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Q150 slope switch trick - any help?
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Author Q150 slope switch trick - any help?
Rex Coil 7
I've exhausted my efforts to search the forum via the "site:www.muffwiggler.com" syntax in my regular search engine on this one, so my apologies if this topic has been hashed, rehashed, and hashed out.

How does one add toggle switches to the Q150 filter to provide access to all four slopes?


For some reason my mind is simply not friggin working (again! dammit!) and I cannot seem to figure this one out on my own.

I figure it's one of those super simple things, but I am really having trouble with this one. My high school education level and total lack of any formal electronics education and training often times shows itself, such as right now. I feel as though I should be able to do this .. but nope. Pass the dunce hat, I'll be sitting in the corner.

I'm in the middle of designing a Front Panel Express file for the Q107/Q162/Q150 ensemble, and ~now~ is the time to add as many of the easy mods as practical. I'm all done, all I need to do is work out the four-slope-toggle mod for the Q150 and I can put this panel together and order it!

It's peanut butter jelly time!

I need some help on this issue, please.

Thank you, Brian of Earth.

EDIT: It doesn't help that my wife is sitting in the other room watching classic Star Trek episodes, it's distracting the hell out of my braynz (in a good way!).
Huba-Swift
Have you taken a look at the Q150 datasheet? Scroll down to page 5.
https://synthesizers.com/products/q150/q150data.pdf

I haven't tried this myself, but I have an Idea on what to do.

It seems that you could use a DP3T On-On-On switch to switch between 1,2, and 3 poles when the slope switch is on the -12db position.

In this picture I've circled the 12 pins with different colors to help explain. The 3 red pins are all connected to each other, and the 3 blue pins are connected to each other. these will be the two commons for the two poles on the switch. the red pole will switch between the 3 different green pins, while the blue pole will switches between the 3 different orange pins.

Rex Coil 7
Thanks for the reply, member Huba_Swift. I kicked this around (your idea) for a bit. I understand what you've done.

Yes, I've seen the datasheet.

After looking your suggestion over (and comparing it to my own ideas on the matter) ... I have to wonder if a more eloquent solution might involve the use of a 2P-4T rotary switch? The switch logic would be (pretty much) what you've outlined so nicely there, while also tackling the 4 pole position at the same time.

The rotary switch wiring might take me awhile to work out (especially with my brain on strike) but after grinding away for a few minutes on your (and my own) solutions the rotary switch seems cleaner, less messy.

My work-up on this involves using the stock toggle, in addition to two other switches. But talk about messy! Nerp, fergit it.

(WARNING! - A lot of thinking out loud in the following paragraph):

Hmmm ... If a fella could work out a rotary switch with a 12 pin header connector wired up to it .... now that would be an elegant solution! Extending from that .... I wonder if a 2x6 pin double row housing (2.54mm/0.1" pitch) multi-connector would fit that bunch of pins? If I could carefully (c.a.r.e.f.u.l.l.y.) terminate 12 wires with the proper female pins then just use heat shrink to isolate them, and then make my own "housing" out of hot glue with the female pins inserted on another 12 pin header (used as a set of alignment mandrels). Or just blow off the hot glue and simply stick the female pins over the males on the PCB.

(OK, nonsense mumbling complete, returning to topic).

Shit. Well, I think what I may do for the time being is design the new 5 space panel with one switch hole, and I'll (try to cleverly) work out a spot that could be drilled at a later time for a 2nd DP3T on-on-on toggle (to adopt your suggestion) ~~or~~ not drill it at all and simply ream out the existing switch hole to accommodate a 2P4T rotary switch. If I can be clever enough, the panel layout won't betray the fact that it's prepared to handle either/or one of both methods.

Hmmmm .... thinking .... thinking .... (don't mind the smoke, it comes out of my ears when my brains is overheated a bit).

(thanks!)

Huba-Swift wrote:
Have you taken a look at the Q150 datasheet? Scroll down to page 5.
https://synthesizers.com/products/q150/q150data.pdf

I haven't tried this myself, but I have an Idea on what to do.

