Computer noise through system and RME ADI-2 Pro Questions

[Holmz]

I am not trying to use the ipad/MBP as a source.
I want to input analogue into the RME and capture the music to a digital file.

Just because my location is listed as Australia, it not very gentlemanly (or lady like) to suggest criminal bahviour.

 

[Wicky]

Just because my location is listed as Australia, it not very gentlemanly (or lady like) to suggest criminal bahviour.

Crims, each and every one
A Kiwi

 

[Holmz]

Crims, each and every one
A Kiwi

Being in the antipodes does not mean we should be trampled on.

 

[AnalogSteph]

The RME’s analogue level went from -45-50 dB(FS) to about -80 dB(FS).

That's the volume setting displayed, right? While the ADI-2 Pro can output about 16 dB more than an unbalanced consumer source, this still suggests that you have rather too much gain following it. Is the volume on the preamp cranked up all the way by any chance?

Since the RME easily passes as preamp grade, you may want to consider turning the setup on its head, running the ADI-2 Pro into the power amp directly and recording the preamp's recording output as needed.

 

[Dilettante]

@Holmz , does your noise sound similar to one I have attached to this post: https://www.audiosciencereview.com/forum/index.php?threads/usb-bus-noise.34694/ ?

 

[Holmz]

@Holmz , does your noise sound similar to one I have attached to this post: https://www.audiosciencereview.com/forum/index.php?threads/usb-bus-noise.34694/ ?

Yeah pretty much like that.

 

[Dilettante]

Hmm... Can you measure VAC off the wall socket? I wonder if our network has anything to do with it.

 

[Holmz]

That's the volume setting displayed, right? While the ADI-2 Pro can output about 16 dB more than an unbalanced consumer source, this still suggests that you have rather too much gain following it. Is the volume on the preamp cranked up all the way by any chance?
…

That was at a fixed preamp volume of -20dB.
What do you mean by “Too much gain following it”?
The preamp feeds into the RME. The RME feed into the computer.
The levels were the bars that beat with the music.

…
Since the RME easily passes as preamp grade, you may want to consider turning the setup on its head, running the ADI-2 Pro into the power amp directly and recording the preamp's recording output as needed.

I am using the RME as a recorder.
If I used it as a preamp, it it would be playing and be a DAC.
But I am using it as an ADC.

 

[Holmz]

Hmm... Can you measure VAC off the wall socket? I wonder if your (edited) network has anything to do with it.

I can probably use a transformer, or a gin up a voltage divider.
And then use the RME to record the VAC.

I was trying of making up a connector to run the RME off of a battery or use a more stable power supply.
I have a decent power supply with 2 extra ports, but it says 12V/1A max….and there are 4 of those ports.
And the RME draws 2A… but I should have <=4A total in the power supply.
So I was thinking about pulling the top off the power supply to have a peek at how it is distributing the power.
If the 4 outputs are all regulated with small transistors then I will not likely try powering the RME off of it.
But the local shop was getting in a linear 12V supply.

The network is wirelessly served to the computer.

 

[threni]

Just because my location is listed as Australia, it not very gentlemanly (or lady like) to suggest criminal bahviour.

There's only one use for an adc - communism.

 

[AnalogSteph]

I am using the RME as a recorder.
If I used it as a preamp, it it would be playing and be a DAC.
But I am using it as an ADC.

Ah, now I get it.

First of all, your recording levels seem awfully low. -80 dBFS is barely anything.
How much higher does preamp volume go, does it stop at 0 dB or can it go to +16 dB or even higher? (Which model preamp is this anyway?)
The ADI-2 Pro has four different input sensitivity settings, ranging from +4 dBu all the way to +24 dBu. For recording consumer-level analog sources, I'd start out with the lowest setting and see whether you're anywhere near clipping. I'd generally expect peak levels of about -10 to -20 dBFS on vinyl... substantially more than what you've found so far in any case.

Regarding the interference, I would suggest unplugging everything from the preamp that isn't absolutely necessary for recording. If that doesn't cut it, please give us a list of the entire signal chain ahead of the ADI-2 Pro input (devices and how they're powered).

 

[Holmz]

Ah, now I get it.

First of all, your recording levels seem awfully low. -80 dBFS is barely anything.

That -80dB was without anything playing... on an unused input.
It was ~-50dB when it had the bad USB noise, on an unused input.
I am about -45dB on on phono, and there is a nasty hum.

