Noise on left input on Cocoquantus 2

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batchas
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Noise on left input on Cocoquantus 2

Post by batchas » Thu Jun 07, 2018 12:49 pm

Does anyone have a clue how I can get rid of the noise, means clean the buffer other than having input and loop gain fully CCW and speed full CW while sampling?
It works fine on right channel but not on my left channel.

Of course some noise remain on right channel and it's normal afaik, plus it does not disturb for sampling like it does on left channel where the buffer is never empty.


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Hainbach
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Post by Hainbach » Thu Jun 07, 2018 5:01 pm

Dolby switch up on Coco should help.

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batchas
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Post by batchas » Fri Jun 08, 2018 12:25 am

Hainbach wrote:Dolby switch up on Coco should help.
I will try again then :tu:
Thanx!

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Post by jimmie » Sat Jun 09, 2018 5:21 pm

Hey I also have the same difficulty on the left coco. It's hard to clear the buffer, right one is so easy. My coco2 had a few parts missing when came to my home and I sent it back to Peter. It didn't fix the buffer issue, though. So I still have the problem, but when I'm trying to clearing the left coco (meaning when it's recording), wiggling speed/loop knobs somewhat from extreme position often help clearing (if not perfect). And don't forget it takes long to clear when the recorded sample is long. Hope this will help.

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Post by batchas » Sun Jun 10, 2018 11:40 pm

:tu: :tu: :tu:

Thank you for sharing.

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Post by jo.spieth » Sun Dec 16, 2018 6:58 pm

Hello Cocoquantus people.
I also need help! I don't find a way to clear the buffer of the right Coco. l already tried Dolby switch up and down,.... Could you maybe have a quick look at the video and tell me if this behaviour is normal?
Thanks a lot in advance and all the best!
Jo

https://youtu.be/h3iW2SXEKyw

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Post by knows » Sun Dec 16, 2018 8:00 pm

I usually have the Dolby switches in the middle position and the turn the feedback down and the speed up and push the black button a few times.
In your video it sound like the buffer is not being cleared.
Is that a ground banana on the right not plugged into anything?
Sometimes ciat lonbarde does weird things, try unplugging it.
Maybe you have a loose solder somewhere?
Is it always like this? Or did it just start?
Do you have another power supply to try?

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Post by jo.spieth » Sun Dec 16, 2018 8:37 pm

Hey.
Thanks for your quick response!
I have tried everything, Dolby switches up/middle/down position, grounded, not grounded, other power supply... but it seems the buffer is never completely cleared... sometimes it's a little bit less noisy, but it's never like in the left coco.... I have just got the Cocoquantus two weeks ago and I am superexitced. I know noise is part of game, but it's kind of annoying that I can't clear the buffer....

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Post by mrhoudis » Sun Dec 16, 2018 8:57 pm

h ave you tried significantly gaining the input signal?

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batchas
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Post by batchas » Mon Dec 17, 2018 12:29 am

@jo.spieth: what you show with the right side of the Coco is exactly what I show with the left side on mine in first post (forgot to mention I bought mine new). Except that I just switched it on, so the sound in buffer is only noise, but if I had the audio sample like in yours, it would sound like yours.
My opinion: I don't think there's a solution other than circuitwise and I'm not sure I'll ever find the time to check the circuit!

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Post by sungja » Mon Dec 17, 2018 10:24 am

My cocolase has this problem with noise in the delay feedback same with coco2. If i turn the dolbyswitch for feedback in middle position the noise starts but fades quickly depending on the feedback knob. When the noise starts i flip up the dolbyswitch and it is silent. If you have noise in the delay with the dolby on then i guess peter must fix it.

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Post by sungja » Mon Dec 17, 2018 10:27 am

Dolby switch for the feedback must be up. Dolby for input does not matter.

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Post by jo.spieth » Mon Dec 17, 2018 7:46 pm

Hi everybody.
Thanks a lot for your help! I wrote an email to Peter last night and today already got an answer. He had a look at my video and recommends to take the Coco back to Patch Point in Berlin, where I bought it, to have them check it out. "There may be a tiny thing like an unsoldered leg."
Thanks again and all the best!

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Post by sungja » Tue Dec 18, 2018 9:01 am

If you can solder or have a friend who can fixing this problem is easy. Unscrew all 15 screws holding the top sandwich together. Lift the top off from the base and turn it. Now you can see the bottom of the pcb. I have done this myself many times with the plumbutter and tetrax. Good luck!

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Post by Scories » Fri Dec 21, 2018 2:07 pm

Faulty design? Peter should be aware...

