ShibaSoku Automatic Distortion Analyzer - 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 9th March 2013, 11:34 AM   #1
PChi is offline PChi  United Kingdom
diyAudio Member
 
Join Date: Jan 2012
Location: Staines, UK
Default ShibaSoku Automatic Distortion Analyzer

I thought that it was time to start a new thread for the ShibaSoku Distortion Analyzer. I have reverse engineered part of an AD725C and have attached some schematics. I am in work at the moment so time is limited which is my excuse for the messy schematics. I can't guarantee the accuracy.
The equipment is old school and I think that a better way to go is to use a Sound Card preceeded by a Notch Filter as recommended elsewhere.
Attached Files
File Type: pdf ShibaSoku AD725C part schematics.pdf (617.3 KB, 499 views)
  Reply With Quote
Old 10th March 2013, 04:03 AM   #2
RNMarsh is offline RNMarsh  United States
diyAudio Member
 
RNMarsh's Avatar
 
Join Date: May 2012
Location: 2457 Cascade Trail; Cool, CA. 95614
Quote:
Originally Posted by PChi View Post
I thought that it was time to start a new thread for the ShibaSoku Distortion Analyzer. I have reverse engineered part of an AD725C and have attached some schematics. I am in work at the moment so time is limited which is my excuse for the messy schematics. I can't guarantee the accuracy.
The equipment is old school and I think that a better way to go is to use a Sound Card preceeded by a Notch Filter as recommended elsewhere.
So far, I have found most of the old school analyzers and source gen have excellent topology and are easily improved by selective replacement of the opamps with new low noise/low distortion opamps.

I am following the adc/pc/notch filter saga as well. Right now, the limit has been noise floor and poor ADC's with limited dynamic range to about 90dB - artifact free. But with the notch, that -90Db and FFT can see very low harmonics. But its still a cludge of bits and pieces and integrating hardware and software isnt quit There, yet IMO.
For fast testing, Plug N Play still is better with existing hardware. But I am making an active notch filter now and have a B&K passive notch filter also. But then you need another cludge -- to limit input level from power amps etc. it wont be long until a complete integrated package is made just for testing - such as the QA400 but taking it further and without usb driver bugs.

The ShibaSoku, upgraded, could be astonishing. The same opamp mods done in other instruments with similar old opamps has made 20 dB and more improvements.

Thank you for the sketches.... they help A LOT. Now I can go and look at them some more and start changing out selected opamps and see what happens to this analyzer.

Thank you,
Richard Marsh

Last edited by RNMarsh; 10th March 2013 at 04:10 AM.
  Reply With Quote
Old 10th March 2013, 08:17 AM   #3
RNMarsh is offline RNMarsh  United States
diyAudio Member
 
RNMarsh's Avatar
 
Join Date: May 2012
Location: 2457 Cascade Trail; Cool, CA. 95614
I am looking at the drawings..... they seem to have changed the board numbers on mine... for example board A5 is S340076B-3. A3 is a Twin-T circuit... so it says on the pcb.
Do you have the analyzer monitor output circuit schematic?

Thx-RNMarsh
  Reply With Quote
Old 10th March 2013, 04:37 PM   #4
1audio is offline 1audio  United States
diyAudio Member
 
Join Date: Mar 2004
Location: SF Bay Area
Blog Entries: 3
Richard:
I think they did a major rework between this unit and my unit and your much newer unit. The fundamental design is probably the same but many of the circuits may have been changed to deal with parts availability and different features. Yours has two inputs and balanced interface and GPIB. Mine has a single unbalanced input and parallel remote control. Very different at that level. Similar ultimate performance but different surroundings.
__________________
Demian Martin
Product Design Services
  Reply With Quote
Old 10th March 2013, 05:26 PM   #5
RNMarsh is offline RNMarsh  United States
diyAudio Member
 
RNMarsh's Avatar
 
Join Date: May 2012
Location: 2457 Cascade Trail; Cool, CA. 95614
yes, after more investigating... they are sufficiently different that I cant use the drawings. :-(
I need to get hold of an actual service manual. Until then, all is on hold.

