TTSH Ver.3 (rev.8) General build thread

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hofmann25
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Post by hofmann25 » Tue Jan 01, 2019 5:12 pm

fuzzbass wrote:Minimally, your TTSH needs three CVs, pitch, gate and trigger. There is a another CV possible from the MIDI2CV for note velocity but only in Mono or Dual mode. In your build, the Gate Booster is being used to generate trigger from gate.

Gate CV is used to turn on the EGs on the TTSH. This signal should be 0V at key off, and +10V at key on. Think of this signal like a momentary switch. The EG inputs don't like in-between states. They just want On and Off.

Trigger CV is only used by the TTSH ADSR, which requires it for proper operation. It's range should be 0 to +10V, and it should be 0V at gate off and +10V at gate on. Triggers are short (2-3ms) transients that reset the ADSR cycle. Trigger has no effect on the AR cycle.

You would connect pitch, gate and trigger CVs in the usual way, and you may add a layer of modulation on top of that by applying velocity CV to either the filter cutoff or VCA gain (or ring mod or whatever). And as I said above, its going to work best if velocity CVs range between 0 and +10V, and are connected to the more linear CV inputs.

VCOs on the TTSH will respond to pitch CVs across a wide range, nearly -10V to +10V. The TTSH kinda expects 0 to +10V from the keyboard's pitch CV source and that setting is available on the Midisizer.

Its not totally clear how to set up the Midisizer from the online docs, but some things are, and others can be inferred. I recommend checking the behavior of the CV outputs as you go with DMM. I also recommend making the Learn switch externally accessible.

Suggested serving:

1. Use DIP switches 5-6 (both off) to set MONO mode.
(in Mono mode, i'm guessing CV_OUT pin 2 is pitch and pin 3 is velocity.

2. On the CV1LVL header, jumper pins 1-2 for 1V/oct and range of 0 to +10V for pitch CV1.

3. On GATELVL header, no jumper, to select +10V gates.

4. Use outputs:
Pitch CV < CV_OUT header pin 2 wire to TTSH kbd CV bus
Velocity CV < CV_OUT header pin 3 wire to panel jack for patching
Gate CV < GATE_OUT header pin 2 wire to Gate Booster GATE_IN
Mine is setup (CV LVL) as 0+5v as I found 0+10v was too higher pitch. DO I need to re-tune the TTSH for lower ranges with the MIDI2CV in mind? I tuned it using your methods.
fuzzbass wrote:I think you can get velocity CV into the appropriate voltage range with the above config.

You already have a Gate Booster, but its possible you don't need one, assuming that Gate LVL also sets Strobe level. Strobe here equals Trigger on the TTSH.

1. Change the default behavior of Strobe from hi on GateOff to high on GateOn. I think this is a sysex command, but results in persistent config. You will want to test the level and polarity of the generate strobe (using a scope) and the persistence across reboots. Strobes are very quick and you won't see them on a DMM.

2. I'm guessing in the above suggested config, Strobe will be at GATE_OUT pin 3.

3. Connections:
Gate CV < GATE_OUT header pin 2 wire to TTSH gate in
StrobeCV < GATE_OUT header pin 3 wire to TTSH trigger in
Ok so things are a bit clearer now. Thanks fuzzbass. You have a way of simplifying these things for the dumb asses like me.

Some things I will try, Probably in this order.

1. Wire a jack (Non permanent) to MIDI2CV Velocity and try jacking that to ADSR IP.

If that works I stop screwing around.

2. Change CV LVL to 0+10v? Do I need to do I need to do this for my point 1. to work?

3. Do I need to screw around with the Gatebooster > MIDI2CV/Strobe thingy? Its working happily and I have cut a trace already.

I'm surprised no one has come up with a standard MOD for this. Velocity is SOOOOO important. At least to my mind. :mrgreen:

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Post by fuzzbass » Wed Jan 02, 2019 9:01 am

hofmann25 wrote: Mine is setup (CV LVL) as 0+5v as I found 0+10v was too higher pitch. DO I need to re-tune the TTSH for lower ranges with the MIDI2CV in mind? I tuned it using your methods.
I would. You want CVs that go all the way to +10V, to make the best use of the TTSH.

Tuning depends on how you use the instrument. Being a bass player, my personal preference is to set the coarse freq to left, fine to center, and then calibrate with standard:

VCOs
C1 (MIDI24) = 0.00V = 32.7Hz.
4012 filter
C1 (MIDI24) = 0.00V = 130.8Hz.

This shifts the accuracy zone to the bass end of the keyboard. As you play up, tracking diverges. You can set the base freq of the TTSH during calibration to whatever frequency works best for you if bass is not the place (or C1 *neq* 0.00V on your midi gadget - some don't go there!).
hofmann25 wrote: 3. Do I need to screw around with the Gatebooster > MIDI2CV/Strobe thingy? Its working happily and I have cut a trace already.
If it ain't broke, don't fix it. If you keep the booster in place, I recommend you enable the "strobe gate" function of the Midisizer. Note: you do not need to connect the strobe output.

From the docs:
"If “strobe gate” option is in effect, gate signal is pulled down for the duration of the strobe every time a key is pressed while some other key is down. This allows envelopes to re-trigger for synths that don’t have Strobe input."

(i.e. it causes the Gate Booster to output a trigger impulse for every key pressed).
hofmann25 wrote: I'm surprised no one has come up with a standard MOD for this. Velocity is SOOOOO important. At least to my mind. :mrgreen:
The mods I have been involved in (sync, gateboost, shapers, EG range selection, etc) are inserted unobtrusively into existing lanes in the TTSH routing scheme. Their presence does not change the base character of the instrument, unless they are engaged. So you could think of them as expansions "in the spirit of" the ARP 2600 architecture.

Velocity is a digital keyboard function that did not exist when the 2600 came about. If translated into the analog realm, it can be used to modulate the TTSH, but there is no lane available for this CV in the TTSH/2600 normalization scheme because the CV did not exist back then. A panel output jack is the simplest approach in this case.

Note: its kind of a bummer that the Midisizer MKII does not put out mod wheel as a CV. Maybe this can be remedied in the software. If it did, I could show you how to use that in the typical way, using the standard TTSH.
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Post by hofmann25 » Wed Jan 02, 2019 4:36 pm

fuzzbass wrote:
hofmann25 wrote: Mine is setup (CV LVL) as 0+5v as I found 0+10v was too higher pitch. DO I need to re-tune the TTSH for lower ranges with the MIDI2CV in mind? I tuned it using your methods.
I would. You want CVs that go all the way to +10V, to make the best use of the TTSH.

Tuning depends on how you use the instrument. Being a bass player, my personal preference is to set the coarse freq to left, fine to center, and then calibrate with standard:

VCOs
C1 (MIDI24) = 0.00V = 32.7Hz.
4012 filter
C1 (MIDI24) = 0.00V = 130.8Hz.

This shifts the accuracy zone to the bass end of the keyboard. As you play up, tracking diverges. You can set the base freq of the TTSH during calibration to whatever frequency works best for you if bass is not the place (or C1 *neq* 0.00V on your midi gadget - some don't go there!).
I already have it tuned in this way
fuzzbass wrote:
hofmann25 wrote: 3. Do I need to screw around with the Gatebooster > MIDI2CV/Strobe thingy? Its working happily and I have cut a trace already.
If it ain't broke, don't fix it. If you keep the booster in place, I recommend you enable the "strobe gate" function of the Midisizer. Note: you do not need to connect the strobe output.

From the docs:
"If “strobe gate” option is in effect, gate signal is pulled down for the duration of the strobe every time a key is pressed while some other key is down. This allows envelopes to re-trigger for synths that don’t have Strobe input."

(i.e. it causes the Gate Booster to output a trigger impulse for every key pressed).
I'll try this.
fuzzbass wrote:
hofmann25 wrote: I'm surprised no one has come up with a standard MOD for this. Velocity is SOOOOO important. At least to my mind. :mrgreen:
The mods I have been involved in (sync, gateboost, shapers, EG range selection, etc) are inserted unobtrusively into existing lanes in the TTSH routing scheme. Their presence does not change the base character of the instrument, unless they are engaged. So you could think of them as expansions "in the spirit of" the ARP 2600 architecture.

Velocity is a digital keyboard function that did not exist when the 2600 came about. If translated into the analog realm, it can be used to modulate the TTSH, but there is no lane available for this CV in the TTSH/2600 normalization scheme because the CV did not exist back then. A panel output jack is the simplest approach in this case.

Note: its kind of a bummer that the Midisizer MKII does not put out mod wheel as a CV. Maybe this can be remedied in the software. If it did, I could show you how to use that in the typical way, using the standard TTSH.
Surely there is a way to insert it unobtrusively?...

Ok did some tests. Doesn't seem to work...
>>>>

---------------
Last edited by hofmann25 on Wed Jan 02, 2019 10:45 pm, edited 1 time in total.

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Post by Jaytee » Wed Jan 02, 2019 9:43 pm

Surely there is a way to insert it unobtrusively?...
To do what you’re looking to do, you’re gonna want to build a VCA, hijack the envelope signal from somewhere on the TTSH board to run through the VCA, and use the velocity CV to control it. Then you send that final signal back into the TTSH where it expects the envelope.

You’ll probably want to have some kind of control for it on the front panel, like if you want to turn it off (especially important if you ever want to control it without using MIDI).

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Post by duff » Wed Jan 02, 2019 11:46 pm

fuzzbass wrote:Note: its kind of a bummer that the Midisizer MKII does not put out mod wheel as a CV. Maybe this can be remedied in the software. If it did, I could show you how to use that in the typical way, using the standard TTSH.
The Midisizer Midi2CV outputs note, velocity, pitch bend and a controller which defaults to mod wheel in Mono mode. You can change which CV goes to the control output by using midi learn. I have all these on jacks at the back of my TTSH - not the most ergonomic way, but it avoided me having to deface the front panel.

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Post by hofmann25 » Thu Jan 03, 2019 1:21 am

Has ANYONE watched the video I posted above? >>>
duff wrote:The Midisizer Midi2CV outputs note, velocity, pitch bend and a controller which defaults to mod wheel in Mono mode. You can change which CV goes to the control output by using midi learn. I have all these on jacks at the back of my TTSH - not the most ergonomic way, but it avoided me having to deface the front panel.
Can you post a video how you use the velocity and a picture of your MIDI2CV setup? As as you can see from the video above it's not working for me.

Also Mod wheel or LFO would be cool if you know how. :mrgreen:
Jaytee wrote:To do what you’re looking to do, you’re gonna want to build a VCA, hijack the envelope signal from somewhere on the TTSH board to run through the VCA, and use the velocity CV to control it. Then you send that final signal back into the TTSH where it expects the envelope.
You’ll probably want to have some kind of control for it on the front panel, like if you want to turn it off (especially important if you ever want to control it without using MIDI).
Do we need an extra VCA? This is probably the sticking point I would say as a switch and a trimmer pot would be easy.

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Post by hamildad » Thu Jan 03, 2019 7:59 am

You can use the Ring mod on DC setting as an additional VCA???
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Post by Jaytee » Thu Jan 03, 2019 9:58 am

hofmann25 wrote:Has ANYONE watched the video I posted above? >>>
I watched it. It’s working about how I would expect.

It seems like maybe you’re not 100% familiar with how the TTSH works. I strongly suggest spending the upcoming weekend curled up with the ARP 2600 user manual so you can come at this issue with a better understanding of how things are expected to work, but I’ll do my best to give a quick rundown.

The jacks along the middle of the panel are all inputs, and they are all “normalled” to the signal listed just below the jack. This means that without anything in the jack, it’s like the signal listed is plugged in, and when you insert a cable, it breaks that connection to allow the signal on the cable through. Above many of the jacks are sliders, which attenuate incoming signals, whether those signals are coming from cables inserted into the jacks or from the jacks’ normalled connections.

Above most of the sliders/jacks are arrows telling you where that jack is routed. Generally, if the arrow points into the side of a module, it is an audio path, and if it points into the bottom of a module, it’s a control voltage. So for instance, the VCA has two audio inputs and two control inputs.

Now on to your MIDI2CV and its velocity signal. You hit a MIDI key, and the MIDI2CV outputs (among other possibilities) pitch CV (for controlling your VCO pitch), gate (to trigger your envelopes), and velocity. At note on, the velocity signal is just a static voltage for each note, and the voltage is proportional to the MIDI velocity. So if your velocity is 0, the velocity CV is 0V; if your velocity is 127, your CV is 5V; if your velocity is 63, your CV is 2.5V; etc. As discussed earlier, you’ll probably want to put this through 2x gain to get a full range of 0-10V, but let’s ignore that for now. The important thing is understanding that all your MIDI2CV outputs for velocity is a static voltage for each note.

So now, your video. You start out with the velocity signal plugged into one of the control jacks for the VCA. In doing so, you break the connection to the envelope signal that normally goes through that jack to control the VCA. The result is what we hear in the video: an unchanging velocity signal acts somewhat like a gate. Sounds like BEEPoffBEEPoffBEEPoff, etc.

Then, you plug the velocity signal into the mixer input. This is an audio path input, and inserting a jack here breaks the connection to the VCA that normally goes through the jack. You hear nothing because the velocity signal you’ve plugged in here is just a CV, not audio. Same with the next jack you plug it into; it’s an audio path jack, you break the connection of the VCF going into the VCA and you’re just “listening” to a CV going through the VCA. Next, you plug the velocity into a filter control input. This could make an audible difference, but it sounds as though your filter is already completely open, which means there is nothing for a control voltage insterted here to do with the filter, and the result is no change in the sound.
Jaytee wrote:To do what you’re looking to do, you’re gonna want to build a VCA, hijack the envelope signal from somewhere on the TTSH board to run through the VCA, and use the velocity CV to control it. Then you send that final signal back into the TTSH where it expects the envelope.
You’ll probably want to have some kind of control for it on the front panel, like if you want to turn it off (especially important if you ever want to control it without using MIDI).
Do we need an extra VCA? This is probably the sticking point I would say as a switch and a trimmer pot would be easy.
To do what you describe elsewhere in the thread—changing the amplitude of the envelope according to the velocity of incoming MIDI, yes, you need a VCA. Basically, you need a way to attenuate the envelopes using the voltage from your velocity signal. At full velocity, you would open the VCA completely and the envelope will happen at full amplitude; at half velocity, the VCA will open halfway and play the envelope signal at half amplitude, etc.

An alternate way of doing things would be to run your velocity into, for instance, the filter’s control input that is normalled to VCO2, while also using the envelope. This will not scale your envelope to the velocity, but it will change the base frequency of the filter cutoff according to velocity—think of it as adjusting the “frequency” slider as velocity changes on every note—and then the envelope will add modulation on top of that. Simpler to patch, but not as natural sounding.

As Hamildad mentions, you can use the ring mod as a VCA while it’s in DC mode. Put your envelope signal into input 1, your velocity signal into input 2, and run the output wherever you want to apply the envelope.

The caveat here is that both of the above examples involve external patching. You would bring your velocity signal out to a jack on the front panel, as suggested earlier in the thread, and then patch the TTSH in such a way that it responds to velocity. If you want velocity to work as though it were a native feature, so it works automatically and without patch cables, then yes, you need to build yourself a VCA and follow the plan I gave in my last response. (Alternatively, I suppose you could cut some traces and route your envelope and velocity CV through the ring mod as new normalled connections, but I didn’t suggest this earlier as it represents a pretty major change to the basic functionality of the TTSH.)

So yeah, in conclusion, I still think simply bringing the velocity out to its own jack—and, more importantly, learning how your synth works and how to patch it effectively—is the best solution here.
Last edited by Jaytee on Thu Jan 03, 2019 11:00 am, edited 2 times in total.

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Post by fuzzbass » Thu Jan 03, 2019 10:56 am

hofmann25 wrote:
fuzzbass wrote:
The mods I have been involved in (sync, gateboost, shapers, EG range selection, etc) are inserted unobtrusively into existing lanes in the TTSH routing scheme. Their presence does not change the base character of the instrument, unless they are engaged. So you could think of them as expansions "in the spirit of" the ARP 2600 architecture.

Velocity is a digital keyboard function that did not exist when the 2600 came about. If translated into the analog realm, it can be used to modulate the TTSH, but there is no lane available for this CV in the TTSH/2600 normalization scheme because the CV did not exist back then. A panel output jack is the simplest approach in this case.
Surely there is a way to insert it unobtrusively?...
I'm too long winded again and you miss my actual point: you can insert a CV signal anywhere you want in the normalized connections, or elsewhere. But because this is a CV that was not considered in the ARP 2600 design, you will have to cut off the path used for some other CV so you lose original functionality. My mods are always intended to preserve core functionality.

(I'm not telling you what do, its your synth!)
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Post by fuzzbass » Thu Jan 03, 2019 11:33 am

hofmann25 wrote:Has ANYONE watched the video I posted above? >>>
duff wrote:The Midisizer Midi2CV outputs note, velocity, pitch bend and a controller which defaults to mod wheel in Mono mode. You can change which CV goes to the control output by using midi learn. I have all these on jacks at the back of my TTSH - not the most ergonomic way, but it avoided me having to deface the front panel.
Can you post a video how you use the velocity and a picture of your MIDI2CV setup? As as you can see from the video above it's not working for me.

Also Mod wheel or LFO would be cool if you know how. :mrgreen:
Jaytee wrote:To do what you’re looking to do, you’re gonna want to build a VCA, hijack the envelope signal from somewhere on the TTSH board to run through the VCA, and use the velocity CV to control it. Then you send that final signal back into the TTSH where it expects the envelope.
You’ll probably want to have some kind of control for it on the front panel, like if you want to turn it off (especially important if you ever want to control it without using MIDI).
Do we need an extra VCA? This is probably the sticking point I would say as a switch and a trimmer pot would be easy.
I watched. The red patch cable is providing gates, not velocity CV. And because it is not distorting like mad I suspect this gate is +5V. A 10V gate going into exp cv in on the vca, with the control maxxed, will drive the VCA output to ~ 20V P-P; it would be clipped and very distorted.

Your TTSH is fine, but you need to get a better handle on the Midisizer. Measure the voltages you are getting from the various CV out and Gate out terminals on the Midisizer. Velocity CV will measure as a set of voltages, that step and hold to new values with each new key press, and those voltages will be proportional to your key velocity. I don't have a Midisizer, but would be suprised if this CV output ever goes down to 0V.

In the video it sounds like you are using Strobe out to drive your EGs. You want to use gate out > booster gate in > booster gate out > TTSH ext gate in. Do not connect the Strobe output to anything. You are using the gate booster to generate triggers for the ADSR.
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Post by fuzzbass » Thu Jan 03, 2019 11:41 am

Jaytee wrote:
Surely there is a way to insert it unobtrusively?...
To do what you’re looking to do, you’re gonna want to build a VCA, hijack the envelope signal from somewhere on the TTSH board to run through the VCA, and use the velocity CV to control it. Then you send that final signal back into the TTSH where it expects the envelope.
You can definitely do that and it won't hurt anything. But velocity CV can be applied directly to TTSH sections such as VCF and VCA directly into the CV mixer sections. For instance, connecting the velocity CV into the right-most CV input of the VCF allows key velocity to modulate the cutoff frequency. Don't need no stinkin' badges, vca or eg.
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Post by Jaytee » Thu Jan 03, 2019 11:56 am

fuzzbass wrote:
Jaytee wrote:
Surely there is a way to insert it unobtrusively?...
To do what you’re looking to do, you’re gonna want to build a VCA, hijack the envelope signal from somewhere on the TTSH board to run through the VCA, and use the velocity CV to control it. Then you send that final signal back into the TTSH where it expects the envelope.
You can definitely do that and it won't hurt anything. But velocity CV can be applied directly to TTSH sections such as VCF and VCA directly into the CV mixer sections. For instance, connecting the velocity CV into the right-most CV input of the VCF allows key velocity to modulate the cutoff frequency. Don't need no stinkin' badges, vca or eg.
Right, I cover that possibility in my next response down. I was talking about how to modulate the ADSR because that’s what hofmann25 said they wanted to do in their post up at the top of this page, unless I misunderstood them.
Some things I will try, Probably in this order.

1. Wire a jack (Non permanent) to MIDI2CV Velocity and try jacking that to ADSR IP.

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Post by fuzzbass » Thu Jan 03, 2019 12:09 pm

hofmann25 wrote:Has ANYONE watched the video I posted above? >>>
duff wrote:The Midisizer Midi2CV outputs note, velocity, pitch bend and a controller which defaults to mod wheel in Mono mode. You can change which CV goes to the control output by using midi learn. I have all these on jacks at the back of my TTSH - not the most ergonomic way, but it avoided me having to deface the front panel.
Can you post a video how you use the velocity and a picture of your MIDI2CV setup? As as you can see from the video above it's not working for me.

Also Mod wheel or LFO would be cool if you know how. :mrgreen:
Jaytee wrote:To do what you’re looking to do, you’re gonna want to build a VCA, hijack the envelope signal from somewhere on the TTSH board to run through the VCA, and use the velocity CV to control it. Then you send that final signal back into the TTSH where it expects the envelope.
You’ll probably want to have some kind of control for it on the front panel, like if you want to turn it off (especially important if you ever want to control it without using MIDI).
Do we need an extra VCA? This is probably the sticking point I would say as a switch and a trimmer pot would be easy.
Can we back up a bit here? You keep asking for advice and yet when I give some, you ignore :youkids:

1. Forget about your TTSH for a moment, and make sure you are getting the right signals AND LEVELs from the outputs of you Midisizer using a DMM. Report those values here. All the CVs should be operating in the range between 0 and +10V. Velocity CV may never go all the way to 0 or +10V, but your key presses should be able to drive it in both general directions off a center point of +5V.

2. If the point of all this is to use [dynamic / performance control], why are you testing the arrangement with a desktop gadget, instead of a velocity capable midi keyboard you can play to directly observe the velocity CV results on your DMM?

3. You said after the first responses that Gate out is not working on the Midisizer. That is a RED / FULL STOP issue that needs to be resolved before moving forward. Strobe just won't work for driving the EGs gate inputs - period. It helps to think of the EGs as special purpose lag generators. Whatever input voltage you put in, that is what comes out. And said input (gate) voltage should remain high until you release the key. Otherwise, the attack phase will end before reaching full +10V. (BAD). Strobes are too short to do this. With strobes, as you increase the attack duration, the peak EG output level will drop.

4. Early on I suggested using (for instance) the linear CV input of the VCA for velocity control, because the exponential one will not have a suitable response for this CV. In the video, you are testing with the exponential CV input! :bang:

One more thing you should consider regarding modulating the VCA with velocity: if my suspicion is correct that velocity CV deviates from a center point of +5V, then this CV, going into the VCA, is going to hold it at least somewhat open after the EG cycle is complete. So you may find using velocity to modulate the VCF more pleasing.

Maybe at the beginning here you were trying to use velocity CV to modulate the amplitude of the envelopes. Then back to Jaytee's idea (sorta). Because of the quirky behavior of the EGs here (i.e. behaving more like lag generators than one-shot LFOs), you should be able to module the amplitude of the EG outputs using velocity CV to modulate the amplitude of the gate CV you put IN. You would require a VCA with a linear CV input. Use the VCA to process a gate en route to the TTSH EGs, under control from velocity CV. There is zero room for the gate booster in this arrangement, however. If you use a VCA to attenuate a gate and then feed it into the booster, out comes a +10V gate!

While the TTSH Ring Mod can function as a secondary VCA in DC mode, its "control" input (the right one) is exponential, so its not a good fit here. So an outboard VCA is probably a better choice. In a pinch, you could use the TTSH VCA for this processing (one of it's control inputs is linear), so long as you can live with use the Ring Mod in DC mode as your primary VCA.

The more I think about this, the more I wonder if you would get better results doing all the gate and cv processing for this outboard in a Maths. You have a Maths, right? You could definitely use a Maths to generate envelopes of varying amplitude under CV control, not to mention you could also modulate rise and fall times with velocity. You can actually dial in linear, log or exp response curves for this.
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Post by hofmann25 » Thu Jan 03, 2019 5:35 pm

First of all can we all just chiiiill. :guinness:

I really appreciate everyone's help and I thank you.

Apologies for not testing with a DMM/Scope. I'm trying to avoid pulling this thing fully apart again and on the work bench so that why I tried jerry rigging the velocity to a jack.

I'm back at work already so my time is limited. Plus I work in the TV industry and it has been taxing lately. Sound Design for Re-branding of channels blah blah blah....

AND I'm away this weekend so I can't test anything till Monday. SO I will try and answer some of these questions quickly from work while I eat my breakfast. :razz:
fuzzbass wrote:1. Forget about your TTSH for a moment, and make sure you are getting the right signals AND LEVELs from the outputs of you Midisizer using a DMM. Report those values here. All the CVs should be operating in the range between 0 and +10V. Velocity CV may never go all the way to 0 or +10V, but your key presses should be able to drive it in both general directions off a center point of +5V.
Noted. Will do.

But until then Duff posted here >>> viewtopic.php?p=2802908#2802908
fuzzbass wrote:2. If the point of all this is to use [dynamic / performance control], why are you testing the arrangement with a desktop gadget, instead of a velocity capable midi keyboard you can play to directly observe the velocity CV results on your DMM?.
Thats a Elektron Digitakt, are you familiar with them? https://www.elektron.se/products/digitakt/
It has 8 MIDI tracks. Steps 1 & 9 have a velocity of 120, Steps 5 & 13 have a velocity of 50. This is shown at the start of the video...
fuzzbass wrote:3. You said after the first responses that Gate out is not working on the Midisizer. That is a RED / FULL STOP issue that needs to be resolved before moving forward. Strobe just won't work for driving the EGs gate inputs - period. It helps to think of the EGs as special purpose lag generators. Whatever input voltage you put in, that is what comes out. And said input (gate) voltage should remain high until you release the key. Otherwise, the attack phase will end before reaching full +10V. (BAD). Strobes are too short to do this. With strobes, as you increase the attack duration, the peak EG output level will drop.
Gate is working. I later said I forgot (And so did Jaytee) pin 1 is GND> I have my MIDI2CV (This is its name). As far as I know I'm not using strobe to drive the gates. I have the GateBooster hooked up like so and the MIDI2CV is NOT spitting Strobe anywhere near my TTSH. We have been here before Fuzzbass :mrgreen:

Posted: Mon Apr 30, 2018 9:44 am >>>
Dali wrote:Anyway. This turned into a bit of a mess. Probably cause I asked so may questions....

My concern was the gatebooster and midi2cv pcb's damaging each other with pulses. This was my initial question..
But they don't as far as I can see.

So the way you should set your GateBooster & Midi2CV board up with internal wiring and the least amount of screwing around with your board; is this>

Midi2CV Output
CV OUT > CV Header (You will need to insert a dummy plug into the KBD CV Jack when using the Midi2CV [Thanks DSL-Man!])
Gate OUT > Gate Header

Gatebooster Input
Gate input Jack > Gate in Gatebooster (cut the trace from the S/H/Gate switch)

Gatebooster Output
Trigger Out > Trigger Header
Gate Out > S8 Gate Select Switch

This all works with no problem. :mrgreen:

I would have tested this weeks ago but I had to get the Midi2CV Atmega programmed and then I had problems with the PCB.

Thanks fuzzbass, duff, av500 and most of all Patrick. :tu:
Image
fuzzbass wrote:4. Early on I suggested using (for instance) the linear CV input of the VCA for velocity control, because the exponential one will not have a suitable response for this CV. In the video, you are testing with the exponential CV input! :sb:

One more thing you should consider regarding modulating the VCA with velocity: if my suspicion is correct that velocity CV deviates from a center point of +5V, then this CV, going into the VCA, is going to hold it at least somewhat open after the EG cycle is complete. So you may find using velocity to modulate the VCF more pleasing.
Interesting.
fuzzbass wrote:Maybe at the beginning here you were trying to use velocity CV to modulate the amplitude of the envelopes.
That's ALL I am trying to go...
fuzzbass wrote:Then back to Jaytee's idea (sorta). Because of the quirky behavior of the EGs here (i.e. behaving more like lag generators than one-shot LFOs), you should be able to module the amplitude of the EG outputs using velocity CV to modulate the amplitude of the gate CV you put IN. You would require a VCA with a linear CV input. Use the VCA to process a gate en route to the TTSH EGs, under control from velocity CV. There is zero room for the gate booster in this arrangement, however. If you use a VCA to attenuate a gate and then feed it into the booster, out comes a +10V gate!
Do I need to remove my gatebooster?
fuzzbass wrote:While the TTSH Ring Mod can function as a secondary VCA in DC mode, its "control" input (the right one) is exponential, so its not a good fit here. So an outboard VCA is probably a better choice. In a pinch, you could use the TTSH VCA for this processing (one of it's control inputs is linear), so long as you can live with use the Ring Mod in DC mode as your primary VCA.
Probably. Not interested in cannibalising a good modulation source. And not one that isn't a good fit.
fuzzbass wrote:The more I think about this, the more I wonder if you would get better results doing all the gate and cv processing for this outboard in a Maths. You have a Maths, right? You could definitely use a Maths to generate envelopes of varying amplitude under CV control, not to mention you could also modulate rise and fall times with velocity. You can actually dial in linear, log or exp response curves for this.
No. The TTSH is my first foray into Modular/SemiModular...

BUT I have been thinking about getting into it and probably should have instead of spending the last 2 years building SDIY gear. :bang:

I need to work out a good power supple and so I'd probably start with 3U. I was thinking of making a case using the same Aussie wood I used to make my TTSH case. Australian Acacia.

Power like Ed704/ed705 at http://www.elby-designs.com/contents/en ... oards.html ? And build my own case...

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Post by fuzzbass » Fri Jan 04, 2019 9:38 am

hofmann25 wrote:First of all can we all just chiiiill. :guinness:
fuzzbass wrote:Maybe at the beginning here you were trying to use velocity CV to modulate the amplitude of the envelopes.
That's ALL I am trying to go...
Sorry, I'm all better now!

So yes you need an extra VCA. Currently your gate booster is in-line between the gate input jack and the EGs. There is no insert point. With the Booster here, you can't really modulate the gate amplitude to indirectly modulate the envelope amplitude. You can directly modulate the amplitude of the envelopes that are generated, by routing them through an extra VCA, as Jaytee suggested.

I know your gadget puts out velocity, but to test touch response, don't you want to be touching the keyboard? Its not a binary on/off function, but something you will want to tune into a zone that give you the control you want.
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Post by hofmann25 » Wed Jan 16, 2019 4:41 am

fuzzbass wrote:
So yes you need an extra VCA. Currently your gate booster is in-line between the gate input jack and the EGs. There is no insert point. With the Booster here, you can't really modulate the gate amplitude to indirectly modulate the envelope amplitude. You can directly modulate the amplitude of the envelopes that are generated, by routing them through an extra VCA, as Jaytee suggested.
Ok, did some tests (Finally).

Having the gate booster in line makes NO difference to how the MIDI2CV operates. None. So I have left it in.

The best use of Velocity I could get was with the VCF CV, as you suggested. And that was not so great. I think your right, there isn't enough voltage. Even on the 10.5v setting on the MIDI2cv. :cloud:

Some scope results below. Apologies for the not greatly earthed signal. It's in my studio and not on the work bench...

Velocity p-p 7.7v
Image

CV p-p 3.135v

Image

Pitch Bend p-p 4.86v

Image

Clock p-p 10.76v

Image

Control/Modulation p-p 4.567v

Image

Gate p-p 10.99v

Image

Strobe p-p 10.76v

Image



Clock p-p 10.76v

Image

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Post by fuzzbass » Sun Jan 20, 2019 2:06 pm

hofmann25 wrote:
fuzzbass wrote:
So yes you need an extra VCA. Currently your gate booster is in-line between the gate input jack and the EGs. There is no insert point. With the Booster here, you can't really modulate the gate amplitude to indirectly modulate the envelope amplitude. You can directly modulate the amplitude of the envelopes that are generated, by routing them through an extra VCA, as Jaytee suggested.
Ok, did some tests (Finally).

Having the gate booster in line makes NO difference to how the MIDI2CV operates. None. So I have left it in.

The best use of Velocity I could get was with the VCF CV, as you suggested. And that was not so great. I think your right, there isn't enough voltage. Even on the 10.5v setting on the MIDI2cv. :cloud:

Some scope results below. Apologies for the not greatly earthed signal. It's in my studio and not on the work bench...

Gate p-p 10.99v

Image

Strobe p-p 10.76v

Image
Thank you for posting these screen grabs. Although it's off topic, these prove that your Midi to CV device removes the need for a gate booster. 10V gates - check; 10V stobes [triggers] - check.
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Post by Jaytee » Sun Jan 20, 2019 3:10 pm

Of course, the gatebooster also makes sure all external gate sources will work too :)

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Post by hofmann25 » Tue Jan 22, 2019 4:17 am

Jaytee wrote:Of course, the gatebooster also makes sure all external gate sources will work too :)
THIS. ↑

And it makes no difference to how the MIDI2CV functions........

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Post by amir » Thu Jan 24, 2019 11:24 am

Recently I was changing out reverb tanks and I think that I accidentally shorted something in the reverb section for a second without noticing. The reverb continued working fine but by chance I noticed that one of the 172s was burning up. After some inspection I noticed that the 100ohm resistor was a bit discolored also. So I probed around and changed some components that I had on hand until I resolved the issue.

This got me thinking though, do we have any voltage reference sheets for the ttsh floating around? My synth seems to be behaving like normal but I’d probably sleep better at night knowing my opamps were all behaving as they should. I got some unusual readings probing around the whole synth but it’s hard to know if they are acting like they should be or not with out knowing what the inputs and outputs of each should be doing. The rails are always fine on them.. even with a fried 172 in the reverb section the rails on the lm301s all seemed fine which is deceiving.

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Post by fuzzbass » Thu Jan 24, 2019 3:13 pm

amir wrote:Recently I was changing out reverb tanks and I think that I accidentally shorted something in the reverb section for a second without noticing. The reverb continued working fine but by chance I noticed that one of the 172s was burning up. After some inspection I noticed that the 100ohm resistor was a bit discolored also. So I probed around and changed some components that I had on hand until I resolved the issue.
The MJE172 and 100 ohm resistor are in the speaker/headphone section. A common way these get stressed or blown is a short via the headphone jack between Tip or Ring and Sleeve. Could be your jack wiring, or, maybe a TR plug was inserted where only a TRS plug should go. If your speakers ever worked, then probably the latter.
amir wrote:This got me thinking though, do we have any voltage reference sheets for the ttsh floating around? My synth seems to be behaving like normal but I’d probably sleep better at night knowing my opamps were all behaving as they should.
If you were able to complete the ARP 2600 calibration from the service manual, then all of your op amps are working fine and you can go back to sleep.

Lastly, and if you were doing this before... don't change the reverb pan hookup under power. Transients generated doing this are enough to take out the LM301 in the reverb return amp (experience talking here).
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Post by amir » Thu Jan 24, 2019 5:40 pm

fuzzbass wrote:
The MJE172 and 100 ohm resistor are in the speaker/headphone section. A common way these get stressed or blown is a short via the headphone jack between Tip or Ring and Sleeve. Could be your jack wiring, or, maybe a TR plug was inserted where only a TRS plug should go. If your speakers ever worked, then probably the latter.

If you were able to complete the ARP 2600 calibration from the service manual, then all of your op amps are working fine and you can go back to sleep.
Sorry I should have been more specific, I meant the 2n5172, there are two of them in the reverb section, only one had blown and was overheating and doing some weird stuff with the voltage (leaking it back or something). It calibrates fine and seems to be working as intended apart from the usual weird stuff like the exponential vca issues and crap speaker setup. I still think on a build this big that it would be nice if there were a few key spots to check references to make sure nothing weird is happening. Sometimes a tiny short or an insignificant component might not fully reveal itself in calibration but will over time injure more important / hard to find components. I've built enough MI boards at this point to know that things can still seem fine even though there is a hidden short somewhere.
fuzzbass wrote: Lastly, and if you were doing this before... don't change the reverb pan hookup under power. Transients generated doing this are enough to take out the LM301 in the reverb return amp (experience talking here).
Good to know, I usually turn it off before removing anything but the reverb section tends to be frustrating with the coax wires that I am running. So there have been a few times where I may have disconnected them unintentionally while powered.


thanks for the help!

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Post by hamildad » Fri Jan 25, 2019 6:58 am

I had a reverb connection with lose connections in the MTA. I had to bang the panel to make it work sometimes, so disconnection and reconnection doesnt automatically fritz it, but sounds like I might have escaped les smoke Majik before I fixed it.
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Post by Jaytee » Tue Feb 05, 2019 1:10 pm

Just a heads up for anyone interested. There’s a group buy happening in the TTSH Facebook group for slider caps, the same type from the Behringer Ultragraph EQs. I think there’s a few sets left up for grabs.

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Post by Vast_Halo » Tue Feb 05, 2019 6:48 pm

That's too bad! I am interested, but I don't Facebook.

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