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mph
Joined: Aug 25, 2007
Posts: 88
Location: France
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 Posted: Fri Dec 07, 2007 10:09 am Post subject:
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Hello
I am still waiting for some parts to finish this project... I hope it will be ready-to-plug before the end of this year 
and I would like to know what could be this "bounce" circuit? what kind of function does it do?
Is it going to be easy to add this to the "deluxe" version?
Thanks! |
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funkyfarm
Joined: Jan 21, 2007
Posts: 583
Location: France
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| Posted: Fri Dec 07, 2007 10:30 am Post subject:
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| mph wrote: | I would like to know what could be this "bounce" circuit? what kind of function does it do?
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"your thumb on the reel"... 
http://home.debitel.net/user/jhaible/jh_storm_tide_flanger.html
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The summed control voltage (Manual, Pedal, LFO, Envelope follower) is fed into a sub audio BPF, then into a nonlinear amplifier with positive feedback (not a schmitt trigger, but similar), and then filtered by a second BPF. A variable portion of this is mixed to the straight CV to control the BBD's clock frequency. The effect is most prominent on single-shot, non-periodic CV changes, such as a fast single Manual of Pedal sweep. The single sweep is followed by smooth "echoes" that go in either direction (faster clock and slower clock). This is to emulate the "bouncing" tape speed of reel-to-reel tape machines when the friction from a thump against the reel is suddenly released.
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Here's another description :
| StephenGiles wrote: | I can't find my manual right now but I found this reference from the manual:
When the BOUNCE control (a knob on the front) is full clockwise, only changes in the control signal (0 - 5 VDC, or what Steve refers to as CV in his post) affect the flanging while at full CCW only the control signal itself affects it. The control signals can come from the oscillator, the envelope follower, a manual adjust on the front panel, and a socket called remote (for a footpedal or other CV source). Unlike the Phaser, the FL-201 allows for combinations of the these four sources - for example the oscillator can be sweeping along at a given rate AND the envelope follower can add transients or longer releases.
At one extreme of the knob, the user brings a signal differentiator, pulse shaper, and an active filter on-line. At the other extreme a VCO for setting the low frequency limit and a full-wave rectifier are in the path. The knob allows for mixing between these two extremes.
They say, "(a)s this control is rotated clockwise, the flanging control signal is progressively substituted for by a damped sine wave initiated by changes in the control signal. This damped signal swings the flanging back and forth by a diminishing amount for each swing, simulating the "hunting" effect created by an AC or servo motor changing speed."
How the electrons flow is described in great detail in the section called "Circuit Description" But without the schematic in front of you, the IC references won't make any sense I'll quote what's relevant. Let me know if you are bored.
It seems IC11 is the differentiator and its output is dependent upon the rate of change of the input. They say, "(t)hus, when the oscillator changes from positive slope to negative slope," (crossing zero, right?), "the output of IC11 changes polarity." It says later, "The effect of all this circuitry is to generate a damped sinusoidal oscillation at a low frequency when the control voltage changes direction" (rising or falling, essentially anything but zero).
Then it says, "(t)his corresponds in classical flanging to removing the load from the reel motor. The damped oscillation in flanging is caused by the mechanical inertia of the motor - when it reaches its proper speed, it cannot stop changing speed instantly, and thus tends to overshoot, causing it to slow down, etc." |
http://electro-music.com/forum/topic-19784-25.html
I've understood it is a process applied on the incoming modulation, the same thing as for "smooth switch" but for a totally different effect...
Last edited by funkyfarm on Sat Dec 08, 2007 12:27 am; edited 1 time in total |
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mph
Joined: Aug 25, 2007
Posts: 88
Location: France
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| Posted: Fri Dec 07, 2007 11:16 am Post subject:
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| funkyfarm wrote: |
"your thumb on the reel"...
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thanks! that makes sense...
seems very interesting!!! (even if I don't really understand all the details  )
well, let's be "educated"!
Cheers. |
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yusynth
Joined: Nov 24, 2005
Posts: 1314
Location: France
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| Posted: Sat Dec 08, 2007 8:32 am Post subject:
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Hi Jürgen
I have completed one of the two boards I got and I ran the first tests feeding it with a Crumar Multiman S and it does work and sound nicely and as expected. Great stuff indeed. Thanks Jürgen.