It seems that you could use a DP3T On-On-On switch to switch between 1,2, and 3 poles when the slope switch is on the -12db position.

In this picture I've circled the 12 pins with different colors to help explain. The 3 red pins are all connected to each other, and the 3 blue pins are connected to each other. these will be the two commons for the two poles on the switch. the red pole will switch between the 3 different green pins, while the blue pole will switches between the 3 different orange pins.

Squattamolie
I made a vid years ago about this, but bear in mind that my (lame ass) version created a thump (or discontinuity) when changing from 1-pole>2-pole>3-pole.

The work-around I found was that whenever I wanted to switch between the 1/2/3-pole settings, I'd first move the factory toggle to the 4-pole setting (so any switching I did of the 1/2/3-pole had no audible effect i.e. "thump"), and would then switch the factory toggle back (so I could hear the effect of my 1/2/3-pole setting - I'm hoping this makes at least some sense).

If I was going to try this again, I'd pay someone (probably Phil from MegaOhm) to "do it right" (his works needs no caveats or apologies about thumps or problems, etc.)

I'll also mention that in the intervening years, I've ended up disabling this, as I like the Q150 with the standard 2/4 pole settings, and other VCFs (like the Mankato) give me a lot more of what I wanted from the other slopes....

That said, I think the Q150 is great. I just wish I had other TSL filters to compare it to....hoping to try the Oakley/Krisp1 at some point.....

EDIT: if your wife is watching vintage Trek, be grateful! I just watched "no, NO, kill you all, die, make you suffer" (Wolf in the Fold) and my wife was like, "I'm going to bed"....



Huba-Swift
After a bit of prodding around, the -24/-12db switch commons don't seem to have the same commons as the red and blue pins, which may rule out using a 2 pole rotary switch. For that to work you would need a 4P4T switch, which as far as I know doesn't exist. you could use a 2 gang 4P3T rotary switch, though they're typically a bit pricey. Unless there's some clever solution that is.

If you want to jump in the deep end, you could do something along the lines of what the old polysynths used for routing controls to multiple voices, that is using VCAs or AND gates, which would be turned on/off by a SP4T switch with the common going to +15v to route all of the signals by using only a single pole.... But that's a lot of VCAs or AND gates that you would need.... I'm trying to think of something better.

As far as the thump when switching modes goes, this is just speculation, but I wonder if using a make-before-break, vs a break-before-make switch would make a difference.
Rex Coil 7
I've slept on it, that said I've pretty much given up on it. Transported it into deep space, full power, widest dispersion setting.

I don't feel comfortable with messing with part of a circuit that I don't fully understand. For instance, do some of those pins go to ground? In other words, when one of the jumpers is installed, is it simply connecting one of the pins to ground (or 0-volt)? Or is the jumper actually completing a circuit in another manner? See my point?

Too many datum pieces missing.

For instance, If I knew ... factually so ... that the jumpers are simply icompleting a connection to a ground point to create the slope changes, then this whole ~switch thing~ would be really easy to figure out.

But, I don't know that, in fact I don't know anything for that matter (regarding the workings and theory of how the Synthesizers.Com Q150 works or the circuit scheme).

And, I'm ok with abandoning this notion. In fact, the following quote makes a lot of sense to me (regarding this exact modification that member *Squattamolie had performed on his own Q150) .....

Squattamolie wrote:
... I'll also mention that in the intervening years, I've ended up disabling this, as I like the Q150 with the standard 2/4 pole settings...

So just keeping the Q150 as-is when it comes to these different poles is fine with me. Now, I'll gladly eat those words if some more data comes along that would make concocting this switch setup easy and doable in a well-executed manner. But until then, I'm good with the 12/24 setup from the Arrick Robotics factory.

And regarding this ....

Squattamolie wrote:
.... my ... version created a thump (or discontinuity) when changing from 1-pole>2-pole>3-pole.

