NCD1 problems: No blue led blinking at startup

[wtfaidh]

Sorry to read about your misfortune...

Mine runs for over a year now and sometimes at it's max power using dual-mono setup and 2x1000va transformators. No sweat whatsoever

Unfortunetely I have no suggestions
Good luck next time, or do you call it a Day ?

Eric.

[Sharkythefrog]

This is how it is all setup - after making a drawing that has been sent to Lars.

230V AC ground is connected to the case. The power supplies and the NCD modules are mounted on aluminum plates that are NOT in electrical contact with the case. The XLR input contacts are in electrical contact with the case, the RCA input and the speaker outlets are NOT.

As far as I can see everything is connected as it should according to the cookbook, the power supply has 56,5V+ to Gnd, 56,5V+ to Gnd, and 37,5V from Vgate to Gnd.

The GND are all connected together on the RCA input L, XLR L, XLR R and RCA R, and are also connected to "chassi GND" on XLR L and XLR R as well as to input GND on both modules.

Measurements gives as follows on speaker outlets with low-medium listening volume from Mp3 AC=0,4V, from unbalanced PC-card=0,8V, balanced=0,8V. DC from Mp3=0.03V, unbalanced PC-card=0,04V, balanced=0,04V.

Measures on unbalanced input terminal=0,0002V DC, unmesaurable AC (lower than internal variations of instrument)

Thats about it - only one channel measured as the other one is dead....

[Sharkythefrog]

More info:

The difference in ground between PC-chassi=signal-gnd (as there is no difference betwwen them) and ground (on external gnd-contact) on the soundcard is 0,15 Ohm. Not much :-)

[Sharkythefrog]

I don´t know this will turn out, or which steps that will be involved but I´m not giving up. The sound from the amp is far to good not to try to repare and correct the problems to.

Maybe the NCD1 needs adjustement on the input side to be able to handle certain soundcards? This E-MU 1616M is a proffesional soundcard used everywhere in smaller studios etc so it should be fairly good electrical wise.

Or maybe the NCDX has a better chance of adapting to PCs etc????

[Thzar]

Holysmoke

That Vgatevoltage seems little to high?

I dont know the maximum limit but Lars have set it to 20vdc.

[Sharkythefrog]

If the Vgate should be max 20VDC and I´m using the standard NewclassD power supply one wonder how that can be?

The colours on the four trafo wires are not the usual standard ones but I have measured:
42V between Yellow&Red,
42V between Grey&Blue
31V between Yellow&Blue
48V between Grey&Red
5V between Yellow&Grey
5V between Blue&Red

I also measure 0 Ohm between Yellow&Red, as well as between Blue&Grey when the power is off, and Full resistance between all the other combinations.

So I put Yellow at pin 1, Red on 2, Grey on 3 and Blue on 4 on the power supply. I hope this is the right way?!?!?

[Workhorse]

Cookbook cooked you all

Nice recipe from Lars.........!!!

Have a good day

[Thzar]

Only use the 2x42 wires, skip the rest.
The vgate gets its voltage from a built in vreg on the 4wire NCD power supply

[Sharkythefrog]

The Vgate should according to Lars be measured between V- and Vgate. Doing so I get 18,6VDC.

So once again. Everything is OK but it still wreckes! ! ! !

ANY suggestions???????????????

[teflon1]

I know you won't believe this because each module goes through Lars' infamous testing procedure, but it sounds like you have a defective pair.

Try usingp liars to pull on the magnet wire of the filter coil hard enough to slightly deflect the PCB to ensure it's properly soldered. Do both ends and both modules.

You may find a dry socket. No, this MCU isn't smart enough to leave the amps off upon a critical fault so it will just keep hammering your speakers until they pop, but I guess you know that now. Didn't save the module either hm wow that's interesting wonder why.

Failing that perhaps you should try the 627 input stage as it seems to cure all other ailments.