also swapped them around and hum is the same, I. E. It does not follow a cable.
Now here is the weird bit.
I replaced the vD cable, right one going from buffer to pre with the vdH or a cheap lead, hum stops.
WTF is going on?
laying the cables different distances apart changes the loop area of the loop formed in the input section where the source has a common Signal Return.
If you change the loop area to VERY SMALL, you will reduce the interference picked up on the two connected returns.
Do this for both cable types and see if you can measure any difference in H+N at the outputs.
BTW,
your ears/brain are NOT any good at measuring. Use a voltmeter.
Download D.Joffe's paper on HBRR+HBRL. He explains why the interference and a solution.
If you change the loop area to VERY SMALL, you will reduce the interference picked up on the two connected returns.
Do this for both cable types and see if you can measure any difference in H+N at the outputs.
BTW,
your ears/brain are NOT any good at measuring. Use a voltmeter.
Download D.Joffe's paper on HBRR+HBRL. He explains why the interference and a solution.
I kinda follow that - I did try moving the cables away from the mains leads and to be at right angle to mains lead, no difference, admittedly I did not try to make the loops smaller (vD cables are 0.5m whereas vnH are 1.0m so the vD have smaller loop .... BUT why does it happen with 4 van Damme cables but not with 3 van Damme and 1 other cable?
Photo below shows the set up.
Orange cable is the van Damme - nothing usual about it.
Valve buffer connected with 4 van den Hul D102, 4 yellow cables.
Upper two cables are output, lowest two are input., It is the input right (lowermost cable, red mark on socket) that when replaced, makes the hum go away.
Photo below shows the set up.
Orange cable is the van Damme - nothing usual about it.
Valve buffer connected with 4 van den Hul D102, 4 yellow cables.
Upper two cables are output, lowest two are input., It is the input right (lowermost cable, red mark on socket) that when replaced, makes the hum go away.
Attachments
Oops, should have mentioned that. That was my thought too as the WBT connector are of larger diameter, so first I put pieces of paper to insulate them, then I removed all the outer body barrels (they are screw on type that allow tightening of the outer onto the phono socket) and it made no difference.
This is the one he was referring to https://www.updatemydynaco.com/documents/GroundingProblemsRev1p4.pdf
Different cable construction? An unbalanced connection should use coax but many 'audiophile' cables are some form of twisted pair, sometimes with a shield. As a general rule, the more you pay for an audio cable the less well engineered it will be as a means for getting signals from A to B unharmed.
hmm difference in resistance between copper and silver is minute, there has to be something else going on
Silver 1.59x10-8
Copper 1.68x10-8
the module that the cables are linked to in the picture have no physical support for the RCA's and with the heft of those cables i'd say there's a ground going open and producing hum.
it may be worth a close inspection of the solder joints with a magnifying glass to see if there's any cracked or bad solders.
it may be worth a close inspection of the solder joints with a magnifying glass to see if there's any cracked or bad solders.
Nothing unusual about the vdH cables or wbt plugs, inner conductor soldered to central pin, braided screen to outer.
In photo you should be able to see a 1/2 squash ball (2 yellow dots) that supports the middle two cables, and I did wiggle the cables to check for intermittent connection. I also measured diameter of centre pin on the vdH and vdH cables and seem OK.
The seller of vD cables sent another set but with different phono plus but no different.
I will check the soldering for the phono plugs.
Just realised that I have a virtually identical valve buffer I can try, this one was modified to be follower with improved heater supply.
In photo you should be able to see a 1/2 squash ball (2 yellow dots) that supports the middle two cables, and I did wiggle the cables to check for intermittent connection. I also measured diameter of centre pin on the vdH and vdH cables and seem OK.
The seller of vD cables sent another set but with different phono plus but no different.
I will check the soldering for the phono plugs.
Just realised that I have a virtually identical valve buffer I can try, this one was modified to be follower with improved heater supply.
Spent some time on this. Thought I sorted it by wiring a phono socket directly to the input which would indicate faulty phono socket on board. So then removed the pair of sockets and soldered another set. Same, damn.
So next made little bracket for 2 better quality phono, and same.
I will route the rh signal directly to the input resistor.
What I have noticed if I put my finger on the top of the capacitor nearest the rh input (capacitor is part of voltage multiplier circuit), hum goes away.
So right now it looks like the rh input is picking up interference, doesn't expect why it only happens with the vD cable.
So next made little bracket for 2 better quality phono, and same.
I will route the rh signal directly to the input resistor.
What I have noticed if I put my finger on the top of the capacitor nearest the rh input (capacitor is part of voltage multiplier circuit), hum goes away.
So right now it looks like the rh input is picking up interference, doesn't expect why it only happens with the vD cable.
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