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How to solve aliasing noise - converter Digital Converters
Old 8th April 2018
  #31
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KIDBILL's Avatar
 

Thread Starter
Results at 192khz
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How to solve aliasing noise - converter-line-left-36db-gain-192khz.jpg   How to solve aliasing noise - converter-line-right-36db-gain-192khz.jpg   How to solve aliasing noise - converter-bal-out-left-line-right-36db-gain-192khz.jpg   How to solve aliasing noise - converter-bal-out-right-line-right-36db-gain-192khz.jpg  
Old 8th April 2018
  #32
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stinkyfingers's Avatar
 

i checked out the 192 kHz file with and noticed that the level of DC to be the highest (0 Hz @ approx. -74.5 dBFS) , followed by (approx) 5,255.7 Hz and then 93,372 Hz.

these are some of the rough frequencies (Hz) for 3 major "clusters" (patterns) i saw...

49.98
149.97
249.95
449.92
640.94

1,459.5
2,919
4,377.5
========5,255.7
5,837.4
6,946.7
8,753.5

67,094
72,348
77,605
82,861
88,116
93,372

i used iZotope RX5 for the analyzer/frequencies, which has a demo (newer version) if you wanted to check it out. normally i use Span but the RX analyzer is nice when you need higher resolution and/or a different window or scale.

here's a screenshot of what i found > https://i.imgur.com/1p7La4f.png

don't know if any of that helps but thought i would share what i had.

Last edited by stinkyfingers; 8th April 2018 at 07:50 PM..
Old 10th April 2018
  #33
Here for the gear
 

Quote:
Originally Posted by KIDBILL View Post
Here's how sound like my problem
Sorry if it was mentioned already. Have you tried to reset the JCF converter? We recently had a similar issue with Avid Native and resetting the unit helped to resolve it.
Have you tried to take the JCF to a different place (not in your studio)? Does it produce the same noise there?
Old 11th April 2018
  #34
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jrasia's Avatar
Open up almost any JCF unit and you will notice tons of flux residue all over the pcb boards. I'm sure it's a no clean type flux, but even most no clean fluxes need some cleaning. Especially when dealing with ad da converters. Total pain in the arse but a lot of the weird digital noises mentioned above drastically dropped after I cleaned my ad8s.
Old 11th April 2018
  #35
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jrasia's Avatar
Oh, and turn off any CPU throttling, power saving modes in your computers BIOS. That has a big effect on PCI/pcie interface cards in regards to noise.
Old 11th April 2018
  #36
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Quote:
So I guess I should try another aes ebu interface, maybe it comes from the Lynx Aes16e
As I wrote before it's very unlike to me, that transformer isolated AES I/O would pass such noise into the converter, nor that some specific digital source could create particular buzz.

You could try that of course, I'd bet, it won't change anything.
Well if you really like to test something different and possibly prove it has nothing with digital source, then you can connect some audio interface via Latte digital optical I/O (SPDIF).. there will be total galvanic isolation.

...
Quote:
Originally Posted by jrasia View Post
Oh, and turn off any CPU throttling, power saving modes in your computers BIOS. That has a big effect on PCI/pcie interface cards in regards to noise.
I wouldn't talk about a big effect there.
We're talking about supposedly professional digitally connected external converter, which is connected via transformer isolated AES I/O. This isn't $15 internal Soundblaster like card with converters in the box. And even in this case, it would be rather rare, that it would cause described issues.
Throttling and CPU powersaving might affect other aspects like low latency performance with short buffers, or there will be some periodic clicks, but not analogue noise.

Quote:
Originally Posted by KIDBILL View Post
I just talked to a mastering studio working with the Latte and he got the same noise issue, and there's balanced and filtered power supply in his studio...
Anyway did you have some further call with JCF about that? Did they tell you anything besides nonsense with aliasing. Can they approve, that unit is working well according to your idle recordings and FFT plots?
However when another studio has facing exactly the same issue, it's either common HW fault (not so sure about that) or simply attribute of that design.

Some own further serious analysis and step by step elimination is IMO/IME very hard to do without some lab like environment with further tools and some solid measurement devices (like dual domain AP audio analyzer). It's possible, some skillful audio tech/engineer could at least find the culprit and improve that. However unless you have some good friend, who can do that just for you and his technical challenge/curiosity , it could cost you some money..
Question it's then, whether it will be worth of effort to do some tweaks/mods here.. if that really cause you audible issues at your workflow and vendor will remain confident, it's normal, then simply return/sell the converter and look for something else in that vein (I don't know - Burl stereo AD and DA).

Michal
Old 23rd April 2018
  #37
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Thread Starter
Quote:
Originally Posted by jrasia View Post
Open up almost any JCF unit and you will notice tons of flux residue all over the pcb boards. I'm sure it's a no clean type flux, but even most no clean fluxes need some cleaning. Especially when dealing with ad da converters. Total pain in the arse but a lot of the weird digital noises mentioned above drastically dropped after I cleaned my ad8s.
Wow seriously?
It feels weird for me to buy a 7200$ device and have to clean the pcbs!
Old 24th April 2018
  #38
Lavry said, not need to pass 96 Khz,
Lynx 16E Syncr lock off...
too many, new beta test companies out there?
Old 9th June 2018
  #39
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KIDBILL's Avatar
 

Thread Starter
Old 10th June 2018
  #40
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Hi KIDBILL,

I see, that you've decided to sell it back with some loss back to your dealer. And it's nice by him, that he made this possible.

As I've expressed, whole vendor reasoning and replies according to your description, is rather strange and doesn't make much sense to me.
Maybe he's otherwise fine guy, who has some complicated moment.. who knows .
Nowadays, when internet or global sales are rather common and such kind of support inquiries might be also common, is quite weird, he doesn't have prepared or doesn't come with some basic steps, how to setup the device into some common initial state (levels, internal setup) and obtain comparable FFT plot using some readily available software analyzer. That way it's possible to see idle noisefloor and spectrum. When one would find, it's right (eg. up to specs), it's possible to make loopback form its D/A part with software signal generator.. again such basic check whether it's working at intended ballpark before shipping back to vendor is very useful. Even if end user couldn't do that according to guide (unlikely), your dealer should be competent enough to make that happen.
Of course, if you'd like to fix possibly faulty device or at least further isolate the issue to some component, you'd need a technician and other lab gear, but that's IMO the next step.

Anyway good luck with your other converter.

Michal
Old 10th June 2018
  #41
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Indeed Michal, that's what I thought.
It was borderline disrespectful to me, especially considering the price of the unit.
I was not buying a berhinger soundcard, and I'm sure berhinger support would have been better.
When this guy, told me he wouldn't even reply me anymore that was kind of crazy feeling...
Dave Hill told me this converter is a high jitter one
Nice to breath again!
Thanks!
Old 10th June 2018
  #42
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the fxs's Avatar
 

what a shame. i have been drooling over the JFC LATTE many times, well, no more it seems.
Old 4 weeks ago
  #43
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KIDBILL's Avatar
 

Thread Starter
Switched to old UA 2192...
Absolutely no hiss and no digital noise using exact same setup!

The Latte was hissing a lot too

JCF audio was ruining my audio life! not anymore!!

Last edited by KIDBILL; 4 weeks ago at 03:24 AM..
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