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WIGGLING 'LITE' IN GUEST MODE

BUILD THREAD: 266-style PCBs
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page 1, 2, 3 ... 18, 19, 20  Next [all]
Author BUILD THREAD: 266-style PCBs
wohali
I took delivery of a set of the v1 PCBs, vactrols, and faceplate about 6 months ago. I finally got around to completing the project this past weekend.

Picture:

Picture in my custom TTSH/Eurorack case:

Total power draw with LEDs on: 175mA +12V, 122mA -12V.

I did take a bunch of notes; the ModularSynthesis site covered most of it, with L-1's modifications in the last 2 pages of this thread being useful as well. I had to make a few additional adjustments on my unit to get it responding reasonably and working appropriately. I'll try and blog about this soon so others can follow along.

Thanks to L-1 and Dave Brown for their excellent work, it made dealing with this error-riddled set of PCBs much easier.
appliancide
Wow. It looks like there are a few additional modifications recommended since the last euro 266 I built.

None of the level shifters on PCB 3 are needed? So just jumper the input side of R11 to the output side of R13 on the IC1 shifters, and the input side of R19 to the output side of R21 on IC2?

I am curious to see which of the modularsynthesis and L-1 mods are useful on the 12v build. I'd much rather make adjustments to make it work on 12v, than to mess around with voltage boosters.

Madness!
JJCarr
all issues with my module are solved.
for anybody else with this problem in the future, look for the photos of the power section of the euro pcb in the middle of the thread.
this thing has never worked so well, I'm so glad I finally figured out this issue. my S+H and SRV have never functioned properly since I purchased it and now it's BRILLIANT.
thanks to Janvolt for the info he provided in a pinch.
over and out (hopefully forever).
JJCarr
OK, I'm back after 2 years with the same Euro build to troubleshoot. yaaaay!

what is the DEFINITIVE/FINAL mod for the power converter section on PCB 1?
i've read through the thread and applied what seems to be the latest omissions/jumps/etc. but am still having problems.

this is what's currently implemented:

-All traces that were cut in schematic now reconnected
-omitted d12, d13, L3, L4, IC15, IC14, C14, C41, C40
-C37 currently installed but conflicting info in thread on whether this is needed
-i have L3 jumped to C14 so that +12v actually exits the circuit like the schematic reads even though I don't see anything about this anywhere.
-when I take readings at the THRU outputs right now out1 reads +12v, out2 ground, out3 +10v (should be -12v, right?).

is this module supposed to run on 15v? what is this mod doing and why is the module (when functioning) seemingly just fine running 12v now?

I did not build this module and was having issues with the S+H and possibly the SRV. again, this is for a Eurorack format module.

Dead Banana PLEASE HELP Dead Banana
JJCarr
i've had one of these 266c modules for a while but i've never been able to get the s+h section to do anything?!
i'm guessing it got damaged in shipping somehow. any delicate parts or known issues i should be looking for?
cables and chips seem to be seated correctly.
davebr
L-1 wrote:
SRV1SRV has 256 possible output states. So to have 1/4 semitone per state, we need 5.33V output range.

I removed this 12K marked red, which was installed because I made modularsynthesis.com modifications.
Also I made R84-R91 exact 25K, 50K, 100K, 200K, 400K, 800K, 1600K, 3200K.

I made simulation where added a resistor after D4. To have 5.33V range it must be 88K.

Of course you could drop the 2 LSBs for semitones outputs (5.33/64 =83 mV).

Dave
L-1
SAMPLE AND HOLD

Sample and hold has PULSE IN, and two pulse outs which are near IN sighned ALT wth arrows. They produce positive odd and even pulses from IN.

