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snorkeldata
Joined: Nov 18, 2016 Posts: 5 Location: Sweden
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Posted: Mon Sep 04, 2017 7:53 am Post subject:
CGS92 SSG Acting real slow |
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The case:
I just built the CGS92 SSG and its only kinda working.
The smooth side oscillates but it is really slow. With both the trimmer and the Rate knob at -15V it oscillates at about 1hz. from what I have read it should be about 2khz with this setting right?
And the stepped side is just not doing anything.
The strange part is that if i feed it +15V in the CV Rate input it becomes fast and nice and behaves as it is supposed to, for both smooth and stepped side.
I have used the following parts:
LM13700 - National
LM3900 - Texas
for PN4250 I used: 2N3906
for J201 i used: 2N5457
Here are my questiones:
Have you experienced this behaviour in the SSG and did you solve it?
Does anyone had a working SSG with any or all of these parts?
Is some of these parts just not right?
Does it make a difference which brand a IC has?
Which is the best LM3900 for example?
Think that´s all.
I would be very happy for a response, I really wanna get this thing running properly! |
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wackelpeter
Joined: May 05, 2013 Posts: 461 Location: germany
Audio files: 10
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Posted: Mon Sep 04, 2017 1:06 pm Post subject:
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Build that thing on stripboard some time ago...
But from Ken's notes should be about 100Hz in the smooth section.
Those IC manufacturers shouldn't be critical and almost aren't if at least you didn't got broken IC's from less reliable sellers on eBay or so. _________________ https://soundcloud.com/bastian-j |
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snorkeldata
Joined: Nov 18, 2016 Posts: 5 Location: Sweden
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Posted: Tue Sep 05, 2017 5:06 am Post subject:
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wackelpeter wrote: | Build that thing on stripboard some time ago...
But from Ken's notes should be about 100Hz in the smooth section.
Those IC manufacturers shouldn't be critical and almost aren't if at least you didn't got broken IC's from less reliable sellers on eBay or so. |
Thanks for the reply!
Hopully your right about the IC:s.
I´ll put some real J201:s in there and see if that helps.
(now that I got them)
And about the 100hz. Yep, your right, that´s what kens page says. I read somewhere that it can go a lot faster than that.
But yeah, hopefully I can get it going faster than 1hz.
Here are some pics too:
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wackelpeter
Joined: May 05, 2013 Posts: 461 Location: germany
Audio files: 10
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Posted: Tue Sep 05, 2017 6:46 am Post subject:
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As far as i remember i played around with some resistor values... But i really don't remember if i did this because i had some trouble get it working properly or if i wanted to speed it up a bit...
But anyway... Keep us updated and maybe someone else with some more technical insight will chime in. _________________ https://soundcloud.com/bastian-j |
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snorkeldata
Joined: Nov 18, 2016 Posts: 5 Location: Sweden
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Posted: Tue Sep 05, 2017 12:22 pm Post subject:
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Ok, I seem to have solved it.
I changed the 2N5457 for J201. (the one from Kens BOM)
And I also changed the LM13700 to CA3080.
Not sure which of them fixed it since I changed them both at the same time.
But it works and runs great!!
Yay! |
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wackelpeter
Joined: May 05, 2013 Posts: 461 Location: germany
Audio files: 10
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Posted: Wed Sep 06, 2017 6:47 am Post subject:
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Good to hear you got it fixed.
I had used 2SK30 maybe that was the point why i had or maybe had not, don't remember now, mess around with some resistor values...
Also had some broken LM13700 sometimes, maybe that was the cause... I had 2 were one side wasn't working.... But they've got used in other circuits were i only needed one OTA. _________________ https://soundcloud.com/bastian-j |
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The Bad Producer
Joined: Mar 08, 2009 Posts: 282 Location: The Manhole
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Posted: Thu Oct 12, 2017 7:18 am Post subject:
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I had this problem when using LM13700 vs 3080, I just tried again today (using LM13700) on a new build and same problem, seems odd that using a LM13700 would slow it down, and just using 3080 = works properly... I don't have time right now but it would be worth investigating more as it would certainly be better to use the 13700 vs the 3080's...
By the way, that's the best looking SSG I've ever seen! _________________ http://loudestwarning.tumblr.com/ |
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