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haxster
Joined: Feb 01, 2006 Posts: 246 Location: MONTEREY PARK, CA 91754
G2 patch files: 2
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Posted: Tue Jun 23, 2009 2:50 am Post subject:
SH101 VCF QUESTION |
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Would it be possible to use an LM13700 for the Transc. op-amps and some kind of transistor pair for the Exponential function converter? I am trying to breadboard this filter but I am stuck on the converter.
Does any one know a simple Anti log function generator circuit?
I found this(see pic) but I am not sure if this one is the correct one to use here. I think the one in the picture is a Lin/log converter. I think I need a log/lin converter. I am not sure how to do that.
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beep
Joined: May 05, 2013 Posts: 105 Location: Germany
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Posted: Mon Oct 28, 2013 4:35 pm Post subject:
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P U S H
This man made a great post and I'll need some advice, cause I'm about
to try this circuit. _________________ Is the future obsolete? |
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haxster
Joined: Feb 01, 2006 Posts: 246 Location: MONTEREY PARK, CA 91754
G2 patch files: 2
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Posted: Mon Oct 28, 2013 5:00 pm Post subject:
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Here is an update to help you build a roland sh101 type of filter. These guys did the hard part of figuring out what the resistor values are to replace the BA obsolete chip with Discrete components: http://mutable-instruments.net/shruthi1/build/smr4mkII. There is a schematic at there website. |
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jackdamery
Joined: Apr 26, 2010 Posts: 75 Location: UK
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Posted: Mon Nov 04, 2013 6:20 am Post subject:
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Hey not sure if you're on the SDIY facebook group. But I have done it and yes, it is totally possible.
I have some real IR3109s and with advice from guys on the SDIY mailing list I figured out the internal resistor values between the gain cells non-inverting inputs and ground as 432 ohms.
I used one LM13700 to make a 12db version of this filter
For the expo converter I used the standard Thomas Henry current source type. The thing I haven't figured out is the buffers between the gain cells. I used a TL072 in my circuit but next im going to try a FET as it's what Roland preffered to use.
Here's a recording.
https://soundcloud.com/dot/ir3109-12db-ota-build |
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jackdamery
Joined: Apr 26, 2010 Posts: 75 Location: UK
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roglok
Joined: Aug 28, 2010 Posts: 202 Location: uptown
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Sethkaine
Joined: Sep 26, 2015 Posts: 16 Location: Suisse
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wackelpeter
Joined: May 05, 2013 Posts: 461 Location: germany
Audio files: 10
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Posted: Tue Oct 20, 2015 12:48 pm Post subject:
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just finished that above mentioned 121 VCF and hmmm... i'm not so glad with my result... i have used 2xLM13700 and 4x 2SK30 instead of the original parts...
the filter does self oscillate but only in the very low spectrum and the Output is rather a square than a sine... even with no Input at Audio in...
tried playing aroud with the resistors in the Feedback path of resonance...
reducing that 6,8k resistor even lowered the frequency so i thougth ok let's increase it... so i soldered a 4,7k with a 10k trimmer in series and well it's slightly higher and the resonance Output is lower in Amplitude but i only get more of a humming frequency and when i only had 68k in self oscillation disappeared...
any idea how it's original behaviour is?
does it cover a wider range of frequencies in self oscillation?
any Information or Input would be welcome as usual... thank you _________________ https://soundcloud.com/bastian-j |
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roglok
Joined: Aug 28, 2010 Posts: 202 Location: uptown
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Posted: Sun Nov 01, 2015 4:21 am Post subject:
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wackelpeter wrote: | just finished that above mentioned 121 VCF and hmmm... i'm not so glad with my result... i have used 2xLM13700 and 4x 2SK30 instead of the original parts...
the filter does self oscillate but only in the very low spectrum and the Output is rather a square than a sine... even with no Input at Audio in...
tried playing aroud with the resistors in the Feedback path of resonance...
reducing that 6,8k resistor even lowered the frequency so i thougth ok let's increase it... so i soldered a 4,7k with a 10k trimmer in series and well it's slightly higher and the resonance Output is lower in Amplitude but i only get more of a humming frequency and when i only had 68k in self oscillation disappeared...
any idea how it's original behaviour is?
does it cover a wider range of frequencies in self oscillation?
any Information or Input would be welcome as usual... thank you |
something must be wrong with your build. i am getting a very nice sine wave across the whole spectrum:
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roglok
Joined: Aug 28, 2010 Posts: 202 Location: uptown
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Posted: Sun Nov 01, 2015 4:24 am Post subject:
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did you pay attention to the FET pinouts?
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wackelpeter
Joined: May 05, 2013 Posts: 461 Location: germany
Audio files: 10
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Posted: Sun Nov 01, 2015 10:31 am Post subject:
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Hi Roglok,
thanks for your reply.
Have soldered the FET according to the SK30 data sheet i found at my suppliers pages.
These are as per front view (where you can read the identifier) from left to right source, gate and drain...
and when i read the original schematic correct, then there is the gate connected to the Output of the OTA the source to +15V and the drain goes to the next stage and -15V via resistor. correct?
Wasn't there something about 2N3819 Fet's where sometimes the Pins where swapped? _________________ https://soundcloud.com/bastian-j |
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wackelpeter
Joined: May 05, 2013 Posts: 461 Location: germany
Audio files: 10
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Posted: Tue Nov 03, 2015 10:31 am Post subject:
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Problem fixed...