PULSE OUT1 yellow and PULSE OUT 2 blue:




PULSE OUT 2 blue with PULSE IN green:




I fed triangle wave into CV IN.
Also it has 1+2 CV OUT and CV1 OUT and CV2 OUT which are sighned ALT with arrows.
CV1 yellow and CV2 blue outs:




CV1+2 out produces only positive:



But look - how thick and terry is the wave. It's selfoscillation from an opamp. To remove this I installed 100p capacitor between 1 and 3 pins of IC4.
And look how nice it's now:

L-1
INTEGRATOR

I trimmed integrator to have a slope 10 s when pot is on max, and 10 ms when pot is on min.

Longest slope 10s:




Shortest slope 10 ms:

L-1
SRV2

SRV has 256 possible output states. So to have 1/4 semitone per state, we need 5.33V output range.

I replaced R113 with 17.6K to have 5.33V range.

I got acceptable tracking. It's possible to understood from the video - interval between states is about 1/4 semitone or 25 cents. Watch and listen SRV2 out controls L-1 Basic VCO:



Scope SRV2 out:

L-1
SRV1

SRV has 256 possible output states. So to have 1/4 semitone per state, we need 5.33V output range.

I removed this 12K marked red, which was installed because I made modularsynthesis.com modifications.
Also I made R84-R91 exact 25K, 50K, 100K, 200K, 400K, 800K, 1600K, 3200K.



I made simulation where added a resistor after D4. To have 5.33V range it must be 88K.



I installed this 88K and got good tracking. Not cent-by-cent but pretty acceptable.
1/4 semitone or 25 cents per state. Watch and listen SRV1 out controls L-1 Basic VCO:




Scope SRV1 out:

L-1
I've got good tracking at QRV1 out too!!! Now it plays pure notes.
It controls L-1 basic VCO prototype, square wave.
Watch and listen:




The schematic has an error or inaccuracy. QRV2 plays pure notes when range is 5 octaves. QRV1 needs 5 octaves + 3 semitones to play pure notes.

To fix this I added a bit of gain to IC4B. I changed R19 to 5.3K.

Now the module can be used for creating music, not only noises.

to be continued...
L-1
I wanted to make QRV to play pure notes. I've matched all resistors at QRV circuit to 0.1%. QRV2 (n+1) out now tracks perfect but QRV1 (2n) out tracks not so good, will try to make something with it.

I fed QRV2 out into L-1 Basic VCO prototype which tracks perfect (+- 1 cent) within 5 octaves. Triangle out recorded.

Watch and listen how QRV2 out plays pure notes:




QRV scope shots:

QRV1, pot at max:


QRV2, pot at max:



to be continued...
davebr
L-1 wrote:
I even never seen in reality an original Buchla module. So I publish these shots to someone, who have and know, could check me.

But on the basis of the schematic, I think that my unit is working properly.

Those six images look correct. I have a number of scope images on my 266 SOU Module page and a description of what most of the functions are. You can use that to compare yours to.

Dave
L-1
spotta wrote:
L-1 wrote:
To be continued...

This was my trickiest build to date due to the lack of info and I've always wondered if it was working correctly, nice to see someone who knows what they are doing tackling this thumbs up



I even never seen in reality an original Buchla module. So I publish these shots to someone, who have and know, could check me.

But on the basis of the schematic, I think that my unit is working properly.
spotta
L-1 wrote:
To be continued...

This was my trickiest build to date due to the lack of info and I've always wondered if it was working correctly, nice to see someone who knows what they are doing tackling this thumbs up
L-1
I corrected my post about voltage converter modification on previous page. The positive rail inductor must be changed too.

I removed my scope shots from previous page. They will be new.

I removed all voltage shifters from PCB 3. The device started to work correct. Power consumption reduced too because I remoced all chips from PCB 3.

Power consumption:

222 mA for V+

144 mA for V-


QRV now produces random gates when pot is on min. They are exactly 5V. And started to produce random melodies when to turn the pots.


QRV1, pot at min:


QRV2, pot at min:





FRV now produses very slow motion when pot is at min. One square is 10 s. Good to create howling winds.

