Plaits DIY

From circuitbending to homebrew stompboxes & synths, keep the DIY spirit alive!

Moderators: lisa, luketeaford, Kent, Joe.

User avatar
moncks_crossing
Common Wiggler
Posts: 58
Joined: Thu Apr 07, 2016 1:39 am
Location: NSW,Australia

Knit ( Antumbra plaits redesign)

Post by moncks_crossing » Tue Mar 05, 2019 6:29 pm

This is odd behaviour.
Knit - fully built - all parts in place and soldered; MCU flashed and verified;
- calibrated with 1V and 3V
- all LEDs exhibit correct behaviour with mode changing and including the LPG and envelope adjustment represented by 2 pairs of 4 LEDs glowing yellow and frequency range adjustment with the yellow LEDs indicating the setting;
The problem - the module only has output from the last green mode;
I found that if I give LVL jack a CV - I have output on all the green modes but ony on first 3 red modes.?.
Please help.

User avatar
moncks_crossing
Common Wiggler
Posts: 58
Joined: Thu Apr 07, 2016 1:39 am
Location: NSW,Australia

Post by moncks_crossing » Wed Mar 06, 2019 6:17 am

New development on Knit - each mode in both green and red gives a brief ping of audio on power up. Still WTF?

User avatar
cnicht
Veteran Wiggler
Posts: 699
Joined: Mon Sep 23, 2013 9:23 am

Post by cnicht » Wed Mar 06, 2019 7:20 am

Again as suggested by brycecake check the normalisation signal is getting through to the microcontroller via the input jacks.

collumn2016
Learning to Wiggle
Posts: 47
Joined: Mon Aug 29, 2016 4:42 am
Location: in orbit

Post by collumn2016 » Wed Mar 06, 2019 4:16 pm

HI brycecake, when i said the harmonics knob wasnt working i meant on the chord mode, as it doesnt seem to effect chord type on a regular basis, guess it depends on the other settings. LOads of variation possible with this module.
Last edited by collumn2016 on Thu Mar 07, 2019 5:24 pm, edited 1 time in total.

brycecake
Common Wiggler
Posts: 63
Joined: Wed Oct 04, 2017 1:02 pm
Location: Las Vegas, NV

Post by brycecake » Thu Mar 07, 2019 1:52 am

moncks_crossing wrote:New development on Knit - each mode in both green and red gives a brief ping of audio on power up. Still WTF?
Yes, I built a Rings that did exactly that. It was a problem in the BAT54 associated with the normalization probe. Your module thinks you have something plugged into the level jack. Check around there and around the jacks for shorts.

User avatar
jondent
Veteran Wiggler
Posts: 578
Joined: Sun Mar 03, 2013 5:09 am
Location: Australia

Re: Knit ( Antumbra plaits redesign)

Post by jondent » Mon Mar 11, 2019 5:46 pm

moncks_crossing wrote:This is odd behaviour.
Knit - fully built - all parts in place and soldered; MCU flashed and verified;
- calibrated with 1V and 3V
- all LEDs exhibit correct behaviour with mode changing and including the LPG and envelope adjustment represented by 2 pairs of 4 LEDs glowing yellow and frequency range adjustment with the yellow LEDs indicating the setting;
The problem - the module only has output from the last green mode;
I found that if I give LVL jack a CV - I have output on all the green modes but ony on first 3 red modes.?.
Please help.
:hmm:

collumn2016
Learning to Wiggle
Posts: 47
Joined: Mon Aug 29, 2016 4:42 am
Location: in orbit

re plaits

Post by collumn2016 » Wed Mar 13, 2019 6:20 am

TEsted the output from the DAC and got these: OutL or pin6 = 700mV RMS, OutR or pin 7 = 1.5v RMS as measured on my scope. Seems like there is a problem with the DAC? I have ordered a new one and hopefully the very low volume and distortion i am hearing from the Out socket, will be sorted. Aux is about right volume wise. Cheers

User avatar
cnicht
Veteran Wiggler
Posts: 699
Joined: Mon Sep 23, 2013 9:23 am

Post by cnicht » Wed Mar 13, 2019 7:43 am

What signal are you seeing on your oscilloscope?