Thx-RNMarsh

Last edited by RNMarsh; 10th March 2013 at 05:27 PM. Reason: On hold -
  Reply With Quote
Old 10th March 2013, 09:41 PM   #6
PChi is offline PChi  United Kingdom
diyAudio Member
 
Join Date: Jan 2012
Location: Staines, UK
Quote:
Originally Posted by RNMarsh View Post
I am looking at the drawings..... they seem to have changed the board numbers on mine... for example board A5 is S340076B-3. A3 is a Twin-T circuit... so it says on the pcb.
Do you have the analyzer monitor output circuit schematic?

Thx-RNMarsh
Unfortunately I haven't reverse engineered the analyzer monitor output schematic.
Like 1audio's unit mine only has a single ended input and guessing from the IC date codes was manufactured around 1990. I have attached a photograph of board A5 which is one of the bridged T stages.
Attached Images
File Type: jpg ShibaSoku AD725C Board A5.JPG (157.5 KB, 1082 views)
  Reply With Quote
Old 10th March 2013, 10:22 PM   #7
RNMarsh is offline RNMarsh  United States
diyAudio Member
 
RNMarsh's Avatar
 
Join Date: May 2012
Location: 2457 Cascade Trail; Cool, CA. 95614
Default Revamped -

It seems to be completly revamped. A5 is nothing like your A5.
:-(

DSC00656.jpg

[Also, I think yours is a Bridge-T and this one is a Twin-T osc.]

Lets try to find a manual/copy for each.

Thx-RNMarsh

Last edited by RNMarsh; 10th March 2013 at 10:25 PM.
  Reply With Quote
Old 11th March 2013, 09:00 PM   #8
PChi is offline PChi  United Kingdom
diyAudio Member
 
Join Date: Jan 2012
Location: Staines, UK
Thanks for the picture. As you say the 725D has been completely revamped. My guess is that your A5 Board has the distortion residual HPF and LPF filters and RMS to DC Converter which on the 725C is Board A6 which again looks different apart from the collection of capacitors in the bottom right of the board and the metal can TO-100 package. Even the mother board is different with the 725C using PCB edge connectors and the 725D a dedicated connector.
I did an internet search for a 725C manual but was unsuccessful. ShibaSoku have kept a very low profile in the UK. I had never heard of them before visiting this forum.
  Reply With Quote
Old 11th March 2013, 09:39 PM   #9
RNMarsh is offline RNMarsh  United States
diyAudio Member
 
RNMarsh's Avatar
 
Join Date: May 2012
Location: 2457 Cascade Trail; Cool, CA. 95614
I'll keep looking. You are correct about my A5 board... filters. I'll replace them with quieter opamps. I hope someone will be able to point me/us in the right direction as to where we can obtain the service manual.

Thx-RNmarsh
  Reply With Quote
Old 20th March 2013, 05:26 AM   #10
RNMarsh is offline RNMarsh  United States
diyAudio Member
 
RNMarsh's Avatar
 
Join Date: May 2012
Location: 2457 Cascade Trail; Cool, CA. 95614
Still looking for schematics... took a break to try the AD797 opamp as an oscillator. Got mixed results.
-RNM
  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
Meguro MAK-6571B Automatic Distortion Meter srh Equipment & Tools 8 19th January 2014 11:01 PM
Distortion Analyzer - Again Zero Cool Equipment & Tools 4 29th June 2013 11:14 PM
ADC SS-525X Automatic Spectrum Analyzer 503Timber Swap Meet 4 13th July 2011 10:05 PM
Shibasoku Distortion Meter, UK only dhaen Swap Meet 9 21st January 2011 03:53 PM
Recommendation on Distortion Analyzer Mark245 Solid State 2 19th December 2009 10:06 AM


New To Site? Need Help?

All times are GMT. The time now is 09:45 PM.


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