*Squattamolie, just to let you know, my own factory stock Q150 "thumps" when switching between 12/24db slope settings. So I don't think it's actually avoidable. Unless ... perhaps ... the situation would respond to adding a "soft switching resistor/cap" across the terminals, like some circuits seem to. Adding a resistor and a cap can sortof slew the voltage spike and reduces or eliminates that "pop" when engaging the switch. That is, if I recall correctly, it's been awhile since I messed with such things.

Ok ... good. Now I can put this idea behind me and work towards getting get that Front Panel Express order done!

nanners

Building that house one swing of the hammer at a time!
cornutt
I wonder if that thump problem could be fixed by using a make-before-break switch. I've been looking for some for a muting circuit.
Rex Coil 7
cornutt wrote:
I wonder if that thump problem could be fixed by using a make-before-break switch. I've been looking for some for a muting circuit.
Could be! I know that my suggestion of the resistor/cap is a lousy one, that's for certain.

So, on your suggestion of using a make>break switch just might fix the issue.

seriously, i just don't get it
Squattamolie
Rex Coil 7 wrote:
... just to let you know, my own factory stock Q150 "thumps" when switching between 12/24db slope settings.

That sounds wrong to me. On both Q150s I use regularly, the 2-pole/4-pole switch makes no "thump" at all when changing, even when full levels are going through the filter, so I have no idea why that would be happening for you.

While I liked the sound of the Q150 in 1-pole and 3-pole mode, it didn't really do it for me. I'm no engineer (and so have no idea why one 6dB design sounds a lot different from another), but - for instance - with the Q150 in the 1-pole setting, the res had almost no effect - but when using the Mankato in the 1-pole setting, the res has a very significant effect while still staying very musical.

And even given that, I'm sure the circuit topologies are radically different, the Sea Devils (3-pole) filter really sounds different, and (just as importantly to me) acts _way_ different when modulating than the Q150 in 3-pole mode did. If that makes no sense, chalk it up to me being semi inarticulate.

I know STG's redesigned Post Lawsuit VCF now has a 1-pole output and I'm quite interested in trying that (mine is an older version without that output).

I guess the lesson (for me) is that one can't have too many VCFs......
Rex Coil 7
Squattamolie wrote:
Rex Coil 7 wrote:
... just to let you know, my own factory stock Q150 "thumps" when switching between 12/24db slope settings.

That sounds wrong to me. On both Q150s I use regularly, the 2-pole/4-pole switch makes no "thump" at all when changing

No clue, mangs. Dunno whut to tell you, it just ~does that~ sometimes (most times). To the point that I sortof "grit my teeth" just before switching back up from 12 to 24db, because I know the ~thump~ is coming. I would try it again to see if there are some sort of certain conditions that encourage this, but I've disassembled my synth all the way down to the bare cabinet and the circuit boards! I finished all five new panels ... I sent in a test panel to have a look at what their engraved graphics look like and to see what I can do with them. But once I have decided what to do about graphics/finishing, I'll place the entire order for all seven panels, and get this synth back together!

Squattamolie wrote:
I guess the lesson (for me) is that one can't have too many VCFs......
Heard that! I only have room for three module spaces worth of VCFs, so I've coupled together the Q107 and the Q150 in ways that will allow me to ~create~ different filters by using various combinations of different states with the LPF of the Q150, as well as being able to swap between having the Q107 in series, or in parallel with the Q150 with the flip of a single switch. I've also added every single jumper option to toggle switch operation on both the Q107 and the Q150. Along with switchable feedback, and pre VCF overdrive as well as post VCF overdrive, I'm hoping to provide myself with plenty of filtering options and plenty of different sounds with the Dual VCF Multi-Circuit (as I've called it on the panel). It's been named the Q678 (Q147 + Q107 + Q162 + Q150 + Q112). I ended up squeezing all of that into 5 module spaces, plus 5 extra toggle switches (full sized toggles that use 1/2" holes). I also added a 3rd channel that has it's own send/return to allow me to route the signal out of the VCF panel outboard to ~whatever~ filter/wavefolder/racketmaker I wish, just as if it were another filter path.

