DIY Analog-to-Digital Converter project.Audio measurements tool - diyAudio
Go Back   Home > Forums > Design & Build > Equipment & Tools

Equipment & Tools From test equipment to hand tools

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 1st February 2010, 07:35 PM   #1
Frex is offline Frex  France
diyAudio Member
 
Join Date: Nov 2009
Post DIY Analog-to-Digital Converter project.Audio measurements tool

Hello,


Does anyone would be interested by an high-end analog to digital converter ?
For my own use, i develop a new ADC .It's main use is a high performance measurements tool, for testing my DIY audio projects.
It's main features are :

Cirrus Logic CS5381KZZ 24 bits 192kHz flagship ADC
Fully differential and single-ended switchable analog inputs.
AC and DC coupling input switchable.
48, 96 and 192kHz on the fly selectable sampling rate.
Optical (toslink) and BNC SPDIF digital outputs.
Very small from factor (120x70x20mm)
Zero calibration allow all offset cancellation.
+/-10V FS input sensitivity.
Standard SMD or TentLab Master clock oscillator
Need +/-15Vdc power supply (SSR01/02 or other low noise PS. Allow 4 wires with sense connexions)
Use MAX3000 PLD functions controlling (no uC)
Allow low-cost or Scientific-Conversion High-end SPDIF digital transformer.

This is my 2nd ADC design (the first use the AK5394 ADC).
Here the PCB design use 4 layers with massive ground plane and very clean signal path routing
Now, the schematics and the PCB design is done, but not already sent to the PCB manufacturer.
I verify again and again each one before to order it.

If some DIYers are interested by this project, i can post more details about it.


Below, You can see what it should look like.

Click the image to open in full size.


Frex
  Reply With Quote
Old 2nd February 2010, 06:39 AM   #2
diyAudio Member
 
Join Date: Jan 2008
Very interested - the only similar project I'm aware of is AD24QS - Audio Analog to Digital Converter 24 Bit / 192 kHz
  Reply With Quote
Old 3rd February 2010, 05:33 PM   #3
Frex is offline Frex  France
diyAudio Member
 
Join Date: Nov 2009
Default Audio ADC, the schematic...

Hello,

With only one reply, i'm not really sure that many people are interested by the project.
I post the full schematic in pdf, constructive comments are welcome.
----) AA5381v1Sch.pdf

Below, the PCB design finished (only the top layer is displayed).

Click the image to open in full size.


The ADC is designed as audio measurements tool. It replace a sound card, with more easy to use because it's an external unit with direct BNC connexion.
It allow DC or AC coupling, single ended or differential input, offset calibration,
overload detection on each channel and 48/92 and 192kHz sampling rate are supported.
The digital output can use optical or coaxial link (SPDIF).
It need only a low noise dual rail +/-15V dc power supply.

I wait comments...


Frex.
  Reply With Quote
Old 3rd February 2010, 05:56 PM   #4
ghg is offline ghg  Austria
diyAudio Member
 
ghg's Avatar
 
Join Date: Apr 2002
Location: Vienna
Hi Frex

Impressive pcb work, fine.

Maybe you are looking for something readymade, and possible unbeatable, take a look at TI's PCM4222EVM ( US $ 149,-- +shipping ).
You just need a dual 15V and single 5V powersupply.

Here a FFT; source Krohn-Hite 4400A, both units SLA battery driven, PC interface RME-PAD via AES/EBU.
Attached Images
File Type: png KH4400A_PCM4222EVM.png (35.1 KB, 5115 views)
__________________
I hate "sounding amps", except these are Marshalls, driven by Eric C. or Jeff B., period.

Last edited by ghg; 3rd February 2010 at 06:05 PM.
  Reply With Quote
Old 3rd February 2010, 07:30 PM   #5
Frex is offline Frex  France
diyAudio Member
 
Join Date: Nov 2009
I have already build another high-end ADC, with AK5394.
It's actually my measurement reference, largely better than I/O of my ESI Juli@ sound card. I know the PCM4222 from TI, it's also a top grade ADC chip.

I prefer largely build my own device, for many reason.
First for the pleasure (DIY or not DIY !).
Second, it's technically very interesting to investigate on each steps
of this type of design.
Third, i build exactly for my need, with all convenience i want.
I love too when the finished work is "beautiful" to look.

About the spectrum of the EVM, how exactly the measure has been done ?
Digital, analog, all setup ?..

