When the preamp has an output cap why put another one at the input of the power amp?
Capacitors are evilso avoid them when possible.
i thought it haven`t.
if it does no need for another one.
I am a bit confused with the AC coupling cap thing and common DC support on nc400. Well, i have DAC with balanced out that produces common DC between "+" vs "gnd" and "-" vs "gnd" and no caps in the output (namely Buffalo II Dac with Legato 3.1 output stage). Ok, that might be a problem with nc400, i get it.
BUT, if you look at the nc400 datasheet, there is the optimum setup for XLR input, where the input signal gnd is not even connected. To my logic that would make the problem go away. Right?
Have people who are worried about this not read the nc400 datasheet? Or is there still problem with the common DC in the XLR input?
BUT, if you look at the nc400 datasheet, there is the optimum setup for XLR input, where the input signal gnd is not even connected. To my logic that would make the problem go away. Right?
Have people who are worried about this not read the nc400 datasheet? Or is there still problem with the common DC in the XLR input?
Moi!
Even if common-mode DC is pretty well rejected, you might still have a differential DC offset...
Even if common-mode DC is pretty well rejected, you might still have a differential DC offset...
Ok. right. Some output stage implementations have that as well. That answered my question. Thanks!
That will be something very small with Legato 3.1's. Something like 0.00X - 0.01V (+- voltage meter error). That should be quite ok?
I got custom Arduino based system that controls the volume from the DAC chip itself, using i2c control registers. No pots.
edit/add: If the volume control is before the output stage is the possible 0.01V differerential common DC already a problem?
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No idea, but since the thread is in the Vendor's Bazaar now I expect one of the guys of Hypex to pop in to answer that question.
I had trouble with getting my legato 3.1 balanced outs to work with NC400. The problem was that I connected the nAMPON to chassis ground and the SMPS was not grounded to chassis.
So the XLR ground which is the ground that comes from the legato, (which also becomes the part of the hypex SMPS600 ground) was not sharing the same ground as the nAMPON so it didnt turn on the AMP.
I have about 8.8volts DC from + and - to GND from the legato 3.1, and it doesnt seems to be a problem for the NC400 so far (i havent have time to test it thoroughly yet thought).
I tried to connect the legato 3.1 to the NC400 without using XLR ground from the legato and that resulted in some NASTY noise. Probably because the NC400/SMPS600 isnt grounded to chassis/ common power ground.
This ground thing is so confusing..
The AES48 standard tries to clear things up and they state the XLR ground/should be a part of the chassis ground on both sides, but it all depends on the makers of the equipment on how they use chassis ground, audio ground and common power ground..
http://www.rane.com/pdf/ranenotes/Sound System Interconnection.pdf
So the XLR ground which is the ground that comes from the legato, (which also becomes the part of the hypex SMPS600 ground) was not sharing the same ground as the nAMPON so it didnt turn on the AMP.
I have about 8.8volts DC from + and - to GND from the legato 3.1, and it doesnt seems to be a problem for the NC400 so far (i havent have time to test it thoroughly yet thought).
I tried to connect the legato 3.1 to the NC400 without using XLR ground from the legato and that resulted in some NASTY noise. Probably because the NC400/SMPS600 isnt grounded to chassis/ common power ground.
This ground thing is so confusing..
The AES48 standard tries to clear things up and they state the XLR ground/should be a part of the chassis ground on both sides, but it all depends on the makers of the equipment on how they use chassis ground, audio ground and common power ground..
http://www.rane.com/pdf/ranenotes/Sound System Interconnection.pdf
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True, but I do recall JBL recommended a small cap in series with their horns even in a fully active system.
No, GND goes through from source. Both source and input GND is connected to the chassis. The recommended balanced setup is shown below, and my green arrows show where the chassi GND connections are.
Attachments
You're right. Apparently everyone has read the datasheet and with better eyes.
Did i get this right? You connected nAMPON (which i assume is the amp enable wire) appropriately to the amp module and then connected one corner hole (the "improve EMI performance" screw hole) of the SMPS600 to the chassis? Or how did you ground the SMPS?
Passive volume controls
Has anybody tried any of the opto-volume controls such as this: P&S TECHNOLOGIES INC.
with the Hypex modules? From what I have been reading, this type is the very best available as far as passive control goes. I'm thinking about buying the balanced kit 4 version and making a integrated amp with my ncores now. With this system it's also possible to use a jumper cable between amps to control the volume of several amps with the same remote, via the control panel in the main amp. That would be great for active systems.
Has anybody tried any of the opto-volume controls such as this: P&S TECHNOLOGIES INC.
with the Hypex modules? From what I have been reading, this type is the very best available as far as passive control goes. I'm thinking about buying the balanced kit 4 version and making a integrated amp with my ncores now. With this system it's also possible to use a jumper cable between amps to control the volume of several amps with the same remote, via the control panel in the main amp. That would be great for active systems.
There is already a fuse on the SMPS, so there is no need for an additional one....
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