It should be possible to see if other signals are present too such as VNEG on pin 5 to see if the charge pump is working and digital information on its inputs.

collumn2016
Learning to Wiggle
Posts: 47
Joined: Mon Aug 29, 2016 4:42 am
Location: in orbit

Plaits still not working correctly

Post by collumn2016 » Wed Mar 20, 2019 7:10 am

HI cnicht, I put the DAC in the other day and tested it and it seems to work okay. Still a bit baffled with low levels from algorithm 8, the vocal one. Though i still have low output on out socket and on some algorithm's like the chord mode, for example, i get a lot of distortion. I tested the TL072 with an external sine wave and it looked okay. I am clueless where this distortion and low volume is coming from. I have tested all the passives around the DAC and the TL072 and they look okay. When you say test the vneg i am not sure what to look for on the scope. Could it be the MCU? I have checked all voltages and they seem fine. Any ideas? Thanks a lot guys this has me stumped.

collumn2016
Learning to Wiggle
Posts: 47
Joined: Mon Aug 29, 2016 4:42 am
Location: in orbit

diy plaits 10 volts on pin 1

Post by collumn2016 » Fri Apr 05, 2019 10:40 am

Hi, still having problems with plaits. Output is very low but aux seems fine? Measured voltages around IC 8 TL072 and VEE and VCC are correct but i have found a DC offset on pin 1 of 10 volts. Is this normal for the plaits? I have changed the IC twice now and today measured pin 1 with the IC off and there is no 10 volts. Anyone got any ideas? Cheers

User avatar
cnicht
Veteran Wiggler
Posts: 699
Joined: Mon Sep 23, 2013 9:23 am

Post by cnicht » Fri Apr 05, 2019 11:30 am

Seems like there’s a bridge to the -10V reference somewhere?

collumn2016
Learning to Wiggle
Posts: 47
Joined: Mon Aug 29, 2016 4:42 am
Location: in orbit

Post by collumn2016 » Sat Apr 06, 2019 11:49 am

Hi cnicht, I have looked around and cant find a bridge. I have traced the -10v line around and cant see where it could interact. Have you made a plaits? Do you have a DC offset on the output? Weird. I dont know enough about failure modes of TL072's or how sensitive they are to temperature or static. I handled it he same as all my other IC's in other modules i have made. Thanks for your help. Cheers

User avatar
emmaker
Veteran Wiggler
Posts: 622
Joined: Sat Mar 10, 2012 5:07 pm
Location: PDX

Post by emmaker » Sat Apr 06, 2019 4:56 pm

collumn2016 wrote:Hi cnicht, I have looked around and cant find a bridge. I have traced the -10v line around and cant see where it could interact. Have you made a plaits? Do you have a DC offset on the output? Weird. I dont know enough about failure modes of TL072's or how sensitive they are to temperature or static. I handled it he same as all my other IC's in other modules i have made. Thanks for your help. Cheers
Sometimes there are shorts in the PCB and not from soldering. Hold the PCB up to a strong light and see if you can see through it and look for shorts. And also just look for shorts on traces under the solder mask.

Another trick if you have a really good DVM ohm meter is measure the resistance on the traces through the circuit. The closer you are to the short the less resistance you will have. But we're talking very small resistances. Usually 0.1 ohm or less.

Good luck.
Jay S.

User avatar
cnicht
Veteran Wiggler
Posts: 699
Joined: Mon Sep 23, 2013 9:23 am

Post by cnicht » Sun Apr 07, 2019 12:13 pm

I’ve built 4 Plaits and not had this problem.

It just seems odd that the output should be at this voltage as there’s a -10V reference and an inverting op amp at the output. As emmaker said there could be a PCB track short.

Another thought is, does the output op amp have both supply rails connected to it?

User avatar
SphericalSound
Wiggling with Experience
Posts: 300
Joined: Thu Feb 01, 2018 9:23 am
Location: Spain

Post by SphericalSound » Sun Apr 07, 2019 7:48 pm

collumn2016 wrote:I dont know enough about failure modes of TL072's or how sensitive they are to temperature or static. I handled it he same as all my other IC's in other modules i have made. Thanks for your help. Cheers
TL072s are built like a tank. Static or high temp iron should not harm them. Look at other places

collumn2016
Learning to Wiggle
Posts: 47
Joined: Mon Aug 29, 2016 4:42 am
Location: in orbit

Post by collumn2016 » Mon Apr 08, 2019 10:15 am

HI, voltage on pin 1 was -10 volts, Pin 8 +12, Pin 4 -12, with the IC on. Voltages on pin 4 and 8 were the same with the IC removed and 1 had no DC voltage. All the other pins had no DC voltage on them. I took the IC off to check underneath and there were no shorts. Checked all passives on the board for shorts etc found nothing. Checked the traces and could not see any shorts. Tried holding the board up to the light but could not see through. To me this means that the fault is with the IC? Got them from uk farnell so they should be okay. Cheers for all your help.