Frex
  Reply With Quote
Old 4th February 2010, 11:12 AM   #6
ghg is offline ghg  Austria
diyAudio Member
 
ghg's Avatar
 
Join Date: Apr 2002
Location: Vienna
Quote:
Originally Posted by Frex View Post
About the spectrum of the EVM, how exactly the measure has been done ?
Digital, analog, all setup ?
Analog oscillator KROHN-HITE 4400A ( SLA battery driven ) -> unbalanced to PCM4222EVM ( SLA Battery driven ) ->
AES/EBU-out to AES/EBU-in RME-Digi96/8-PAD -> Spectralab 5.0 demo.

Gary
__________________
I hate "sounding amps", except these are Marshalls, driven by Eric C. or Jeff B., period.
  Reply With Quote
Old 4th February 2010, 03:27 PM   #7
grenert is offline grenert  United States
diyAudio Member
 
Join Date: Jan 2008
Hello, Frex.
I think this is an interesting project. However, I do not understand how it works. Could you explain how to acquire and analyze the converted digital signal? Do you have software that will do real-time analysis of a digital stream?

Thanks for sharing it with us!
  Reply With Quote
Old 4th February 2010, 04:56 PM   #8
Frex is offline Frex  France
diyAudio Member
 
Join Date: Nov 2009
Hello,

It's easy to use.
The ADC has a SPDIF digital output, then you need in your PC a sound card
with digital input. Be careful, if you want use the ADC at high sampling rate the SPDIF input of your sound card must support it.
I personally use the ESI "Juli@", it's a low cost solution and very powerful solution (~100$).

After that, you can make all processing you want with the digital stream with appropriate software. Many FFT software are available to do that.
Spectralab is one of the best, but it's very expensive.
Oscillometerz is also very good software.
All of this software allow to make real-time processing including FFT spectrum and much more...

Frex
  Reply With Quote
Old 4th February 2010, 10:34 PM   #9
diyAudio Member
 
Join Date: Jan 2010
Default ADC comments

You're probably a little impatient, give us a few days to chew over your good work

Some comments:

1. +-15v supplies are bad for portability. Think +-12 or even +-9V.

2. Put TWO pre-amp options on: one for adjustable for audio levels and one fixed that can see right down to the thermal floor, which means using a low-noise opamp like AD797 or LT1028 in the first stage.

<puts flamesuit on>

Quote:
Originally Posted by Frex View Post
Hello,

With only one reply, i'm not really sure that many people are interested by the project.
I post the full schematic in pdf, constructive comments are welcome.
----) AA5381v1Sch.pdf

Below, the PCB design finished (only the top layer is displayed).

Click the image to open in full size.


The ADC is designed as audio measurements tool. It replace a sound card, with more easy to use because it's an external unit with direct BNC connexion.
It allow DC or AC coupling, single ended or differential input, offset calibration,
overload detection on each channel and 48/92 and 192kHz sampling rate are supported.
The digital output can use optical or coaxial link (SPDIF).
It need only a low noise dual rail +/-15V dc power supply.

I wait comments...


Frex.
  Reply With Quote
Old 5th February 2010, 05:54 AM   #10
Frex is offline Frex  France
diyAudio Member
 
Join Date: Nov 2009
Hello noisewarrior,

Your comment is welcome. I'm not so impatient.
The ADC has been designed for +/-15v supply, but it can be supply with +/-12V without modification. For +/-9v operation, it need probably only slight modifications.

In my schematic, the analog input stage use OPA134, because i want use this instrument with many sources of signal, with high and low source impedance.
The opa134 is very good compromise for high input impedance, low voltage noise and very good THD specifications.
LT1028 and AD797 are the lowest noise available AOP, but it's bias current is very high and current noise too.
Any "single" AOP can be use in place of the OPA134.
Of course, maybe sligh value modifications can be done for optimisation.

Last thing, if you change OPA134 with LT1028/AD797, you must add much more $$.
  Reply With Quote

Reply


Hide 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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
need an analog-to-digital converter schematic prorms Digital Source 0 28th March 2008 09:29 PM
Digital to Analog Converter DAC With Cable mg16 Swap Meet 1 11th September 2006 07:27 AM
Analog to Digital converter amirmk Digital Source 9 26th November 2005 01:50 PM
Differences between Digital and Analog Audio oscarcasalini Digital Source 1 8th January 2004 12:32 AM
Digital to Analog converter condor655 Digital Source 4 15th May 2003 11:02 PM


New To Site? Need Help?

All times are GMT. The time now is 04:29 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2