electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Articles  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links  |  Store
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 
Live streaming at radio.electro-music.com

  host / artist show at your time
  Twyndyllyngs Live tonight Chez Mosc
Please visit the chat
 Forum index » Instruments and Equipment » Modular Synthesis
Line Level -> Gate & Amplified Signal
Post new topic   Reply to topic
Page 1 of 1 [9 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
joshs



Joined: Dec 05, 2014
Posts: 32
Location: Home

PostPosted: Fri Feb 06, 2015 9:43 am    Post subject: Line Level -> Gate & Amplified Signal Reply with quote  Mark this post and the followings unread

I've been searching around the Internet but haven't had much luck finding a circuit that does something like the following:

1. Takes as input a low signal... I was thinking guitar, but maybe it makes more sense to work at line level and do a little preamplification? Ideally the circuit could deal with either using some kind of trimmer. I'd want to be able to use different sources (thinking also a cheap casio keyboard, maybe even a microphone)

2. Outputs a 5v gate signal and an amplified version of the original signal (amplified enough to work in a synth circuit so it could be run through low pass filters, vca, etc)

I found some articles that mentioned the problems associate with this sort of thing (signal cutting out too soon, false triggers etc). I don't mind if it's a little glitchy though, especially if there are ways to adjust the sensitivity of the gate generator circuit.

Anyway, are there any circuits out there that could at least show the basics? I'm no electronics genius, but I've built a few things, so I have some ability to modify a circuit if it's in the ballpark.

Oh, and I have access to a +/-15V supply, so I could make use of that.
Back to top
View user's profile Send private message
kkissinger



Joined: Mar 28, 2006
Posts: 1274
Location: Kansas City, Mo USA
Audio files: 32

PostPosted: Fri Feb 06, 2015 10:32 am    Post subject: Reply with quote  Mark this post and the followings unread

Suggest that you look for an Envelope Follower -- in particular, one that has a comparator to fire a trigger for you. The other function -- to amplify an instrument-level signal -- would simply be a pre-amp.
_________________
-- Kevin
http://kevinkissinger.com
Back to top
View user's profile Send private message Visit poster's website
wackelpeter



Joined: May 05, 2013
Posts: 453
Location: germany
Audio files: 10

PostPosted: Fri Feb 06, 2015 3:52 pm    Post subject: Reply with quote  Mark this post and the followings unread

Maybe something like the Korg Ms20 external Signal processor?

You can adjust Level on incoming Signal... you can set the Treshold when it Triggers ... Of course you would need as i suppose 5V Triggers and not s-Triggers like this produces...

Also wonder if my slope detector from Ken Stone could be of useful help...
will give it if i don't Forget it tomorrow a try and feed some Audio Signal in...

_________________
https://soundcloud.com/bastian-j
Back to top
View user's profile Send private message
joshs



Joined: Dec 05, 2014
Posts: 32
Location: Home

PostPosted: Fri Feb 06, 2015 11:54 pm    Post subject: Reply with quote  Mark this post and the followings unread

I should add that I'd like to build this myself (couldn't find schematics for the MS-20 external processor)...

I gave some thoughts to how this might work, but couldn't get very far. My initial thought was to use a transistor biased so that the signal would saturate it at a fairly low level of input. But that seems like it would be problematic, because there would be an area between saturation and cut off where it would be in a linear state, which I think I'd want to avoid. Then again, maybe the linear region wouldn't be a big deal so long as noise was below the cutoff. Not really sure how to calculate the proper setup. Then I guess I'd want to use an op amp before it to buffer the input so that I could split the signal between the gate and the signal output. I really don't have the technical knowledge to design it, so it'd be great to find a solution out there to start with. Seems like something someone would have done already.
Back to top
View user's profile Send private message
wackelpeter



Joined: May 05, 2013
Posts: 453
Location: germany
Audio files: 10

PostPosted: Sat Feb 07, 2015 2:35 am    Post subject: Reply with quote  Mark this post and the followings unread

Here's a PDF of the Korg Service Manual with Korg ext.Sig.Processor which is on page 4.

What's interesting for you is the part from IC7 and the components below...


Korg_MS-20_ServiceManual.pdf
 Description:
Korg MS20 Service manual

Download
 Filename:  Korg_MS-20_ServiceManual.pdf
 Filesize:  3.41 MB
 Downloaded:  352 Time(s)


_________________
https://soundcloud.com/bastian-j
Back to top
View user's profile Send private message
joshs



Joined: Dec 05, 2014
Posts: 32
Location: Home

PostPosted: Sat Feb 07, 2015 7:10 am    Post subject: Reply with quote  Mark this post and the followings unread

Cool, lots of interesting stuff in that circuit, thanks for posting it! Looks like it outputs trigger and not gate? But then again it has an envelope out, which would probably be good enough if not better than what I was thinking. Any idea if that C1685 transistor is something that could be substituted with a more available transistor? And is that part of the circuit only to run the LED anyway?
Back to top
View user's profile Send private message
wackelpeter



Joined: May 05, 2013
Posts: 453
Location: germany
Audio files: 10

PostPosted: Sat Feb 07, 2015 7:46 am    Post subject: Reply with quote  Mark this post and the followings unread

that Transistor drives only the LED...
the Trigger Output is from what i think an S-Trigger... As the MS-Series work with S-Triggers (a short contact to GND)
But i think it can be easily converted to a normal Trigger or Gate... maybe the Output pin7 on the lower OP AMP already offer This... should be from what i guess be configured as a comparator with variable treshold...
guess some of our more experienced friends with more technical knowledge and Background can answer this more precise...

but i'm not exatctly sure... i only know that i converted normal Trigger and gate signals to S-Trigger with a simple circuit consisting of a Transistor and 1 or 2 resistors...

_________________
https://soundcloud.com/bastian-j
Back to top
View user's profile Send private message
joshs



Joined: Dec 05, 2014
Posts: 32
Location: Home

PostPosted: Mon Feb 09, 2015 8:11 am    Post subject: Reply with quote  Mark this post and the followings unread

Okay, well it at least sounds like this is worth looking into. I still have lots of planning to do (for the other circuits involved as well) so it'll be awhile before I figure this out, but please chime in if you have more advice or circuits to look into. Thanks!
Back to top
View user's profile Send private message
tubeampguy



Joined: Oct 29, 2009
Posts: 12
Location: Long Beach, Ca

PostPosted: Tue Jan 19, 2016 11:23 am    Post subject: Reply with quote  Mark this post and the followings unread

I have found modules in both Frac and Euro that will work for you.
The Blacet module would gives you both Gate and Trigger as well as two Envelope Followers.
BUT for just boosting signals the 1979 works very well.
One that I do NOT have (yet) is the Paia Preamp.

http://www.blacet.com/BlacetUserPage/IO2225user.pdf
http://www.theharvestman.org/1979.php
http://www.paia.com/proddetail.asp?prod=9754K&cat=12

Hope that help you!
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic
Page 1 of 1 [9 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
 Forum index » Instruments and Equipment » Modular Synthesis
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
e-m mkii

Please support our site. If you click through and buy from
our affiliate partners, we earn a small commission.


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