User avatar
cnicht
Veteran Wiggler
Posts: 699
Joined: Mon Sep 23, 2013 9:23 am

Post by cnicht » Mon Apr 08, 2019 10:21 am

Another thought - have you got the IC in the right way round? Also is the feedback resistor the correct value?

Halfgeleider
Common Wiggler
Posts: 148
Joined: Sun May 14, 2017 1:53 pm
Location: Belgium

Post by Halfgeleider » Mon Apr 08, 2019 2:04 pm

Question about the beehive plaits, i have a pcb on order and was already reading on github about the flashing part. I read about the jtag plug and st link but i only did a rings few months back and that was quite simple. Now i read that to flash plaits you have to connect the jtag to the st link in a specific way with wires? How do i have to do that?
Thanks in advance

User avatar
Altitude909
Super Deluxe Wiggler
Posts: 3394
Joined: Wed Aug 24, 2011 5:13 pm
Location: Meesheegan

Post by Altitude909 » Mon Apr 08, 2019 2:14 pm

Halfgeleider wrote:Question about the beehive plaits, i have a pcb on order and was already reading on github about the flashing part. I read about the jtag plug and st link but i only did a rings few months back and that was quite simple. Now i read that to flash plaits you have to connect the jtag to the st link in a specific way with wires? How do i have to do that?
Thanks in advance
Beehive has both the JTAG and SWD headers, just use the JTAG if you dont want to deal with SWD. i hate that 10 pin thing, glad she switch to the SWD header for the new modules. The "JTAG" header is wired for SWD anyway, its just a nuisance to use..

collumn2016
Learning to Wiggle
Posts: 47
Joined: Mon Aug 29, 2016 4:42 am
Location: in orbit

success

Post by collumn2016 » Tue Apr 09, 2019 8:12 am

HI cnicht, i forgot to mention the board i am using. Its a 0603 version from amazingsynth. The layout is a little bit different from the 0402 version. Been over a month since i made it and had forgotten how confused i was about the labelling. I had swapped r22 with c45 and that's why it wasn't working. Your idea of checking the feedback resistor and IC orientation put me on to this as i then traced the feedback path and realised my mistake. Everything is fine now. Thanks for eveyone's help.

User avatar
col
Wiggling with Experience
Posts: 462
Joined: Tue Feb 04, 2014 3:47 pm
Location: Melbourne

operating at a higher octave range

Post by col » Sat Apr 13, 2019 11:55 pm

Hi, wondering if anyone has any ideas on whats going on with one of my Beehives. I built two of them, one works perfectly and one seems to be operating in a range a few octaves higher. If I try to calibrate it, the calibration fails with all the leds glowing red. The good one calibrates fine. I have reloaded the firmware 3 times both using compiled from source with Vagrant and also, trying the MI .wav file.

Iv'e been looking at the schematic and reading through all the datasheets on the various IC's, traced everything with audio probe and oscilloscope. The only thing that looks/sounds different is the frequency coming out of the DAC chip, which I have reflowed. And quadruple checked all the components around it. I find it hard to believe that the DAC is just decided to convert everything at a higher frequency?? :bang:

Played with all the tuning settings. If I select LFO mode it actually sounds like it's running in normal mode!

Any ideas much appreciated!

User avatar
Chrutil
Veteran Wiggler
Posts: 518
Joined: Thu Mar 21, 2013 11:39 am
Location: San Rafael, California

Post by Chrutil » Sun Apr 14, 2019 1:10 am

Hi all,
I posted in the 5U forum about this, but should post here too.
I made a large format MU version of Plaits and built a bunch of them.
Footprint has been increased to 0805 for most components.
If anyone is interested in building it I put all the files up on GitHub at:

https://github.com/Chrutil/PlaitsMU

It's an awesome module that sits even better in large format!

Image

Image

Image

Halfgeleider
Common Wiggler
Posts: 148
Joined: Sun May 14, 2017 1:53 pm
Location: Belgium

Post by Halfgeleider » Fri May 10, 2019 5:24 am

Hi there,
building plaits with PCB from pusherman, but i dont know where to put the crystal Q1... my guess is next to the ARM, but there are 4 pads empty, which do i use? :despair:

Halfgeleider
Common Wiggler
Posts: 148
Joined: Sun May 14, 2017 1:53 pm
Location: Belgium

Post by Halfgeleider » Fri May 10, 2019 5:27 am

:bang: :bang: how could i miss, crystal also has 4 pads... :tu:

User avatar
djthopa
Super Deluxe Wiggler
Posts: 1823
Joined: Thu Mar 22, 2012 5:48 pm
Location: Somewhere between a nappy and a wire

Post by djthopa » Fri May 10, 2019 5:28 am


Post Reply

Return to “Music Tech DIY”