i've been on a synthy guitar sounds quest of late..
which tried n tested good synthy filters have you built / incorporated into a pedal...or as a stand alone unit.?
recommendations?. ;)
Quite frankly, just about ANY filter sounds more "synth-ey" on a guitar if it has a relatively quick decay. I modded up a Bass Balls with a variable decay, filter stagger, and filter blend control, that you can hear here. You'll have to excuse the overly lengthy techtalk at the beginning, and the fluorescent light him picked up on the audio, but you can still hear what that various controls are able to do to an otherwise nondescript circuit. For my part, I think it nails some of the sounds of EHX's old Mini-synth keyboard.
Phunkpunk: http://www.youtube.com/watch?v=eoAIKHFGOcQ
Minisynth: http://www.youtube.com/watch?v=Mi9Kh4bgl5Y
And one should also note that audible envelope ripple can be "cured" in one of two ways: making the decay time slower so that ripple is more averaged out, or making it faster, so that ripple doesn't have a chance to be heard. So not only does a faster decay sound more synthey, but it also has less ripple. Win-win.
I would like to get my hands on the EH Riddle Q Balls schematic, there is some wonderful smooth sweep circuitry in there by the sound of it!
cheers mark, i have messed with the bassballs on breadboard before...
i liked it a lot , but didn't want the dirt with it. i'd rather the 'option' of adding my own dirt to it.
the synth sounds are more like it... 8)
Quote from: StephenGiles on August 30, 2013, 01:33:32 PM
I would like to get my hands on the EH Riddle Q Balls schematic, there is some wonderful smooth sweep circuitry in there by the sound of it!
Here is a little clue to what it could be based on, check the bit I have circled in red.
(http://i90.photobucket.com/albums/k243/lenny1dog/riddle_zps472f8773.jpg) (http://s90.photobucket.com/user/lenny1dog/media/riddle_zps472f8773.jpg.html)
lol...yeah...subtle. 8)
any write ups on those bassballs mods? i'm intrigued
The 'Wah' setting on EHX The Worm is a great filter-sound. I used to try and simultaneously adjust the rate and range knobs while playing, which was a bit easier on the old big box version. It has somewhat of that filter sound Air used in 'All I Need'.
I also build a The Worm and replaced the LFO with the envelope-driver of a Q-tron which made for a great envelope filter. Really smooth compared to the grittier Q-Tron sound.
Quote from: Ice-9 on August 30, 2013, 01:45:19 PM
Quote from: StephenGiles on August 30, 2013, 01:33:32 PM
I would like to get my hands on the EH Riddle Q Balls schematic, there is some wonderful smooth sweep circuitry in there by the sound of it!
Here is a little clue to what it could be based on, check the bit I have circled in red.
(http://i90.photobucket.com/albums/k243/lenny1dog/riddle_zps472f8773.jpg) (http://s90.photobucket.com/user/lenny1dog/media/riddle_zps472f8773.jpg.html)
The filter circuit may well be common to the Qtron & Riddle but certainly not the sweep generator.
Quote from: musiclikscreams on August 30, 2013, 02:00:03 PM
any write ups on those bassballs mods? i'm intrigued
If you're referring to the thing I posted, the first 5-6 minutes of me droning on and pointing to a schematic outline the specifics of the mods. I wouldn't watch it if you're up past your bedtime, but if you're not easily lured into yawning, it's all there.
MFOS Subcommander?
http://www.musicfromouterspace.com/index.php?MAINTAB=SYNTHDIY&VPW=1024&VPH=550
Its just so darn cool.
^ yeah seen that... 8)
i'm just looking for simple - ish filters to mess with and maybe add a simple slow lfo..
edit: i was looking at the Q&D filter / escobedo circuit/s....but can't find the link with clips?.
By far the best, and most synthy-sounding filter I have tried is the "Korg MS-20" low pass filter: Escobedo has a very simple 9 volt version, as does Eric Archer (search "eric archer voltage controlled filter") which is the version i built. It's superb! The resonance can be dialled right up to self-oscillation, and it is super squelchy and synth-like. The circuit has a pot for the cut-off frequency, and I use an expression pedal to control the sweep like some kind of uber-wah, but it wouldn't be difficult to use an add-on envelope detector or LFO to control the sweep: Or all three.
sounds cool to me..
funny i was just looking at a vid of that ms20 9v+ version with expression pedal.
envelope detect, lfo would be nice.. 8)
Quote from: nocentelli on August 30, 2013, 03:24:25 PM
By far the best, and most synthy-sounding filter I have tried is the "Korg MS-20" low pass filter: Escobedo has a very simple 9 volt version, as does Eric Archer (search "eric archer voltage controlled filter") which is the version i built. It's superb! The resonance can be dialled right up to self-oscillation, and it is super squelchy and synth-like. The circuit has a pot for the cut-off frequency, and I use an expression pedal to control the sweep like some kind of uber-wah, but it wouldn't be difficult to use an add-on envelope detector or LFO to control the sweep: Or all three.
Plenty of folks like to humorously refer to the MS-20 filter as "the world's most dangerous filter".
At least part of what tends to differentiate wah from "synth-ey filter" sounds, for guitar players, is use of high resonance lowpass settings. Wahs are essentially bandpass filters, and a great many autowahs Though not all) are also bandpass. In contrast, if you're going to skimp in a synth, you'll have a lowpass filter and that's it, so we have a mental association between lowpass filtering and synths.
It is also the case that synth filters usually have more poles than guitar pedals. Even the almost-a-synth EHX Microsynth has a 3-pole lowpass filter. The "Minimoog sound" we all love so much is the result of a 4-pole lowpass filter. And the thing you need to remember about steeper filters is that when the corner frequency changes, you tend to alter the harmonic content a lot more than a shallower filter does. So where a single or 2-pole bandpass or lowpass filter still lets through a lot of top end, and has to sweep way down low for it to completely disappear, a 4-pole filter doesn't have to sweep all that far for the timbral character to change a lot.
But yeah, that Eric Archer 9V MS-20 video does sound sweet.
While envelope following would be nice, don't forget triggered sweeps using a transient generator, where you can have more control over both attack and decay, start and stop points.
