[Build Thread] UltraFlop-08 Sequencer

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Jonachi
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Post by Jonachi » Sun Jan 29, 2017 3:25 am

The switch is working. However set in up it counts forward and in both middle and down position it counts backwards. No ping-pong! Been like this since I built it. Would connecting the pads backwards on the pcb cause this kind of bahavior? I'm trying to figure it out.

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Post by Jonachi » Sun Jan 29, 2017 12:03 pm

Looking at the schematics "2" is connected to ground. I guess beeping what I think is pad 2 and a ground conection on the PCB should show me what way to look at the pcb and decide which pad is which.

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Post by Jonachi » Sun Jan 29, 2017 1:25 pm

Wirering checks out. Must be the switch. Disconected all wires and made some tests with just the jumper on the switch. position 1 is a perfect match to mattias sketch, but 2 and three are identical - using the very same outputs. Must be something wrong with the switch or the wrong kind.

Edit: This is the exact switch I'm using, mine is black instead of blue: https://www.taydaelectronics.com/mini-t ... on-on.html

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Post by Jonachi » Mon Jan 30, 2017 11:45 am

Finally solved it! Turned out there are two kinds of DPDT's. Type 1 (the usual one" and "Type 2" more uncommon. Fonics picture was of a Type 2 switch which has the middle position reversed. By wireing it the opposite way to the picture provided in this thread it came to life! I know have the ping pong mode! :hihi:

I also revired switc h10 but don't have a gate at home to throw at it to see if receives clock in. We'll see when I get it back to the studio.

My longest lasting build so far, somehow I don't want it to end!

:hihi:

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Post by J3RK » Mon Jan 30, 2017 12:29 pm

:lol:

Very glad to hear that you got it working! Yes, DPDT and SP3T look the same physically. They are connected differently inside though. I'll keep this in mind if it comes up again. Let me know how it goes when you get it connected again.

There are definitely some updates I'd like to make to this PCB/Project at some point, so I'll probably revisit it sometime.
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Post by Jonachi » Mon Jan 30, 2017 12:36 pm

You should! Such a usefull module. Needs a pcb for jacks and sliders, also the ground missing needs fixing.

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Post by ndf » Wed Apr 26, 2017 2:11 am

Hi, I just completed an Ultraflop 08 kit from SynthCube - following the wiring diagram posted elsewhere (J3rk UltraFlopWiring.pdf) I found two very minor problems: The direction switch SW9 was a little backward compared to the diagram and the SW10 wires brown and tan were reversed. With the ground plane fixes from above and those two changes it works very well.

I didn't need to use the extra bypass cap or 680k resistor: There was a 10k resistor in the place of the 680k and the clock was stable as wired. There's a little switch bounce when swapping between internal and external clock, but otherwise no prob.

Image

Thanks for a challenging build :)

Sorry I can't attach files for some reason, you can see the SW9/10 change here:

http://metarace.com.au/j3rkwirefix.pdf

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Post by Jonachi » Wed Apr 26, 2017 3:14 am

Thanks for your input, I struggled with the same problems as documented above. It was a challenging build indeed, but one of the most dear to my heart anyways! I love this seq!

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Post by synthcube » Fri May 19, 2017 9:21 pm

with thanks to mike cameron for the hard work on the additional documentation, here's an updated set of build notes etc:
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Post by aphantomvaper » Sun Nov 03, 2019 9:53 pm

Hey! I spent about 12 build hours on this Sequencer, and amazingly it fired up first time with only one issue. The direction switch goes forward up and backward middle and down just like some of the previous posters.

This is a Synthcube kit, so I'm assuming they just sent the wrong switch. Testing gives connectivity on SW9 pad one on up position, and pad three on the middle and down position.ImageImage
The only thing that stays the same is change

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Re: [Build Thread] UltraFlop-08 Sequencer

Post by Jonachi » Fri Jun 05, 2020 1:36 pm

long time no see.

Just wondering, are there any resistor changes one can make to tame this beast. Mine outputs 0-8v and although it is great for modulate filters and used as a clocked oscillator I find it kinda hard to dial in the correct frequencies when used as a standard sequencer.

Would love to revisit this module, do the OR-mod (that I never got around to first time around) as well as tame it somewhat.

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Re: [Build Thread] UltraFlop-08 Sequencer

Post by J3RK » Fri Jun 05, 2020 2:08 pm

Yes, it's pretty simple actually. There is a voltage divider buffered by an op amp that supplies the CV pots. I don't have the schematic in front of me, but you could easily bring that down to any voltage you like by changing that divider. If I remember correctly the divider is two 100K resistors in parallel to make 50K against a single 100K. Also, if you wanted something more accurate, you could make a tiny sub-board with a precision source, and feed the pots with that instead. (or if you have +5V in your system, you could use that)
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Re:

Post by J3RK » Fri Jun 05, 2020 2:11 pm

aphantomvaper wrote:
Sun Nov 03, 2019 9:53 pm
Hey! I spent about 12 build hours on this Sequencer, and amazingly it fired up first time with only one issue. The direction switch goes forward up and backward middle and down just like some of the previous posters.

This is a Synthcube kit, so I'm assuming they just sent the wrong switch. Testing gives connectivity on SW9 pad one on up position, and pad three on the middle and down position.ImageImage
Sorry I didn't see this. I'm just now starting to get back to synths again after a pretty long time of not being able to. The direction switch is an SP3T, and has to be wired specially as a 3-way selector. There is an excellent diagram floating around out there by Fonik, just google SP3T Switch Wiring, and look through the images.
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Re: [Build Thread] UltraFlop-08 Sequencer

Post by Jonachi » Fri Jun 05, 2020 2:34 pm

Thanks for fast reply as always!

