Rollz-5+ Kit from Meng Qi (2014 Revision 3)

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Waz
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Post by Waz » Fri Aug 09, 2019 10:14 am

I am pretty much done with this build, just waiting on the 1uF caps to come in from Mouser. I had simple question; Is the power switch for this unit a SPDT ON/ON switch?

*Edit
It's on/on

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Waz
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Post by Waz » Fri Aug 16, 2019 12:33 am

So I finished. It took me a while to figure it all out and get it making sound. After a year of slowly piecing things together, it actually works... 8-)

I only have one issue; the power supply. I have a box of over 100 wall warts saved from various electronics over my life. This will not work properly with any of them. It only works with my bench supply. My bench, unfortunately, is outside of my studio space. I assume it plays best with linear or regulated supplies. Is there some sort of “hack” I can do so I can use these wall warts? Any wall warts on the cheap the play well with this synth?

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Post by GrantB » Fri Aug 16, 2019 11:00 am

12V DC center positive should work

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Post by rmro » Fri Aug 16, 2019 11:44 am

I bought a bunch of these https://cpc.farnell.com/powerpax/std-12 ... 20supplies they're the same as the patch point ones

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Post by Waz » Fri Aug 16, 2019 2:26 pm

GrantB wrote:12V DC center positive should work
You'd think but I have dozens of 9 - 12VDC center pos wall warts and all of them have a hum with only this gear. I found a beat-up Meanwell laptop PSU in my garage and this is the only one that works. I looked it up and it seems to be regulated. I think this is the issue? I really don't know the EE theory behind why this is happening. Would love to know why if someone wants to drop some knowledge.

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Post by GrantB » Fri Aug 16, 2019 9:40 pm

I'm using 3 of the DA36J12 regulated adapters for my Ciat gear. Cheap on Ebay.

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Re: Rollz-5+ Kit from Meng Qi (2014 Revision 3)

Post by flx » Sat Feb 01, 2020 12:06 pm

I just realized that the voltage starve feature on my secondhand Meng Qi Rollz-5+ doesn't work at all and I was not too stupid for the device after all :party: So I desoldered the 1k pot and it looks as if it's broken and "stuck" at around 1k resistance. Maybe that was also the reason why I couldn't run the device properly with a 9V PSU and had to use a 12V one?!

I temporarily added a new pot and also tried out various fixed resistors and finally had the desired voltage starvation effect. Of course I then tried out the vactrol, and it had almost no effect. You could only hear a very very faint effect when the voltage was already starved almost to death by the pot/resistors. I tried various voltage source from other Ciat Lonbarde gear, even the Sidrax, like in the Instagram video form the OP.

Can anybody help me troubleshoot this? Maybe the vactrol is broken too, I thought. My temporary voltage starve resistors got quite warm quickly, so maybe the original pot was burnt out by taking too much heat from the resistance/starvation process?


Edit: I see that a burnt out voltage starve section is actually not that uncommon here. Has there been a fix for this, or is it still a bit hit and miss? If so, I might just bridge the circuit and remove the section. Anything else that one could put there instead easily? :mrgreen:
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Re: Rollz-5+ Kit from Meng Qi (2014 Revision 3)

Post by GrantB » Sat Feb 01, 2020 2:17 pm

flx wrote:
Sat Feb 01, 2020 12:06 pm
Has there been a fix for this, or is it still a bit hit and miss? If so, I might just bridge the circuit and remove the section.
This feature was fixed in the last revision of the PCB by removing it. :foul:

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Re: Rollz-5+ Kit from Meng Qi (2014 Revision 3)

Post by flx » Sat Feb 01, 2020 2:25 pm

GrantB wrote:
Sat Feb 01, 2020 2:17 pm
This feature was fixed in the last revision of the PCB by removing it. :foul:
Hah, alright then :lol: Thanks!
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Re: Rollz-5+ Kit from Meng Qi (2014 Revision 3)

Post by jimmie » Sun Feb 02, 2020 12:16 am

flx wrote:
Sat Feb 01, 2020 12:06 pm
I just realized that the voltage starve feature on my secondhand Meng Qi Rollz-5+ doesn't work at all and I was not too stupid for the device after all :party: So I desoldered the 1k pot and it looks as if it's broken and "stuck" at around 1k resistance. Maybe that was also the reason why I couldn't run the device properly with a 9V PSU and had to use a 12V one?!
Mine (sold but missing now cuz some sounds from it can't be covered by PB) also had starve circuit broken but I didn't have a problem using a 9v adopter. I preferred using 9v to 12v for tamed feeling.

