Quantizer

[numbertalk]

Finally got it working! Had to use Useemu's fix (thank you SO much for finding this!!!) as well as bumping up R1 to 240K, which Ray describes on his site. I had been emailing with Ray about my problems and told him I had to change R40 to 51K with a 150pf cap in parallel, as did several people here, so he really should look into it. Kind of frustrating - I'm not sure how the ones he's built have worked. Also not sure why he didn't replace R1 with a trimmer and resistor, but oh well, all the matters is it's working!!

[jordroid]

I just finished one of these up using a recent board and the latest schematic, and it works right off the bat. I just calibrated it by ear because i was anxious to try it out quick and it is definitely good enough for music. It is keeping my soundlab oscillators in tune over about four octaves, which is about all they are good for anyways.

Just in case anyone planning one of these is nervous about it working (i was) the most recent revision seems to work great with no tweaks. I did spend the time matching up the ladder resistors.

I left out the whole tone and fourth options, but i don't think that would affect the working of the whole unit.

[numbertalk]

This is puzzling. The board is exactly the same, as far as I can tell. He made a few component changes that effect more the stability with changing voltages I believe, that would not effect the calibration issue I and others have had. Ray has not really looked into the fix suggested here, for example, so nothing major has changed. Seems a lot of people have had a problem that was solved by the fix suggested here but others have not run into this issue.

[jordroid]

Weird, i guess maybe it is just a temperamental circuit and you either get lucky or not. I have been reading this thread while building it, expecting to finish it up, find that it doesn't work correctly and implement the Useemu tweaks you guys talked about. I was happily surprised that it worked without any messing around.

I meant to say in my first post, nice job getting yours going, and thanks for posting the tweaks that got it there, it seems like they will still be helpful when the $%^$%$@ things just won't cooperate.

[werock]

There was a small error in the parts list which Ray has changed today. R1 was listed as 120K in the parts list & schematic, but the text mentioned it should be 200K to get the right clock rate.

R1 should be 200K.

[mattias]

Just want to throw in another vote for the changes of R40 and R13 and R1. I stuffed two boards last summer without looking at this thread. Now while powering them up they were showing all the issues mentioned before.

So I applied all those changes:

(1) increased R1 from 120K to 680K (too much, have to adjust this guy).

(2) decreased R40 to 51k (I'm running it off +/- 15V)

(3) soldered 220p in parallel with R40

(4) decreased R13 to 47k.

Now one board is doing what it was designed for. Since I run out of 51K-resistors, I could just fix one baord.

Thanks to Useemu and funkyfarm all for all the hard work.

[kindredlost]

Just now stumbling upon this thread.

My quantizer is not behaving at all correctly. I am unable to bring a legitimate voltage to task for the D/A and I think I'm having trouble with the counter.

I have a more detailed description in a new thread..
http://electro-music.com/forum/topic-48599.html

... but here it is for the sake of brevity;

It is outputting zero volts in WHOLE and FOURTHS mode and 90mv in HALF mode. No response from either the Initial Voltage Pot or external voltage inputs.

I'm running on a 15 volt supply but I've changed R13 to 51K as specified.

My scope read 52.17KHZ on pin 2 of U1 clock. I changed R1 to 220K so it is slower at 47KHZ but there is still no improvement.

I have some over-rated caps. C18 (.002uF) is 500 volt rated and C1 through C4 (100pF) are 200 volt rated. I have some 50 volt caps coming in.

Any ideas of where to check?

I don't think it is the caps. Maybe U1 handshaking with U3 and U2? I'm not seeing a polarity change on U7 so it could be the D/A U5-A is not behaving right. I see counter output from pin 2 of U3 but I think I was not seeing good output from pins 3, 6 & 7. CARRY out from U3 to pin 5 of U6 (UP) is high steady with no change. U5-A pin 1 doesn't show the steps but stays steady high continuous.

[Luka]

well my quantiser is showing similar errors as reported here
skipped notes, glitches, ranges are a little off

i made a video

https://vimeo.com/44561647

my clock is running at 47khz using a 160K resister as R1
decreased R40 to 51k
i tried adding a 220pf cap to R40 but it didnt change the glitches or skipping notes

stuck on this one - seems like the circuit is really sensative
i might try rebuild it to see if using a fresh set of components will change my problems

[pjbulls]

So, I know this thread is wayyy old, but I also stumbled on it just now while builting a MFOS Quantizer. I really want to love this circuit since it's pretty much the only one out there that isn't based on a microcontroller, but it sure is finicky.

I've gotten the scaling to work pretty well (went out of my way to get 0.1% SMT resistors), but the output is really glitchy. As in, it will drop to 0V or jitter between two unrelated voltages every few steps. Has anyone been able to get this more stable? I'm considering increasing the hysteresis on U7, or maybe replacing it with a proper comparator, but I have no idea if that would help..

[kkissinger]

I had the same issue and slowing the clock made a big difference.

Adjust the value of R1 - a higher value for R1 results in a slower clock speed.

Another mod I made was to replace R43 with a 175K resister in series with a 10K trimpot. This is to match the input volt per octave scaling with the output scaling.

Another mod that I want to make (but haven’t yet) is to add a bypass switch. With matched input and output scaling it should work smoothly.

Good luck!

Here is a link with some good info:

http://musicfromouterspace.com/analogsynth_new/VOLTAGEQUANTIZER/VOLTAGEQUANTIZER.php

[pjbulls]

Thank you so much! I was building from that page, but kind of glossed over the clock section it seems. I've never had much trouble with Ray's designs in the past, they are all excellent.

Turns out my clock was running at around 54kHz with 200K for R1. Plonked a 100K trimmer in series, the quantizer behaves so much better clocked at 45kHz, it's crazy! I can tune down to around 37kHz now which makes it even smoother, I'll probably leave it around 40-ish.

Next step: get two of these circuits behind a 2HP panel!

[kkissinger]

Excellent! Glad that worked for you. Ray’s designs are wonderful, indeed.