Need to find those 2 100k resistors though. Here is the schematics (and build info) from synthcube:

https://synthcube.com/cart/index.php?ro ... ad&did=186

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Re: [Build Thread] UltraFlop-08 Sequencer

Post by J3RK » Fri Jun 05, 2020 3:36 pm

They are R10, R15, R16.
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Re: [Build Thread] UltraFlop-08 Sequencer

Post by Jonachi » Sat Jun 06, 2020 2:03 am

chinging them to 2k would give me 4v? I don't know how to calcultate these things... 5V might be too much since I rarely (never) write sequences spanning 5 octaves.

They seem to be 1k and not 100k as stated above.

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Re: [Build Thread] UltraFlop-08 Sequencer

Post by nigel » Sat Jun 06, 2020 6:55 pm

Jonachi wrote:
Sat Jun 06, 2020 2:03 am
chinging them to 2k would give me 4v? I don't know how to calcultate these things... 5V might be too much since I rarely (never) write sequences spanning 5 octaves.

They seem to be 1k and not 100k as stated above.
Comparing that schematic to the original BOM, there seem to be a lot of 100k resistors that have magically become 1k.

To reduce the CV range (on a 12V supply, since this is Eurorack) remove both R10 and R16, and replace one of them with 100k. Remove R15 and replace it with 47k (for about 4V) or 33k (for about 3V).

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Re: [Build Thread] UltraFlop-08 Sequencer

Post by soup » Sat Jun 06, 2020 8:24 pm

The schematic from the stroh doc's zip is different than the schematic in that synthcube doc for some reason but the schematic from the zip matches the original BOM. It can be found here...
viewtopic.php?t=150552&highlight=

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Re: [Build Thread] UltraFlop-08 Sequencer

Post by Jonachi » Sun Jun 07, 2020 12:57 am

nigel wrote:
Sat Jun 06, 2020 6:55 pm
Jonachi wrote:
Sat Jun 06, 2020 2:03 am
chinging them to 2k would give me 4v? I don't know how to calcultate these things... 5V might be too much since I rarely (never) write sequences spanning 5 octaves.

They seem to be 1k and not 100k as stated above.
Comparing that schematic to the original BOM, there seem to be a lot of 100k resistors that have magically become 1k.

To reduce the CV range (on a 12V supply, since this is Eurorack) remove both R10 and R16, and replace one of them with 100k. Remove R15 and replace it with 47k (for about 4V) or 33k (for about 3V).
Ah interersting! If I replace only one of r10 and r16 but remove both (as suggested above) what do I use for the other one?

Also I used the original bom for this. What was the values for these resistors back then? Don’t have the docunents anymore.

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Re: [Build Thread] UltraFlop-08 Sequencer

Post by nigel » Sun Jun 07, 2020 4:51 am

Jonachi wrote:
Sun Jun 07, 2020 12:57 am
nigel wrote:
Sat Jun 06, 2020 6:55 pm
Comparing that schematic to the original BOM, there seem to be a lot of 100k resistors that have magically become 1k.

To reduce the CV range (on a 12V supply, since this is Eurorack) remove both R10 and R16, and replace one of them with 100k. Remove R15 and replace it with 47k (for about 4V) or 33k (for about 3V).
Ah interersting! If I replace only one of r10 and r16 but remove both (as suggested above) what do I use for the other one?
Leave the other spot empty. R10 and R16 are in parallel, so they could have been replaced by a single resistor in the original circuit too. (I suspect it was designed to use common values.)

Alternatively, you could fill the empty spot with a capacitor, anything from 100nF (probably polyester) to 1uF or so (probably electrolytic). That would help to keep any noise out of the control voltages.

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Re: [Build Thread] UltraFlop-08 Sequencer

Post by Jonachi » Sun Jun 07, 2020 5:32 am

Thanks! Will try tomorrow!

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Re: [Build Thread] UltraFlop-08 Sequencer

Post by Jonachi » Sun Jun 07, 2020 6:39 am

Any other mods one could consider with this one?

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Re: [Build Thread] UltraFlop-08 Sequencer

Post by Jonachi » Mon Jun 08, 2020 2:29 am

47k gave me 3.84v out which was not covering 4 octaves to swapped it to 56k which gave me about 4,3v. I'll leave it at that. Off to the OR mod. Thanks for all your help.

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Re: [Build Thread] UltraFlop-08 Sequencer

Post by Jonachi » Mon Jun 08, 2020 5:56 am

Did the OR-mod and have som mixed results. All chanel indicviaul outputs work except 3 and 5 which doesn't output anything when it is time for their step (those doesn't show up at the OR output as well) and channel 8 is always hih no matter how I set the switch.
I have checked for shorts etc, might be broken switched (cheap ebay if I remeber correcly).

Any help would be appreciated. This mod is sweet though.

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Re: [Build Thread] UltraFlop-08 Sequencer

Post by Jonachi » Mon Jun 08, 2020 6:38 am

So after further investigation I can turn on and off channel 8, is behaving strange though, when on it outputs the same patterns s the clock output jack. must hve missed something somwhere, gate out 3 and 5 are still dead both in the or outpput as well as the individual. You can here the clock countind those steps but the gate out never goes high.

EDIT: Found a small solder bridge on output 8 so problem solved. Now I just need to figure out why channel 3 and 5 doesn't output any gates.

EDIT Again: Gate 3 and 5 now output gates from their own jacks but are not in the or output, tripled checked the wiring bwetween mod pads, diiodes etc but nothing.

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