[AVAILABLE] TTSH V4 Build Thread

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search64
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Re: [AVAILABLE] TTSH V4 Build Thread

Post by search64 » Fri Aug 14, 2020 7:39 am

synthcube wrote:
Fri Aug 14, 2020 7:29 am
14 August 2020 update---

According to USPS tracking the slider caps should arrive here TODAY. They will be shipped out ASAP to those who ordered them, along with any other missing bits you might be expecting (midimplants, et al)

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Re: [AVAILABLE] TTSH V4 Build Thread

Post by Jruss993 » Sat Aug 15, 2020 4:11 pm

Hmmmm. Getting this on the vco 1 saw. Moving to different waveforms I’m still getting the exact same weirdo waveform.

Voltage at headers is rock solid. Voltage at all the LM301’s is between 14.90 to -14.98 at the Vcc and vee. Any tips for troubleshooting? I found a bent vee pin on an lm301 in the lag processor area. Fixed it but it didn’t change anything. And full disclosure, I did NOT match the transistors, as I had a synthcube kit with a strip of them and figured they’d be close enough. Fully ready to be flamed for this haha.

This waveform is present across each VCO.

Lastly, I did have to pull out the 2N3954, because I reversed the pins without heat shrink and realized the reversed pins would totally short. In doing so I’m worried I damaged one of the pin traces on the bottom (front panel side).

Any help is super appreciated! I’ll post more pictures when I get back home

EDIT: Did more debugging last night. I am getting output from the noise generator through the headphones, but not through the speakers. I am not getting any sound from the oscillators in headphones or the speakers. I’m still getting to know my oscilloscope, but from the other oscillator sources I tested out, the waveform coming from the TTSH issue looks almost 15 or 20 Vpp.
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Re: [AVAILABLE] TTSH V4 Build Thread

Post by makers » Sat Aug 15, 2020 4:51 pm

search64 wrote:
Fri Aug 14, 2020 7:39 am
synthcube wrote:
Fri Aug 14, 2020 7:29 am
14 August 2020 update---

According to USPS tracking the slider caps should arrive here TODAY. They will be shipped out ASAP to those who ordered them, along with any other missing bits you might be expecting (midimplants, et al)

Image
How many caps are needed for a complete set?

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Re: [AVAILABLE] TTSH V4 Build Thread

Post by NekoNeko » Sat Aug 15, 2020 6:18 pm

Just finishing up my first TTSH and have a puzzling issue with the ADSR. Everything else is working and calibrated. VCO calibration was one of the quickest i’ve ever done (few turns and perfect).

I’ve poured over the schematics and circuit description but can’t see the wood from the trees so any hints appreciated.


Problem
With no gate signal active, ether from clock or external. Raising the release fader gives a positive constant voltage. This keeps the VCA open when router there. With the release fader at zero and gate triggered it behaves quite normal, without release stage. The decay slider however is slightly longer when at 0 than at 1-2, which is weird.

If i use the manual gate behaviour is the same except if i keep the button depressed after pushing the release behaves normally. As soon as i release the constant voltage raises again.

If i send a gate from keystep i have same behaviour as the manual gate except i keep the key depressed. Keystep is sending +12v gate.

I have had the problem without the gate booster installed. I installed it and nothing has changed.

Solutions tried so far
Reflowed all joints
Checked all resistor values
Checked cap values
Replaced all transistors
Replaced all faders except attack
Swapped out ic with known good one
Replaced all diodes

Observations

Working through the schematic and circuit description i have tried my best to decipher what is the problem. Heres some things i think are ok.

Q2 seems to work fine
Q7 receives the trigger and appears ok although if it’s supposed to turn off it’s faster than i can see on the scope.
The rest, i’m unsure, most voltages are present and appear fine at the transistors but there must be something i’m missing.

My best guess at the moment is something is latching a transistor in on state and holding a key/manual gate down reverse this allowing the release stage to discharge properly.

Again any help massively appreciated. Its driving me crazy.

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Re: [AVAILABLE] TTSH V4 Build Thread

Post by Altitude909 » Sat Aug 15, 2020 7:31 pm

are you sending both a gate and trigger?

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Re: [AVAILABLE] TTSH V4 Build Thread

Post by NekoNeko » Sat Aug 15, 2020 7:57 pm

Altitude909 wrote:
Sat Aug 15, 2020 7:31 pm
are you sending both a gate and trigger?
Not exactly sure to be honest

Schematic seems to show s&h send gate to both gate and trig input. I’ve mostly used that for debugging.

I’ve tried it with the keystep through gate booster hooked up, which i guess creates gate and trigger.

Problem is the same :bang:

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Re: [AVAILABLE] TTSH V4 Build Thread

Post by KSS » Sat Aug 15, 2020 9:40 pm

Where is sustain slider in all this?

There is a known issue with the 4020 where AD does not work as expected with some slider settings which 'should' be okay. I can't remember the exactdetails right nowk, though i should be able to! First two sliders if I'm thinking straight, and it should be less when using manual start button or S/H which as you noticed both send G/T together.

Move the sliders around. Re-test.
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Re: [AVAILABLE] TTSH V4 Build Thread

Post by search64 » Sun Aug 16, 2020 12:04 am

makers wrote:
Sat Aug 15, 2020 4:51 pm
search64 wrote:
Fri Aug 14, 2020 7:39 am
synthcube wrote:
Fri Aug 14, 2020 7:29 am
14 August 2020 update---

According to USPS tracking the slider caps should arrive here TODAY. They will be shipped out ASAP to those who ordered them, along with any other missing bits you might be expecting (midimplants, et al)

Image
How many caps are needed for a complete set?
58 I think.

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Re: [AVAILABLE] TTSH V4 Build Thread

Post by fuzzbass » Sun Aug 16, 2020 10:56 am

NekoNeko wrote:
Sat Aug 15, 2020 6:18 pm
Just finishing up my first TTSH and have a puzzling issue with the ADSR. Everything else is working and calibrated. VCO calibration was one of the quickest i’ve ever done (few turns and perfect).

I’ve poured over the schematics and circuit description but can’t see the wood from the trees so any hints appreciated.


Problem
With no gate signal active, ether from clock or external. Raising the release fader gives a positive constant voltage. This keeps the VCA open when router there. With the release fader at zero and gate triggered it behaves quite normal, without release stage. The decay slider however is slightly longer when at 0 than at 1-2, which is weird.

If i use the manual gate behaviour is the same except if i keep the button depressed after pushing the release behaves normally. As soon as i release the constant voltage raises again.

If i send a gate from keystep i have same behaviour as the manual gate except i keep the key depressed. Keystep is sending +12v gate.

I have had the problem without the gate booster installed. I installed it and nothing has changed.

Solutions tried so far
Reflowed all joints
Checked all resistor values
Checked cap values
Replaced all transistors
Replaced all faders except attack
Swapped out ic with known good one
Replaced all diodes

Observations

Working through the schematic and circuit description i have tried my best to decipher what is the problem. Heres some things i think are ok.

Q2 seems to work fine
Q7 receives the trigger and appears ok although if it’s supposed to turn off it’s faster than i can see on the scope.
The rest, i’m unsure, most voltages are present and appear fine at the transistors but there must be something i’m missing.

My best guess at the moment is something is latching a transistor in on state and holding a key/manual gate down reverse this allowing the release stage to discharge properly.

Again any help massively appreciated. Its driving me crazy.
Look for a solder bridge, reversed polarized cap or reversed diode.
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Re: [AVAILABLE] TTSH V4 Build Thread

Post by NekoNeko » Mon Aug 17, 2020 4:30 pm

fuzzbass wrote:
Sun Aug 16, 2020 10:56 am
Look for a solder bridge, reversed polarized cap or reversed diode.
Not that its not a possibility but i have poured over the board maybe 6-7 times now. Replaced diodes. Tested new ones. Replaced the caps for good measure. Reflowed many times. I even replaced the attack fader. So all faders have been replaced.

Nothings changed. I’m starting ti get my head around the circuit more. The trigger section works ok and i can retrig it at the base of the transistors with the scope, only when the manual gate is depressed.

Everything seems to work but the release fader is brings positive voltage into the circuit when raised. This is causing the gate of q3 & 4 to open and Causing the adar to stay open.

I just cannot see what is causing this.

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Re: [AVAILABLE] TTSH V4 Build Thread

Post by jet » Thu Aug 20, 2020 5:46 pm

synthcube wrote:
Fri Aug 14, 2020 7:29 am
14 August 2020 update---
They will be shipped out ASAP to those who ordered them, along with any other missing bits you might be expecting (midimplants, et al)
Edit: just heard from Synthcube, the package I received was all the missing parts from my V4 kit

Maybe that's the mystery package I received today. I haven't even opened the box for the V4 kit yet, I'm trying to finish the working restoration of a real ARP 2600 and have no room on the bench.
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Re: [AVAILABLE] TTSH V4 Build Thread

Post by makers » Thu Aug 20, 2020 10:02 pm

I just finished up and was going through the check-out phase on my first TTSH build.

I've got no sine output whatsoever. After some calibration I'm able to get a nice triangle out though. Yes, I carefully swapped pins 5 and 6 on the 2n3954 and used heat shrink tubing to insulate the pins.

I also have nothing coming out of Sample and Hold. There is no signal on "Clock Out" and a square wave into "Clock In" doesn't seem to trigger anything.

I found this in an earlier post that got me hopeful that I should keep moving through calibration before too much concern. Did anyone else have a similar experience?

funzel wrote:
Sat Jan 25, 2020 4:25 pm


Another little issue was my sine output. Not seeying a sine on startup can be caused by no calibration. Mine came alive after doing so. But I was allready thinking the shaper was broken....

Last but not least, a dead s&h and clock can come alive after you start calibration. So did mine anyway. All of a sudden the whole synth works, and boy it sounds good and is a joy to program. Reading the schematics and calibration routines is a joy. Very well documentation on its functions.

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Re: [AVAILABLE] TTSH V4 Build Thread

Post by KSS » Thu Aug 20, 2020 10:37 pm

Yes, that post is solid information.

It's also true that the FETs are likely the single most senstive parts of the build. Did you heatsink their legs when soldering?

The dual is what makes the sine and the FET is the switch from S to H in the S/H.

But do the cals first. The internal clock can be fussy. Part of that is due to its design, and part of that is due to how its layout was handled in the TTSH.
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Re: [AVAILABLE] TTSH V4 Build Thread

Post by fuzzbass » Fri Aug 21, 2020 3:50 pm

The center of the S&H circuit is Q4 2N4392. I would trace outward from there in three directions. The clock impulse is coming in from the bottom right in the schematic. On the collector of Q5 BC558 you should see the clock signal transformed into very quick spikes (negative going IIRC). You should see them on both sides of the diode there. These spikes turn on Q4 for sampling. If you don't see the spikes, the problem is on the clocking side. The drain for Q4 should have a facsimile of your input signal (noise by default). If you have both the spikes plus the input signal, but nothing happening on the source for Q4 it may be Q4 or anything to the north of that. Q4 is a common source of problems in the S&H. I believe 2N4392 is particularly fragile for heat or static damage.
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Re: [AVAILABLE] TTSH V4 Build Thread

Post by makers » Fri Aug 21, 2020 4:43 pm

Thanks for the tips- I do really apreciate them. I've ordered replacements for the 2N4392 and 2N3954. I did not use any heat sinking on the leads when I soldered them in.

I was trying pitch calibration when I discovered I had the wrong resistor values for R44, R67 and R86. It turns out my kit had 3k3 resistors in a bag labeled 3M3 :eek:

There are two 3M3 Resistors in the S&H circuit where I used 3K3 so I'll replace these too and keep moving forward. I don't think this would have effected the Sine shaper but it may help my sample and hold.

I'm glad I bought a Hakko FR-301 before I started this build- but now it looks like I need a variety of tip sizes.

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Re: [AVAILABLE] TTSH V4 Build Thread

Post by makers » Sun Aug 23, 2020 3:29 pm

Replacing the resistors did the trick and I didn't need to rework the FETs. Everything is falling into place now with Sine output and Sample and Hold working as expected. Onwards and upwards!

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Re: [AVAILABLE] TTSH V4 Build Thread

Post by KSS » Sun Aug 23, 2020 6:12 pm

Glad it was a simple solution. Wrong resistor is the single most common builder error. That's why it's long been a staple of those selling or consulting DIY to emphasize that swapping semi's should *not* be the first step in troubleshooting.

With the sometimes strange colors on some resistors, and the two way readability of 1 and 2% types, it makes a lot of sense to measure each one before insertion.

This doesn't require much extra time if you set up a little two bare wire 'trough' that you can lay the resistor in, and which is connected to a cheap meter.
gold-plated guitar strings or gold j-wires from old organ KBDs make great contact 'tray's once you put a bend in them so the Resistor falls into contact and is easily placed and removed. But solid copper works too. Literally adds only seconds to each placement. HF cheap meter is fine since you're looking for egregious errors, not precise values.
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Re: [AVAILABLE] TTSH V4 Build Thread

Post by search64 » Tue Aug 25, 2020 4:50 am

Image

Caps are here. Took a bit longer than expected, but I think it's worth it. Really puts the finishing touch on the TTSH.

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Re: [AVAILABLE] TTSH V4 Build Thread

Post by C_C » Tue Aug 25, 2020 1:14 pm

Looks amazing!

The anticipation for my TTSH to get here just keeps building. Every demo I've heard of the TTSH has pretty much told me its my dream synth. :hyper: :goo: :hyper:

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Re: [AVAILABLE] TTSH V4 Build Thread

Post by makers » Tue Aug 25, 2020 6:53 pm

Everything is working well on mine and I'm almost finished. I'm still waiting on a MIDImplant to install.
I spent an hour last night poking around a malfunctioning Gate Booster before I found Fuzzbass's post about a run of Gate Boosters with Gate and Trigger Out label flipped. Once I flipped them everything was working as expected.
Can't decide whether to cap my sliders or not :hmm:
Check it out in Synthcube's road case.
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Re: [AVAILABLE] TTSH V4 Build Thread

Post by Purveyor2 » Wed Sep 02, 2020 7:01 am

I’m back with oscillator calibration issues. Originally I had one VCO board that would track about 3 octaves, the other 2 would only go about one octave. Did some troubleshooting to no avail. The “good” board exhibited same behavior in all three osc slots.
Got a fresh set of osc pcbs and rebuilt. Checked all resistor values with dmm prior to build. Got fresh caps and ICs. Can’t get any of the new boards to track well. I can tune them all at c1 and c5 but everything in between is a garbled mess. If I calibrate them at c1 and c3, then c2 and c4 are way out. Went back to the “good” osc and it does fine from c1 to c3, but the c4 is wildly sharp.
Thoughts? Is it the faulty 5459s I’ve read about?

EDIT - Bad soldering - reflowed the switches (keyboard on/off) and redid the headers for the the sub boards and it’s good.

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Re: [AVAILABLE] TTSH V4 Build Thread

Post by search64 » Fri Sep 04, 2020 1:48 pm

Does anybody get a clicking sound from the VCA when it’s overdriven? On my ttsh, when you push the VCA with high input (sliders on the filter fully open), or with a high CV on the VCA I get a kind of LFO like click in the sound. Could that be a trimmer issue in the VCA gain or something like that?

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Re: [AVAILABLE] TTSH V4 Build Thread

Post by KSS » Fri Sep 04, 2020 10:56 pm

@search64
Yes, that's a known thing for TTSH and 2600 alike.

A mistake was made in the Expo trim supply connection, which ARP never fixed and TTSH -AFAIK- didn't either.

It can also be due to poor tranny matching -and other tranny parameters- in the 4019 portion of the VCA circuit.

It's part of why the 'soul-killing' DC blocking caps get added to the Filter inputs.
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Re: [AVAILABLE] TTSH V4 Build Thread

Post by search64 » Sat Sep 05, 2020 4:30 am

So if I did match the transistors in the VCA and it still happens, not much more I can do about it? I also have the AC coupling caps in the filter already.

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Re: [AVAILABLE] TTSH V4 Build Thread

Post by sduck » Tue Sep 08, 2020 9:54 pm

I promised myself I would learn at least some basics of 3D printing CAD type stuff during my furlough period, and I finally got around to it. The first thing I finished up and actually printed is a speaker baffle for the TTSH. This will work with all versions of the TTSH. You may or may not have to cut off part of the PCB to use this - the last one of these I built that used baffles was a version 2, and I can't remember if I actually needed to cut out a part of it, or if it just made it easier. It's 5mm thick, which is about right if you use the peerless speakers, but way overkill for some other kinds - if you want to make it thinner you can adjust the height in your slicer program. Whether or not these make a big enough difference to bother with is up to you - I've always used a version of these in my TTSH builds, I used to get them built by front panel express - these are cheaper by several orders of magnitude.
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