Now it's time to adjust the various trimmers and if the gain and resonance trimmers can be adjusted as see fit, can you provide us with some guide lines for adjusting the pitch trimmer and the V/Oct trimmer. For the V/Oct for example, the module cannot oscillate and it's difficult to figure out an octave interval... how do proceed to adjust it ? Does just measuring a mere 18mV variation at pin 3 of U5A, for a variation of 1V at the input, is good enough or should I proceed otherwise ?
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Yves |
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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
Audio files: 24
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| Posted: Mon Dec 10, 2007 10:30 am Post subject:
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| mph wrote: | | funkyfarm wrote: |
"your thumb on the reel"...
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thanks! that makes sense...
seems very interesting!!! (even if I don't really understand all the details )
well, let's be "educated"!
Cheers. |
He he, that was "eductional", as in opposed to "commercial".
Not, me becomming less cryptical, suddenly. 
As I finish building the extra stuff on verobaord, I'll post updates.
But it will take time. With all these commercial stuff runing, building my own phaser has become low priority - sad but true.
That version will also have a resonance that can be switched to self oscillation.
JH.
_________________
"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
Audio files: 24
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| Posted: Mon Dec 10, 2007 10:36 am Post subject:
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| yusson wrote: | Hi Jürgen
I have completed one of the two boards I got and I ran the first tests feeding it with a Crumar Multiman S and it does work and sound nicely and as expected. Great stuff indeed. Thanks Jürgen.
Now it's time to adjust the various trimmers and if the gain and resonance trimmers can be adjusted as see fit, can you provide us with some guide lines for adjusting the pitch trimmer and the V/Oct trimmer. For the V/Oct for example, the module cannot oscillate and it's difficult to figure out an octave interval... how do proceed to adjust it ? Does just measuring a mere 18mV variation at pin 3 of U5A, for a variation of 1V at the input, is good enough or should I proceed otherwise ? |
Change the 220k resistor that's in series with the resonance trimmer to 180k. Now it should self oscillate with the resonance pot all turned up. Then adjust the V/Oct trimmer by ear or with a guitar tuner.
Don't expect perfect tracking. It's a phaser, not a MOTM VCO.
In my Tau, I'm using a 100k "Pull Pot" for resonance.
The formerly 220k is changed to 180k on the board,
The 100k resonance pot has a 20k (final value tbd) resistor in series with its cw end. (i.e., cw end of pot goes to 20k resistor, 20k resistor goes to board connector.)
The switch of the pull pot is connected to short the 20k resistor, when the knob is pulled out. So I get nice high resonance *without* oscillation with the knob pushed in, and screaming oscillation when pulled out.
You can also wire this up with an ordinary pot and switch, of course.
JH.
_________________
"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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yusynth
Joined: Nov 24, 2005
Posts: 1314
Location: France
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| Posted: Mon Dec 10, 2007 10:39 am Post subject:
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Hi Jürgen
Thanks for the tips.
Yves
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Yves |
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eframp
Joined: Sep 11, 2007
Posts: 25
Location: Atlanta, GA
Audio files: 2
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| Posted: Sun Jan 20, 2008 3:24 pm Post subject:
Troubleshooting and calibrating |
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So I finally got my Tau Pipe put together, and I've found a few things that I can't figure out.
The unit is cleanly passing audio, except...
First, the LFO doesn't seem to work. The Tau will sweep if I hook an external LFO up to it, but not otherwise. Without the external LFO hooked up, if I move the Rate pot, the board will sweep to a new position (slightly), but then settles down and won't move again unless I move the pot.
Second, when hooked up to the external LFO (my MOTM one), when the LFO goes negative in output, the Aux Out on the Tau Pipe goes crazy, while the Main Out doesn't. There's a huge variation in level there, too. This is when set to Phasing, not vibrato.
Lastly, is there a post (or a document somewhere) that describes how we should calibrate this thing for optimum performance, aside from the 1V/Oct calibration?
thanks, y'all.
eric |
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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
Audio files: 24
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| Posted: Mon Jan 21, 2008 3:06 pm Post subject:
Re: Troubleshooting and calibrating |
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| eframp wrote: | So I finally got my Tau Pipe put together, and I've found a few things that I can't figure out.
The unit is cleanly passing audio, except...
First, the LFO doesn't seem to work. The Tau will sweep if I hook an external LFO up to it, but not otherwise. Without the external LFO hooked up, if I move the Rate pot, the board will sweep to a new position (slightly), but then settles down and won't move again unless I move the pot.
