I am considering using 4 x Ncore modules to power the tweeters and mid range drivers in my Linkwitz Orions, I already have 2 x Ucd400s driving the 4 10" Peerless LF drivers and am now thinking about replacing the AKSA Nivarna amps that I built 8 or so yrs ago.
I need to know what is the BEST PS option for driving those 4 Ncore modules in this situation. The Tweeter Ncore modules will probably be used to drive the pairs, in Parallel, of Seas drivers that the Orion uses.
cannot work out if I need SMPS, or traditional Linear PS, or if it does not matter with the Ncore...
cheers in advance.
Brad
I need to know what is the BEST PS option for driving those 4 Ncore modules in this situation. The Tweeter Ncore modules will probably be used to drive the pairs, in Parallel, of Seas drivers that the Orion uses.
cannot work out if I need SMPS, or traditional Linear PS, or if it does not matter with the Ncore...
cheers in advance.
Brad
Hello,
In this configuration and if the NCore is connected to chassis GND too, as it will be the case mostly I believe, the double connection of the input shield will allow two current paths, one of them through the shield. This one will produce unnecessary shield induced EMI as Bruno described many posts before. I would connect the shield at one side only instead, at the input GND in this case.
Any strips of the shield act as antennas as I experience at the physics equipment at work very often. So the best shield connection should be to solder it directly to the board allowing only the shortest free legs (possibly not easy for the NCore assembly).
Cheers, Timo
In this configuration and if the NCore is connected to chassis GND too, as it will be the case mostly I believe, the double connection of the input shield will allow two current paths, one of them through the shield. This one will produce unnecessary shield induced EMI as Bruno described many posts before. I would connect the shield at one side only instead, at the input GND in this case.
Any strips of the shield act as antennas as I experience at the physics equipment at work very often. So the best shield connection should be to solder it directly to the board allowing only the shortest free legs (possibly not easy for the NCore assembly).
Cheers, Timo
Nice question for Hypex. The thread is in the Vendor's Bazaar after all.....
Where are you Hypex guys? Not enjoying Chinese New Year do you??
That would at least contradict the wiring instructions, and in general, would violate the class 2 appliance regulations.
It would mean that the enclosure everybody is bolting his ncore;s to is directly linked to power ground. If you connect that to mains earth, you could run into issues. That, and if you connect two ncore's with 2 smps'es, you'd have to be pretty sure that the smps'es would deliver exactly the same voltages.
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''I need to know what is the BEST PS option for driving those 4 Ncore modules in this situation. The Tweeter Ncore modules will probably be used to drive the pairs, in Parallel, of Seas drivers that the Orion uses.
cannot work out if I need SMPS, or traditional Linear PS, or if it does not matter with the Ncore...''
Brad, I would drive each side tweeters/mid-woofer with one PS. I believe to obtain optimal results out of the NCores, SMPS600 should be used.
Please let us know how your Orion's perform with the NCores.
Jacq.
cannot work out if I need SMPS, or traditional Linear PS, or if it does not matter with the Ncore...''
Brad, I would drive each side tweeters/mid-woofer with one PS. I believe to obtain optimal results out of the NCores, SMPS600 should be used.
Please let us know how your Orion's perform with the NCores.
Jacq.
Attachments
Hello,
Bruno clarified it already:
Cheers, Timo
edit:
It would be nice to have a hint for that in the datasheet, at least I did not find any. Thanks!
Bruno clarified it already:
Cheers, Timo
edit:
It would be nice to have a hint for that in the datasheet, at least I did not find any. Thanks!
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nCore datasheet says it has CM input impedance of 1.5Mohm and DM input impedance of 104kohm. Any idea what those CM and DM mean? CM is "Common Mode"? Does that mean the input AC coupling caps could be optimized for that impedance value, which would mean around 50nf caps (-3db at 2hz). With the DM impedance the caps would be 770nf.
Which way to go?
And how much does those caps color sound, say 1uf vs 50nf? By that i mean measurable differences, not subjective experience of bee wax caps etc. Worth the optimization?
