MUFF WIGGLER Forum Index
 FAQ & Terms of UseFAQ & Terms Of Use   Wiggler RadioMW Radio   Muff Wiggler TwitterTwitter   Support the site @ PatreonPatreon 
 SearchSearch   RegisterSign up   Log inLog in 
WIGGLING 'LITE' IN GUEST MODE

A couple of questions about Rob Hordijk´s Zeitgeist circuit
MUFF WIGGLER Forum Index -> Music Tech DIY  
Author A couple of questions about Rob Hordijk´s Zeitgeist circuit
notmiserlouagain
About to build some of those.

1. Now I always thought, something on the schematics was missing, only now I realized that Rob is implementing the delay time control completly different than anybody else, by injecting a variable voltage to the control pin 6.

While this intuitivly makes sense with voltages below 2.5V(from the control port) there is the chance of voltages higher than 2.5V reaching pin 6.
Has anybody experience with this (or latch-up problems with the Zeitgeist)?

2. The opamps are powered by +2.5V and -2.5V. Does this even work with tl074 (as specified)? I thought +/- 3.5V was required minimum supply to work...? If so, what opamps would work better?

3. What are D2 and D3 doing, highpass filtering ac above/below +0.6V/-0.6V?

Also, any experiences about building as well as playing the Zeitgeist would be very welcome! I´ll be using the layout fellow wiggler Constantin3000 posted in this thread.

Thanks!
notmiserlouagain
Day off from work today so I etched and drilled 2 Zeitgeister (and am right now populating them). So I hopefully will be able to answer above questions myself soon. Still it would be nice, if someone would chime in with some experiences or analysis of this circuit! Mr. Green

Below the only interesting mentions of the circuit I could find on MW (->the web), I cannot believe it, Hordijk is the designer du jour, isn´t he?
Admittedly they sound very promising, just what I was looking for!

andrewF wrote:
The zeitgeist is nothing like a normal PT2399 delay, probably shouldn't even call it a delay.....its one of those beautiful designs that seems to ignore the datasheet and sounds quite unique & wonderful


andrewF wrote:
imo the zeitgeist is the best thing that ever happened to the 2399. Total chip abuse love it.


xahdrez
I've actually just got a board made up for this too - waiting on components, but will check in when I get a chance to build/troubleshoot! It's peanut butter jelly time!
TimoRozendal
the demo video I found makes me think that andrew might be inspired by this one to design the DelayNoMore, it might be useful to compare schematics (I haven't done that btw)
andrewF
TimoRozendal wrote:
the demo video I found makes me think that andrew might be inspired by this one to design the DelayNoMore, it might be useful to compare schematics (I haven't done that btw)


The DnM uses two PT2399 chips in series with 3 different feedback paths plus 2 feedforward paths.
The delay time is controlled by a 1M pot on one stage and a vactrol on the other, the value of this pot should be 50k for normal operation. Using a much larger pot gets it to zipper and stutter.

It is completely different to Rob's design, although the realisation that the PT2399 is capable of all sorts of audio shenanigans certainly came from playing with the Zeitgeist.

Schematic is HERE if you are interested.

There is also the giant B0N0 which mates a PT2399 with a 4046PLL:
TimoRozendal
great stuff Andrew!
so, yes it is somehow inspired but not as much as I thought :-)
notmiserlouagain
uups
notmiserlouagain
xahdrez wrote:
I've actually just got a board made up for this too - waiting on components, but will check in when I get a chance to build/troubleshoot! It's peanut butter jelly time!

thumbs up
andrewF wrote:

Schematic is HERE if you are interested.

You bet! Thanks! Animal!
animalman
Would like to build one too. So, curious how this turns out. any progress? hyper
Did that pcb design work? I normally build diy stuff on veroboard, but somehow i feel that i cant totally wrap my head around the Hordijk schematics, so would need to get a pcb etched for this project.
notmiserlouagain
Coming soon...

Zuzweitgeist

xahdrez
Managed to build my version yesterday - not had a chance to explore it thoroughly, but preliminary tests have been good! One thing that might be handy for others to know is that when the two delays pots are fully CW (on my build at least) the PT2399 is overloaded and actually cuts out, so make sure you test on less than that value!

I put a korg monotron through mine just to sample it, incredibly low quality footage here

https://www.instagram.com/p/BCDrwU4ScHJ/
inlifeindeath
i can't seem to find the pcb transfer on the electro music forum anymore. can someone help me out please?
Oscilloclast
I built one of these from an original board from Rob (got it when he came to America some years ago). The thing I really love about the delay is that you can increase the delay time to really degrade the signal and eventually make the chip sputter out (which has never hurt my chips), you get to hear the 1 bit mechanism fail. good luck.
notmiserlouagain
Hey inlifeindeath, there´s a link at the end of the first post...
animalman
while eagerly awaiting my benjolin pcb from the recent group buy, thought I'd just check in to see if anyone had luck figuring out the schematic, or actually built a working Zeitgeist?
I'm getting confused with the "HDR" (?) in the schematic here seriously, i just don't get it schematic


Would be really awsome to pair up the benjolin and zeitgest in the same box.
cygmu
animalman wrote:

I'm getting confused with the "HDR" (?) in the schematic here seriously, i just don't get it schematic


I think that's a header i.e. a bunch of pins.
animalman
that's what i figured, but how/what do I connect at the header? There is also a "J"...jumper?
xahdrez
I don't have the schematic in front of me, but from memory the HDR is just for you to wire panel components, and the jumper is to allow switching between controlling the delay time with an ldr or CV - but it's been a while since I've looked at this so could be wrong!
CLee
Trying to figure this out too.