FRV1, pot at min:


FRV2, pot at min:


When FRV pot at max. It creates fast motion. (One square = 0.4s)

FRV1, pot at max:


FRV2, pot at max:


To be continued.....


-
L-1
I thought that is all but no.

Since I made modularsynthesis.com modifications, those 1.2V/oct - 1v/oct dividers are not needed. It's understandable. I removed them for all outs.

One FRV out has -5V shifter, second - no. I made 0.. +5V modification for both outs and removed it. It's understandable too.

But these +5V shifters for other CV ins are for what?
They produce +5V offset even when nothing fed into CV ins. The module can't work correct with them.

I think they are not needed at all.

I described the integrator modification in previous post (and already deleted). But it's not needed if to remove this shifter and offset with them.

So I think all level shifters must be deleted, and modularsynthesis.com modifications for CV ins applied.

Will do it tomorrow. Please write if I don't right.
L-1
Also I normaled SRV and QRV clock ins one to another:

L-1
I've built Euro version but used 15V supply. Now as I written above I decided to prepare the module for sale. So I decided to install the voltage converters.
The voltage converter for negative rail is made incorrect . And the modification where V- is inverted from the positive rail is working but is not good too.
So I've beadborded this negative converter to fix this.
The problem was in ON/OFF 5-th pin of the LM2576. Whed I turn the supply voltage on, the IC start switching, but the supply voltage raises not momentary and swith stops in OFF position. As result LM2576 is not working.
To fix this some startup delay for 5-th pin must be made.
I've installed simply RC-filter which provide a few ms startup delay.
Now it's working correct.

Power consumption:

165 mA for V-.

260 mA for V+.


How to fix.

Do not apply convertor mods described in schematic-1 V.1.1 or restore if already made.
Disconnect 5-pin of LM2576.
Connect resistor between 5-pin and voltage out.
Connect capacitor between 5-pin and ground.
Change the 470uH inductor at the positive voltage converter to 100uH.

Also I replaced L1 and L2 with links.

I started to make this RC filter from 0.1uF and 47K. It worked when I fed a cable from already powred case. But when I connected the module and turned on whole case, it not worked. I decided it's because big PSU capacitors charge and the voltage raises slower. I increased time constant by increasing values to 0.47uF and 750K. It started work with Doepfer case but not worked with Cwejman case. Further increasing values has no effect. The circuit started work with Cwejman case only when I changed inductor at the positive voltage converter to 100uH.




Tsese 4 additional resistors are because I used regulated versions LM2576T-ADJ and LM2577T-ADJ.


L-1
This is link. Yes they are for 5U but Euro has also 15V supply and identical schematic.
http://modularsynthesis.com/roman/buchla266/266sou.htm
bkbirge
L-1 wrote:
I applied all the mods from modularsynthesis.com


Do you have a direct link to the mods? I don't see it on his page, just an informational page on the 5U version. I've stuffed the diodes/zeners in my euro version but that's as far as I've gone because everybtime I think to work on it I get confused on all the mods that have to be done.
L-1
How to fix this?

1. Remove this IC and R19 across it.
2. Replace R18 with 10K, R21 with 2K.
3. Connect inner pin (which is closer to IC) of R21 to outher pin of R19.
4. Connect inner pin of R18 to outher pin of R20.




L-1
Fixed thumbs up

L-1
I didn't read all pages of this thread. Maybe someone already noticed that, maybe no.

I've built this project (Eurorack) about year ago but didn't used the module.
But now I decided to sell this module therefore make everything as it must be. I applied all the mods from modularsynthesis.com (thank you Dave!)

Everything seems to wprking correct now but FRV OUT1 - no. It is -5V shifted. And schematic shows here 0+10V - -5+5V shifting instead of 1.2 - 1V/oct as at OUT2.
Now sorting out, how to correct this.

Yellow FRV OUT2, green FRV OUT1



elmegil
I figured it was something like that, Dave. I've said elsewhere, this particular project has so many different versions in the wild it can be a pain.....
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