Author Topic: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter  (Read 100102 times)

slacker

Re: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter
« Reply #140 on: May 09, 2009, 11:01:26 AM »
I think you need rail to rail opamps for that envelope follower to work. The second stage has the + input referenced to ground and "normal" opamps often only work to within a few volts of the rails.

frequencycentral

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Re: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter
« Reply #141 on: May 09, 2009, 01:09:47 PM »
I think you need rail to rail opamps for that envelope follower to work. The second stage has the + input referenced to ground and "normal" opamps often only work to within a few volts of the rails.

Thanks Ian, so what would have to change (and how) in that envelope follower to make it work with a 4558?
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frequencycentral

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Re: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter
« Reply #142 on: May 12, 2009, 06:45:26 PM »
I think I might have found the bug in this design. I just breadboarded the envelope follower for another circuit I'm working on. I used a 4558 for the two opamps that make up the envelope generator - and it didn't work. As soon as I changed to an LM324 for those two opamps it worked. Is that it? I hope so. Strange, I would have thought it would work the same with 4558s.

I think you need rail to rail opamps for that envelope follower to work. The second stage has the + input referenced to ground and "normal" opamps often only work to within a few volts of the rails.

Thanks Ian, so what would have to change (and how) in that envelope follower to make it work with a 4558?

I did get my breadboard circuit using the 4558 to work by switching the 220K and 100K resistors (after the Range control) from ground to vref. This may affect the range of the output of the unity gain buffer after the detector, so the biasing of the resistors at pin 1 and 16 of the 13700 may need tweaking.
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chicago_mike

Re: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter
« Reply #143 on: May 13, 2009, 05:39:26 PM »
Mine are being built off the pcb pdf. I think I should be fine. :)

I just need to get off my butt and order the lm13700's I need about 10 anyways. :icon_redface:

orangetones

Re: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter
« Reply #144 on: May 13, 2009, 09:24:36 PM »
Do let us know if you get it working off that PCB.  Others have not had any luck.

chicago_mike

Re: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter
« Reply #145 on: May 14, 2009, 02:58:17 AM »
UH OH!!!!!! :-[

Well once i get the lm13700's ill be bale to find out.

What seems to be the biggest issue? And when you say not working off the pcb, is not working in any way shae or form or does it kinda sorta work?

Damn! :-X

orangetones

Re: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter
« Reply #146 on: May 14, 2009, 02:23:52 PM »
My suggestion would be to go back and read through this entire thread.  If I am correct there was much discussion about the functionality of this project.

chicago_mike

Re: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter
« Reply #147 on: May 14, 2009, 02:44:11 PM »
Oh god...the read the thread answer....

Thats never good. :P :icon_cry:

frequencycentral

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Re: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter
« Reply #148 on: May 14, 2009, 08:11:28 PM »
My suggestion would be to go back and read through this entire thread.  If I am correct there was much discussion about the functionality of this project.

$h!t, am I going to have to build myself another to salvage my tarnished reputation? It's hardly rocket science - but a more complex build than a Fuzz Face!
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chicago_mike

Re: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter
« Reply #149 on: May 14, 2009, 09:43:24 PM »
I just need some of those ota's to give mine a run through.

I have the ca3280's and if I knew how to do it, I would make some kind of converter board and just use those.

perhpas you should build another...but really for the purpose of having another filter. you can never have too many. And us bass players need cool diy pedals..NOt another ff or tonebender, or derivative. :)

chicago_mike

Re: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter
« Reply #150 on: July 08, 2009, 04:04:34 AM »
Well I orderd my LM13700's and I have the LM324's and the tlo72 / 062's.

I was wondering if theres any progress on this project from others. :icon_smile:  I have the schematic for another ef that uses the 13700 but I would like to get this going first.

T1bbles

Re: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter
« Reply #151 on: January 23, 2010, 10:31:12 AM »
Has anyone anywhere got this circuit to work yet? Other than the mighty Rick of course ;) I've sat for about an hour now switching between the schem and the PCB layout and it all seems to be right, unless I've overlooked something, which isn't unlikely!

It'd be a shame to have to give up, cuz this baby looks and sounds a beast!
Behringer don't do signatures, but if they did, they'd probably stop working mid sen

frequencycentral

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Re: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter
« Reply #152 on: January 23, 2010, 10:52:24 AM »
Development thread for a future version 2 with more features and less issues here: http://circuitworkshop.com/forum/index.php?topic=235.0
http://www.frequencycentral.co.uk/

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svstee

Re: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter
« Reply #153 on: February 19, 2010, 05:32:22 PM »
Anything new with version 2? Should I wait for it or build V1?

frequencycentral

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Re: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter
« Reply #154 on: February 19, 2010, 05:33:30 PM »
Anything new with version 2? Should I wait for it or build V1?

Wait.............................
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svstee

Re: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter
« Reply #155 on: February 19, 2010, 06:37:06 PM »
Awesome! Looking forward too it.  ;D

Altitude

Re: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter
« Reply #156 on: February 28, 2010, 05:25:52 PM »
Greetings all. I've been lurking around here looking for a worthy filter for a expanded 8 bit sampler I am working on and this thing sounds like exactly what I am looking for.. In lieu of the issues with the envelope follower could it just be dropped and the filter run wide open permanently? For my needs, that would be fine. Frequency Central, you mentioned that someone else got this working with a different env design, can you elaborate?

frequencycentral

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Re: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter
« Reply #157 on: February 28, 2010, 05:29:06 PM »
Greetings all. I've been lurking around here looking for a worthy filter for a expanded 8 bit sampler I am working on and this thing sounds like exactly what I am looking for.. In lieu of the issues with the envelope follower could it just be dropped and the filter run wide open permanently? For my needs, that would be fine. Frequency Central, you mentioned that someone else got this working with a different env design, can you elaborate?

Boogdish made three posts on page 2, including a vero layout for the filter section: http://www.diystompboxes.com/smfforum/index.php?topic=73021.msg593387#msg593387
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Altitude

Re: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter
« Reply #158 on: February 28, 2010, 05:31:45 PM »
Gotcha, thanks.

So just tie pin 1 and 16 and it will be "open"?
« Last Edit: February 28, 2010, 05:36:30 PM by Altitude »

frequencycentral

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Re: "Funky MF (Multimode Filter)" - LM13700 Multimode Envelope Filter
« Reply #159 on: February 28, 2010, 05:38:54 PM »
Gotcha, thanks.

So just tie pin 1 and 16 and it will be "open"?

Yeah, you can use other stuff to modulate the filter then. Don.t forget a resistor between your modulator and pins 1/16.
http://www.frequencycentral.co.uk/

Questo Ŕ il fiore del partigiano morto per la libertÓ!