If I'd make a string chorus PCB, what kind of multi-BBD circuit would you prefer? |
Solina style (also: Crumar Performer, Böhm Phasing Rotor, and others) |
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62% |
[ 28 ] |
ARP Omni style |
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13% |
[ 6 ] |
Elka Synthex 4 BBD circuit |
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11% |
[ 5 ] |
other (please name in thread) |
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6% |
[ 3 ] |
I would want neither - it's old fashioned and overused, and if I need it, there are digital FX boxes |
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6% |
[ 3 ] |
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Total Votes : 45 |
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JoeMorris
Joined: Apr 26, 2009 Posts: 161 Location: Brighton
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Posted: Mon Aug 10, 2009 9:48 am Post subject:
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I followed JH's advice in getting a cheap analogue scope for £70 and I have to say I've not looked back. |
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eframp
Joined: Sep 11, 2007 Posts: 25 Location: Atlanta, GA
Audio files: 2
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Posted: Mon Aug 17, 2009 11:10 pm Post subject:
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OK - now I own a scope!
It's delay line 1 (the top-most on the board, closest to the power inlet) that is kaput.
Probing at the chip side of the 10K resistors at the inputs of the three 4011's, I've made video of the working channels (they look identical) and the non-working one.
First video is at test point side of the 10K resistors at the inputs of the 4011; first line 3, then 2, then 1.
Second video is at the chip side of the same 10K resistors. You'll see on the non-working one that it gets to what would be the highest point in the Slow LFO sweep and glitches out.
Thoughts?
Description: |
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test point side.MOV |
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11.63 MB |
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871 Time(s) |
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chip side.MOV |
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850 Time(s) |
_________________ Eric Frampton, keyboards Atlanta, GA
www.ericframpton.com |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Tue Aug 18, 2009 1:41 am Post subject:
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So, from what I can gather, the LFO Modulation signal seems to be there, in all 3 channels. But teh clock oscillator of channel 1 doesn't work properly. Have you tried to replace that 4011? And double checked the component values in that clock generator?
JH. _________________ "I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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eframp
Joined: Sep 11, 2007 Posts: 25 Location: Atlanta, GA
Audio files: 2
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Posted: Tue Aug 18, 2009 11:12 am Post subject:
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jhaible wrote: | So, from what I can gather, the LFO Modulation signal seems to be there, in all 3 channels. But teh clock oscillator of channel 1 doesn't work properly. Have you tried to replace that 4011? And double checked the component values in that clock generator?
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Whatever's happening is going on before it even hits the 4011. I've tried swapping chips, and it seems to be related to the line, not the chip. I can even remove the 4011 entirely and the picture doesn't change.
hmmm. _________________ Eric Frampton, keyboards Atlanta, GA
www.ericframpton.com |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Tue Aug 18, 2009 2:13 pm Post subject:
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eframp wrote: | jhaible wrote: | So, from what I can gather, the LFO Modulation signal seems to be there, in all 3 channels. But teh clock oscillator of channel 1 doesn't work properly. Have you tried to replace that 4011? And double checked the component values in that clock generator?
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Whatever's happening is going on before it even hits the 4011. I've tried swapping chips, and it seems to be related to the line, not the chip. I can even remove the 4011 entirely and the picture doesn't change.
hmmm. |
From what I can see on your scope shots, the good channels show some 4011-generated "action" on the chip-side of the 10k, while the bad channel does not. So *removing* the 4011 wouldn't bring as much of new information as *replacing* it with another 4011 ...
JH. _________________ "I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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eframp
Joined: Sep 11, 2007 Posts: 25 Location: Atlanta, GA
Audio files: 2
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Posted: Wed Aug 19, 2009 8:13 pm Post subject:
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jhaible wrote: | From what I can see on your scope shots, the good channels show some 4011-generated "action" on the chip-side of the 10k, while the bad channel does not. So *removing* the 4011 wouldn't bring as much of new information as *replacing* it with another 4011 ...
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Problem solved!
The clue in your text was in talking about swapping 4011's vs. not having one in there at all - it didn't make any difference, which said to me that signal wasn't even making it to the 4011.
I figure there are only 4 components between the last point that works and the first point that doesn't, let's start swapping. So after pulling one lead of the cap, 10K resistor, and both diodes, and checking and seeing that they were all OK (but the circuit still wasn't working), I thought, what the hell, and re-flowed the solder on all the pins of the 4011 socket (even though they _looked_ good, even under the magnifying glass). Apparently that last step is what did it, 'cause now we're all modulating happily.
yaaaaay!