Which way to go?
And how much does those caps color sound, say 1uf vs 50nf? By that i mean measurable differences, not subjective experience of bee wax caps etc. Worth the optimization?
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The differential-mode impedance is the real load impedance that the amp module presents to the balanced input signal, so your ac coupling caps need to be sized to work into this load.
The common-mode impedance is the load presented by the module if you were to tie the two input leads together and apply an ac signal w.r.t. 0V. Basically, the higher the CM impedance is, the better.
The common-mode impedance is the load presented by the module if you were to tie the two input leads together and apply an ac signal w.r.t. 0V. Basically, the higher the CM impedance is, the better.
Thanks! So some ~1uf caps that works well in audio bandwidth would be just fine then.
edit: I got some 2.2uf 50V Wimas available, would those color the audio too much? I would like to know, that what is worth the trouble and what is the relation between capacitor value and undesirable distortion? What is "too much" if the "optimal" (-3db @ 2hz) is 770uf?
edit: I got some 2.2uf 50V Wimas available, would those color the audio too much? I would like to know, that what is worth the trouble and what is the relation between capacitor value and undesirable distortion? What is "too much" if the "optimal" (-3db @ 2hz) is 770uf?
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Input impedance?
Is the 104 kohms per phase:
+ to ground=104 Kohms and - to ground also=104 Kohms?
or is it:
+ to ground=52 Kohms and - to ground=52 Kohms
My source is cap coupled, it is more affordable to go with smaller caps, and since one needs four of them for balanced, the price difference between 4 x 1 uF and 4 x 1.5 uF can be significant. 1 uF would be sufficient for 104Kohms per phase input impedance.
Is the 104 kohms per phase:
+ to ground=104 Kohms and - to ground also=104 Kohms?
or is it:
+ to ground=52 Kohms and - to ground=52 Kohms
My source is cap coupled, it is more affordable to go with smaller caps, and since one needs four of them for balanced, the price difference between 4 x 1 uF and 4 x 1.5 uF can be significant. 1 uF would be sufficient for 104Kohms per phase input impedance.
Given that the CM impedance is much higher than the DM impedance, then you can forget about the impedance to 0V and simply consider that there is an effective 104k between the + input and the - input. If you are runnning this with an unbalanced source, then you will simply be connecting either the + or - input to 0V and feed your signal into the other, depending on whether you want the amp to be inverting or non-inverting.
It does not hurt to have plan B sorted, if I'll run into problems with Legato 3.1 + nCore combo after all. And i am tempted to compare the sound with and without the caps. It's DIY after all.
No problems with the Legato so far?
A word of caution to fellow (semi-)noobs: if you power on the smps600 without it being connected to the nc400, then power it off and disconnect the ac cord, and then connect the nc400 module to the smps, you will see sparks and hear loud bangs when the connector touches the pins. So by trying to be as careful as possible, I pretty much caused the modules to explode. At least the Hypex support people seem to be helpful.
Is it common knowledge that this procedure will cause your expensive new smps to kill the ncore?
Is it common knowledge that this procedure will cause your expensive new smps to kill the ncore?
Neither. You don't reference a differential/balanced input to ground - except when you are discussing common mode noise.
So the signal input impedance is 100 Kohm. The common mode impedance to ground is > 1Mohm.
Thanks for the warning and i'am sorry for your loss. I don't know about common knowledge, but so far i have taken the 10 minute rule after powering off the smps seriously. Semi-noob DIYer that i am and without better knowledge, i need to do that.
From SMPS-600 manual:
"Disconnect the unit from the mains and allow all capacitors to discharge for 10 minutes before handling it."
if it does that even after 10 minutes, then its a different story.
3lviz: yeah I saw that too, but at first I just thought it meant that you should wait before touching it, not that you couldn't connect it for that time period. And anyway I waited about 3 hours before connecting again, and some sparks appeared again, so that wouldn't have saved me anyway.
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