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Post by batchas » Sat Dec 22, 2018 9:47 am

Forgot to mention: like it was said earlier in this thread, having Dolby switched on mutes this noise on playback, but having it switched on while cleaning the buffer has no effect.
jo.spieth wrote:I wrote an email to Peter last night and today already got an answer. He had a look at my video and recommends to take the Coco back to Patch Point in Berlin, where I bought it, to have them check it out. "There may be a tiny thing like an unsoldered leg."
I opened mine reading your last post.
I see with magnifying glass no SMD unsoldered or bent leg or any cold joint (except on all pots, but I guess these were soldered form the top or they'd have no contact).

I reflowed the biggest chip though to be sure, but same as earlier.
So it would be great to know which part of the circuit to look at exactly and reflow if necessary. I'm gonna ask where I bought it.

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Post by corpusjonsey » Sun Dec 23, 2018 5:33 pm

+1 for noise on the right channel.

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Re: Noise on left input on Cocoquantus 2

Post by trax » Tue May 12, 2020 8:11 am

How did people get this sorted?

I am having this exact same issue on a "new" Coco2. (I have another Coco that is perfect - as far as perfect on these things go) The RIGHT coco buffer works as expected - no problem - but the LEFT one on this unit is does not want to clear (it always has LOUD noise like everyone is describing in this thread- or "clicking/blown out sound when it does record no matter what gain staging I do) I was also getting strange grounding issues with this one that seems to "clear up" when I ground it to my mixer.
Again - my "older" coco does not have this "grounding" problem....or this loud noise static in ONE (LEFT) buffer issue.

I returned the unit and they cannot duplicate any of the issue(s). Strange. :hmm:

After reading posts on this - it seems lots of us have/had this issue detailed in this post - but no one talks about how it gets resolved....
I am not a stranger to this CL stuff and am aware of the quirks (most of us have the same issues that are resolved by a little experimenting and reading what others get/do....but this one I cannot figure out.

batchas how did u resolve this? - your video is an excellent example of this problem I am having...

Thanks for your help!

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Re: Noise on left input on Cocoquantus 2

Post by jimmie » Tue May 12, 2020 11:45 am

I've decided to live with it... I mean, mine still has difficulty completely clearing left (or right?) buffer upon 'clear the buffers' sequence but recording something on it diminishes the noise at least to the level not annoying. it's not a hifi looper/delay anyways ;)

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Re: Noise on left input on Cocoquantus 2

Post by trax » Tue May 12, 2020 11:59 am

I understand the "quality" of these things and love it... but the noise I have on the left is at "BATCHAS" level (the video above) the other buffer and my other unit is just "CL noisey". I am trying to figure out why.....

Thanks Jimmie for chiming in!

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Re: Noise on left input on Cocoquantus 2

Post by batchas » Tue May 12, 2020 2:38 pm

trax wrote:
Tue May 12, 2020 11:59 am
I understand the "quality" of these things and love it... but the noise I have on the left is at "BATCHAS" level (the video above) the other buffer and my other unit is just "CL noisey". I am trying to figure out why.....

Thanks Jimmie for chiming in!
I'm interested in knowing too.

I asked back then via email where I bought it, but I did not get any answer how to solve it, unfortunately.
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Re: Noise on left input on Cocoquantus 2

Post by sungja » Tue May 12, 2020 3:10 pm

I took my coco2 for a ride just now and i have not this problem. Feedback buffer is clean even when full clockwise and dolby up. If i have dolby off in the middle some noise but only when feedback knob is almost full clockwise.

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Re: Noise on left input on Cocoquantus 2

Post by sungja » Tue May 12, 2020 3:17 pm

I see in the video on top that sample is on. If the loop is not cleared then it will loop when feedback is up. Have you tried to have sample off? Try it in delay mode (light off) with speed full clockwise and input down. Both dolbys up and then turn feedback up slowly.

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Re: Noise on left input on Cocoquantus 2

Post by trax » Tue May 12, 2020 3:20 pm

After looking around it looks like this is the issue ( or a similar issue). Joe even brings up he thinks he has a grounding problem. ( it’s a good way to describe it since it sometimes intermittent and manifests itself similar to a grounding problem)

Turns out it May be a chip issue?

viewtopic.php?t=88679

Why do some of these units have this problem and some don’t...very strange and very difficult to get a straight answer.

When you purchase one it seems to be a crap shoot. I have one that is very usable and sounds fantastic and another that I just sent back to where I purchased sounds horrible ( in my studio). ( not in the CL horrible good way)
Last edited by trax on Fri May 22, 2020 10:42 am, edited 1 time in total.

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Re: Noise on left input on Cocoquantus 2

Post by sungja » Tue May 12, 2020 3:35 pm

If you read down in the comments section on the cocolase manual you see peter discussing different op amps and the issues they can cause. I am not experienced with components but i guess a bad batch of these could cause this noise problems maybe.

https://ciat-lonbarde.net/cocolase/man/index.html

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