Quote from: Mark Hammer on August 30, 2013, 02:35:37 PM
Quote from: musiclikscreams on August 30, 2013, 02:00:03 PM
any write ups on those bassballs mods? i'm intrigued
If you're referring to the thing I posted, the first 5-6 minutes of me droning on and pointing to a schematic outline the specifics of the mods. I wouldn't watch it if you're up past your bedtime, but if you're not easily lured into yawning, it's all there.
Very interesting video Mark.
Here's a link to a recent MS-20 thread. (http://www.diystompboxes.com/smfforum/index.php?topic=97062.0) I've breadboarded it with LFO and LED/LDR kinda crap and it blew my mind. Haven't built a hard wired version yet, though, so I guess that's a little OT. :P Worth trying for sure.
Here's Escobedo's circuit snippets. (http://folkurban.com/Site/GuitarEffects-681.html)
Check out some of Ray's single-sided filter circuits. (http://www.musicfromouterspace.com/index.php?MAINTAB=SYNTHDIY&VPW=1590&VPH=1009) Look under 'guitar projects' or 'LO-FI noise boxes' for simple filters.
I have great fun with simple switch cap filters - modulating them and the like..... check out my ring modulator post and the video demo - after the first two minutes I demonstrate some of the filter effects. Very easy to implement for filtering/ phase shifting.
http://www.diystompboxes.com/smfforum/index.php?topic=103348.msg920233#msg920233 (http://www.diystompboxes.com/smfforum/index.php?topic=103348.msg920233#msg920233)
@rring, thats pretty cool, but im not really a fan of ring modulators, 8)
When it comes to annoying everyone around you, not much beats the Ring Stinger.
Always wanted a modular synth (budget issues...), and FC's link in the MS20 thread does not help! When I finish some of the stuff in the queue, I might have to breadboard up a filter circuit :D
This is a treasure trove of modular synth circuitry:
http://www.musicfromouterspace.com/ (http://www.musicfromouterspace.com/)
I was going to get into playing with some of this stuff but never did. Nice sound samples, PCB's available, some stuff designed for guitar, etc, etc...
Yes - forget the ring modulator - in the schematic you can just see an example of how I use the filter. The ease in adjusting the curve and steep cut off allows for great modulated filter effects and envelope effects, etc. In general when I just play around with these type of filters on a breadboard - I can generate very synth like sounds with few parts and little effort.
@gary: cheers for the links. 8)
what IC is used for the Q&D, just an op amp?..
http://folkurban.com/Site/QDVCF-714.html
Will this one run on a lm13700n ?
http://folkurban.com/Site/9VpoweredMS20SallenKeyLPVCF-690.html
yes and yes, cheers!
goody gumdrops.. 8)
before i breadboard these up, has anyone added a nice slow lfo or envelope detect to either or both already?..
I've made a similar MS-20 style filter and used LFO for the cutoff frequency, definitely synthy. You can get great sci-fi sounds, too.
Here's some advice from Taylor:
QuoteHis MS20-ish design is better for a more typical synth filter sound. You can lower the resistors from the CV pot to the Iabc pins of the OTAs to get higher frequency range with it, which I definitely recommend.
The Q+D VCF does a surprisingly good job of faking a lowpass resonant filter considering how basic it is. But it distorts very easily because it's using a diode trick to get voltage control.
from Paul Perry (frostwave), MS-20 champion:
QuoteIn most circuits, there isn't a difference between the 13600 and 13700.
Cool, i have the Q&D on breadboard at the mo.....ive trimmed it down to basics a bit more...no resonance , etc.
been tapping whilst changing the freq pot, its pretty cool.....interesting.
i'll try the ms20 later...
I just finished Wasp VCF from a modular synth design. Runs on +9V and has multi modes: LP, BP, HP, Notch! And, the one I did has switchable overdrive! I have not made sound samples yet as I have to replace a bad potentiometer and have not had much time for circuits. But here are links in this thread:
http://www.diystompboxes.com/smfforum/index.php?topic=102714.0 (http://www.diystompboxes.com/smfforum/index.php?topic=102714.0)
*EDIT: I did this as a pedal format "standalone" not as a synth module! works well - might need an LFO or Envelope follower but I use LFO from my Gristliezer right now, patched to the CV input of Wasp VCF.
^ cool that looks very interesting..i'd llove to hear it.
being a total synth noob i don't really understand this CV lark though.... ???
CVs are regularly in use by guitarists in their pedals. It's just that we tend not to talk about them, or plan around them. For example, virtually every modulation effect uses a control voltage to make something happen. Many (though not all) expression pedals use a CV to control something. Where we tend to get confused about such matters is that in a guitar pedal, a CV is connected directly and exclusively.
So, for example, consider the EA tremolo. The LFO produces a control voltage, and the current from that is applied to the gate of a JFET, that acts like a voltage-controlled resistor, and varies the gain of another transistor. It IS a CV-based effect, BUT...it is a closed system. That is, the CV from the LFO is connected directly, and not made available to other pedals.
In contrast, were one to have a modular synth, you'd likely have a standalone module with one or two LFOs, and a bunch of jacks for patching the LFO outputs to other circuits in other modules. It is primarily the open-ended aspect of control-voltages that differentiates how synth players use them, versus how guitarists use them.
Of course, being open-ended imposes certain requirements. Guitar pedal X might only make use of control voltages between this min and that max, and has the luxury of having its own self-contained LFO that provides that particular range. In the synth world, it is assumed that - as standalone modules - one does not know where an envelope generator or LFO or joystick or breath-controller is sending the CV to, or indeed how many devices it will be "shared" by. So they are designed around standards, such that system A might assume CVs ranging from 0-5v, system B might presume a 0-10V range, and system C might assume 0-15V (somewhat rare). Both the circuits providing the control voltages, and the circuits being controlled by those CVs assume a particular standardized range of possible CVs.