Second, when hooked up to the external LFO (my MOTM one), when the LFO goes negative in output, the Aux Out on the Tau Pipe goes crazy, while the Main Out doesn't. There's a huge variation in level there, too. This is when set to Phasing, not vibrato.
Lastly, is there a post (or a document somewhere) that describes how we should calibrate this thing for optimum performance, aside from the 1V/Oct calibration?
thanks, y'all.
eric |
Sounds like two different faults at least.
Have you checked supply voltages at Opamps (+/-15V)?
Any different components than on the BOM?
Checked all solder joints?
JH.
_________________
"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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ericcoleridge
Joined: Jan 16, 2007
Posts: 889
Location: NYC
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| Posted: Tue Jan 22, 2008 9:57 am Post subject:
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I had a similar results so far with my Tau Pipe. It passes audio, but no phasing and no LFO. Actually it might be phasing, it sounds like the audio is filtered--but no movement. A couple times when I powered it up initially, it would give a burst of "swoosh", and the LEDs would blink, but then it immediately stops.
I checked the power, cap and chip orientation, etc, but am at a loss. So, I sent it to a friend to take a look at. I probably overlooked something very obvious. |
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eframp
Joined: Sep 11, 2007
Posts: 25
Location: Atlanta, GA
Audio files: 2
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| Posted: Tue Jan 22, 2008 10:34 am Post subject:
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| ericcoleridge wrote: | I had a similar results so far with my Tau Pipe. It passes audio, but no phasing and no LFO. Actually it might be phasing, it sounds like the audio is filtered--but no movement. A couple times when I powered it up initially, it would give a burst of "swoosh", and the LEDs would blink, but then it immediately stops.
I checked the power, cap and chip orientation, etc, but am at a loss. So, I sent it to a friend to take a look at. I probably overlooked something very obvious. |
Bingo. That's what I'm seeing here. Nice clean +/-15V, all the controls work, all the jacks accept CV's and do the correct things with them, there's nice strong phasing (boy does it sound good!), but no sweep unless I give it an external LFO or sweep the Pitch pot manually. Or move the Rate pot, but then it settles back down again and doesn't actually keep moving. |
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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
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| Posted: Tue Jan 22, 2008 12:30 pm Post subject:
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Are the two LEDs taking turns in glowing?
Are all the diodes soldered in with the right orientation?
(If D2 in http://www.jhaible.heim.at/tau/jh_tau_sch_page3_control.pdf is reversed, the LFO would oscillate, but with an offset where it would be blocked by D1 ...)
If the LFO does not oscillate, what are the voltages on all 8 pins of U6 (the TL071 closest to the voltage regulators) ?
JH.
_________________
"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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eframp
Joined: Sep 11, 2007
Posts: 25
Location: Atlanta, GA
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| Posted: Tue Jan 22, 2008 3:47 pm Post subject:
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>Are the two LEDs taking turns in glowing?
On mine, the "Down" LED is stuck on.
>Are all the diodes soldered in with the right orientation?
The bands match the silkscreening.
>If the LFO does not oscillate, what are the voltages on all 8 pins of U6 (the TL071 closest to the voltage regulators) ?
1: 0.135
2: 0.006
3: 0
4: -15.11
5: 0.134
6: gnd
7: 14.61
8: 15.14 |
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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
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| Posted: Tue Jan 22, 2008 4:05 pm Post subject:
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| eframp wrote: |
1: 0.135
2: 0.006
3: 0
4: -15.11
5: 0.134
6: gnd
7: 14.61
8: 15.14 |
That looks like a perfectly valid condition within an ordinary LFO cycle.
Pin 1 should further ramp down, and when it crosses 0V, Pin 7 should jump to -14V, causing pin 1 to ramp up.
Strange that apparently it doesn't.
In that state you described, the center pin of the "Rate" connector should be positive. Is it? (If you turn the Rate potentiometer all the way clockwise, it should be about +14V.)
Another thought: Could C54 be leaking? It should be a 470nF polyester cap - you don't have an electrolytic cap here, no? (Just to be sure.)
JH.
_________________
"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
Audio files: 24
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| Posted: Wed Jan 23, 2008 1:47 am Post subject:
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| jhaible wrote: |
In that state you described, the center pin of the "Rate" connector should be positive. Is it? (If you turn the Rate potentiometer all the way clockwise, it should be about +14V.) |
Is it around +14V when the pot is fully cw?
JH.
_________________
"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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eframp
Joined: Sep 11, 2007
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| Posted: Wed Jan 23, 2008 8:19 am Post subject:
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JH -
Between center pin and either side is 0V. Between center pin and ground is about 0.006V.