Whew! Too much bla bla bla .... lol
Huba-Swift
Squattamolie wrote:
That sounds wrong to me. On both Q150s I use regularly, the 2-pole/4-pole switch makes no "thump" at all when changing, even when full levels are going through the filter, so I have no idea why that would be happening for you.


Mine clicks/thumps as well. It would be interesting to know if at some point over the years, Roger changed the design of the Q150 to get rid of the thump. My particular Q150 is from 2009.
Rex Coil 7
Huba-Swift wrote:
....My particular Q150 is from 2009.
June, 2012 here.
hsosdrum
My Q150 thumped (quite loudly) the very first time I switched it between -24dB and -12dB, but switching it hasn't caused a thump since that one time. I have no idea whatsoever what levels I may have been running into and out of the filter when it thumped (it happened when I first got my synth in early June of 2017).

I'm pretty sure the build date on my Q150 is around March of 2017.

FYI
Rex Coil 7
hsosdrum wrote:
My Q150 thumped (quite loudly) the very first time I switched it between -24dB and -12dB, but switching it hasn't caused a thump since that one time. I have no idea whatsoever what levels I may have been running into and out of the filter when it thumped (it happened when I first got my synth in early June of 2017).

I'm pretty sure the build date on my Q150 is around March of 2017.

FYI
Well, see that's an easy one.

All you did was simply let the thump out. Now that you've let it out, it won't be back.

meh

lol nanners
gregae
FWIW, I've switched the jumpers to the 18db/oct response and am really digging the result. With the Res fully cranked, the filter has that wonderful liquid rubberband response without the high freq resonance whistling you otherwise get in the 24dB/oct postion.

Sounding pretty good to me... Rockin' Banana!
Rex Coil 7
gregae wrote:
FWIW, I've switched the jumpers to the 18db/oct response and am really digging the result. With the Res fully cranked, the filter has that wonderful liquid rubberband response without the high freq resonance whistling you otherwise get in the 24dB/oct postion.

Sounding pretty good to me... Rockin' Banana!
So you're set up with 24db on one throw, and 18db on the "12db" throw?
gregae
Rex Coil 7 wrote:
gregae wrote:
FWIW, I've switched the jumpers to the 18db/oct response and am really digging the result. With the Res fully cranked, the filter has that wonderful liquid rubberband response without the high freq resonance whistling you otherwise get in the 24dB/oct postion.

Sounding pretty good to me... Rockin' Banana!
So you're set up with 24db on one throw, and 18db on the "12db" throw?

Yep, as simple as that. I can already get 12db responses from some of my other filters (Q107A, Mankato, & Fun VCF), so I don't miss not having the 12db option on the Q150.

BTW - I forgot to mention that Squattamolie's video was what got me interested to try the jumper switch. Thanks SQ!
Rex Coil 7
A SOLUTION I LOVE! (though it may not be suited for everyone):

This is my solution for the multiple slope selection issue. It requires:

** A full single space panel.
** Six 1/4" TRS jacks.
** Two 1/4" TRS plugs.
** Two 0.1" pitch 6 pin housings, with female pins installed.
** Wire, probably 24ga PVC insulated, or 20ga Teflon insulated wire.
** One 6 inch length of something like around 12ga or 10ga copper wire, either stranded or solid. This is to be used as a mechanical "tie" to attach the two plugs together, in a sortof "U" fashion.

Ok, so what's happening here is the two 6 pin housings will be slipped on to the Jumper Pin Array on the Q150 PCB. Wires from the housing are soldered to the TIP and RING terminals of the 6 TRS jacks. The jacks are mounted in such a way that they are grouped as 3 pairs. 3 pairs of jacks, each pair mounted side-by-side on a single wide module panel.

The two TRS plugs have their TIP and RING terminals soldered together inside of each plug, effectively connecting the TIP and RING of the plug together. Each plug is transformed into a giant "jumper link" this way.