What all of this means is that many synth filter modules CAN be used for guitar. What is required is a suitable source of control voltage that matches the requirements of the filter. So, although a Dr. Q / Nurse Quacky will provide an envelope voltage to control a filter, it may not provide enough of a voltage to make a synth filter sweep very far within its range. Consequently, either the sensitivity of the filter needs to be modified to anticipate a more restricted range on CVs, or else the circuit providing the CV has to be modified to deliver a wider voltage range, so as to make the filter behave in the desired manner.
There, clearer?
^ brilliantly explained...thanks mark. 8)
Quote from: Strategy on September 10, 2013, 06:03:36 PM
I just finished Wasp VCF from a modular synth design. Runs on +9V and has multi modes: LP, BP, HP, Notch! And, the one I did has switchable overdrive! I have not made sound samples yet as I have to replace a bad potentiometer and have not had much time for circuits. But here are links in this thread:
http://www.diystompboxes.com/smfforum/index.php?topic=102714.0 (http://www.diystompboxes.com/smfforum/index.php?topic=102714.0)
*EDIT: I did this as a pedal format "standalone" not as a synth module! works well - might need an LFO or Envelope follower but I use LFO from my Gristliezer right now, patched to the CV input of Wasp VCF.
I'd love to hear what this sounds like, too. 8)
~ Charlie
QuoteSo, although a Dr. Q / Nurse Quacky will provide an envelope voltage to control a filter, it may not provide enough of a voltage to make a synth filter sweep very far within its range.
Can the control voltage from, say, the envelope follower in the Dr. Q, be amplified for sweep like a LFO? For instance, can one easily* tap into the envelope voltage, run it through an op amp and send it on its merry way?
i had a thought last night of using both opamps with 2 Q&D filters.. :icon_idea:
just breaded both up and sound great...one filter is as per escobedo's..the other has 1uf/4.7n caps..sounds nice and thick...
if i can add a nice smooth slow lfo to both it should sound pretty good imo....tinker tinker.. 8)
https://dl.dropboxusercontent.com/u/7464107/2q%26dfilters.mp3
q&d experiments clip
1st hi filter...
2nd low filter
3rd both filters..
I was looking at the Q&D filters only a few weeks ago, and thought they looked interesting. With that demo, they have moved rather near the top of my list. What LFO are you using?
No lfo at the mo, just tapping and turning pot...
Sounding good D'Astro! I'm gonna breadboard two of these in series and hook `em up to the ol' TAPLFO. This is going to turn into a fun project, I can feel it...
cheers man, lfo and envelope follower would be cool too.
bit busy for the next few days, but it sounds so nice its defo going to be on my breadboard for a while... :)
i'll post up a schemo of what i have so far later if i get time .
check my last post about the remote wah mad and the gain control. very synthy for a wah pedal.... Cheap mods to make if you have a wah lying around.
Interesting, clip sounds almost phaser like!
Could anyone recommend an envelope detector-> CV output circuit that might well with guitar and might be suitable for these synth-y filters? I've tried the Meatball arrangement, but it's a bit tricky to get it too work, and the "attack" and "decay" controls are so interactive. I only end up leaving one at max and one at minimum, so they are somewhat superfluous.
Well, it is an Escobedo-related thread, check out the Phuncgnosis?
Read this thread. (http://www.diystompboxes.com/smfforum/index.php?topic=37679.0)
From Mr. Escobedo:
QuoteThe CV signal is injected into the signal path as a kind of fluctuating DC component, causing the LED(s) to vary in resistance, which dynamically tunes the filter.
Some 20 years ago, maybe more, I built an Anderton/EPFM Super Tone Control into a wah shell, sweeping it with a dual-ganged pot, and installing a reverse-sweep switch to flip the outside lugs of the dual pot around so that I could change the direction of sweep for toe-forward. The STC is a basic state-variable filter, as found in the Mutron, Meatball, and a zillion other things.
The unit would provide lowpass, bandpass, highpass, and band-reject (notch) if you combined lowpass and highpass. You wouldn't think that a foot-operated pedal requires a direction-reverse, the way that something like an autowah does. However, where sweeping toe-down moves the centre frequency of a bandpass and band-reject upward, and the corner frequency of a lowpass upwards, it also completely guts the outcome of a highpass filter as you sweep forward. One's natural inclination for a foot-swept pedal is that you lean forward for greater emphasis, so getting a wimpier sound in toe-down just works counter to your inclinations. So I built in a means to reverse the direction of sweep. Worked great.
Indeed, modding any autowah that uses a state-variable filter to be controlled by a foot-pedal will get you some nifty, and synth-ey, sounds. Part of that is because the sweeps you can get with foot-control start to approximate what you can get with long attack times...but without requiring a trigger and transient generator. The reverse-sweep also provides for the sorts of sweeps that are very hard to get from an autowah.
Just a caveat that not all dual-ganged pots will fit in the available space in wah shells, or accept the gear in the rack-and-pinion systems. I suppose one could use an existing single pot to control the current feeding one or two LEDs that govern a pair of LDRs.
Quote from: Mark Hammer on August 30, 2013, 01:30:09 PM
Quite frankly, just about ANY filter sounds more "synth-ey" on a guitar if it has a relatively quick decay. I modded up a Bass Balls with a variable decay, filter stagger, and filter blend control, that you can hear here. You'll have to excuse the overly lengthy techtalk at the beginning, and the fluorescent light him picked up on the audio, but you can still hear what that various controls are able to do to an otherwise nondescript circuit. For my part, I think it nails some of the sounds of EHX's old Mini-synth keyboard.
Phunkpunk: http://www.youtube.com/watch?v=eoAIKHFGOcQ
Minisynth: http://www.youtube.com/watch?v=Mi9Kh4bgl5Y
And one should also note that audible envelope ripple can be "cured" in one of two ways: making the decay time slower so that ripple is more averaged out, or making it faster, so that ripple doesn't have a chance to be heard. So not only does a faster decay sound more synthey, but it also has less ripple. Win-win.
Hey Mark,
On your Phunkpunk for your decay knob I believe your video states that you replaced the 330k with a 47k and a 500kto1M pot. I assume this controll responds in a linear fashion? So a linear pot would be most beneficial?
