hypex ncore

[cab]

Originally Posted by jtwrace

Well, being that this is you Core Audio Technology Hypex Ncore Linear Power Supply | Solid state | Sherman Oaks, California 91403 | AudiogoN - The High-end Audio Community one would think that you have done fully objective long term tests. Can you provide us with all the power supply measurements?

Core Audio offering $6000 linear supplies for the ncore as a commercial product on audiogon? Wow.....I would have thought it was a tested, working product for that kind of money....

[tony399]

Omholt;

You shouldn't get any hum, did you test with the inputs shorted?
A couple of things,
1) Your speaker wires aren't twisted
2) The casework may not be fully grounded due to the anodising, test with a meter for continuity between top, bottom and back panel

[matjans]

Originally Posted by Omholt

I'm hearing a slight hum from mine. Is this normal?

No. They should be dead quiet. Mine are. Both in their cabinet as they are currently, as when they were "naked" on the table.

- Try with source connected and disconnected. Is the hum in the source?
- check all solder connections on the XLR and input cables
- check whether there's no litze spilling from the speaker/output terminals on the nCore modules
- Is mains earth connected to chassis? --> Don't
- Is XLR connector pin 1 connected to chassis? --> Do (and make sure, as tony mentions above, that contact is actually good)
- Using a Y-cap AC conditioner? --> Don't

This has all been discussed before (do a search, you don;t want to go reading 5000 posts... )

For the rest, just make sure you follow wiring guidelines from the datasheet on Hypex' site, nothing to it. Keep power & signal lines separated, keep output wires away from the coils, twist everything except Mogami input cable and you should be good to go.

[ChrisPa]

I get hum with nothing connected to the inputs using RCA -> XLR adapters
But dead silent once connected

When testing, as I was building and installing into cases, I used a Galaxy S2 as a music source with a cable from the headphone socket going to 2 x phono, plugged into RCA -> XLR adapters. Every time the music was paused there was hum because the phone's output was going open circuit.

[tony399]

Which is why I asked if the inputs were shorted (pin 2 and 3 of the xlr linked), mine give an increased hiss when inputs are 'open' (but no hum) and dead quiet when shorted or connected to source

[Julf]

Originally Posted by ChrisPa

When testing, as I was building and installing into cases, I used a Galaxy S2 as a music source with a cable from the headphone socket going to 2 x phono, plugged into RCA -> XLR adapters. Every time the music was paused there was hum because the phone's output was going open circuit.

Do I remember something about adding a 10K resistor when using unbalanced RCA's? I guess it was mainly to deal with the DC offset, but...

[ChrisPa]

Originally Posted by Julf

Do I remember something about adding a 10K resistor when using unbalanced RCA's? I guess it was mainly to deal with the DC offset, but...

You're probably right

My comments were simply about what I'd observed rather than any recommendation. My system is fully balanced, and it was silent with RCAs all the time a (non-open-circuit) source was connected.
The comment on the behaviour of my S2 as a source was really just to observe that even if you've got a source connected, the input may still effectively be open circuit.

[Mintzar]

Originally Posted by Bruno Putzeys

It sounds like he's got one channel out of phase.

No. Phase is correct.

[ChrisPa]

Originally Posted by Mintzar

Having an issue with a pair of Ncore modules I am building for a friend.

There's no bass. It's almost as if there's a 6dB high pass filter above 100hz. The gain on the amp is also fairly low. With high sensitivity speakers I have to turn the volume fairly high to get it to a normal listening levels.

It also depends
- what amps you are replacing and what their bass response/control was with the speakers you're using
- what the gain of your previous amp was
- what the output levle is from your source

- what speakers and previous amp?
- input wiring/connections?
- try different speakers as a reference?

[matjans]

when using rca, from the datasheet:

Input bias current may cause a small DC offset
when wired according to 12.3.2 or 12.3.3 and no
source is connected.

Strap 47k across the RCA input to provide DC path.

(rtfm! )