hypex ncore

[Julf]

Originally Posted by Audioschipper

Maybe it is not the best wáy to switch on the nCore but given the fact that it also 'tics' when I mute the Marantz pre, it shouldn't make a difference I guess?

Do you also get the tic when leaving the nCores on, and turning off/muting the Marantz (so with the remote control cable between the Marantz and the nCores disconnected)? Would you happen to have a 12V relay handy to try a temporary test circuit to use SMPS standby instead of the Hypex softstart module?

(edit: I realize the Marantz control output can only drive 150 mA, but that should still be enough for a small-signal relay)

[3lviz]

Originally Posted by lm1no2

Hi, my NCore, excellent sound.
Only one question: Does connection between case and ground is correct, the green wire.

Look at nc400 datasheet again: "Figure 2: Preferred connection". There is no connection from IEC ground to chassis. Also, check that XLR pin 1 is connected straight to the chassis and also the signal ground from the module should be also connected to the chassis. I did not see those chassis connections in your build.

[3lviz]

If I have removed the R141 from NC-400 (and would like to keep it that way), is it possible to match the gain of UCD-400 with the NC-400? That is with UCD-400HG HxR powered by SMPS400 and NC-400 powered by SMPS600.

gain_nc = 4.17*(1+2*Rf_nc/Rg_nc)
gain_ucd = 4.5*(1+2*Rf_ucd/Rg_ucd)

gain_ucd = gain_nc
4.5*(1+2*Rf_ucd/Rg_ucd) = 4.17*(1+2*Rf_nc/Rg_nc)

R141 removed, so
rg_nc = infinity

=> 4.5*(1 + 2 * Rf_ucd / Rg_ucd) = 4.17
<=> Rf_ucd / Rg_ucd = (4.17 / 4.5 - 1) / 2
=>Rf_ucd / Rg_ucd = -0,03666...

=> no can do but it is very close to 0.

SO,

Does this mean that if i set rg_ucd=infinity (remove the R3 altogether) difference in gain will be very negligible and close enough to bi-amp UCD-400HG with NC-400 with R141 removed?

Does that -0.0366 somehow describe the 0.2dB difference in overall gain according to datasheets?

[analog_sa]

Originally Posted by ChrisPa

Go and have a look at Bruno's papers on Class D design - you should find it answered there
and it's probably fair to assume that subsequent designs have tried to improve upon performance from his original papers

Fair to assume? With hundreds out in the field no one has ever hooked a scope to the output???

[Julf]

Originally Posted by 3lviz

Does that -0.0366 somehow describe the 0.2dB difference in overall gain according to datasheets?

Well, the gain ratio is actually 1.0791366906 (4.5/4.17) - so 0.7 dB. Anyway, still not a big difference.

[3lviz]

Originally Posted by Julf

Well, the gain ratio is actually 1.0791366906 (4.5/4.17) - so 0.7 dB. Anyway, still not a big difference.

Right...thanks! No, that is not a big difference.

[Julf]

Originally Posted by analog_sa

Fair to assume? With hundreds out in the field no one has ever hooked a scope to the output???

More than happy to do it next time I have my amp up on the workshop desk.

[Corpius]

Originally Posted by Audioschipper

Maybe it is not the best wáy to switch on the nCore but given the fact that it also 'tics' when I mute the Marantz pre, it shouldn't make a difference I guess?

Hi Audioschipper,

At the moment i'm switching the amps on with the power switch at the IEC power inlet. Because I positioned my amps and other audio gear different in my audio rack it is now a bit hard to reach. Therefore I designed a simple circuit that detects the incomming line signal and then switched on the amps. It also switched off the amps when there is no signal for about 15 minutes.

I got the schematics from Elliott Sound Products and designed a little pcb myself using his schematics. I just received the pcb's and soldered the components to it this afternoon. I'll build it soon into my amps and see how this works out. Perhaps this is also a nice solution for you? Because I had to order 10 pcs I have some pcb's left

[jlaakso]

Originally Posted by Corpius

Hi Audioschipper,

At the moment i'm switching the amps on with the power switch at the IEC power inlet. Because I positioned my amps and other audio gear different in my audio rack it is now a bit hard to reach. Therefore I designed a simple circuit that detects the incomming line signal and then switched on the amps. It also switched off the amps when there is no signal for about 15 minutes.

I got the schematics from Elliott Sound Products and designed a little pcb myself using his schematics. I just received the pcb's and soldered the components to it this afternoon. I'll build it soon into my amps and see how this works out. Perhaps this is also a nice solution for you? Because I had to order 10 pcs I have some pcb's left

Does that mute the amps (nAmpon) or switch the psu to standby? This would be very useful for lot of people, at least me If I ever get to build these, that is.

[cab]

nampon puts the amp into standby, not the power supply. To put the smps in standby, you need an external signal to pin 1 of the J1 header of the smps.