To get lower DSP load I made new setup with 48 kHz sampling, but get other problem with it. Seems Najda asynchronous sampling rate converter is not very asynchronous.
48 kHz setup works correctly only with 48 kHz SPDIF input, with 44k or 96k I get strange holes. Measurements made 1m from speaker, brown is 48k signal blue is 44k. Fall on 20 kHz is because mic was not perfectly on axis.
With old 96kHz sampling setup I have not seen this kind of holes.
48 kHz setup works correctly only with 48 kHz SPDIF input, with 44k or 96k I get strange holes. Measurements made 1m from speaker, brown is 48k signal blue is 44k. Fall on 20 kHz is because mic was not perfectly on axis.
With old 96kHz sampling setup I have not seen this kind of holes.
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I have a similar (?) problem on one of the Najda channels, when doing a measurement sweep there is clear aliasing or clipping problem at around 10 kHz as I remember it resulting in a deep dip in measured response. It is wery audible when playing the shirp but I can't say that I have heard any problem when playing music. It sounds like the normal sweep up to around 10k and then some Tj Tj Tj Tj sounds, continued by the end of the sweep.
I made more measurements with 48 kHz sample setup. With 44, 88 and 96 kHz sampled signal I get similar problems and yes, it is some kind of aliasing. It is not visible on measurement graphs but clearly understandable with sweep signal by ears.
I have also had the same problem. I noticed that it was possible to remove the problem by switching the setup file and then rereading the one I was using. At some point, I also was able to deal with the problem by shooting down one of the channels.
I have not however been able to reproduce those so the problem seems to be random.
My Najda is boxed and so built by WAF. I have the USB in card aslo original fit.
I have not however been able to reproduce those so the problem seems to be random.
My Najda is boxed and so built by WAF. I have the USB in card aslo original fit.
If the voltages match Najda's requirements, it should be fine. I salvaged a power supply from an old Rotel DVD player and it worked fine. There might be some concerns about the noise levels on a power supply that was not designed for audio purposes, but the only way to really know if it is an issue is to try it out.Does anyone know if ant atx power supply could be used with the Najda?
Najda's power supply requires +5V 1A, +12V 1A and -12V 0,3A. Any ATX power supply will do this even the original IBM PC. But to be sure check out this link.
http://gcctech.org/cec/powersupply/All about the various PC power supply cables and connectors.htm
I think much of the talk about noisy power supplies goes back to the era when we did build all amplifiers from discrete components. The noise-rejecting circuits were not at the same level as in today's circuits.
There are several YouTube videos where it has been shown that the noise from switching power supplies is negligible.
But I understand the HiFi need for perfect components so everybody must choose his or her own level of commitment to the perfect sound.
http://gcctech.org/cec/powersupply/All about the various PC power supply cables and connectors.htm
I think much of the talk about noisy power supplies goes back to the era when we did build all amplifiers from discrete components. The noise-rejecting circuits were not at the same level as in today's circuits.
There are several YouTube videos where it has been shown that the noise from switching power supplies is negligible.
But I understand the HiFi need for perfect components so everybody must choose his or her own level of commitment to the perfect sound.
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Another dumb question. I was about to purchase some hypex ucd250 modules for a multichannel amp to use with the Nadja.
I just read that they need an input buffer and the input sensitivity is about 6.5v. Does this mean I can't connect them directly to the Nadja? From what I read it can deliver up to 6v output or is this unrelated?
I just read that they need an input buffer and the input sensitivity is about 6.5v. Does this mean I can't connect them directly to the Nadja? From what I read it can deliver up to 6v output or is this unrelated?
Don't know if CS3318 is directly fed to output or some kind of output stage is in place in Najda. Lowest load for CS is 2k ohm and hypex ucd250 is 1.8k ohm so it's lower. So some buffer may be needed if CS is directly fed to output. If not then it will depend how this output stage looks like.
Below 2k distortion will rise and CS may heat bit more, probably it will not damage but for sure it's not optimal. Evening I could measure resistance from CS output to RCA socket. This could tell us if there is anything on cs output that could help with low hypex ucd250 input impedance.
Looks line in series it's only 47 ohm and CS is already loaded with 4,7k inside of Najda so I would not connect anything with lower input impedance then that.
I would say you need a buffer in front of those hypex ucd250, even simple one.
I would say you need a buffer in front of those hypex ucd250, even simple one.
Thanks, any idea if any of these will do the job?
https://www.ebay.com.au/itm/173381402996
https://www.ebay.com.au/itm/184207154688
https://www.ebay.com.au/itm/185385405285
I really appreciate your input, I haven't got a clue. Thankyou.
https://www.ebay.com.au/itm/173381402996
https://www.ebay.com.au/itm/184207154688
https://www.ebay.com.au/itm/185385405285
I really appreciate your input, I haven't got a clue. Thankyou.
Anyone want to buy a broken nadja board? I connected the 5v power backwards last night, fried the little input choke from what I can tell.
Did the same thing some time ago. You can easily fix it.. You needs this or similar
Murata LQH43MN220K03L
https://www.mouser.pl/ProductDetail/Murata-Electronics/LQH43MN220K03L?qs=rMxjHOpQ3awDvVQWZYQ/QQ==
Probably all those buffets will work fine.
Murata LQH43MN220K03L
https://www.mouser.pl/ProductDetail/Murata-Electronics/LQH43MN220K03L?qs=rMxjHOpQ3awDvVQWZYQ/QQ==
Probably all those buffets will work fine.
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If you fix it, Hypex make their own evaluation board which includes a buffer and faston breakout board too. The buffer is basic but it would solve the problem.
https://www.hypex.nl/product/nc500-evaluation-board/51
https://www.hypex.nl/product/nc500-evaluation-board/51
Thanks guys, I have ordered the part, hopefully fixes the issue.
Has anyone got the original pcb layout sheet with pin numbers and polarity? I have lost mine somewhere.
Has anyone got the original pcb layout sheet with pin numbers and polarity? I have lost mine somewhere.
I too did the 5v +/- wrong way around thing a few years back.
There was no way back for that Najda board.
The first red board Najda's, didn't have the polarity markings as clear as the later boards.
Good luck and keep us posted.
There was no way back for that Najda board.
The first red board Najda's, didn't have the polarity markings as clear as the later boards.
Good luck and keep us posted.
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