Thanks for the point in the right direction!
e _________________ Eric Frampton, keyboards Atlanta, GA
www.ericframpton.com |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Thu Aug 20, 2009 2:05 pm Post subject:
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eframp wrote: |
Problem solved!
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Congrats!
JH. _________________ "I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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TekniK
Joined: Aug 10, 2008 Posts: 1059
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Posted: Sat Dec 05, 2009 3:42 pm Post subject:
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My pcb is made and frontpanel designed. |
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numbertalk
Joined: May 05, 2008 Posts: 992 Location: Austin, TX
Audio files: 5
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Posted: Sun Dec 06, 2009 10:59 am Post subject:
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TekniK wrote: | My pcb is made and frontpanel designed. |
Nice! |
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TekniK
Joined: Aug 10, 2008 Posts: 1059
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Posted: Sun Dec 06, 2009 11:09 am Post subject:
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numbertalk wrote: | TekniK wrote: | My pcb is made and frontpanel designed. |
Nice! |
Thanks |
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slaughterhousesam
Joined: Aug 27, 2010 Posts: 16 Location: london
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Posted: Fri Aug 27, 2010 9:49 am Post subject:
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hi guys
just built one of these triple choruses, and am having an odd issue. i seem to be getting a lot of highish frequency hash/buzzing in the output that sounds unpleasant.
when listening to the individual outputs, you can barely hear it - its like a slight jitteriness in the high frequencies, but when the outputs are summed you get this rapid jittery phasing against each other that just doesnt sound right. i have tried playing with the waveform/fast/slow adjustments but cant seem to shake it off, other than by filtering off all high frequencies from the input source, but then you can barely hear any effect, desired or not, at all.
now im guessing this is due to some issue with the stability/speeds of the modulation sources, so am looking for some guidance on the expected behaviour in that area and have a few questions...
a) what are typical rates for the fast and slow modulation sources?
b) i have brought out the fast/slow trimmers to the front panel so can easily play around with them, and i think they should be trimming the speeds of the fast and slow modulations, but can anybody confirm that? are there any amplitude effects here?
c) jurgen's page makes reference to moving in and out of clipping with the waveform control, but is this just an amplitude or a direct waveshape adjustment?
i have a multimeter and a soundcard oscilloscope (no low freqs...boo!) and am trying to come up with cunning ways to analyze the modulation outputs, but it would be good to be more informed on what im looking for
thanks |
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slaughterhousesam
Joined: Aug 27, 2010 Posts: 16 Location: london
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Posted: Fri Aug 27, 2010 11:46 am Post subject:
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further to the above, i have managed to monitor the modulation signal just before it goes into 4011 chips by using probes and sending the voltage to the fm input of an e340 sine wave, and can hear the slow modulator and the effects if the trimpot, but cant seem to identify the fast component in there.
where would be the best places on the board to tap the fast and slow mod signals independantly? i have had a look at the circuit diagram and tried a few of the pins on the tl082/72 chips but no luck yet, and tbh i dont understand enough about that part of the circuit to know if i should be getting any joy or not.....
....all advice welcome :p |
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jumunius
Joined: Apr 19, 2010 Posts: 346 Location: San Francisco, CA
Audio files: 13
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Posted: Thu Sep 23, 2010 11:16 am Post subject:
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Hi folks, I am a relative newbie testing my first JH build -- the Triple Chorus. At present I think I have three issues, and since tomorrow is the only time in the next 2 weeks I'll be at a proper electronics store, I thought I would post my current status in case there are any parts I should buy to test with. Any help/schooling from the forum would be most appreciated.
Issue 1: Output 3 is very very quiet (if on at all -- unless I'm getting some bleed I think I hear something from it). I assume from other posts that this could be a cold solder, or possibly a wrong value for a resistor. Anything else worth checking?
Issue 2: Outputs 1, 2, and Mix Out are noisy / hissy. (Output 3 isn't, perhaps resulting from Issue 1.) Not like the squeals people report, just your standard white noise hiss. Noise floor unlike anything in Jürgen's demos. In case anyone wants to hear what I mean, I've attached a wav of each individual out, and then for the mix out I switch the bypass on and off. There is no input. (Since you hear the clean sound of the bypass, you can tell it isn't my audio interface adding noise.) I also sweep the shape on each out, since that has an effect on the noise. (Also, I boosted all files 10db for the purposes of hearing.)
