Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Equipment & Tools From test equipment to hand tools

QuantAsylum QA400 and QA401
QuantAsylum QA400 and QA401
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 6th March 2019, 10:00 PM   #2571
RNMarsh is offline RNMarsh  United States
diyAudio Member
RNMarsh's Avatar
Join Date: May 2012
Location: 2457 Cascade Trail; Cool, CA. 95614
Nice upgrades... very useful ones.

  Reply With Quote
Old 14th March 2019, 05:01 PM   #2572
QAMAtt is offline QAMAtt
diyAudio Member
Join Date: Nov 2017
Location: Seattle, WA, USA
Thanks RNMarsh, yes agree there's a lot of value in these types of plug-ins. The next release of the QA401 software posted last night on github, and it is almost a complete re-write of the graphing and plug-in subsystem. From a code standpoint, it's greatly unified and there's a lot more code shared across the different plug-ins. After a bit more cleanup we'll publish the plug-in sources. The hardest thing to wrestle with thus far is the creeping needs for graphing flexibility, and I think we're off in a good direction on the latest release. It's far from perfect, but the foundation is there.

Here's a link to a new video showing how these plug-ins can be used to stack traces and let you see tone knob versus gain changes (for example) overlaid atop each other. The new plug-in design should make this type of task even easier.

Fast Amp Characterization

  Reply With Quote
Old Today, 02:01 AM   #2573
1audio is offline 1audio  United States
diyAudio Member
Join Date: Mar 2004
Location: SF Bay Area
Attached are selftest plots of my QA401. First with a generic USB cable and then with a slightly better USB cable. Normally I would expect dropped frames or other ugly with a bad cable but NOT a major difference in the distortion pattern.

If you get bad results it may be the cable. ijn this case since nothing else was attached I could see no other possible issues and I was first worried that my QA401 had failed somehow. . . but just a funky cable. FWIW the cable shield measures about 500 milliOhms, a decent cable should be closer to 100 milliOhms.

I need to check the voltage at the QA401 end of the cable.
Attached Images
File Type: png Selftest USB cable #2.png (61.2 KB, 56 views)
File Type: png Selftest USB cable #1.png (54.7 KB, 51 views)
Demian Martin
Product Design Services
  Reply With Quote
Old Today, 08:02 AM   #2574
gazzagazza is offline gazzagazza  New Zealand
diyAudio Member
Join Date: Jun 2004
Location: NZ
Now that is interesting. I was at a presentation last week given by a manufacturer of music servers (Antipodes Audio). The owner and product designer was delivering the talk. He was very focused on getting very low noise transfer of digital signals and was able to demonstrate quite clearly sonic changes with different cables, including Ethernet and USB between server and renderer and renderer and DAC. Your results here may be relevant.

His previous working life was in data transmission in a telecommunications environment.
  Reply With Quote
Old Today, 08:26 AM   #2575
phofman is online now phofman  Czech Republic
diyAudio Member
Join Date: Apr 2005
Location: Pilsen
IIUC the USB cable serves as power supply as well. 0.5Ohm resistance at the 500mA specified power consumption = 250mV at 5V - that is not a negligible voltage drop.
  Reply With Quote
Old Today, 08:42 AM   #2576
chris719 is offline chris719  United States
diyAudio Member
Join Date: Jun 2004
Location: Connecticut
QuantAsylum QA400 and QA401
Yes, maybe the switching regulators are having issues.
  Reply With Quote


QuantAsylum QA400 and QA401Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
QuantAsylum 401 & 405 B&W_arthur Equipment & Tools 5 22nd March 2016 04:27 PM
QA190 and QA400 Gains sgtnoah Equipment & Tools 4 17th July 2015 03:46 AM
Question on QA400 Alan0354 Equipment & Tools 7 10th July 2015 06:34 PM
FS QuantAsylum QA400 audio analyser jan.didden Swap Meet 3 29th September 2014 05:10 PM
New Quantasylum QA190 Differential Input Probe stellavox Equipment & Tools 3 20th March 2014 06:06 PM

New To Site? Need Help?

All times are GMT. The time now is 11:33 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio