[serengetiplains]

Airborn, I also received two different cable types, one Mogami and the others Hypex.  The blue wire's polarity is inverse as between the Mogami and Hypex cables.

If I recall, the Hypex cable differs from the Mogami in that the former uses an inner rubber (?) filling that looks to me to target microphonics.

[bruno]

We did indeed decide to roll our own. It's a full custom product designed by yours truly. The manufacturer is "one of the usual suspects".

[jmbulg]

We did indeed decide to roll our own. It's a full custom product designed by yours truly. The manufacturer is "one of the usual suspects".

there have been several users which had problems with Figure 2 on p12 on the ncore documentation relating them to the pin numbering of the audio input/nampon. It could be helpful to recall pin numbers on the ncore board depicted on this figure and possibly indicate the color of your new cable as it is provided now (could save some moments of doubts)

[drubin]

there have been several users which had problems with Figure 2 on p12 on the ncore documentation relating them to the pin numbering of the audio input/nampon. It could be helpful to recall pin numbers on the ncore board depicted on this figure and possibly indicate the color of your new cable as it is provided now (could save some moments of doubts)

+1

[studley]

Ok got one monoblock working but didn't have time to put the other together. The balanced signal cable is indeed not the Mogami cable earlier purchasers received.  This cable is stamped on the jacket "hypex electronics QuietConduit low-noise balanced audio cable."  So it appears hypex is now making the balanced signal cables itself.  I don't know if this is because of supply issues with the Mogami cable or why they switched.  In any case the connectors are as described above, i.e., J9 pin 4 is the yellow shield wire and goes to xlr pin 1, J9 pin 3 is the black nampon wire and goes to chassis/ground, J9 pin 2 is the white inverted audio wire and goes to xlr pin 3 and J9 pin 1 is the blue audio signal that goes to xlr pin 2.  Hope this helps.

Even one channel sounds good; can't wait until I have time to fully complete both amps.

Airborn, glad I found these posts of yours as I have just received my modules and have the same new hypex cable.  The change of colours is very confusing!  However I am still puzzled as to why you describe the shield as a yellow wire - mine is just bare silver coloured wire mesh -?

And a technical question for those with the knowledge:  I don't have any enclosures yet so I intend to connect both the nampon and the shield to pin 1 of the XLR socket.  Will that work ok?

[Airborn]

However I am still puzzled as to why you describe the shield as a yellow wire - mine is just bare silver coloured wire mesh -?

Check the other end of the Hypex cable where the 4 separate wires enter the 4 pin molex connector that plugs into J9 on the Ncore.  If you pull back the black outer sheathing you should see the yellow wire at the J9 pin 4 position.  That is the shield wire, which is the wire mesh around the inner rubber sheathing on the Hypex cable.  See my pic above.

[drubin]

Hypex have updated the data sheet for the Ncore 400 (new as of July 27) to reflect the change in cable colors.  They show the blue cable to Pin2 and the white to Pin 3.  Not clear to me how the nAMPON and shield are supposed to be connected, though.

[drubin]

I finished my build (dual mono) on Friday, though I'm going to make some small changes to parts here and there. The amp sounds excellent, but it seems to have a fair bit less gain than, for example, the Sanders Magtech I have been using.  The Sanders is 26dB gain.  What are the Ncores? 

[jtwrace]

What are the Ncores?

~26dB

Which I have confirmed.

[drubin]

Right.  So is there anything I might have done that could produce this effect of lower apparent gain?  Such as wiring the J9 connections improperly, for example?

[jtwrace]

Right.  So is there anything I might have done that could produce this effect of lower apparent gain?  Such as wiring the J9 connections improperly, for example?

Phase of output wiring is correct?

[jhm731]

~26dB

Which I have confirmed.

What is the input voltage required for full output on NCores?

[jtwrace]

What is the input voltage required for full output on NCores?

http://www.audiocircle.com/index.php?topic=108251.0

[jhm731]

http://www.audiocircle.com/index.php?topic=108251.0

I'm sorry, but I don't see any spec for input sensitivity that tells me how much input voltage is required for full rated output on NCores.

