Hmm... As you don't have an oscilloscope, could you try measuring the output voltage with the AC range of your multimeter (instead of DC)? It might provide at least some indication of possible HF oscillation going on.
AC voltage is approximately the same as DC.
DC - 0.47
AC - 0.4 (meter only reads in tenths on AC)
AC voltage is approximately the same as DC.
OK, then what you are seeing is probably real DC, and not artefacts of some HF oscillation. Good.
btw, the data sheet says some dc is to be expected when using rca connectors. somewhere at the end. solve with 47k across the inputs.
btw, the data sheet says some dc is to be expected when using rca connectors. somewhere at the end. solve with 47k across the inputs.
Ah yes! In the "Bugs and known issues" section. So yes, a 47k resistor seems to be the solution.
Well spotted, Matjans!
Seems like I am the only one who can not like SMPS . I use Transformers and caps .
So my next question is what to do with the lead from pin 5 on the J 7 ( n fatal : Catastrophic fault indication, inverse of internal FATAL bit )
Cannot find anything in the Datasheet about this.
Hi Erland
Have you not spotted the correlation between this quote and the fact that you are the only NC400 owner who is not listening to music?
Solution..... buy 2x SMPS600's....plug'n'play and there will be music..
Bruno designed the NC 400 and the SMPS 600 to work in perfect harmony....it's a 'no brainer'
These amps will transcend any differences you perceive between trafo/caps and SMPS... move on man and become 😀 rather than

Remember..... 'if it ain't broke...don't fix it !'
Best
John
Erlend,
Before pulling out the solder iron and inadvertedly destroying your modules, please wait for hypex dudes to respond.
Before that, can you post pictures of your wiring of:
- XLR connectors
- power supply connector
Please describe (preferably in the picture) what voltage goes where on your psu connector.
You stated you have a teeny weeny bit of sound somewhere very deep down, my first idea would be a switch on a ground/+ connection somewhere in the xlr wiring. If that is not the case, maybe the wiring of the psu towards the buffer stage has gone wrong somewhere (depending on the buffer, that could mean no sound at all or a teeny ittle bit of distorted sound).
The fact that your module behaves ~normal (dropping dc offset on speaker connection), or at least, comparable to what other describe, probably means that the output stage is working fine.
I will not destroy anything . Evrything is as in the datasheets except I am not using the SMPS , the pin 5 lead and the pin 11 is not connected anywhere.
I will not solder on the board . I just short circuited the 3,3 ohms in the external supply for the input section. Did not help at all. Next step is a lead from the gnd of the supply to the cabinet !
Hi Erland
Have you not spotted the correlation between this quote and the fact that you are the only NC400 owner who is not listening to music?
Solution..... buy 2x SMPS600's....plug'n'play and there will be music..
Bruno designed the NC 400 and the SMPS 600 to work in perfect harmony....it's a 'no brainer'
These amps will transcend any differences you perceive between trafo/caps and SMPS... move on man and become 😀 rather than
Remember..... 'if it ain't broke...don't fix it !'
Best
John
Yes indeed a wonder why I am the only one with problems and I think it have something to do with the pin 5 nfatal
Thank you very much but I hate SMPS. Maybe I have to send them back to check evrything is ok.
JUst heard it playing. I soldered a lead from the start of the gnd to the cabinet. It is playing but the sound goes of and on !
Will take the gnd from the starpoint to the gnd by the xlr maybe that fix all.
Very special this modules.
Will take the gnd from the starpoint to the gnd by the xlr maybe that fix all.
Very special this modules.
i'm not using rca connectors
No, but it might still be worth trying with a 47K resistor.
Yes indeed a wonder why I am the only one with problems and I think it have something to do with the pin 5 nfatal
How about measuring the voltage on pin 5 to see if the amplifier is asserting it?
Thank you very much but I hate SMPS.
We understand that that is your personal choice and fobia - no prob. The nc400 should also work with a linear supply, but perhaps not as well (assuming your power supply is not tightly regulated).
JUst heard it playing. I soldered a lead from the start of the gnd to the cabinet. It is playing but the sound goes of and on !
Will take the gnd from the starpoint to the gnd by the xlr maybe that fix all.
Very special this modules.
NO the same problem. I wrote to Hypex and asked if it is possible to use it without the SMPS.
Looks like they are on vacation.
Like I already mentioned i'm not much of an electronics guy so I don't know much about this stuff.
Is there a certain wattage I would need to get. Also where would it attach? "Across the input" may be enough for somebody more knowledgeable but I have no idea.
Is there a certain wattage I would need to get. Also where would it attach? "Across the input" may be enough for somebody more knowledgeable but I have no idea.
Will take the gnd from the starpoint to the gnd by the xlr maybe that fix all.
Starpoint? Are you doing one of those "all ground leads into one central point" kind of layouts?
Very special this modules.
They are - unbelievably good sound! 🙂
Erlend Sæterdal;2970000 Thank you very much but I hate SMPS. [/QUOTE said:that is an attitude that this amp and power supply should help dispel.
I have been a skeptic concerning switched mode psu in the past, for good reasons. They are now a pretty mature technology that can give good results. This supply is a good rendition of a well done smps.
one of the reasons I ordered these amps with the smps was to hear an amp with what was purported to be a well designed switched mode supply.
The sound of this amp with the smps is very solid and dynamic. No reason not to use the smps. I would expect that in fact that it sounds better than a linear power supply in this application.
Alan Garren
that is an attitude that this amp and power supply should help dispel.
I have been a skeptic concerning switched mode psu in the past, for good reasons. They are now a pretty mature technology that can give good results. This supply is a good rendition of a well done smps.
one of the reasons I ordered these amps with the smps was to hear an amp with what was purported to be a well designed switched mode supply.
The sound of this amp with the smps is very solid and dynamic. No reason not to use the smps. I would expect that in fact that it sounds better than a linear power supply in this application.
Alan Garren
Maybe you are right but earlier I could always hear a smps even if it was not used for the stereo.
Also I wish to sell this empty cabinets with powersupplys for my friend. I must have something for my work ! 😀
Starpoint? Are you doing one of those "all ground leads into one central point" kind of layouts?
They are - unbelievably good sound! 🙂
When I hear them play they sound really good. Right now they do not play at all again ?

I can measure both ac and dc on pin 5 leadout. It is not constant.
I wish they would answer from the support .
I can measure both ac and dc on pin 5 leadout. It is not constant.
Hmm. Tell us more - how much does it vary, and how rapidly? Randomly, or back and forth between two different levels?
Hmm. Tell us more - how much does it vary, and how rapidly? Randomly, or back and forth between two different levels?
Took some other measurement leads. Now its almost constant. No sound but when I turn it of , it plays for a few seconds !
Overvoltage protection thats not properly adjusted ?
- Status
- Not open for further replies.
- Home
- Amplifiers
- Class D
- Hypex Ncore