How much higher does preamp volume go, does it stop at 0 dB or can it go to +16 dB or even higher? (Which model preamp is this anyway?)

If I turn up the preamp to -5dB then the RME's bar display shows it loading close to full-scale (closer towards clipping_
Preamp is a Nagra Jazz, and there is no dedicated line level out for a tape deck. (Which is funny if we thing about that.)
It does also have a +12dB switch.

The ADI-2 Pro has four different input sensitivity settings, ranging from +4 dBu all the way to +24 dBu. For recording consumer-level analog sources, I'd start out with the lowest setting and see whether you're anywhere near clipping. I'd generally expect peak levels of about -10 to -20 dBFS on vinyl... substantially more than what you've found so far in any case.

I set etc reference level to +4 on the analogue inputs.
When I run the preamp at -0dB I d get up there, so I just turn off the speaker amp.
On the RME Main 1/2 output it says reference is +24dB, but I cannot click on the right kets to lower that to +4 dB.

Regarding the interference, I would suggest unplugging everything from the preamp that isn't absolutely necessary for recording. If that doesn't cut it, please give us a list of the entire signal chain ahead of the ADI-2 Pro input (devices and how they're powered).

AC --> transformer ---> power strip
Powerstrip --> Nagra MPS --> Phono amp
Powerstrip --> Nagra MPS --> preamp
Powerstrip --> Mac Wall wart --> computer
Powerstrip --> RME SMPS --> RME (I am suspicious of this SMPS)
Powerstrip --> Speaker amp
Powerstrip --> Phono wart --> Phono
Powerstrip --> Mac Charger --> Mac
MacBookPro connected to RME via USB.

I suppose I can get a Lemo connector to replace the Phono wall wart, but I also have a new unit headed my way for that.

The 30dB cut to the USB noise seemed to happen with connecting the RME's XLR outputs to the preamp's XLR inputs.
My hypothesis was that make it need to be grounded to the preamp better... and I put together a 1 foot pair of XLRs and the shield is a lot of copper connected to pin-1.
Since it went way down, I think that the hypothesis was good, (Or something else happened and I got lucky,)

However there does seem to be a hefty increase in 50Hz AC hum, and a bit of increase on higher frequency noise.
I can hear the high freq noise if I tweeter whisper, but I need to rail the volume up to hear it, and with the AC on... except on the phono stage which was previously quiet.
So I guess now I am left with the addition of phono hum. I'll add a ground wire between the phono and preamp.

I cannot seem to attach a wav file...?
And I cannot find the output reference level setting.

 

[Dilettante]

I can probably use a transformer, or a gin up a voltage divider.
And then use the RME to record the VAC.

I was thinking of using true-RMS multimeter to see if Aussie power networks have anything to do with it. Anyway, with @AnalogSteph in this thread , your case is in good hands I will follow this topic.

 

[Holmz]

I was thinking of using true-RMS multimeter to see if Aussie power networks have anything to do with it. Anyway, with @AnalogSteph in this thread , your case is in good hands I will follow this topic.

Well they may be good bad, and maybe a 230v–>115v acts as as a choke?
But it was “XMAS mouse” quiet, and once the RME appeared then floor has risen…
So maybe the SMPS, or some ground loop thing… I’ll set up some Ishikawa (fishbone) and work through it i over the weekend.

 

[Holmz]

…

Regarding the interference, I would suggest unplugging everything from the preamp that isn't absolutely necessary for recording. If that doesn't cut it, please give us a list of the entire signal chain ahead of the ADI-2 Pro input (devices and how they're powered).

Pre-Channel Source
A. RME DAC (230v/12V Wart)
B. TV (230v power)
C. CD Player (Not connected)
D. Headphone 1/8 jack (iPad)
E. Turn Table (115v/12V wart)
Bypass Not connected (AVR when if it was)

Pre-Outputs Device
Out-1
RCA-1 Power amp (115v)
RCA-2 RME ADC (230v/12V Wart)

Out-2
XLR Not connected

 

[PcChip]

Two things changed last week.
1) Got the RME ADI-2 Pro in the mail
2) Got a 3mm to RCAs lead to facilitate playing the iPad through the system.

So I hooked up an RME ADI-Pro and it would not record in any quality way.
I spent a day copying the SSD in a MacBook Pro (MBP) and upgrading the OS.
I could get to not sound bad with an Intel NUC running windows.
And a second NUC running Linux I would also not get to record.