For example, drubin's Sanders Magtech requires 2 volts for its full rated output of 900 watt at 4 ohms. 

If the NCore has the same input sensitivity as the Magtech and it's putting less than half the power, I think you're going to notice a "fair bit less gain"/SPL level.

[mgalusha]

I'm sorry, but I don't see any spec for input sensitivity that tells me how much input voltage is required for full rated output on NCores.

For example, drubin's Sanders Magtech requires 2 volts for its full rated output of 900 watt at 4 ohms. 

If the NCore has the same input sensitivity as the Magtech and it's putting less than half the power, I think you're going to notice a "fair bit less gain"/SPL level.

input voltage required = Vout/gain = 40/20 = 2 (26dB calc)
input voltage required = Vout/gain = 40/19.5 = 2.05 (25.8dB calc)

Vout = sqrt(Watts * Ohms) = sqrt(200 * 8 ) = sqrt(1600) = 40

26dB gain = voltage gain of 20.
25.8dB gain = voltage gain of 19.498

Per the data sheet, the NC400's have a gain of slightly under 26dB, 25.8dB but for almost all purposes this is close enough to 26 not to matter. The required input voltage changes by .05V. I have measured the gain on perhaps 6 of these, they are all same.

If the Sanders amp has a gain of 26dB, the level should be the same at any power level below clipping. Gain is not related to power output. But 900W @ 4Ohms works out to an output of 60V and with 26dB of gain that means it would need 3V to reach full power. If it really reaches full power at 2V of input, then it would have a gain of ~29.54dB, a voltage gain of 30.

hth

[gasdqman]

The XLR cable that came with my NC400 has blue and white wires running through the braided shield and a black wire running along side the shielded cable .  I believe the blue wire goes to the number 2 pin.  I believe the white wire goes to the number 3 pin. 
The  shield is already grounded to the chasis through the NC400, does it need to be attached to the chasis at the other end?
Where should the black  wire attach?

[jtwrace]

The XLR cable that came with my NC400 has blue and white wires running through the braided shield and a black wire running along side the shielded cable .  I believe the blue wire goes to the number 2 pin.  I believe the white wire goes to the number 3 pin. 
The  shield is already grounded to the chasis through the NC400, does it need to be attached to the chasis at the other end?
Where should the black  wire attach?

http://www.audiocircle.com/index.php?topic=105438.msg1112325#msg1112325

[mkcarnut]

Pardon the stupid question, but somewhere here on the AC - I saw someone saying they thought for an on-off switch it was best to use a DPDT toggle, and I didn't understand that at all.  I can't find that post again, but the person said something about it being related to the nCore design (but again - didn't make sense to me at the time...)

I was thinking that the standard approach of cutting the hot power-in line from the IEC to the power supply & splicing in a basic switch that either connects or disconnects the line would be the right way to add a power line.  (Note:  the switch I have on order is nothing fancy...just the basic toggle from Hypex...not tied in with an IEC, no light involved, etc.)

Am I missing something here or is my thinking correct?

Thanks,

Mark

[jtwrace]

Am I missing something here or is my thinking correct?

You are correct.  You want to use a SPST switch whether it's for the AC power in or nAmpon.

[TomS]

Pardon the stupid question, but somewhere here on the AC - I saw someone saying they thought for an on-off switch it was best to use a DPDT toggle, and I didn't understand that at all.  I can't find that post again, but the person said something about it being related to the nCore design (but again - didn't make sense to me at the time...)

I was thinking that the standard approach of cutting the hot power-in line from the IEC to the power supply & splicing in a basic switch that either connects or disconnects the line would be the right way to add a power line.  (Note:  the switch I have on order is nothing fancy...just the basic toggle from Hypex...not tied in with an IEC, no light involved, etc.)

Am I missing something here or is my thinking correct?

Thanks,

Mark

That should be fine. DPST would probably be appropriate if you ever intend to use balanced AC power.