And the cap is indeed a poly, not electrolytic.
e |
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eframp
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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
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| Posted: Wed Jan 23, 2008 5:18 pm Post subject:
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| eframp wrote: | JH -
Between center pin and either side is 0V. Between center pin and ground is about 0.006V.
And the cap is indeed a poly, not electrolytic.
e |
All right - I think I have figured it out:
The clockwise end of the pot (red wire in your picture) must have the same voltage as Pin 7 of the TL072. Which also must be the same at the right end of the 12k resistor (near the "LM317" silkscreening).
If it's not the same, you have a broken connection along that way.
Let me know what you find. Broken wire, bad solder joint, or broken copper trace, or bad IC socket.
JH.
_________________
"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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eframp
Joined: Sep 11, 2007
Posts: 25
Location: Atlanta, GA
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| Posted: Thu Jan 24, 2008 2:51 pm Post subject:
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| jhaible wrote: | All right - I think I have figured it out:
The clockwise end of the pot (red wire in your picture) must have the same voltage as Pin 7 of the TL072. Which also must be the same at the right end of the 12k resistor (near the "LM317" silkscreening).
If it's not the same, you have a broken connection along that way.
Let me know what you find. Broken wire, bad solder joint, or broken copper trace, or bad IC socket.
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You called it right. Turns out it was the pad of pin 7 that I'd inadvertently pulled off the board from an earlier soldering mistake. Some bus-wire from the pin to the resistor, et voila, oscillation! It seemed so obvious after you pointed it out... <sigh>
Thanks for designing a cool module, and for your extra help getting mine going.
e |
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Techman
Joined: Jun 07, 2007
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funkyfarm
Joined: Jan 21, 2007
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| Posted: Wed Jan 30, 2008 2:48 am Post subject:
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Spectacular !
but i guess i can hear some clicks when you use an "external CV via a P3 sequencer and a PolyDAC"
Did you try the smooth function ? (or is it another matter ?) |
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Techman
Joined: Jun 07, 2007
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yusynth
Joined: Nov 24, 2005
Posts: 1314
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| Posted: Thu Jan 31, 2008 12:48 pm Post subject:
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I have finished the Tau-Phase Shifter module for my YUSYNTH modular. Here is a photo of the finished module.
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Yves |
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v8pete
Joined: Jan 27, 2008
Posts: 43
Location: UK
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| Posted: Thu Jan 31, 2008 2:37 pm Post subject:
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Hi Juergen - as a newbie to this site, I've just discovered this great little project of yours! - must have missed it somehow on your main site. You've probably been asked this a lot, but do you happen to have any more PCBs available as I'd love to get one!
Hey, is that a double exponential in the control circuit? - with the two series transistors for temp compensation - can't quite figure out exactly what's going on!
Keep up the excellent work!
Pete.
BTW - I also take my hat off to you for that rather marvellous voltage controlled ADSR design of yours on the website - inspirational stuff !!  |
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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
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| Posted: Thu Jan 31, 2008 3:25 pm Post subject:
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| v8pete wrote: | | Hi Juergen - as a newbie to this site, I've just discovered this great little project of yours! - must have missed it somehow on your main site. You've probably been asked this a lot, but do you happen to have any more PCBs available as I'd love to get one! |
These are sold out, I'm afraid.
But I'm getting more and more requests, so maybe I'll get enough for another run at some time.
If you want to be put on my waiting list, please send me an official order form email (scroll back in this thread to find it) - and mention that you're doing so to get on the waiting list.
| Quote: |
Hey, is that a double exponential in the control circuit? - with the two series transistors for temp compensation - can't quite figure out exactly what's going on!
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It's tricky. It's a circuit that has an exponential input and a 1/x input.
| Quote: |
BTW - I also take my hat off to you for that rather marvellous voltage controlled ADSR design of yours on the website - inspirational stuff !! |
Thank you! I hope this will appear as an official MOTM module some day.
I have licenced it to synthtech.com for that purpose some years ago.
If Paul should not want to make use of this (but currently I think he still wants), it will be one of the first things I'd make a PCB for, myself.
(I didn't give away any rights, but I had, and still have, the best and most satisfying relation with synthtech, so I rather wait another year or two than just offering it as a PCB myself.)
JH.
_________________
"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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The source is an Alesis Drum machine, and I am using both the Tau internal LFO and an external CV via a P3 sequencer and a PolyDAC.
