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Buchla 100 clones: 158, 180, 140, 156, 106, etc. DEMOS
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page Previous  1, 2, 3 ... 24, 25, 26 ... 31, 32, 33  Next [all]
Author Buchla 100 clones: 158, 180, 140, 156, 106, etc. DEMOS
lasesentaysiete
diophantine
114 is not the easiest to understand. Here is the explanation from the manual:

diophantine
lasesentaysiete
Yes, I'm familiar with the manual. Based on it, I would expect CV Out = max(pot, pressure), or similar.

And that appears to be the case with mine, except that the pressure never goes above 5V, which seems wrong. (Tweaking one of the trimmers I can get it to 6 or 7V, but at that point the Gate out doesn't work.)

I will try checking component values later. Have there been any component value changes that you've made to the BOM?
diophantine
(dupe...)
sanders
lasesentaysiete wrote:
sanders
Build info for all modules is here: https://www.lasesentaysiete.com/build-info

SPDT switch Mouser#: 633-M201203


Sorry bout that, and thank you; i had been looking at it on the mobile site; now I’ve got it.
diophantine
114: I checked and all components appear to be correct according to both the BOM and schematic.

lasesentaysiete What is the max output voltage you can get with just pressure (i.e. CV knob turned FCCW)?

The oscillator output (at the junction of R211 & R212 & C71, measured from right side of R212) is a ~2Vpp sine @ ~20kHz. This seems to be correct.

Looking at the circuit for key 1 (which behaves virtually identical to 2-10):
- Sine wave at Q2 base (measured from bottom of D1) varies from ~.2V with no pressure applied, to almost 4V with maximum pressure applied.
- Voltage at Q2 collector (measured from bottom of D3) varies from 0V with no pressure applied, to ~6V with maximum pressure applied. (This is actually a very low amplitude waveform, so what I call "voltage" is technically the DC offset.)
- So, with the forward voltage drop of D3, it makes sense that the max voltage I see on the output is only ~5V.

So I'm left wondering... is 470R actually correct for R8?

I decided to experiment & put a 1k resistor in parallel with R8, to give 320R. Now I get a maximum of ~8V at the Q2 collector - getting closer! Brought it down to 130R and now I get 12V! (And the gate still works...)

Perhaps R8 is supposed to be 47R, not 470R?

UPDATE: I brought R8 down to 60R and now the voltage at the Q2 collector is ~14V. So it does seem pretty likely that the resistor should be 47R, not 470R. I don't really want to disassemble, so I will probably just buy some 51R resistors to put in parallel with the 470R (46R total).
sanders
Does anyone have good photo of the 191 rotary switch wired up?
diophantine
sanders wrote:
Does anyone have good photo of the 191 rotary switch wired up?

I doubt this will be very helpful... MY ASS IS BLEEDING


Did you see the wiring diagram on the 2nd to last page of the BOM PDF?
lasesentaysiete
diophantine wrote:


Perhaps R8 is supposed to be 47R, not 470R?



It is possible, but the original schematic shows 470r. The 112 schematic is 470R, as well.

The maximum output from pressure alone was ~6v on mine, if I remember correctly. The owner of an original 114 now has one of my builds, so I will ask for a comparison.

In any case, its good that you have sorted it out. I guess the only thing left is to make sure the value change does not have an adverse effects on other functions.
lasesentaysiete
sanders wrote:
Does anyone have good photo of the 191 rotary switch wired up?


diophantine
lasesentaysiete wrote:
The maximum output from pressure alone was ~6v on mine, if I remember correctly. The owner of an original 114 now has one of my builds, so I will ask for a comparison.

That would be great; thank you!

6V doesn't seem very useful for operating a 107 (or 110), so (IMO) it would be shocking if the original only went up to 6V.

I guess I never really noticed it on the 112, because I haven't used the pressure out very much.

lasesentaysiete wrote:
In any case, its good that you have sorted it out. I guess the only thing left is to make sure the value change does not have an adverse effects on other functions.

At least with the 114, yes, all other features work fine, no matter what value of R8 I've used.
sanders
Ok, I got it. The wiring diagram is simplified for sake of clarity, and illustrates one switch wiring, of which there are actually 8 on the switch assembly. I’ll admit I was a little confused when I first looked at the diagram, compared to the switch.

I got it (applause)

lasesentaysiete
sanders
Ok, glad you got it. Its not very fun to wire that thing. And yes, I simplified the diagram for clarity only smile

diophantine
I am curious to find out about the original 114, too. I will report my findings. Either way, you have made a good adjustment to the circuit thumbs up
diophantine
lasesentaysiete wrote:
diophantine
I am curious to find out about the original 114, too. I will report my findings. Either way, you have made a good adjustment to the circuit thumbs up

thumbs up I just tried the 112a. Mine gives 7V on the pressure output. Changing R10 from 470R to 130R gives the full 15V output, and everything else works correctly. (Note: the trimmers on the 112a seem to have minimal effect; I've kept them all near the center.)
lasesentaysiete
diophantine
Excellent. How is the sensitivity on the 112? Can it be subtle or is it jumpy?
diophantine
lasesentaysiete wrote:
diophantine
Excellent. How is the sensitivity on the 112? Can it be subtle or is it jumpy?

It isn't jumpy at all. I was able to smoothly and slowly sweep a 158's frequency across its whole range.

Bear in mind that I also used a polyurethane spray on the touchpad PCBs.
sanders
lasesentaysiete wrote:

The 146 (16 step 123) and 112b (16 key 112) are also in the works.


