nBarrows, nampon gets low in my case by a short connection in the 4 pole connector, sitting in the nCore unit, tied to what has a earth symbol. This should be OK acc to Hypex person I corresponded with.
So pin 3 and 4 in J9 are permanently connected in my amps.This is also what is hooked up to XLR pin 1
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So pin 3 and 4 in J9 are permanently connected in my amps.This is also what is hooked up to XLR pin 1
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OK
understood. I do not understand why you do not just connect a source (anything, preamp, CD player, etc) for test purposes... and make sure the source has no DC as well. Then allow the set up to warm up, and then measure DC at speaker terminals.
If you then have significant DC, contact Hypex for help.
understood. I do not understand why you do not just connect a source (anything, preamp, CD player, etc) for test purposes... and make sure the source has no DC as well. Then allow the set up to warm up, and then measure DC at speaker terminals.
If you then have significant DC, contact Hypex for help.
Currents in the shield (nor anywhere else for that matter) don't drain to ground. They return to their voltage source.
I believe I understand what you're saying, but don't currents drain (flow) to what they're connected to dependent upon the voltage that's driving them there? No connection, no drain (current flow)
And an induced current (in a shield) will drain (flow) to wherever that conductor is connected?
The current that left one terminal of the secondary is trying to get back to the other secondary terminal.
Maybe we can look at it as the secondary of an air core transformer. So where is the other secondary terminal?
Or then maybe the current is leaking through an unintended capacitor.
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So reason and resolution for my DC out problem:
"It looks like the 118 mV on the input in amplified 20x causing 2,3 V on the output.
This appears to be caused by a too large common mode offset on the input. We had a small batch of NC400 modules which were adjusted incorrectly due to an error in the testing procedure. This is normally only a problem for unbalanced applications.
You can adjust the common mode voltage as follows:
Measure the voltage between XLR pin 1 and pins 2 or 3 (no other pins shorted). Then adjust potentiometer R95 (VCM) until the meter reads about 0 mV. Do this when the module is at working temperature. At cold temperature the VCM may be set to -300 mV, this will rise to about 0 V when the module warms up.
If the VCM is adjusted correctly and the XLR pins 1 and 3 are shorted, there should be only a few mV DC on the output."
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"It looks like the 118 mV on the input in amplified 20x causing 2,3 V on the output.
This appears to be caused by a too large common mode offset on the input. We had a small batch of NC400 modules which were adjusted incorrectly due to an error in the testing procedure. This is normally only a problem for unbalanced applications.
You can adjust the common mode voltage as follows:
Measure the voltage between XLR pin 1 and pins 2 or 3 (no other pins shorted). Then adjust potentiometer R95 (VCM) until the meter reads about 0 mV. Do this when the module is at working temperature. At cold temperature the VCM may be set to -300 mV, this will rise to about 0 V when the module warms up.
If the VCM is adjusted correctly and the XLR pins 1 and 3 are shorted, there should be only a few mV DC on the output."
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