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Re: Rollz-5+ Kit from Meng Qi (2014 Revision 3)

Post by flx » Mon Feb 03, 2020 8:51 am

While I’m here, I’ve got another question:

On the Plumbutter there is a frequency pot for each Roll. Does anybody know how this is achieved? I’m looking at Pugix’ 2-Roll circuit here:
https://pugix.com/synth/rollz-5-schematics/

Where/how would one integrate a pot in this schematic?
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Re: Rollz-5+ Kit from Meng Qi (2014 Revision 3)

Post by uglyback » Fri May 01, 2020 4:20 am

Hello flx,

Laszlo here, a new comer !

Wouldn't the answer be around here, on the Plumbutter page ? : http://ciat-lonbarde.net/plumbutter/labrolzpapersz.pdf

I've bought the 2017 revision of Rollz-5 on Modular Addict and put together an updated bom with updated mouser references found on this forum topic, plus Farnell possible equivalents, and few further references like M3 Hex spacer, banana cables, On/off switch, etc.
There might be few mistakes, let me know if you see some, here's the link to libreoffice spreadsheet with everything :


Another week to wait for all components and some days of struggle, I guess, before playing around.

Happy Labor Day to all

Laszlo
Last edited by uglyback on Tue May 12, 2020 5:43 am, edited 1 time in total.

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Re: Rollz-5+ Kit from Meng Qi (2014 Revision 3)

Post by 1n » Fri May 01, 2020 5:04 am

Thanks for this, Laszlo.

I've been comparing various builds and held off buying components...till now. Well, I might hold off a little bit longer, awaiting your build :-)

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Re: Rollz-5+ Kit from Meng Qi (2014 Revision 3)

Post by flx » Fri May 01, 2020 6:20 am

uglyback wrote:
Fri May 01, 2020 4:20 am
Wouldn‘t the answer be around here, on the Plumbutter page ? : http://ciat-lonbarde.net/plumbutter/labrolzpapersz.pdf
Thank you! That PDF has the info indeed! Must have missed that document somehow :doh:
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Re: Rollz-5+ Kit from Meng Qi (2014 Revision 3)

Post by nrrrd » Fri May 01, 2020 4:18 pm

flx wrote:
Fri May 01, 2020 6:20 am
uglyback wrote:
Fri May 01, 2020 4:20 am
Wouldn‘t the answer be around here, on the Plumbutter page ? : http://ciat-lonbarde.net/plumbutter/labrolzpapersz.pdf
Thank you! That PDF has the info indeed! Must have missed that document somehow :doh:
It's a different circuit than the ones on the Rollz-5. It consists of a current source and then each stage of the Rollz has a NPN and PNP transistor in it.
I've made them on breadboard and stripboard. All the info needed is in the Labrolz paper linked above.
You can't just modify the circuits on the MQ Rollz-5, unfortunately.

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Re: Rollz-5+ Kit from Meng Qi (2014 Revision 3)

Post by uglyback » Mon May 04, 2020 2:28 pm

Hey !

I've received the components from Mouser and Farnell today, only mistake I found (edited in red the Google Drive BOM), is that the ON/OFF switch was
momentary and not latching. It wasn't clear on Farnell's product's description...
But the size (4.7mm between each pin), orientation (vertical) and number of pin (3) is good, just need to find one simple alternative, if anyone has a reference, I take.

The other thing I wasn't 100% sure about from the description on Mouser was the female socket pin 2x3 row for Hairy Caps on the Rollz, it fits perfectly.

I'll let you know when it's done and Rollzing soundz.

Best,

Laszlo
1n wrote:
Fri May 01, 2020 5:04 am
Thanks for this, Laszlo.

I've been comparing various builds and held off buying components...till now. Well, I might hold off a little bit longer, awaiting your build :-)

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Re: Rollz-5+ Kit from Meng Qi (2014 Revision 3)

Post by 1n » Tue May 05, 2020 11:17 am

Thanks for pioneering!