If you release a 112b, will it have the blue touch plate (maybe they were all made this way, I don’t know). I saw a photo of one recently, it’s such a beautiful design. I was quite smitten with it.



diophantine
sanders
The plan (mentioned elsewhere in this thread) is that the 112b (16 key) will have the blue touchplate, while the 112a (12 key) has the older style one. I think Don had switched to the blue ones before the 16-key 112 came out.

That's a nicely modded one you've linked to, with the LEDs per key, etc.! Very useful... Interesting that it has tinijax (or more likely, minijacks).
diophantine
lasesentaysiete wrote:
144:

1. Adjust R18 so that oscillation is within audible range. The circuit can oscillate at super high frequencies, or not at all, so you may have to adjust R18 quite a bit.

2. R4 sets the low frequency and R10 sets the high frequency. These two trimmers interact to some degree, so you may have to go back and forth some. Re-adjust R18 if you cannot get reasonable lowest/highest frequencies.

3. R36 sets the amplitude and also affects the AM. I set mine for the lowest amplitude (~1.8v pk-pk in my case) to try and match the 158 as closely as possible. AM still responds well.

I was able to get a a range of 5hz to 15khz on these. They can oscillate at higher frequencies, but you lose low end extension.

I finally got around to calibrating my 144s, beyond R18. All four oscillators have a full 5Hz to 20kHz range. (I did use 2N5020 rather than J175.)

Regarding the amplitude, you mention that you calibrated to 1.8Vpp... that's what your 158 gives? Mine are both ~4Vpp. So I calibrated the 144 to give the max amplitude, which is around 3.6Vpp or so, without turning the trimpot further. AM still seems to work fine.
diophantine
I guess it is calibration day...

Working on the 155. Got it pretty close to 10 seconds max slew (just mentally counting, not actually timing). One thing I notice is that when the input voltage is near +15V and slew rate is at max, there seems to be a "sustain" based on the amount of time it has been at that voltage. So if I'm inputting ~15V and when the 155 output hits ~15V I immediately change the input to 0V, the 155 output starts going down right away. But if I wait a few seconds, it takes the 155 a few seconds before the output starts decaying.

Is this something that others are seeing, too? I'm testing it with a 156... and I'm not seeing this sort of thing when I'm only inputting 10V, for instance.

The manual for the 100 is missing this module (as well as some other obscure modules); I'm wondering if anyone has seen any sort of original description of the module? I'd be curious for historical purposes...
lasesentaysiete
diophantine wrote:
So if I'm inputting ~15V and when the 155 output hits ~15V I immediately change the input to 0V, the 155 output starts going down right away. But if I wait a few seconds, it takes the 155 a few seconds before the output starts decaying.



Do you mean that the positive slew set to maximum, it affects the negative? Are you using the manual offset knob of the 156 as a voltage source? Maybe try discrete voltage from the 123 to compare?

I will have a look today, as well.
lasesentaysiete
diophantine wrote:

I finally got around to calibrating my 144s, beyond R18. All four oscillators have a full 5Hz to 20kHz range. (I did use 2N5020 rather than J175.)

Regarding the amplitude, you mention that you calibrated to 1.8Vpp... that's what your 158 gives? Mine are both ~4Vpp. So I calibrated the 144 to give the max amplitude, which is around 3.6Vpp or so, without turning the trimpot further. AM still seems to work fine.


It sounds like you have got it working nicely. Especially nice is the equal amplitude to the 158. I am likely to build another 158 soon so I will try and find the best way to maximize the output amplitude (to best match the 144).
diophantine
lasesentaysiete wrote:
diophantine wrote:
So if I'm inputting ~15V and when the 155 output hits ~15V I immediately change the input to 0V, the 155 output starts going down right away. But if I wait a few seconds, it takes the 155 a few seconds before the output starts decaying.



Do you mean that the positive slew set to maximum, it affects the negative? Are you using the manual offset knob of the 156 as a voltage source? Maybe try discrete voltage from the 123 to compare?


Yes, I am using the manual offset knob, but no, it is not affected by the positive slew setting. With positive slew FCCW (min) and negative slew FCW (max), if I set the input to +14V (or less) and leave it there for a few minutes... when I turn the input back to 0V the 155 output immediately starts to go down according to the slew rate.

But if I input +15V and leave it there, even for only a few seconds, when I turn the input back to 0V the 155 waits 5-15 seconds before the output starts decreasing.

This weekend I will try it with the 112 or 123, to see if that makes a difference.
diophantine
Also, how good or bad is this attempt at calibrating my 196?:
https://photos.google.com/photo/AF1QipMJhVyFCEFnvyo74vQPC6pDIgnKlsOOIx uOOF7U
lasesentaysiete
diophantine wrote:
Also, how good or bad is this attempt at calibrating my 196?:
https://photos.google.com/photo/AF1QipMJhVyFCEFnvyo74vQPC6pDIgnKlsOOIx uOOF7U


The link did not work for me. Was it a oscilloscope still showing an XY reading?

I was unable to get the two signals to form a perfect circle across the entire frequency range, but it did look acceptable
sanders
I "finished" my 191 tonight. I made a video demonstrating the various filter modes-- but I realized while doing so that there are at least a few issues yet to solve.
First off, I'm getting a lot of noise interference from my case (I presume); I actually filmed the 191 resting on another module, because as soon as I set it inside the case, the noise quite dramatically frequency modulates the filter-- and sounds nice actually-- but I hope I can figure out why this is happening, and fix it.
I noticed one of my outputs isn't wired up correctly, you'll see; and finally, you can see in the video that the LPF output has a lot less volume than the others.

I did the calibrations by ear (which is actually why I used single-turn trims). It took me a minute, but I think I have it fairly well figured out how to do this ok by ear. Tell me what you think:

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