Guess I need a ground to close the circuit.
Just did some more testing with everything connected and tried some music playback... When I stopped playback and measured the outputs it was 0.88VDC at idle.
EDIT - if I remove the xlr cable coming from dac to amp it drops back to 0.5VDC
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Just checked, the "ground" on the J1 connector is an output, does that mean the - of the battery just gets connected to the chassis for a "ground" in order for the standby to work?
Well, yes, the ground on J1 is marked as output, but it is really just ground. So that's where you connect the - of the battery. But which ground is your chassis connected to?
Only thing connecting to the chassis are xlr pin1 and copper jacketing of the ncore 4 pin cable.
one of the things I noted in your photos was the painted/finished chassis.
Make sure the finish is removed under the mating surfaces of the ground connections, such as the metal post on the power supply and were the other connectors attach, if possible use a multimeter to measure the resistance and make sure it is low, this can be a hidden problem that can cause oddities that don't seem to make sense.
also connect the pin 1 on the xlr to the lug next to it on the connector, it is a point to connect with minimal length to the chassis to prevent rfi (not one of your current problems)
I use the nAMPon wire to mute the amp and it works quite nicely, remember this amp only takes approx 5 watts when sitting unused in idle.
Alan
Alan are you referring to the unused tab on the xlr connector to ground the metal body?
Also all paint/anodizing was removed to the bare aluminum for the 2 chassis connectors at the xlr. I didn't remove anything on the one metal leg of the power supply though, it looked totally isolated from the rest of the board.
Also all paint/anodizing was removed to the bare aluminum for the 2 chassis connectors at the xlr. I didn't remove anything on the one metal leg of the power supply though, it looked totally isolated from the rest of the board.
No I used unbalanced as in figure 4 i chapter 12.3.2 Hardbonded RCAs and no mains earth.And you use XLR ?
Kjartan
What on earth is this ? It is not possible to post reply without Quote ! ???
Well now I mounted the XLR and still no sound. Could it be because its impossible without the SMPS supply ?
I use 2x65 V for the output and 2x22 vdc for the input section. Ground from the opamp supply is coupled to the ground on the output supply !
Yes it is. Using the "Post reply" button in the lower left corner.
So, let's just check your connections. Your 2x65 V is connected to pins 1 and 2 (+), 7 and 8 (-) and 3, 4, 9 and 10 (ground), and the 2x22 V is connected to pin 6 (+), pin 12 (-) and 3, 4, 9 and 10 (ground) on J7? And pin 2 on the XLR is connected to pin 1 on J9 (+in), pin 3 on the XLR is connected to pin 2 on J9 (-in) and pin 1 on the XLR to chassis/ground? And finally - pin 3 on J9 (nAMPON) is connected to ground?
Have you measured that your 65V and 22V supplies are within limits even under load?
I just redid my chassis, made sure all ground connections were good on the smps leg and xlr connectors and made sure there is very low resistance between all the pieces of the chassis that are screwed together and i'm still getting > 0.5VDC at the outputs with and without the xlr from dac connected and with and without the wires hooked up to the speakers!
what did you end up doing with the nAMPon wire?
what is the offset with the nAMPon open?
Alan
nampon wire is permanently connected to pin1/case ground. By offset are you referring to voltage difference on the output with the wire grounded and ungrounded? If so I believe it was a 0.2V difference. I'm not home though so I cannot verify, I will double check later though.
Yes Yes Yes Yes to everything.
But but but my gnd on the 2 x 65 is not connected to the chassis.
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