electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links
Forum with support of Syndicator RSS
 FAQFAQ   CalendarCalendar   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   LinksLinks
 RegisterRegister   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in  Chat RoomChat Room 
go to the radio page Live at electro-music.com radio 1 Please visit the chat
poster
 Forum index » DIY Hardware and Software
Osamu Hoshuyama Totem Pole VC LPF
Post new topic   Reply to topic Moderators: jksuperstar, Scott Stites, Uncle Krunkus
Page 1 of 1 [6 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
Ayab



Joined: Oct 27, 2015
Posts: 186
Location: London, UK

PostPosted: Tue Jul 02, 2019 3:44 am    Post subject: Osamu Hoshuyama Totem Pole VC LPF Reply with quote  Mark this post and the followings unread

An elegant and streamlined filter (but maybe a bit tricky). I don't understand how differential pairs work in Moog filters but i'd like to know this and the difference.


http://electro-music.com/forum/phpbb-files/vcftp0211_180.gif

Has anyone here made or heard this fascinating filter?

I cannot find information on the TD62507A Toshiba transistor array Hoshuyama used in the design. Anyone point me to a data sheet or what transistors a substitute for the transistor array would be?

Lastly any likely changes to run on 12V?
Back to top
View user's profile Send private message
mph



Joined: Aug 25, 2007
Posts: 88
Location: France

PostPosted: Wed Jul 03, 2019 1:25 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi
the TD62507A seems to be a simple NPN low gain transistor array, nothing fancy:
https://pdf1.alldatasheet.com/datasheet-pdf/view/32291/TOSHIBA/TD62507F.html

Maybe a CA3086 would do the job, it has already a differential pair + 3 spare transistors.
Back to top
View user's profile Send private message
Ayab



Joined: Oct 27, 2015
Posts: 186
Location: London, UK

PostPosted: Thu Jul 04, 2019 3:53 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi mph

Thanks for finding the data sheet - really helps Smile

But I don't think the 3086 can be used - Totem's configuration is unlike the differential pair (

Suppose I could try to shove in a bunch of standard npn's (matched sort of!) - the chances of me not bungling are high as it is quite a complicated schematic for me to breadboard. Also I am on 12V.

Toshiba's transistors have a 'parasitic diode' am not sure what that is although am guessing it is to stop stuff going the wrong way in the array.

Be really good to know if anyone has heard this filter or some more info
Back to top
View user's profile Send private message
gabbagabi



Joined: Nov 29, 2008
Posts: 652
Location: Berlin by n8
Audio files: 23

PostPosted: Thu Jul 04, 2019 6:43 am    Post subject: Reply with quote  Mark this post and the followings unread

may iam allowed to post an inspiration.

attached my attempt so takkle the ms20-vcf from Jürgen Haible.
This was always to much for my brain drunken to put on stripboard.

As u can see, even that is not finished, the opamp is missing.
The plan was to mount the opamp on a piece of stripboard, and glue it there where it would belong.

If i would do the totem pole i would probably use two tl072 in a similar manner.
And i will do it (both) in the future, i promise Shocked Very Happy Cool

cu


ms20.jpeg
 Description:
 Filesize:  146.72 KB
 Viewed:  279 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

ms20.jpeg


Back to top
View user's profile Send private message
Ayab



Joined: Oct 27, 2015
Posts: 186
Location: London, UK

PostPosted: Thu Jul 04, 2019 4:49 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi Gabbagabi

So many circuits to build, so little time! Maybe going acoustic is a better option Surprised

I like your building method direct onto unetched pcb - I haven't seen that before.
Back to top
View user's profile Send private message
gabbagabi



Joined: Nov 29, 2008
Posts: 652
Location: Berlin by n8
Audio files: 23

PostPosted: Thu Jul 04, 2019 11:30 pm    Post subject: Reply with quote  Mark this post and the followings unread

may the inspiration be with you!

http://www.worldofindie.co.uk/?p=900

https://aa7ee.wordpress.com/2016/02/10/the-muppet-style-construction-of-john-n8rve/

https://www.youtube.com/watch?v=0QbeC0Hw2QA

https://www.youtube.com/watch?v=JszCHXKYK5c

https://www.youtube.com/watch?v=AHYhtbE3gzk
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: jksuperstar, Scott Stites, Uncle Krunkus
Page 1 of 1 [6 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
 Forum index » DIY Hardware and Software
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Forum with support of Syndicator RSS
Powered by phpBB © 2001, 2005 phpBB Group
Copyright © 2003 through 2009 by electro-music.com - Conditions Of Use