Forgot to cut two rails on my stripboard design so that the gates and drains of the FET's between stage 2 and 3 where tied together... luckily nothing blew up and i have now a sine over the whole spectrum with full resonance and the filter sounds like a filter know and not only like an VCA turning tone on and off...
will now tweak and tune it a bit until i'm satisfied...
should consult my doctor and check my eyes as i have checked the layout a few times but always missed that failure... _________________ https://soundcloud.com/bastian-j |
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isak
Joined: Dec 13, 2009 Posts: 847 Location: Israel
Audio files: 18
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Posted: Sat Nov 07, 2015 11:59 pm Post subject:
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Hi wackelpeter
Did you made the VCF on stripboad? Dude, your crazy
Must be a big stripboard
May I be rude and ask for your stripboard design, I will love to build this vcf
Cheers,
Isak E. _________________ http://www.myspace.com/mgmtrance |
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wackelpeter
Joined: May 05, 2013 Posts: 461 Location: germany
Audio files: 10
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Posted: Sun Nov 08, 2015 3:10 am Post subject:
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hm... i've always built all my modules on stripboard... so far 4 cases of 48x35 cm filled with 79 modules are filled...
most competing modules where so far the serge vcadsr and serge vcs and the mfos quantizer...
i mostly use the normal 100x160 mm stripboards... just a very few use the 100x200 mm ones...
can you give me a hint and a link to some good Freeware stripboard layouter? otherwise i could draw it on paper and then scan it... but i think that could be hardly to read...
i also have to say that i used lm13700 and 2sk30 so that this layout is limited to them or equivalent pin compatible stuff (LM13600 would work too)
i maybe start when i have finished replacing two older simple AR-Generators with Ian's AD/AR and Delayed Pulser... just have to twaek it a bit for another LED for the Envelope and include two Switches for different Timings as there are already some holes in my case from the previous modules...
ah nearly forgot it... most important and maybe of interest it's not the SH101 VCF that i've built it's the System 100 121 VCF...
but both are using 4 OTA stages... so i think they are somewhat comparable...
Here's a link to most of the Roland VCF schematics:
http://fa.utfs.org/diy/roland_filters/ _________________ https://soundcloud.com/bastian-j |
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isak
Joined: Dec 13, 2009 Posts: 847 Location: Israel
Audio files: 18
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wackelpeter
Joined: May 05, 2013 Posts: 461 Location: germany
Audio files: 10
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Posted: Sun Nov 08, 2015 1:55 pm Post subject:
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The Program doesn't run on my PC... after installing and trying to open it always two failure reports occur...
tried googling for another Version and downloaded... that one runs but i think it's way to complicated to draw that all with this program..
I think i'll be much faster with drawing it on paper (squared paper or wathever it'S called) and scan that together with some photos guess that will be easier and much faster...
will go on tomorrow... _________________ https://soundcloud.com/bastian-j |
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isak
Joined: Dec 13, 2009 Posts: 847 Location: Israel
Audio files: 18
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Posted: Sun Nov 08, 2015 2:46 pm Post subject:
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ohh sorry about that...
you need to open it as admin.
meaning, right click on the icon, and go to "Run as Administrator"
this will fix it
sorry again, i forgot about it. _________________ http://www.myspace.com/mgmtrance |
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wackelpeter
Joined: May 05, 2013 Posts: 461 Location: germany
Audio files: 10
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Posted: Mon Nov 09, 2015 7:59 am Post subject:
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Just had a few minutes at work left to figure out some things on the Version i downloaded and installed...
seems as most things i could need i'm able to draw them but one Thing i haven't figured out yet... how can i bend a leg of a Transistor...
mean normally you have them in a straight row or triangle
o e
o b
o c
o e
xo b
o c
the o's here are the legs and the x is a cut trace/hole
i wan't to know how i can bend them that it's like below
o emitter
o base
x or other trace
o collector
is this possible? if so how?
anyway this Programm seems better as i first thougth of it... must get rid of my fear about new technoligies... _________________ https://soundcloud.com/bastian-j |
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wackelpeter
Joined: May 05, 2013 Posts: 461 Location: germany
Audio files: 10
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isak
Joined: Dec 13, 2009 Posts: 847 Location: Israel
Audio files: 18
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Posted: Mon Nov 09, 2015 11:33 am Post subject:
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this is great, thank you very much!!!
i have a Q if i may...
what scheme did you use for this layout? _________________ http://www.myspace.com/mgmtrance |
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wackelpeter
Joined: May 05, 2013 Posts: 461 Location: germany
Audio files: 10
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Posted: Mon Nov 09, 2015 11:47 am Post subject:
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that was the original schematic attached in the 121 VCf clone pdf from frequency central... see above in this thread...
just figured out the Pins of the LM13700 vs Ba662 and then going for it..
i have to tell that ialso tried to mod this with a small passive hpf via Rotary swith and different cap sizes... works not as well as thought first... it's more lowering the volume than filtering higher frequencies out...
edited that in my previous post too... have spotted the first mistake... both drains between FEt 2 and 3 should be separated... the same i've forgotten in my first own build... i knew someone, who can endlessy repeat the same stupid mistake... _________________ https://soundcloud.com/bastian-j |
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isak
Joined: Dec 13, 2009 Posts: 847 Location: Israel
Audio files: 18
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Posted: Mon Nov 09, 2015 10:40 pm Post subject:
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Thank you very much!
Very informative
Another Q please, how did you match the FETS? _________________ http://www.myspace.com/mgmtrance |
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wackelpeter
Joined: May 05, 2013 Posts: 461 Location: germany
Audio files: 10
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isak
Joined: Dec 13, 2009 Posts: 847 Location: Israel
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alanwilder81
Joined: Sep 03, 2016 Posts: 310 Location: italy
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