I think J2 and J3 are switches. J2 switches between external CV and a light sensor. And J3 taps the OUTPUT to be with or without the dry signal. Anyone confirm that??

P1 looks like a blend control?

Can anyone confirm that sending 12v into the EXTERNAL CV won't fry the delay chip?
cygmu
CLee wrote:
Trying to figure this out too.

I think J2 and J3 are switches. J2 switches between external CV and a light sensor. And J3 taps the OUTPUT to be with or without the dry signal. Anyone confirm that??


That seems right. Look at the pcb layout and images in this thread: http://electro-music.com/forum/topic-38321.html
In the photo of a completed board you can see that jumpers have been applied to two of the three pins on each of the 3-pin headers J2 and J3. I suppose this is just to keep things low-cost.
ym2612
Has anybody tried adapting one of these to run on +/-12V?

The schematic makes my head spin in some spots.
diophantine
ym2612 wrote:
Has anybody tried adapting one of these to run on +/-12V?

The schematic makes my head spin in some spots.

No changes needed. It just needs a positive voltage, and that goes to a +5V regulator (U1) which powers the circuit.
Siri
Here are my notes, when i built mine. Nothing comes from me, it is basically quotes from different threads on electro-music. Mine works!

Quote:
I noticed a small error on the schematic diagram. It has C9 - pin 9 on the delay chip - as 9100nF. Looking at the overlay and photo here it appears that the extra 9 is a typo, it should probably be 100nF. http://electro-music.com/forum/post-356382.html#356382

can i use 7805? > yes, it's just a 5v line for the delay chip. 7805 work fine. http://electro-music.com/forum/post-356623.html#356623

From Left to Right ( P4, P3, P2, P1 )

Input Level, Wet/Dry mix, Modulation Depth ( from external CV ), Delay Time.

The CV input is to control the delay time? > Yes

What is SENSOR doing?(HDR 10) > It is an LDR, presumably to control delay time according to light level.

What are the functions of JUMPER and the two HDR 3? jumpers for a different settings ? > HDR_3 allows you to bypass the external CV option the jumper allows you to bypass the LDR if you don't want to use it.

The JUMPER next to the led says + and -, should I consider - as Ground?? > Yes -Ve appears to be ground in this circuit. As it works from a single supply. http://electro-music.com/forum/post-428333.html#428333

One switch will switch the audio output to the point right before the delayline or right after the delayline. The other switch will switch between the LDR (or any other resistive) sensor or the delaytime modulation CV input on the 2×5 header. http://electro-music.com/forum/post-271963.html#271963

The Zeitgeist has a +5V regulator that accepts a power supply voltage of +6V to +20V. The Zeitgeist uses roughly between 20mA and 40mA of current, depending on the delaytime. http://electro-music.com/forum/post-271977.html#271977

The output switch selects between “delayed signal” and “delayed signal + input signal”. Is that correct?> Yes, it switches the output 'pre-delayline' or 'post-delayline'.

For the LDR it looks like there are two places on the board where it can be connected: one on the “sensor” input on the 10 pin header and one on the two prong header by the switch to select CV or LDR (for control of the delay time). Is that correct? > It should best be connected to the two prong header. http://electro-music.com/forum/post-272072.html#272072

It is a green LED, but it's burning yellow is caused by too much current passing. So eventually it burns through, as did mine as well. I just removed and bypassed it. That works and is safe as there is a voltage regulator after the LED. Another option is to remove the LED and insert a switch there for power on-off. http://electro-music.com/forum/post-301256.html#301256

For the Op Amp IC, I used an LM 324 per Rob's recomendation. http://electro-music.com/forum/post-274537.html#274537


Edit : Just saw the previous comments were from 2 years ago... Oh well hihi Might be helpful to someone, who knows!
notmiserlouagain
Siri wrote:
Just saw the previous comments were from 2 years ago... Oh well hihi Might be helpful to someone, who knows!


Just recently got a PM of a wiggler going to build this, so, probably yes?
Especially the double LDR connection and the burn-out-LED had me stumped initially---
But I can confirm that all of the above are the right answers, great circuit, totally build two of it!
virtualcrimes
notmiserlouagain

Can you tell me what ground connections are missing, i am about to etch the board from the layout provided. Thanks!
MUFF WIGGLER Forum Index -> Music Tech DIY  
Page 1 of 1
Powered by phpBB © phpBB Group