Testing noise levels

[wtnh]

Hi - I was excited to see this driver, so I dusted off my old 0404 and tried the install on Catalina on a Macbook Pro "late 2013".

Followed directions, except I could not see how to do the step which says "give full access to the driver installer". (I did give full disk access to terminal). This could be my issue, but not sure how to do that because the driver installer does not show up.

The 0404 shows up in USB devices but the driver is listed as the original EMU driver, which does not seem right.
`E-MU 0404 | USB:

Product ID: 0x3f04
Vendor ID: 0x041e (Creative Labs)
Version: 1.00
Serial Number: E-MU-0A-3F04-07D7081D-08926-STATION01
Speed: Up to 480 Mb/s
Manufacturer: E-MU Systems, Inc.
Location ID: 0x14100000 / 10
Current Available (mA): 500
Current Required (mA): 2
Extra Operating Current (mA): 0`

I re-ran the installer and had to answer "y" to a bunch of access questions this time (see attached script output).

EMU driver install log.txt

Also the control panel is blank as mentioned in some other issues.
[EDIT] I was able to open the control panel via terminal and it looks normal - maybe it is working after all - I'll test it.[/EDIT]

Any hints appreciated! Thanks!

[Wouter1]

@wtnh if the control panel shows the EMU info like sample speed etc, it's properly installed.

The log file you attached shows that the EMU does not install because /System/Library/Extensions is read-only.

This might be because you either did not do the csrutil or did not give full disk access to the terminal and driver installer.

I think you can drag the installer program into the browser window after you click on the "+"

[wtnh]

OK - I think it is working. I just did a listening test and the EMU functions fine for sound output. I am now testing the input using REW, an audio analysis program that I want to use for audio amp testing.

When I re-ran the installer, I answered "y" to each of the access override permissions.

What confused me is that in your instructions, it says to give disk access to the installer, but I had not downloaded it yet (that comes later in the instructions), so it was not visible in the list of apps to which I could give access.

So is it OK that in the list of USB devices that it shows up as the original EMU V1 driver, even though your driver is active?

[Wouter1]

@wtnh ok I fixed the install instructions to first download and unzip to fix that confusion.
Good to hear it works now!

So is it OK that in the list of USB devices that it shows up as the original EMU V1 driver, even though your driver is active?

I can't change the USB Devices info, it's hardware

What matters is the EMUUSBAudio info in the About This Mac/System Report/Extensions. It should show the latest version (4.1.0 at this time)

[wtnh]

Thanks for that - it does indeed show correctly in the Extensions report as 4.1.0. So everything is working despite my roundabout installation process (with the exception of the control panel needing to be started from terminal).

As an aside, I am experimenting with the REW application, with the goal of using the EMU as a distortion measuring tool. Attached is a screenshot showing the FFT performance of the EMU looped back on itself. Not too shabby for a 13-year-old interface I paid $150 for back then. So glad I was able to dust it off thanks to your great driver!

[Wouter1]

@wtnh Yes it's a known workaround for the control panel. I don't know any other way to fix it

Almost 120dB -15dB = 105dB range, yes looks good.

Very little at 50/60Hz, are you using something to suppress net hum etc?

[wtnh]

Nothing special to suppress hum. I did try it with the Macbook on battery power only but saw no difference. I am on 60Hz power. The hump around 100Hz is interesting - that could actually be 120Hz (2x line frequency) - I am wondering if the EMU wall wart is contributing some of that. It would be interesting to run the EMU on battery power to see if noise decreases further. Right now I am seeing THD of 0.00016% and noise of 0.0019%, so noise is dominant.

Attached is a better screenshot showing the FFT particulars.

[wtnh]

Closing this issue - thanks for the help!

[Wouter1]

@wtnh thanks for the clarification. Yes I was thinking that you might be running the EMU on battery since I see no 50/60Hz residue. Are you using the original power adapter? Let me know if you find any improvement with running on battery power!

[wtnh]

Yup - that is with the original EMU power adapter. I am thinking of trying one of those cell phone 10,000 mA-hr 5V power packs, but I think they usually have some sort of buck/boost converter built-in, which would add hash to the output. An ideal battery supply would consist of some LiPo cells and a linear 5 V regulator. I might throw something together and test that approach. Right now the EMU is "good enough" for testing (with REW) on a class-A amp I am building: https://www.diyaudio.com/forums/pass-labs/347697-hippie-trail-head-zombie-post6299801.html That thread is a discussion about building clones of Nelson Pass's First Watt F7 amplifier. Cheers

…

________________________________ From: Wouter1 <notifications@github.com> Sent: Wednesday, August 5, 2020 2:15 AM To: Wouter1/EMU-driver <EMU-driver@noreply.github.com> Cc: wtnh <whit.turner@outlook.com>; Mention <mention@noreply.github.com> Subject: Re: [Wouter1/EMU-driver] Catalina install problem 0404 USB (#131) @wtnh<https://github.com/wtnh> thanks for the clarification. Yes I was thinking that you might be running the EMU on battery since I see no 50/60Hz residue. Are you using the original power adapter? Let me know if you find any improvement with running on battery power! — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub<#131 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ADU3AX3CPWI7BHVWZK42FPTR7D2HPANCNFSM4PTVE23Q>.

[Wouter1]

Yes, a plain battery should be used, no switching PSU as then you get other types of noise.

Nice project. Good luck with that!

[wtnh]

Just to follow up on this - I did try a battery pack which eliminated the weird 120 Hz noise caused by the EMU wall wart:
https://www.amazon.com/gp/product/B082NKPPF3/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1
It will run the EMU all day and does not seem to exhibit a lot of switching noise, at least in the audible band.

This is a nice little battery and it has a display showing state of charge.

[Wouter1]

@wtnh thanks for the update!
Can you post the noise spectrum with battery instead of PSU?

BTW I found that it even works on just 4 AA batteries. That may be even better as that will not contain any switching software (which that powerbank probably has)

[wtnh]

Sorry for the slow response - here is an FFT spectrum with the EMU running on the above-mentioned battery pack instead of it's wall-wart. Note that the 120 Hz noise (and its harmonics) is gone. Also note that this shows the fundamental at -20db, so it is not exactly the same measurement setup. I have a common mode USB power filter with a choke and some caps, but have not had a chance to try that yet. Presumably, it would lower the noise floor a bit more.