The 2 plugs are then attached together by soldering that large piece of 12ga wire to the SLEEVE terminals of each plug. The assembly is them bent into a "U" shape. This assembly creates a pair of "jumper links" that can only be separated just far enough so that they may be inserted into any of the 3 TRS jacks pairs.

By removing the Jumper-U and reinserting it into another jack pair, you've done the same thing as installing jumper links on to the correct pins on the PCB. Since the plugs cannot be separated enough to fit anything other than two paired up jacks, it makes certain that only the proper jumper pins are connected together at any given time.

This whole whacky assembly creates a very large ~remote~ jumper link and pin setup to provide front panel access to changing the slope of the filter when the slope toggle is in the "-12db" position. To change from 1 pole to 3 pole, simply remove the "Jumper-U" from the 1-pole pair of jacks and reinsert the Jumper-U into the 3-pole pair of jacks. Since the jacks are spaced so that the Jumper-U can only be inserted into proper pairs, there's no chance of a misconnect.



(below) The pin housings look as if they don't fit properly in this picture, but they're just sortof ~stuck on there~ and not properly fitted. They don't have the female sockets installed in the housings yet, so they are just kindof hanging on there. Not to worry, they'll fit just great once I crimp the female pins on to wire, and then insert them into the housings.








It's LARGE, kinda clunky, "knife switch-esque", and a fitting companion would be a Jacob's Ladder, as if it belongs in an old scientist's lab with a helper named "Igor", and perfect for my kind of synth!

The Jumper-U could be made in many different ways, at the end of the day the main idea being to attach the two 1/4" TRS plugs in such a way that they can only be spread so far apart that they will only be able to plug into properly spaced jacks. There's several methods to get that done, at least five I can think of off the top of my bucket head.

The panel itself has the jacks arranged in pairs that are spaced horizontally just right for the Jumper-U to insert, but spaced vertically too far apart for the Jumper-U to fit into any other pair of holes other than proper pairs. The panel may resemble something ~like~ this ......





I have all of the parts needed on hand, and I am TOTALLY goin' for it! I'll make it out of a blank Dot Com panel, which I will strip the black finish from and cover it in the bedliner coating that I use on my project synth. I have precisely ONE module space left, and it just happens to be located directly next to my Q150!

What a trip!

thumbs up

ALSO: ... I will probably post an exact copy of this posting in my project synth thread, so don't be surprised if you see this in there in the next day (or less). This setup IS going into my synth, doubtlessly. As a general design ethos, it fits right in with other contraptions I've created and installed in my synthesizer ... such as ......





Guinness ftw!
Rex Coil 7
I need to put a cap on this thread. With the search function up and running again, should anyone run across this thread an example of the finished idea would be helpful.

I'm aware that many of the 5U forum dwellers have already seen this "Q150 aid" panel I've made, but I don't want someone who's searched this topic to run across my last post and see no real answer to the question of "How do I move the slope options to the front of my synth?".

So, again, I know that most of you have already seen this, but I want to finish this thread with an answer, so that I may unsubscribe from it (I need to thin out my sub'd threads list again).

Please pardon the redundancy ..... (here we go!)

So here's the final product of the initial "flash inspiration" I had which is posted just above. Instead of making up some type of special plugs that are tied together, I simply used a pair of right angle TRS plugs with three pairs of TRS jacks. The Tip and Ring of the plugs are soldered together inside of the plug, creating a giant "jumper link" out of them. The TRS jacks are just giant "jumper pins".

Inserting the plugs into the appropriate jacks shorts the two appropriate pins together to obtain the desired slope curve. The panel doesn't require labels, it's fairly straight-on sensible. Switch bat UP = 24db/4-pole, switch bat DOWN = whatever slope configuration the "jumper links" (the TRS plugs) are set at.

Following the "UP = Higher" logic:

*** The top pair of jacks = 3-pole.
*** The middle pair of jacks = 2-pole.
*** The lowest pair of jacks = 1-pole.

What happens if the plugs are inserted into jacks other than aligned pairs? No clue! I would presume the exact same "thing" would happen if you installed one of the jumper links in the incorrect locations ... whatever that "thing" would be. Since the Datasheet for the Q150 offers no stern warnings or flashing lights to indicate that misalignment would cause death and destruction, I'm presuming the results wouldn't be catastrophic ... at least I like to think that!

It is a simple thing .... just be sure to put the plugs in aligned pairs. The End.

Here's pictures of the Slope Jumper Panel:









Here's a little progress I've made on preparing the 6 pin housings to fit on to the PCB jumper pin array ... the little ridge had to be cleanly removed so the housings could be properly spaced apart to fit the jumper pin array. I'll be using "RTV Blue" to adhere the 2 housing together to create one 12 pin housing that will nicely fit the pin array on the PCB.

Blue RTV (aka "Blue Pooky") is a silicone-like substance that is thick and gooey when applied, and dries as a flexible adhesive. This will allow me to apply the RTV to the housings, squish them together, slip the pair on to the jumper pins. The still-soft RTV will allow the housings to space themselves at the proper distance when slipped on to the pins until the RTV sets up permanently. This method will produce a 12 pin housing that is spaced precisely wide enough to fit on to the pins wonderfully.





I'm a bit stuck on progress with this thing right now, I have to wait until I get the 8-space wide VCF panel in hand so that I can know how long the wires need to be from the Q150 PCB to the Slope Jumper Panel before I can install the female pins on the wires that lock into the housings. I can't make those wires without the VCF panel, so I can't glue the two housings together with RTV just yet. But all of that will come .... patience.

Ok, so there it is. I'll remain subscribed to this thread for two more weeks so that I can field any questions or respond to posts here. After that I'll unsubscribe, and any questions that require answers from me will have to be presented via Private Message ("PM").

Thanks! Hasta Lasagne!

Brian of Earth.

EDIT: I'll be using Blue Loctite to semi-permanently seal the TRS Right Angle plugs closed, and I'll also be using Plasti-Dip on those two plugs to mark them as "jumpers". I may even fill the innards with hot glue. This will prevent me from being tempted to use those plugs to make some patch cable or something in the event I don't have any of those on hand. It will also mark those plugs as "jumpers" to help identify them should they ever be removed from the panel. I'm not sure what color of Plasti-Dip I'll use to dip the handles of the plugs in to just yet .... blue? ... red? ... yellow? ... dunno?

seriously, i just don't get it
josaka
gregae wrote:
FWIW, I've switched the jumpers to the 18db/oct response and am really digging the result. With the Res fully cranked, the filter has that wonderful liquid rubberband response without the high freq resonance whistling you otherwise get in the 24dB/oct postion.

Sounding pretty good to me... Rockin' Banana!


yep the 18db is far more usefull for me...
Rex Coil 7
Well, my Q150 is now a part of a dual filter setup all in one panel. It's been paired up with a Q107, and using toggle switches I can place the filters in parallel, or series. And when they are in series, using another toggle switch I can reverse their order (107 first going into 150 .. or .. 150 first going into 107).

That said, the pair take on a new life when put together this way. So I want all of the slope shaping capability possible especially when they are in series.

I've also built-in a Q162 Filter Mixer into this 8-space wide panel, so I can really adjust the Q107's output by using a mix of various output states. Add that to the "variable slope" of the Q150 with the Slope Jumper Panel and this Dual Filter Multi-Circuit becomes something of an all new animal. So much so that I've added up all of the "Q" numbers of all of the modules that are built in to the new panel, and I use the sum of those model numbers to name the new module the QX678 Dual Filter Multi-Circuit.

Perhaps now the desire to have the slope adjustments on the front of the synth makes more sense.

EDIT: Woops, after reviewing my previous posts, I see that I've already explained this.