Issue 3: I notice RF problems when using the EQ mode. For these pots, I am using stranded 22AWG wire cut to appropriate length, not twisted. (From pictures I see that Jürgen appears not to twist these wires, whereas Bill and Will from Dragonfly Alley do twist them.) Should I twist these wires?
Final Question: is it recommended that I follow Bernd's advice and add a 33pf cap to all three clock ICs?
Notes about my build: I built from a Bridechamber kit and believe all ICs to be as spec'd. Currently I use shielded wire on all ins and outs except Mix Out (ran out, but given that the noise appears on individual outs I assume the problem is elsewhere).
Description: |
JH Triple Chorus; test of 3 individual outputs plus mix output. |
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JH_ChorusTest.wav |
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2.59 MB |
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2520 Time(s) |
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Serenadi
Joined: Jul 03, 2007 Posts: 89 Location: Germany
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Posted: Thu Sep 23, 2010 12:49 pm Post subject:
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jumunius wrote: | Final Question: is it recommended that I follow Bernd's advice and add a 33pf cap to all three clock ICs? |
Hi jumunius,
only if the clock generators for the bbd chips (U11, U14, U15) don't 'start' (if you don't get good signals at pins 1 and 4 of TDAs, see my old posting).
It seemed to depend on the batch of TDA chips.
Cheers,
Bernd |
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jumunius
Joined: Apr 19, 2010 Posts: 346 Location: San Francisco, CA
Audio files: 13
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Posted: Thu Sep 23, 2010 9:55 pm Post subject:
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Thanks Bernd.
In case anyone is wondering, I twisted my EQ wires, and suddenly my mix out is very quiet. Wonder if I disrupted something.
Then I poked around a bit with my DVM:
[ETA]
Row of TL072s and 1458s have -15 at pin 4.
Row of 1458s/TL071 have -14.7 at pin 4
TDAs read around -14.2 at pin 9 and -13.5 at pin 13
Except for the -14.7, everything else is good right? Wonder why the row of op amps is low?
Then my soldering iron died... so I guess it's time to take the plunge for a good one.
[ETA] My PSU is a Condor +/-15 with nothing else plugged in at present. |
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oozitron
Joined: Apr 02, 2007 Posts: 38 Location: USA
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Posted: Thu Oct 28, 2010 9:33 am Post subject:
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IGNORE! I'm an idiot... a fuse-less idiot :-\
[] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] [] []
I have my Triple Chorus all wired and powered, but have left all the chips out (sockets only). When I check between the ground on the board and the pin where each chip gets powered, I'm only seeing about 0.2 volts.
Even with the sockets empty, there should be at least *one* pin that has at least 5v, right?
The incoming AC seems fine. Any suggestions as to where along the circuit to check for some nice DC volts?
thanks
Drew |
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jumunius
Joined: Apr 19, 2010 Posts: 346 Location: San Francisco, CA
Audio files: 13
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Posted: Mon Jan 23, 2012 1:00 pm Post subject:
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Hi, so after correcting for a bad BBD chip and a bunch of shoddy wiring I had thought I'd gotten my Triple Chorus working, but upon opening it up again to compare the functionality of the TDA1022s against my non-functional SOST Flanger, I find one final flaw. The sound I get is chorus, but not nearly as lush and syrupy as that in Jürgen's demos. When I adjust the waveform pot, it seems like I get about half the range that Jürgen displayed in this clip of him doing the same.
I've attached a clip that I made by taking the audio from the dry section of Jürgen's Plain and simple string demo, processing it with my build, and comparing it to his wet section. So what you hear in this clip is the dry portion once without effect, then the dry portion as I sweep the waveform pot from Min to Max, then the dry portion all the way through at max modulation, then Jürgen's wet section with no additional modulation from me. You can hear for yourself that his clip is signficantly more modulated than mine.
I assume this relates to the search for the optimal "soft-clipping" that Jürgen describes, so I ask whether anyone has ideas about what I might do to improve this in my build.
In case you're wondering:
1) each of my individual modulated outs sounds similar, which says to me that each BBD and corresponding circuitry is working correctly.
2) both the slow and fast modulation respond to turning of the trimpot (though the effect is subtle as suggested elsewhere in this thread)
3) As you can probably hear from the part of the clip where I sweep my waveform pot, the effect is very clear, so my waveform pot appears to be doing something, just not enough. (And indeed, the wiper appears to swing from 0v at CW to -9v or so at CW).
