I revisited my first Ncore build yesterday, that means I opened up the case to take a peek inside... Lo and behold!!! - the PSU cable was not twisted properly, and the speaker wires were not twisted at all! And they came out from the wrong side of the lugs!! Fixed it. Slept really good the following night. 
Yes, although "different points near each other" is a smidgen better in principle, if one wanted to split hairs.
Where you tie Nampon is not critical. That can go anywhere because all it wants to know is "yes" or "no".
Alan et al.,
I can confirm that after twisting everything and keeping away from the coils the background noise level went down. I also realised after playing some more with everything my computer (which is connected to my preamplifier via Soundcard) introduced aditional noise/sounds even though the computer has not been used as source
. Never heard that before.Regarding my other statements about the sound - I find that I can now focus better on the actual sound which probably improves my attitude
. Not really a reason to retract my statements yet, tough. But I will spend some more time.Regards
Sven
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.
A few notes:
1. I designed linear power supplies for the modules.
2. The issue happens with both SMPS and Linear PS. The distortion on the top end is worse with the SMPS, but the bass reproduction faces the same issue.
3. The unit is wired for balanced operation, but I am using an RCA to XLR cable wired per the datasheet.
4. The speakers I'm using have a very high QTS of .95 and are full-range crossoverless (I think I read some comments somewhere about this).
5. The amplifier plays 'music' and LEDs light up as they should.
6. The issue is the same in both channels.
7. No crackles, pops, clicks, hums, or noise
The power supply is talked about here: Class D - Page 6
I know there was a few mentions of defective modules, but wanted to see if you guys had any thoughts in the mean time. Thanks for your advice!
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.
A few notes:
1. I designed linear power supplies for the modules.
2. The issue happens with both SMPS and Linear PS. The distortion on the top end is worse with the SMPS, but the bass reproduction faces the same issue.
3. The unit is wired for balanced operation, but I am using an RCA to XLR cable wired per the datasheet.
4. The speakers I'm using have a very high QTS of .95 and are full-range crossoverless (I think I read some comments somewhere about this).
5. The amplifier plays 'music' and LEDs light up as they should.
6. The issue is the same in both channels.
7. No crackles, pops, clicks, hums, or noise
The power supply is talked about here: Class D - Page 6
I know there was a few mentions of defective modules, but wanted to see if you guys had any thoughts in the mean time. Thanks for your advice!
Alan et al.,
I can confirm that after twisting everything and keeping away from the coils the background noise level went down. I also realised after playing some more with everything my computer (which is connected to my preamplifier via Soundcard) introduced aditional noise/sounds even though the computer has not been used as source
Regarding my other statements about the sound - I find that I can now focus better on the actual sound which probably improves my attitude
Regards
Sven
Having a computer connected via a soundcard to your system is always going to create issues. You would be much better off outputting sound through an external dac, preferably via something like the Audiophilleo reclocker to further isolate computer bourne hash from entering your sound system. Without knowing what specific soundcard you are using (as there are exceptions), I would suggest that getting HQ sound from a computer soundcard is difficult to achieve.
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?
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....
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.
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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.
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.
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.
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?
- Status
- Not open for further replies.