Quote from: deadastronaut on September 12, 2013, 10:22:36 AM
https://dl.dropboxusercontent.com/u/7464107/2q%26dfilters.mp3
q&d experiments clip
1st hi filter...
2nd low filter
3rd both filters..
Sounds great Rob! At first I thought that you were playing a single note and the circuit was playing the 16th notes while it was sweeping, but I'm sure you were alternate picking the 16th notes. Very promising! Time for some "Teenage Wasteland"!
^ ;)
ok ive been breading an lfo here..(ricks)
http://www.diystompboxes.com/smfforum/index.php?topic=74294.msg623245#msg623245
and hooking it up to the CV...( without led) but i'm not getting the Q&D filters full sweep....just a little really..its working, but much weaker than i thought it would.
should i get rid of the freq pot entirely?..
should i be using another lfo to drive the filter sweep?
Quote from: pappasmurfsharem on September 14, 2013, 03:11:47 AM
Quote from: Mark Hammer on August 30, 2013, 01:30:09 PM
Quite frankly, just about ANY filter sounds more "synth-ey" on a guitar if it has a relatively quick decay. I modded up a Bass Balls with a variable decay, filter stagger, and filter blend control, that you can hear here. You'll have to excuse the overly lengthy techtalk at the beginning, and the fluorescent light him picked up on the audio, but you can still hear what that various controls are able to do to an otherwise nondescript circuit. For my part, I think it nails some of the sounds of EHX's old Mini-synth keyboard.
Phunkpunk: http://www.youtube.com/watch?v=eoAIKHFGOcQ
Minisynth: http://www.youtube.com/watch?v=Mi9Kh4bgl5Y
And one should also note that audible envelope ripple can be "cured" in one of two ways: making the decay time slower so that ripple is more averaged out, or making it faster, so that ripple doesn't have a chance to be heard. So not only does a faster decay sound more synthey, but it also has less ripple. Win-win.
Hey Mark,
On your Phunkpunk for your decay knob I believe your video states that you replaced the 330k with a 47k and a 500kto1M pot. I assume this controll responds in a linear fashion? So a linear pot would be most beneficial?
I wish I could tell you, but a guy saw the video, contacted me, and bought it earlier this year. But, given how the ear/brain works, I suspect that log or reverse-log would be optimal; log if the pot is wired to get you smaller resistances (i.e., faster decay) going clockwise, and reverse-log if clockwise gets you slower decay. Alternatively, there is absolutely nothing wrong with using a 3-position toggle to get fast/medium/slow decay (47k, 330k, 1M).
Quoteshould i get rid of the freq pot entirely?
try lowering the 100k CV in resistor?
are you including the 100k on the LFO output?
hi gary,
cv: tried lowering , and totally without the 100k..
got rid of lfo out 100k..
i got a more defined sweep...but its still not the full sweep that the freq pot range is..
A 100k pot across a 9v supply will sweep the CV from 0 to 9V , an LFO running from a 9V supply will have an output swing of quite a bit less , perhaps 2/3 . So , the overall effect will be milder . ( I think ! )
yeah makes sense i guess..
so i need an lfo that sweeps 0-9v...
any ideas?..links?.. :)
just found this from paul
http://www.diystompboxes.com/smfforum/index.php?topic=87861.msg739719#msg739719
edt: just tried that,^ i'm getting 2.7 to 7.3 voltage swing...
so am still missing the crucial low and top end...hmmmm..
Adding gain to your second op-amp will help, but unless you use a rail-to-rail op-amp, the best you can hope for is about 2-7 V. If you have an LM358, that can pull down to 0, which might be helpful.
I had previously sim'd the filter, and just took another look. You're using something like this right?
http://folkurban.com/Site/QDVCF-714.html
As you have probably discovered, the sweep works all the way from 0 to 9V. Bass at 0V, trebble peak at 9V. If you are stuck with ca. 2-7 V, then you probably want to shift the filter response 'down', so you still get a nice resonant peak at 7V. If you can't get there with by reducing the value of the 'resonance' resistor, then you might want to try increasing the value of the two series resistors a little.
cheers sam. yep that filter...
pretty sure i have a few 358's...
is it a case of just swapping the ic, or will (as i suspect) need a different lfo then.?...
Not sure that I have tried, but I can't see why that LFO wouldn't work with a 358. You might want to play with the values of the 100k voltage divider resistors (to the (+) input) to centre the LFO between the rails - say at about 3.5 - 4.0 V.
Quote from: deadastronaut on September 16, 2013, 04:45:34 AM
hi gary,
cv: tried lowering , and totally without the 100k..
got rid of lfo out 100k..
i got a more defined sweep...but its still not the full sweep that the freq pot range is..
You can`t just lower the CV 100k, or else the lowest possible frequency will go upward. Fmin is determined by the resistance between the two .01µf caps and (virtual) ground. This resistance is the parallel combination of the CV 100k, the Freq. 100k (plus the parallel resistances of the divided pot-halves), and the dynamic resistance of the LED. The latter is controlled by the current running through the LED. If you want to increase the LED current for accepting a low-voltage LFO swing by decreasing the LED series resistor (i.e.: the CV 100k) to e.g. 33k, you might want to adapt the whole twin-t filter. This can be done by multiplying the cap values by 3, and dividing the resistor values by 3. In theory ar least. (this concerns the left schematic here: http://folkurban.com/Site/QDVCF-714.html (http://folkurban.com/Site/QDVCF-714.html)).
@sam: tried the 358. much better for the lfo sweep... :icon_cool:
That's the kind of fix we like.
Thanks for explaining Lurco!
ok, for my next trick i shall be breading up the 9v ms20...and then adding lfo. :)
tinker, tinker...
Excellent: Currently got another MS20 on the breadboard in an attempt to get an envelop filter out of it, but please share your LFO findings.
okey dokey..will do.
breaded the ms20 twice with no joy though....hmmmm... ;)
Is it the Escobedo version you can't get to work? I used the Eric Archer schematic -
http://ericarcher.net/devices/diy-lpf/
I used the rail splitter and rail-to-rail opamp specified in the schematic, and initially had some confusion because the 4.5v vref supplied by the rail splitter is labelled as "0v" throughout the schematic. Once I got that sorted, it worked fine. You can omit the mix pot for guitar use, I just connected the 33k/10k junction from the OTA output to vref via a 10k to simulate 100% wet, and left off the dry path from the input->output mixer.
Hi leo, yep its the escobedo. one......its still not having it, i'll attack it again later.....probably pilot error.. ::)
that eric archer one sounds cool, but i have the bits for the escobedo one...
Haven't got 'darlingtons' and other IC....at the mo, so i'll persevere a little with this for now...
have you got your envelope going yet?..love to hear it.
D'Astro, check out the Cliff Schecht version. single side MS-20 (http://www.aronnelson.com/DIYFiles/up/ms20_9vsupply.pdf)
well i think i'll have to go with something other than a 13700n filter...tried 4 IC's...breaded it 3 times ...no joy..bummer
i never had any joy with these IC's, even when i tried the mutron V a while ago either...so they are either fake or fried....or i am more dumb than i thought.. :) (quite plausible)
anyway....
Booooo! Sorry to hear.
Random online filter help:
Analog Filter Wizard, courtesy of Analog Devices. (http://www.analog.com/designtools/en/filterwizard/#/type)
^ cool... 8) ;)
I built an MS20-type filter using LM13700 in a synth/noise box with dual LFO's a while back , just tried it out with guitar . It actually sounds pretty good IMHO , especially if you like Hawkwind-type stuff . I have posted a clip on Youtube , should be up in a while . A minor complication regarding stomp-box use is that it runs on +/- 12 V , but I'm sure that can easily ( ! ) be sorted . The VCF is based on one from the EFM Wildcat synth , the LFO's are from MFOS , as is the noise generator . Very noisy , very lo-fi , very fun !
^ yep i like old hawkwind stuff...and red shift, tangerine etc...i mess around with reason synths quite a bit too.. :icon_cool:
look forward to hearing it man.. 8)
ive temporarily gone back to the dual Q&D for now...sounds pretty good..
If you find a way to get the farty distortion down, let us know.
Right , I have posted a clip on Youtube of this MS20 box . Can any of you wonderful people tell me in simple words how to link it to here ?
I've had three tries , all I get is " Invalid Youtube link " . Please , help the Noob !
copy the link at the top of your youtube vid (url )...not share etc...
then choose youtube from here (top left)
then paste your copied link between the brackets...
[yohttp://www.youtube.com/watch?v=gTjcnvy31zI&feature=player_detailpageutube][/youtube]
If I've got this right , you should see a demo of some MS20 tomfoolery ......
Hmmmmmmm.......... nth time lucky ?!?!
Ha ! It worked at last ! Rob , you are a gentleman and a scholar !
By way of explanation , the other boxes are :-
Middle - by-pass loop switcher
Left - BMP type fuzz
Right - A boost , needed this to make up for a slight loss of volume at min resonance .
The controls on the filter/LFO/noise box are marked and should be ( ? ) self-explanatory .
The demo also includes oscillation at resonance and a bit of noise gen sillyness .
Cool vid - which MS20 schematic and which LFO did you use?
I downloaded the EFM schematics from a site which I have totally forgotten the name of - the schemos had a lot of errors and missing values , so I had trouble getting it to work properly . The main snag was that the resonance control worked like an off/on switch ! Then recently , I found a synth site called Lushprojects - they do a module " Lushone " , which was practically identical apart from the resonance section . I made the appropriate mods , the end result is what you hear !
The LFO's are from " MusicFrom Outer Space " -what a great site ! - look at the " Oldies but goodies " section - there is one called " Super-Simple LFO " - I used that but cut the Saw/Ramp bit . The NoiseGen is MFOS , not sure which one .
If you look at any of these VCF's , the CV is input via a 100K res usually . To use multiple LFO's or other modulation sources like envelopes or exp. redals , just add more 100K's .
I have not yet tried a 9V version , there is one a few posts back by Cliff Schecht - looks slighty more complex , but a similar idea . It has the bonus of a boost on the input , which would solve the problem I had .
I think the only issue in using 9V instead of +/- 12 might be a smaller voltage swing from the LFO , giving a milder effect . Possibly reducing the 10K resistor(s) on the 13700 current inputs could fix this ?
I am going to have a go at a 9V version , with more modulation possibilities - a triggered EG would be cool , perhaps a random LFO as well ? ???
QuoteThe LFO's are from " MusicFrom Outer Space " -what a great site ! - look at the " Oldies but goodies " section
Most of his projects include LFOs, there's a ton of stuff on that site, don't be afraid to adapt some of that simple synth stuff to guitar.
QuoteI have not yet tried a 9V version , there is one a few posts back by Cliff Schecht - looks slighty more complex , but a similar idea.
That version has a nice single sided current source, it's a benefit of Cliff actually being an engineer.
QuoteI think the only issue in using 9V instead of +/- 12 might be a smaller voltage swing from the LFO
+/-12V = 24V. 9V = +/-4.5V. kinda big difference.
QuotePossibly reducing the 10K resistor(s) on the 13700 current inputs could fix this ?
Be careful! Too much current and bye bye OTA
Quotehttp://www.diystompboxes.com/smfforum/Themes/diytheme/images/bbc/quote.gif
I know , max current for13700 is 2mA , so it anybody is not familiar with Ohm's law , learn it NOW !
Cool vid nick...sounds great. 8)
Thanks , Rob ! When I clear up the bench a bit , I'll mess with a 9V version . Not tried the Escebedo version , the resonance section on that looks odd compared to the others - most have an op-amp with diodes (like a TS ) in that area . Perhaps that's why you had trouble with it . I think I'll try mine as it is re-arranged for single-ended 9V , and tweak it up .
Assuming it works , I will share my results .
Nice one, i removed the resonance pot entirely..
i had a thought about having 2 lots of filter caps on each opamp... :icon_idea:
so it can be 4 in total using both opamps....2 each side....
ill give it a go on one opamp to see if it works...
I have good news ! My 9V version of the MS20 clone works ! Not put any modulation on yet , just varied the control current to pins 1 + 16 with a pot .
The schematic I used is basically the Rene Schmidt version ( RS 20 ) , with +15 = 9V
Gnd = Vref
-15V = GND
Vref is from a pair of 100k's as a potential divider into an op-amp buffer . The buffer is important , without it , Vref is all over the place
Lots more work and tweaking to do , but the basic circuit is a runner !
QuoteThe buffer is important , without it , Vref is all over the place
I ran into that problem right away.
cool nice one nick..
i just ordered a couple of 13700's from tayda, ...hopefully these ones will work. :o
then i can try it...AGAIN. :)
I usually get mine from Bitsbox , £1.24 at last look . I got 10 last time , heard rumours that they were getting scarce .
ahhh bitsbox..of course, oh well , i'll wait.. ::)
just messing around with a crude envelope detector...( different sound to light circuit , no 386)
(https://dl.dropboxusercontent.com/u/7464107/efdetect.jpg)
Quotei just ordered a couple of 13700's from tayda, ...hopefully these ones will work.
then i can try it...AGAIN.
Yay! You'll be happy you did. A true VCF with a real current source sounds so super synthy!
Got this running with an LFO now , after a lot messing with the control node . The sweep is not as extreme
as the +/- 12V version , but that is as expected . At low LFO rates , the effect is very mild on a clean signal
unless you crank the resonance - sounds OK with some dirt , though !
Hopefully , I'll post a schematic soon , after a little more twiddling .
I'm still dreaming about a "frostwave resonator" workalike - ms20 lp and hp filters in same box!!!...
Strategy
Quote from: garcho on September 25, 2013, 12:11:14 PM
Quotei just ordered a couple of 13700's from tayda, ...hopefully these ones will work.
then i can try it...AGAIN.
Yay! You'll be happy you did. A true VCF with a real current source sounds so super synthy!
(http://[url=http://s1239.photobucket.com/user/NICKDUNKERLEY/media/SAM_0411.jpg.html%5D%5BIMG%5Dhttp://i1239.photobucket.com/albums/ff510/NICKDUNKERLEY/SAM_0411.jpg)[/URL][/img]
Did that work ? ( Using PhotoBucket for the first time )
(http://[url=http://s1239.photobucket.com/user/NICKDUNKERLEY/media/SAM_0411.jpg.html%5D%5BIMG%5Dhttp://i1239.photobucket.com/albums/ff510/NICKDUNKERLEY/SAM_0411.jpg)[/URL][/img]
nope
(http://i1239.photobucket.com/albums/ff510/NICKDUNKERLEY/SAM_0411.jpg)
Aaaahhhhh .... GOTCHA !
Scanners , don't talk to me about scanners.......... ! It's been one of those days , y'know ?
Anyway , here's a schematic of what I've got in the breadboard right now . One or two points to note -
Separate V/2 connections for filter and LFO , marked as " Vref " and " Vr " . The op-amp buffer for Vref is essential ,
Vr for the LFO probably should be .
I didn't use a level control , the LFO is at max output . If needed , it works just like a volume control ( See box at
bottom of schem ) .
Extra CV inputs can be added at point " X " , via separate resistors - I used 33k , any less and the LFO
output seems to " bottom out " and " thump "
I used 100nF for the LFO rate capacitor which gives a long , slow sweep , several seconds a cycle up to around
5 Hz - adjust to taste ! Slight thump noticed at high rate .
The pot values and tapers are just what was handy , could well be improved on .
There is a slight volume loss at low resonance , so a simple boost at the input would be useful .
Overall , the sound is similar to the +/- 12 V version , but the modulation level needs to be pretty well
maxxed out , though . Sounds good with the resonance well up and fed with some dirt , mind you !
I have to say that the control node section looks a right mess , as a result of my semi-random
fiddling - that 47k to ground looks WRONG - but if you pull it out , it don't work !
Anyway , breadboard it and see what you can come up with - envelopes could be worth trying .
Oh , in my infinite stupidity , I omitted to label the pots - DERRRR !
47k Log = Resonance
100k Lin ( at bottom ) Frequency
100k Lin ( in LFO ) err , LFO rate
Also , the 270R 's in the filter were 220R in the original , but I ran out . Probly makes no odds .
Quote from: nick d on September 26, 2013, 02:33:04 PM
Anyway , here's a schematic of what I've got in the breadboard right now
Thanks for this! Going to try it out soon. Quick question - All other MS20 schematic I've looked at (not that many tbh) have the control voltage going to pin1 and 16 simultaneously, here the LFO seems to connect via a tiny cap to pin 5 where the resonance feedback also connects - What difference, if any, does this make?
Well spotted , Sir ! My boo-boo - pins 1 and 16 SHOULD be connected to the control voltage node , collector of the 3906 .
The 470pF should connect to the output of the op-amp in the resonance circuit .
Been looking at filter schems so much my brain has gone cross-eyed !
Thanks for pointing that out !
No problem, I haven't tried a filter with an opamp for the resonance before, and it's good to kno that it works with that LFO: Thanks again for posting it up.
(http://i1239.photobucket.com/albums/ff510/NICKDUNKERLEY/SAM_0412.jpg)
Amended schematic , old-school cut'n'paste using real scissors . Also added control labels and
+ and - inputs to second half of 13700 . And switched flash on .
Yeah , you can max the resonance and play sirens with the LFO , no bother !
Oh dear , it really isn't my day , is it ? + and - inputs , I accidentally swapped them .
Pin 14 is + , i.e. non-inverting , 13 is - , i.e. inverting .
Fingers crossed , it's all correct now .
Quote from: nick d on September 26, 2013, 07:28:09 PM
Oh dear , it really isn't my day , is it ? + and - inputs , I accidentally swapped them .
Pin 14 is + , i.e. non-inverting , 13 is - , i.e. inverting .
Fingers crossed , it's all correct now .
So the connections you've drawn are correct, just the + and - labels are swapped?
Yeah , pin 13 goes to 10k to pin 9 , pin 14 is from the 10k that comes from pin 8 .
Checked against my 12 V schem and the rats nest on the breadboard , which works !
