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

DIY Audio Analyzer with AK5397/AK5394A and AK4490
DIY Audio Analyzer with AK5397/AK5394A and AK4490
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
Reply
 
Thread Tools Search this Thread
Old 8th August 2015, 07:48 PM   #21
mkc is offline mkc  Denmark
diyAudio Member
 
Join Date: Jun 2002
Location: Denmark
DIY Audio Analyzer with AK5397/AK5394A and AK4490
Hi Jens,

Looks good. You have been busy. What else todo on a saturday night

Cheers,
Mogens
  Reply With Quote
Old 8th August 2015, 08:11 PM   #22
JensH is offline JensH  Denmark
diyAudio Member
 
Join Date: Jul 2009
DIY Audio Analyzer with AK5397/AK5394A and AK4490
Thanks.

I found the problem with the noisy channel. It has been fixed now and the picture below shows a loopback from generator output to the left input.

The generator output level was -9dBFS and -19dBFS. Input set to no gain/attenuation.

The right channel still doesn't work correctly.
  Reply With Quote
Old 8th August 2015, 08:28 PM   #23
JensH is offline JensH  Denmark
diyAudio Member
 
Join Date: Jul 2009
DIY Audio Analyzer with AK5397/AK5394A and AK4490
This is the noise floor. The A-weighted noise level is measured at -126.3 dBFS.
By the way: the PCB has not been put into a box yet, so there is no shielding at the moment.
  Reply With Quote
Old 8th August 2015, 08:35 PM   #24
mkc is offline mkc  Denmark
diyAudio Member
 
Join Date: Jun 2002
Location: Denmark
DIY Audio Analyzer with AK5397/AK5394A and AK4490
Hi Jens,

That's impressive and promising. Interesting to see how higher sample rates perform.

Mogens
  Reply With Quote
Old 8th August 2015, 08:37 PM   #25
skidave is offline skidave  United States
diyAudio Member
 
skidave's Avatar
 
Join Date: Jul 2006
Location: Pennsylvania
Nice work!
  Reply With Quote
Old 8th August 2015, 09:01 PM   #26
JensH is offline JensH  Denmark
diyAudio Member
 
Join Date: Jul 2009
DIY Audio Analyzer with AK5397/AK5394A and AK4490
OK, got the right channel working also. I had deliberately left out the capacitors on the ADC right channel input to make it easier to experiment with different values if needed. I had forgotten all about until a moment ago

Now they are in place and the results are similar to the results for the left channel, see below.

So the basic functionality now seems to be OK. I still need to adjust it and check the performance further.
  Reply With Quote
Old 8th August 2015, 10:19 PM   #27
fireworks is offline fireworks  Switzerland
diyAudio Member
 
Join Date: Feb 2010
Quote:
Originally Posted by JensH View Post
I finished mounting the PCB yesterday. I have attached a picture of the assembled PCB.
JensH,

Nice work ! Did you use a reflow oven or did you solder them by hand ? Also did you use a stencil ?
Also could you tell how long did it take you to
1. place the components and solder paste (if any)
2. to solder them if manually soldered
I'm asking these questions just to get an idea of the effort needed for such a board, should I ever attempt something like that.
  Reply With Quote
Old 8th August 2015, 10:41 PM   #28
JensH is offline JensH  Denmark
diyAudio Member
 
Join Date: Jul 2009
DIY Audio Analyzer with AK5397/AK5394A and AK4490
I soldered the components by hand. No stencil. It probably took me something like 20-25 hours to do so. Excluding the time it took to find the components in different sample kits etc. I used parts from these sample kits for all the uncritical parts. The critical parts, e.g. 0.1% resistors, I ordered from Farnell and Mouser.

I have a Mantis Vision microscope, which helps a lot in the assembly process. Without it, I would have no chance to assemble it by hand. Maybe I could have done it 20 years ago, but not today.

It is a big task to solder it by hand and I have no plans to assemble a second one by hand! But for a first prototype, to verify the performance, it was OK.
  Reply With Quote
Old 9th August 2015, 01:06 PM   #29
JensH is offline JensH  Denmark
diyAudio Member
 
Join Date: Jul 2009
DIY Audio Analyzer with AK5397/AK5394A and AK4490
Two of the attached screen dumps show the noise floor at 192 kHz sampling.

The measurements were done at the 0dB input setting. This means a direct input, no attenuation and no additional gain, max input around 3Vrms.
There is a small noise peak at probably 48kHz on both channels. The right channel is slightly noisier than the left channel. There are also a couple of noise peaks between 80 and 90 kHz on the right channel.
But there doesn't seem to be any discrete noise frequencies apart from these. And there is still no shield/box around the PCB.

I have also measured the frequency response at 192 kHz sampling.
The attached figure shows the loop back response. It does drop a bit at high frequencies. This is primarily due to the generator. So I need to fine tune the filters on the outputs.
Measured separately the input side drops by 0.1 dB at 80 kHz and 0.3 dB at 90 kHz.
  Reply With Quote
Old 9th August 2015, 02:19 PM   #30
mkc is offline mkc  Denmark
diyAudio Member
 
Join Date: Jun 2002
Location: Denmark
DIY Audio Analyzer with AK5397/AK5394A and AK4490
Hi Jens,

This looks very good. It's very impressive that this is just a bare PCB on the table and it is so clean.

Do you have an external generator? Something like Victors?

Mogens
  Reply With Quote

Reply


DIY Audio Analyzer with AK5397/AK5394A and AK4490Hide 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
New AKM Stereo ADC AK5397 announced JensH Digital Source 20 24th December 2014 12:05 PM
New AKM Stereo ADC AK5397 ??? HpW Equipment & Tools 6 16th May 2014 04:26 PM
NTi Audio XL2 Handheld Audio Analyzer Fredenando Equipment & Tools 0 18th April 2010 03:04 AM
AKM AK5394a TobWen Digital Source 41 31st December 2003 06:18 PM


New To Site? Need Help?

All times are GMT. The time now is 03:52 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki