Self made with just 2 wires. Let me ask you.... if we take pin 1 out of the discussion, would it really matter if RCA ground was connected to cold or hot XLR/nCore? I mean, if nCore is really symmetrical balanced, it should not matter really, should it? Now as I have wired it with Cold pin to ground/ampon it does, but if it was not? Then it should not matter rigth?
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2 symmetrical tightly twisted wires, no shield... 🙁
I'm a semi believer... 🙂 call me gnostic in this case.
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I'm a semi believer... 🙂 call me gnostic in this case.
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Yes, I should have more accurately said that at some point you need to make sure that currents in the shield are drained to ground.
I also made assumptions that something in the interconnect cable was connected to the shield and therefore that there was something to connect to pin 1
TNT
Why have you twisted the nampon and shield wires with the signal wires?
These don't contain the desired signal, so IF they contain any signal at all you are helping to induce it into the desired signal.
What have to done with your mains earth?
BTW I use rca -> din interconnects to interconnect 2 systems which are 15m apart and use a twisted pair only (single cat5 pair) and there's no hum in that system). However, I wait your reply re mains earthing.
Well, I first searched for a ground to connect to ampon and found that the 4th socket in the input connector on the nCore unit was indeed ground so I just shorted these 2 to get sound out of the amp. Then I pondered on what to do with pin 1 in my XLR at the input. Perhaps against better wisdom, I connected pin 1 to the ampon/ground. This worked fine with my balanced out DAC. But I have ment to disconnect this to see what happens as I realize this is not really how to wire these up. I will try it today at home.
The single end / MBL test opportunity is gone so I don't have this problem really anymore and I will refrain from trying to connect these to any SE source. But it would be good to understand what/where the wrong was done.
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The single end / MBL test opportunity is gone so I don't have this problem really anymore and I will refrain from trying to connect these to any SE source. But it would be good to understand what/where the wrong was done.
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Mains earth is not connected anywhere. I run my system on a 5KVA 115/115 trafo and there is no mains earth which my components see. This was also the situation in the MBL case.
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My
nCore amp will not be silent (no hum buzz) unless the sheild connection from the NC-400 module connects to the ground of the source component.
So in your test situation, with no chassis, this would mean:
Connect sheild and nAmpon to pin 1, on your XLR to RCA cable, connect pin 1 at XLR end to G at RCA end, connect pin 2 XLR end to hot at RCA end, and connect pin 3 at XLR end to G at RCA end. This approach will silence your amp modules.
Do not ask me why, but even with my true balanced source, pin 1 must reference the sheild wire in the amp, and the ground of my source component, for the amp not to buzz or hum.
nCore amp will not be silent (no hum buzz) unless the sheild connection from the NC-400 module connects to the ground of the source component.
So in your test situation, with no chassis, this would mean:
Connect sheild and nAmpon to pin 1, on your XLR to RCA cable, connect pin 1 at XLR end to G at RCA end, connect pin 2 XLR end to hot at RCA end, and connect pin 3 at XLR end to G at RCA end. This approach will silence your amp modules.
Do not ask me why, but even with my true balanced source, pin 1 must reference the sheild wire in the amp, and the ground of my source component, for the amp not to buzz or hum.
OK Barrows, this is how I understand it should work. But without any source connected but with the 2 wire interconnect, with pin1 and pin 2 (or pin3) shorted and plugged in to the XLR input, I got 1,4 V DC on the output. It was as if when connecting ampon/earth to one of the nCore hot or cold, there was a DC generated on the input (it was equivalent to the DCout/gain)...
Have any of you tried this and confirm that you don't get this?
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Have any of you tried this and confirm that you don't get this?
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Just to be clear. Yes Barrows, connecting it as you say silent the buzz/hum, but up came the DC.
ok, that we did not try: all 3 pins shorted.
We did try 1k instead of short for pin1 to cold - no improvement.
Really strange. Same behavior on both channels.
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We did try 1k instead of short for pin1 to cold - no improvement.
Really strange. Same behavior on both channels.
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more info needed...
do this:
1. Measure DC from your source and let us know, how many mV?
2. Do not connect speaker
3. Plug source into amp, and power up amp
4. Let everything warm up for an hour or more
5. Measure for DC at speaker outputs
6. DC at speaker output should be <50 mV under these conditions, mine is ~10 mV (my source, DAC, is capacitor coupled so it has 0 DC on its output)
do this:
1. Measure DC from your source and let us know, how many mV?
2. Do not connect speaker
3. Plug source into amp, and power up amp
4. Let everything warm up for an hour or more
5. Measure for DC at speaker outputs
6. DC at speaker output should be <50 mV under these conditions, mine is ~10 mV (my source, DAC, is capacitor coupled so it has 0 DC on its output)
So, I tried to reproduce this at home...
No source, no load.
If I hook ampon + earth + either cold or hot together -> raises 2,5 V DC on output. This was done on the XLR input with 15cm 3 wire cable hooked to the nCore.
Why is this?
No source, no load.
If I hook ampon + earth + either cold or hot together -> raises 2,5 V DC on output. This was done on the XLR input with 15cm 3 wire cable hooked to the nCore.
Why is this?
so...
Connect a source. Make sure Nampon is pulled to ground, when the amp is muted (Nampon not pulled to ground) there is a little more DC on output. It is fine for nampon to be connected to XLR pin 1 for testing, but subsequently that pin 1 must be ground referenced somewhere (from the source ground). Nampon will not be pulled low otherwise. As long as you have no DC with source connected, you are all good.
Connect a source. Make sure Nampon is pulled to ground, when the amp is muted (Nampon not pulled to ground) there is a little more DC on output. It is fine for nampon to be connected to XLR pin 1 for testing, but subsequently that pin 1 must be ground referenced somewhere (from the source ground). Nampon will not be pulled low otherwise. As long as you have no DC with source connected, you are all good.
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