Just logged in to say I layed out this circuit last night and had a quick play this morning and it works fine. I could do with a little more resonance, but I'll have a play with the "feedback" opamp and see if I can get a bit more. I'm going to try it with the envelope detector section from the BJFE snow white autowah, which looks like just drop in there. Thanks, nick d.
cool, look forward to hearing your results... 8)
(waiting on my 13700's..)
Got a bit further on with this . Video demo included , you may wish to cover your ears .
Two LFO's tried , value of C changed to 47nF . Vr now from a buffer using similar circuit as for filter Vref .
- this is definitely an improvement .
Added buffer/boost to input to counter volume drop . This works a treat , straight lift from the Cliff Schecht
design .
The LFO's definitely need level controls , particularly for fast rates . Not done this yet , I'm thinking a 47k pot
if using a 33k resistor , and the bottom end of the pot should be Vr , NOT Gnd ?
[youtubehttp://www.youtube.com/watch?v=9UY-fVUos2E&feature=player_detailpage][/youtube]
Cheers Rob ! @ nocentelli , no lack of resonance here , too much if anything !
@nick, sounds really great man..great slow sweep.....that'll be nice with an envelope detect too...awesome. :icon_cool: :icon_cool: :icon_cool:
Thanks Rob ! Yeah , that long sweep is mega , with the res well up . I'm looking at envelopes
too - either follower or triggered . There's a fairly simple ( ! ) on MFOS in the Noise Toaster
project , might be good with a momentary stomp to fire a one-off Attack/Release sweep .
I'll check over mine carefully this afternoon, problem just user error.
With my values ( 47k pot + 12k res ) , the resonance increases up to around 90% pot rotation ,
then oscillation kicks in . I found two things that kill the resonance while I was wiring up - either
the bottom end of the resonance pot , OR the 4k7 from IC3 , pin 2 not connected to Vref .
@nick: just listened to the vid again...really nice. 8)
did you get any further with this?.
I am in the process of a final build - basically the circuit from the demo with a few minor tweaks , plus an expression pedal jack .
Didn't get any further with envelopes - it's an eight-knobber as it is !
When it's done I'll post pics , clips and schemo . The vero is fairly huge and sprawling , so I won't attempt to draw that up , I'm
sure someone else will do a neater job !
8 knobs :icon_eek:
lfo leds?
lfo volumes?.
anyway, cool, look forward to the build demo man... 8)
i now have my 13700's..
Two LFO's , each with level and rate pots and LED , resonance , filter frequency , input boost , output level . The input boost is set-and-forget so could be a trimmer , but it just adds a bit of flexibility . I might add another jack for external CV , so envelopes , sequencer , random etc. could be added later . That's what voltage control as all about !
very nice... 8)
well done! is this HP and LP together like original MS20, or just LP?
Quote from: deadastronaut on November 25, 2013, 12:18:33 PM
very nice... 8)
Just LP . It's actually 9v adaptation based on VCF 2 from the EFM Wildcat , which in turn was based on the MS20 VCF .
Probably nothing like the real Korg circuit , but it seems to work well enough !
(//URL=http://s1239.photobucket.com/user/NICKDUNKERLEY/media/SAM_0416.jpg.html%5Dhttp://%5BIMG%5Dhttp://i1239.photobucket.com/albums/ff510/NICKDUNKERLEY/SAM_0416.jpg)[/URL]][/img] [/img](http://i1239.photobucket.com/albums/ff510/NICKDUNKERLEY/SAM_0415.jpg) (http://s1239.photobucket.com/user/NICKDUNKERLEY/media/SAM_0415.jpg.html)[/img]
IT'S ALIVE !!!!!
Pics above of the outside and a fairly horrific gut shot - if you don't like off-board wiring , don't even think about attempting
this project ! Sounds pretty much like the breadboard demo , with a few minor tweaks and an expression pedal input .
Still got to draw up the final schemo , will post that , with a demo , by the weekend ( hopefully ! )
^ bravo, nice filter
Whoooaahhh that's a monster...glad ya got it sorted man..
excellent...
Here we go chaps..........
in the case of sonic attack on your district follow these rules...play master of the universe... ;)
sounds cool man, love the self oscillation synthy stuff too..very old hawkwind nice... 8) 8) 8)
So you have a slower LFO modulating a faster one? That's what it sounds like, at any rate.
Two LFO's with separate rate and depth controls , mixed at a summing node along with the CV from the expression pedal .
All will become clearer when I draw up the full schemo .
Here's the schemo : -
(http://i1239.photobucket.com/albums/ff510/NICKDUNKERLEY/img003.jpg)
Hope you can all read it , let me know if you spot any glaring errors .
A few points to note : -
I separate buffered reference voltages for the filter and the LFO's ( Vref , V lfo ) . This might be OTT , but I think it helps to minimise ticking .
The 2nd LFO is identical , just uses the other half of the TLO74 .
For the exp. pedal I used a Zoom FP-02 ( because I've got one ) , any other passive pedal should do .
The LFO indicator LEDs don't totally shut off - this can be cured by connecting the emitter of the 3904 to Vlfo instead of Gnd .
The " MOD " stomp just shorts across the 68n caps to stop the LFO's - I added this as an afterthought , so it might not be clear on the schemo .
The Vero is a bit huge and sprawling , and the off-board wiring is a bit of a mare , so if anyone wants to come up with a nice compact layout with on-board pots ,
you are welcome to do so !
bravo!
Nice work on this thread.
When I first did the MS20 filter from Esobedo I couldn´t get it to work tried 4 or 5 times - nothing...
6th time was the winner ;D
Now I have build several modules for my synth, like 6 pole (adpted from jürgen haible phaser).
With this quasi sallen-key topology you can get also hp and allpass(phaser).