4) I have checked values on all components around the waveform pot (everything before the 3 diodes that go to the individual modulators). Since each individual out sounds the same, I assume the problem is something is global rather than individual (unless one of them isn't getting summed, which I can check tonight but seems unlikely).
5) I swapped out U9, the 1458 that the waveform pot feeds, to no effect.
Description: |
Comparison of my Solina build to Jürgen's demos. What you hear in this clip is the dry portion from Jürgen's once without effect, then the dry portion as I sweep the waveform pot from Min to Max, then the dry portion all the way through at max modulati |
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JH_Solina_ModMatching.mp3 |
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1.74 MB |
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2419 Time(s) |
_________________ -Jim |
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jumunius
Joined: Apr 19, 2010 Posts: 346 Location: San Francisco, CA
Audio files: 13
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Posted: Sun Feb 05, 2012 11:50 pm Post subject:
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Does anyone have any advice about the problem above? Does anyone even hear the problem? Am I crazy?
Actually, I realize, upon downloading my own file, that I had cut the beginning of the file off, so anyone downloading missed the raw, unchorused portion of the file and only heard the file as I started to turn my waveform pot to CW.
So I've fixed the file (in the post above), and it now plays as described:
1st musical phrase is from Jürgen's unchorused strings, played 3 times: once without any processing, once with me moving the Waveform pot from CCW to CW, and the 3rd time with the Waveform pot at max setting.
Then a 2nd phrase plays, which is Jürgen's chorused strings with no additional processing from me.
Though it is made a little confusing since he is playing more notes (which thus adds extra harmonic content) it is clear to me that his chorused sound is much warmer and richer that what I'm achieving.
At this point I've scoped each of the modulator test points, checked every component value in on p2 of the schematics, listened to each individual out, as well as each out in pairs, fiddled with different values of resistors around the waveform pot, swapped every IC, etc. Nothing stands out as the problem. _________________ -Jim |
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jumunius
Joined: Apr 19, 2010 Posts: 346 Location: San Francisco, CA
Audio files: 13
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Posted: Tue Feb 21, 2012 10:24 am Post subject:
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After building this and playing with it for a bit, I have some layout and build thoughts that I don't remember expressed in this thread. One thing I want to try is a switch to juice up the modulation even more, but I won't get around to that just yet. More broadly, I think a lot of people build these based on the Bridechamber panel, which is fine, but if you aren't using the Bridechamber panel you might actually reconsider some of the layout choices. Eventually I'm repanelling mine anyway (using a temp panel for now), and here a few ideas I had:
1) get rid of 2 of the individual outs. All you really need is the Mix Out (could also be called "Mono Out") and any one of the individual voice outs (could also be called "Stereo Out"). Jürgen wrote this at some point with regards to Stereo, which is created by using the Mix Out on one side and a single BBD out on the other. Meanwhile using the 3 outputs individually via separate pannings or uneven mixes will only serve to mess up the intended chorus effect and doesn't sound very good.
Only reason to have all these outs is if you found some use for slowly building up a sound out of these individual building blocks into a thick Solina chorus sound. Presumably not a string sound, something more effecty. Seems like a marginal use but you never know.
2) get rid of the Dry Out. Mixing wet and dry signal doesn't sound so good with this chorus, imho.
3) in lieu of using an individual output for the stereo channel, find an alternate effect for that purpose. So for example, your Solina Mix Out is on the right channel, and for the left channel you send the original dry signal to the JH SOST Flanger with Max Wet setting, a little LFO, and minimal Resonance -- that actually sounds pretty good, and sums to mono better than using one of the chorus outs if that matters to you. The more mellow your flange effect, the more it preserves the character of the Solina chorus over the flanger.
4) Adapt the Active/Bypass to be stereo, effecting both the Mix Out and the Stereo Out (Out 1 2 or 3, per note #1 above). So just adapt the current switch to a DPDT switch, where the "bypass" setting just passes through the Dry signal on both sides, while the "Active" setting selects both the Mix Out and the Stereo Out.
5) Add a 3-throw switch to switch out R237, 284, and 288, to add a couple options for increasing/decreasing the modulation level. (This apparently is a bit different than the Waveform pot.) Lower than 1.6k increases the modulation, it seems. Haven't picked the right values yet.
6) If your panel form-factor leaves a bunch of blank panel space, add a couple inputs. When you shut the effect off, it would just work as a very simple mixer, so it might come in handy even when you don't need a chorus. _________________ -Jim |
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