I copying the MacBook’s SSD to a new SSD and upgraded the OS.

Then while the SSD was being copied I noticed that there was a lot of computer noise to coming through the system.
So I removed that 1/8” to RCA cable, but the noise was still there on a TV input.
It took removing the USB connecting the RME to MBP for it to go away.

I went out Saturday to get another brand new USB cable, and finally I was able to flash the RME.
Plugged the MBP into the same power strip as the audio gear.
Still heaps of computer noise coming in, and without anything coming in the background SINAD/lever is -45 to -50 dB, so it is not a clean 24 conversion.

Questions are:

1. How does one prevent the digital computer noises?
   1. (Getting a new MBP battery so I can run it for more than a couple of minutes.)
2. How does one change the sample rate of the ADI-2 PRO? It is on 44.1kHz, and I would like to go higher on ADC

that's one of the reasons I sold the RME ADI-2, it's not galvanically isolated and lets tons of computer noise in via USB

 

[Trell]

that's one of the reasons I sold the RME ADI-2, it's not galvanically isolated and lets tons of computer noise in via USB

So which other DAC or audio interface do you think will work better when using USB if you have ground loop problems?

Using TOSLINK can also be a solution for ground loop issues between a DAC and a PC, but of course, has a drawback of reduced functionality. That might, or might not, be an issue for you.

If you can't solve your ground loop problems otherwise, there are USB isolators from Intona that RME has used and it works, but it is expensive. Assuming that USB is the issue.

USB isolator for Babyface Pro (Page 1) — FireWire & USB series — RME User Forum

USB isolator for Babyface Pro (Page 1) — FireWire & USB series — RME User Forum —

forum.rme-audio.de

 

[Matias]

Pre-Channel Source
A. RME DAC (230v/12V Wart)
B. TV (230v power)
C. CD Player (Not connected)
D. Headphone 1/8 jack (iPad)
E. Turn Table (115v/12V wart)
Bypass Not connected (AVR when if it was)

Pre-Outputs Device
Out-1
RCA-1 Power amp (115v)
RCA-2 RME ADC (230v/12V Wart)

Out-2
XLR Not connected

that's one of the reasons I sold the RME ADI-2, it's not galvanically isolated and lets tons of computer noise in via USB

Just get one of these and problem solved.

MEASUREMENTS: Topping HS01 - USB 2.0 Isolator & Ground Loop Eliminator (and a listen to Santana's "Blessings and Miracles")

A blog for audiophiles about more objective topics. Measurements of audio gear. Reasonable, realistic, no snakeoil assessment of sound, and equipment.

archimago.blogspot.com

 

[Holmz]

So which other DAC or audio interface do you think will work better when using USB if you have ground loop problems?

Using TOSLINK can also be a solution for ground loop issues between a DAC and a PC, but of course, has a drawback of reduced functionality. That might, or might not, be an issue for you.

If you can't solve your ground loop problems otherwise, there are USB isolators from Intona that RME has used and it works, but it is expensive. Assuming that USB is the issue.

USB isolator for Babyface Pro (Page 1) — FireWire & USB series — RME User Forum

USB isolator for Babyface Pro (Page 1) — FireWire & USB series — RME User Forum —

forum.rme-audio.de

I am also using the DAC as an ADC, and I suppose I can check if TOSLINK works, but the computer does not have TOSLINK, nor the iPad.
It looks like one would Bluetooth from the iPad through a device that does TOSLINK output??

Just get on of these and problem solved.

MEASUREMENTS: Topping HS01 - USB 2.0 Isolator & Ground Loop Eliminator (and a listen to Santana's "Blessings and Miracles")

A blog for audiophiles about more objective topics. Measurements of audio gear. Reasonable, realistic, no snakeoil assessment of sound, and equipment.

archimago.blogspot.com

Thanks @Matias mate - I am ordering one.

 

[Yuhasz01]

I am also using the DAC as an ADC, and I suppose I can check if TOSLINK works, but the computer does not have TOSLINK, nor the iPad.
It looks like one would Bluetooth from the iPad through a device that does TOSLINK output??




Thanks @Matias mate - I am ordering one.

Should work here.

You should post your use case on the RmE forum site. Many there have helpful technical insight for hooking up RME products