On a sidenote, the even sicker synthfilter (imo) is the steiner vcf(hp/bp/lp INPUTS!).
http://yusynth.net/Modular/EN/STEINERVCF/ (http://yusynth.net/Modular/EN/STEINERVCF/)
A lot of people are put off by the diode ladder, but you can do this (even 3 or 4 pole):
http://tristandabbles.wordpress.com/2011/06/15/the-steiner-resonant-filter-a-new-adaptation/ (http://tristandabbles.wordpress.com/2011/06/15/the-steiner-resonant-filter-a-new-adaptation/)
I have a demo from my version, I love this filter! Have try!
https://soundcloud.com/noisette-1/wahwahdemo (https://soundcloud.com/noisette-1/wahwahdemo)
Edit: You might also look at the Maestro Sample&Hold Filter, it´s the similar to the m20 iirc and s&h is REALLY synthy ;)
Quote from: noisette on December 07, 2013, 08:14:36 PM
You might also look at the Maestro Sample&Hold Filter, it´s the similar to the m20 iirc and s&h is REALLY synthy ;)
Thanks for this. I tried a FS+H on the breadboard a long time ago, but couldn't get the S+H working so abandoned it. Now I look at the schem again, the filter portion is obviously closely related to the MS_20: Going to give it another go.
Madbean has a version of Maestro Filter S&H right now I think?
Strategy
Quote from: nick d on December 03, 2013, 10:06:37 AM
Here's the schemo : -
(http://i1239.photobucket.com/albums/ff510/NICKDUNKERLEY/img003.jpg)
I breaboarded this on a whim last night (minus the LFO's - exp pedal only) and it sounds great. Thanks again for posting.
That's nice to hear ! OTA's are lots of fun !
I simplified it a bit, I only really want it for a resonant wah with an expression pedal, so no LFO. Here's what I've done to it:
(http://i80.photobucket.com/albums/j190/Leeroyfunk/PumaVCFschematic_small_nocentelli_zps8fbd2215.jpg)
I think the MS-20 is basically textbook, no shame in the game! Looking forward to breadboarding this, thanks for the schemo.
I liked this effect since I found this video on Youtube. It's just really raw. I can understand the scheme (I mean, I get the gist of it). But I see you have made a vero version of it. Do you still have the vero layout? If so, would mind posting it? It would be fantastic.
Quote from: nick d on December 03, 2013, 10:06:37 AM
Here's the schemo : -
(http://i1239.photobucket.com/albums/ff510/NICKDUNKERLEY/img003.jpg)
Hope you can all read it , let me know if you spot any glaring errors .
A few points to note : -
I separate buffered reference voltages for the filter and the LFO's ( Vref , V lfo ) . This might be OTT , but I think it helps to minimise ticking .
The 2nd LFO is identical , just uses the other half of the TLO74 .
For the exp. pedal I used a Zoom FP-02 ( because I've got one ) , any other passive pedal should do .
The LFO indicator LEDs don't totally shut off - this can be cured by connecting the emitter of the 3904 to Vlfo instead of Gnd .
The " MOD " stomp just shorts across the 68n caps to stop the LFO's - I added this as an afterthought , so it might not be clear on the schemo .
The Vero is a bit huge and sprawling , and the off-board wiring is a bit of a mare , so if anyone wants to come up with a nice compact layout with on-board pots ,
you are welcome to do so !
^ that's the "MS-20" style filter, basically from the datasheet for the LM13700, plus the resonance op amp stage, a la Rene Schmitz. If you can't find a vero version of this in particular, look for "MS-20" vero layouts.
Boss is no fun at all.
http://www.bossus.com/products/sy-300/
Glad you like it ! Alas , I did not do a layout as such - more of a " tale that grew in the telling " kind of thing . Never really had the patience to learn how to do proper layouts !
Hello guys,
So lucky to find this post! Thx nick d for the schematic!
I am about to build it but I really want to control it with a CV pedal that works with 0-5V instead of a expression pedal.
How can I modify the expression pedal input to be able to use my CV pedal?
Thank you!
Cheers
The CV from your pedal should go to the R connection on my schemo . You may have to make other changes , that would depend on which CV pedal you have .
Thank you for answer!
My CV pedal have Ground on the sleeve and + (0-5v) on the tip.
Do you mean I can just connect my tip to the 47k resistor that goes to circuit? And the sleeve goes to the 47k resistor that goes to ground?
Using a expression pedal, I suppose we will be sending something like 0-9v to the circuit. Using my CV Pedal that sends 0-5v, l suppose I wouldn't get the whole range of the parameter, right? (I am sorry, I don't have the skils to calculate this by myself. I can put the things together but I can't develop and change things).
I appreciate any help!
Cheers
Tip to 47k , yes . Not sure about the gnd , though .
Thank you, nick_d!
I can't find a 47k pot... It is ok to use one 50k instead?
Yep.
Hey Guys,
I just finished on the vero board and works fine! Thank you for this! The CV works too!
The 2 lfo's are a great plus. But... playing around gave me the wish to have a envelope follower to make the freq follow my pic attack. I don't wanna a auto wah but more like the envelope on the synths. It would be great to have control of the swell of the frequency and also the sensitivity of the attack.
Do somebody knows a envelope circuit like this that I could include on this great filter?
Thank you so much!
Quote from: intergalatico on October 29, 2017, 06:31:14 AM
Hey Guys,
I just finished on the vero board and works fine! Thank you for this! The CV works too!
The 2 lfo's are a great plus. But... playing around gave me the wish to have a envelope follower to make the freq follow my pic attack. I don't wanna a auto wah but more like the envelope on the synths. It would be great to have control of the swell of the frequency and also the sensitivity of the attack.
Do somebody knows a envelope circuit like this that I could include on this great filter?
Thank you so much!
If one reverse engineers an EH Riddle QBalls, you would have a very good envelope circuit!!!
Is done! And was worth the many work hours!
(https://s2.postimg.org/w15797evp/20171110_154446.jpg) (https://postimg.org/image/w15797evp/)
And here on my board:
(https://s2.postimg.org/qr08hi9xx/20171110_154519.jpg) (https://postimg.org/image/qr08hi9xx/)
Thank you for the circuit, nick!
Cheers!
That's beautiful. Nice work!
I love the Korg schematic graphics. It's funny how the different manufacturers have their own instantly recognisable house style. At one point I was thinking of taking the Sequential Prophet 5 voice schematic to a print shop to get a large version to hang on my wall. Maybe I read too many synth schematics? ;)
Tom
Well done ! Excellent work !