I can solder and follow a build guide - give or take some solder sucker and firm pressure to get parts to sit under a front plate! - but I'm needing a long run-up to this one :-)

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Re: Rollz-5+ Kit from Meng Qi (2014 Revision 3)

Post by uglyback » Mon May 11, 2020 11:42 am

Hello everyone,

It is done, but, of course something went wrong.

First problem, rapidly fixed, film caps on the variable GONG caps gave low output level, changed with a Tanta and a Ceramic and it's solved, all good now.
Any other similar experience ?

Second Problem, AVDOG number 4 (rightest top view) doesn't respond.
Changed transistor and Capacitor on Impulse Input and swaped IC's with spare ones, no luck.
When touching the legs of the 557's and 547's with my finger I'm getting a low level glitchy sound in rythm with the pulse, but otherwise nothing.
Any recommandation on where to look, shall I replace all those three 557 and one 547 or it lies somewhere else ?

Thanks in advance for the advices !

Good evening,

Laszlo

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Re: Rollz-5+ Kit from Meng Qi (2014 Revision 3)

Post by uglyback » Fri May 15, 2020 9:45 am

OK,

after few hours of search, it was a bended pin under the TL074...
One last thing I didn't get for sure is if it's necessary or not to put the 22k resistors on the TL072 pins from the ultrasounds on the 2017 version of the board ? Anyone has the info .

*Edit* I'm asking because my ultrasounds have like a high pass filter all the time and I get the medium and bass back when I touch the 4066 IC pins or the 547 transistor pins...

Thanks

Laszlo

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Re: Rollz-5+ Kit from Meng Qi (2014 Revision 3)

Post by nrrrd » Fri May 22, 2020 7:02 am

Has anyone built a Rollz with 3.5mm mono sockets (Eurorack style) rather than bananas?

I've almost finished my first board for a Rollz-5, and I had planned on using 3.5mm sockets, but I keep reading about how these sockets "short to ground" on insertion of a cable. I'm worried about how this will affect the Rollz outputs - I don't want them to short to ground and then fry the transistor that is connected directly to the socket.

Will I be okay if I just don't connect the ground pin out the 3.5mm socket to ground? Am I worrying too much anyway?

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Re: Rollz-5+ Kit from Meng Qi (2014 Revision 3)

Post by serioko » Mon Jun 01, 2020 12:00 pm

Hello folks, I am currently building 3 rollz-5's, one for myself and 2 for sale.

I am currently building my mouser order and am wondering if anyone has suggestions for the variable parts. I don't know what what I want haha.

Thanks in advance for any suggestions.

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Re: Rollz-5+ Kit from Meng Qi (2014 Revision 3)

Post by serioko » Mon Jun 01, 2020 12:03 pm

I am also wondering about the unlabelled parts on the PCB. What did people populate those with?

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Re: Rollz-5+ Kit from Meng Qi (2014 Revision 3)

Post by serioko » Mon Jun 01, 2020 12:16 pm

One more question, I am not seeing on the PCB anywhere where a vactrol goes, can someone point me in the right direction please?

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Re: Rollz-5+ Kit from Meng Qi (2014 Revision 3)

Post by uglyback » Tue Jun 16, 2020 3:02 am

Hey !

There is no Vactrol, and no 15k resistors on the Modular Addict PCB !

For variable parts, it's difficult to settle on values without hearing how it reacts, so I would suggest getting a small stock of a range of values to try them out

I've been soldering and unsoldering different parts but there's somewhere on this topic reference to small pins with socket to be able to swap components easily.

Good luck

Laszlo
serioko wrote:
Mon Jun 01, 2020 12:16 pm
One more question, I am not seeing on the PCB anywhere where a vactrol goes, can someone point me in the right direction please?

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Re: Rollz-5+ Kit from Meng Qi (2014 Revision 3)

Post by Easterner » Mon Aug 03, 2020 12:26 pm

I've started having some issues with my Rollz-5, some jacks and switches don't seem to be functioning any more... Can anyone provide guidance as to who or where someone might be able to repair this, and Ciat-Lonbarde instruments in general (other than going directly to Peter B for his instruments)? I'm based in NYC.

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