Here's a screenshot of the finalized QX678 panel:

Dave Peck
When using two filters that are patched (at least sometimes) in parallel, it's important to include a switch to invert the polarity of one of the filter outputs relative to the other.

Especially since the Q107 multimode normally inverts its output (when in LPF mode) and the Q150 normally does NOT invert its output.

This will cause cancellation of any portion of the signal that is common to both filter outputs - which may be exactly what you want for one patch but not for another.

Also, it's likely that when you use the various optional slopes of the Q150 besides the standard 24 dB /octave, some of those may be inverting and some may not.

I think the best way to address this would be to add an inverting switch at the output of the Q150 after the slope switch, so you can decide to invert or not, regardless of the slope selected.
Rex Coil 7
Excellent (and quite true) advice sir!

Allow me to draw to your attention the fact that the input distributor uses attenuverters (it's a Dot Com Q147 Distributor). So in parallel mode, the input signals sent to each filter may be inverted, which will ~counter~ any inversion or phase cancellation caused by any inversion going on in either filter.

Look closely at the three drill holes on the far left of the panel. The holes are marked on the top and bottom of each knob .... here's the "MASTER" file that depicts the knobs on the panel to make it easier to see how the knobs look and the lettering looks with the knobs in place. The input attenuverters on the far left read:

(TOP KNOB) = "SVF" as in State Varible filter and beneath the knob it reads "Bipolar".

(MIDDLE KNOB) = "LPF" describing the Q150 LPF and beneath the knob it reads "Bipolar".

(BOTTOM KNOB) = "AUX" .... this is essentially just a total bypass circuit that sends the input signal alllllll the way around both filters straight out to the output mixer (drill holes on the far RIGHT with "unipolar" beneath each knob).

Note that circles with little "*" in them indicate toggle switches, a "J" indicates jacks, and the "~" indicates the Technical Earth bolt holes. Everything else is a pot. The circles are large and represent 3/4" knobs, 1" knobs, and two 2.25" knobs for the Cutoff Frequency. The three large toggle circles indicate large format toggle switches and their 7/8" diameter flat washers.





Won't the attenuverters on the Input Distributor provide the inversion that would be needed to take care of (sortof) "re-inverting" any filter outputs that may cause phase cancellation on their output stages?

PLEASE
tell me if I've missed something.

Also, here's two diagrams that spell out the signal paths of the filters with regard to the parallel/series toggle and the "order swap" toggle - they may help to better draw mind's eye imagery:

PARALLEL:



SERIES:




ORDER SWAPPER TOGGLE SWITCH WIRING:






Although this is all sortof "off topic", I've provided all of this to help better describe how I have it all set up.

The input distributor is the Dot Com Q147 Distributor, it is part of the 8 space panel which houses a total of five module circuits (Q147 as the input distributor, Q107 State Variable Filter, Q162 State Mixer, Q150 Ladder LPF, and Q112 four channel mixer as the output mixer).

So there is a single input jack, and a single output jack. One signal goes in and is split three ways, then all three signals are summed to a single output signal.

The large open rectangular boxes have 2mm panels bolted into place behind the panel that house 15 3.5mm jacks in each one. Those jacks are all Send/Return jacks that provide insert points at strategic locations throughout the entire multi-circuit module. I call them "Option Panels":





Thanks for your observations, member *Dave Peck!

cool


Dave Peck wrote:
When using two filters that are patched (at least sometimes) in parallel, it's important to include a switch to invert the polarity of one of the filter outputs relative to the other.

Especially since the Q107 multimode normally inverts its output (when in LPF mode) and the Q150 normally does NOT invert its output.

This will cause cancellation of any portion of the signal that is common to both filter outputs - which may be exactly what you want for one patch but not for another.

Also, it's likely that when you use the various optional slopes of the Q150 besides the standard 24 dB /octave, some of those may be inverting and some may not.

I think the best way to address this would be to add an inverting switch at the output of the Q150 after the slope switch, so you can decide to invert or not, regardless of the slope selected.
Dave Peck
Yup, you got it! This is fun!
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