# clock module Whistling



## arkhhh (Dec 26, 2019)

Hi !

Since there's no marks on clock module I have wired it following forum threads :
"The pads on the clock module are X / GND / VCC"
Left to right from components side, IC at the top (pads at the bottom, indeed!)

It seems ok as tweaking results in moduling the effects (nice!) 

Well there's a problem : when pot is at minimum it's ok, but as it's value is higher I have a high "whistling" In the audio output (higher as the pot is turned) with the normal effect sound. 

And it is present even In bypass if I don't reset the pot to minimum. 

I changed the 4049 but same result... 

Precision : IC is CD4049UBE, can't find difference in datasheet that may explain the whistle.

Someone has a clue about this? 

Thx so much!


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## Robert (Dec 26, 2019)

Where did you connect X on your main PCB?

Connect VCC to the 3.3V supply instead of VCC and see if that helps at all. (Pin 1 of L78L33, or pin 8 of EEPROM)


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## arkhhh (Dec 27, 2019)

Robert said:


> Where did you connect X on your main PCB?
> 
> Connect VCC to the 3.3V supply instead of VCC and see if that helps at all. (Pin 1 of L78L33, or pin 8 of EEPROM)


Thx for the hint, i'll try the 3.3v (for now I desoldered à lot of things, can't test that immediatly, but i'll report asap) 

X is on the pad previously occupied by a cristal leg (the closest to fv1). 

A precision : i have mounted all this with a Switch to keep cristal option (with 2pdt) : the capacitor and cristal have a leg at original pad, the other connected to the switch, reverse position of X. 

Neither cristal nor capacitor are connected when module is on (one leg connected, one leg on the air for both).

The module is constantly powered but disconnected from circuit when cristal activated (No whistle).


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## arkhhh (Dec 29, 2019)

Hello there !

Tried with 3.3v and external 5v, same problem.

I was wrong about the IC ref : its exactly a CD74HC4049BE.

I guess it would be the real problem, don't have No other 4049 to test and I'm lost with references for this one...

Thx !


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## Nostradoomus (Dec 29, 2019)

Could be a matter of needing the Unbuffered 4049 chip. CD4049*U*BE.


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## arkhhh (Dec 30, 2019)

Nostradoomus said:


> Could be a matter of needing the Unbuffered 4049 chip. CD4049*U*BE.


Pretty sure of That by now, found one at local store, i'll give it a try soon !
Thank you !


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## arkhhh (Dec 31, 2019)

It's me again, the whistleblower ! 

Came back from electronic store with a proper 4049UBE.

Finally mounted my circuit and tested it finally, everything is working, except this whistle that is still there... 

First, thx for the build doc that you added, it allowed me to control and everything seems right. 

I have powered the module with 9v and 3.3v (from eeprom power rail) and... The whistle is less in high frequencies when 3.3v but still there, even when module is bypassed (bypass only but still powered, if not => no whistle at all).

Things I've done that could play à rôle :
- i replaced trimer by external pot (pins from Left to right of the PCB : 3,2,1) but it does the job so i guess it's not him
- i have displaced 15p and cristal on a 3pdt switch (switch between them and the module, within the right pad of cristal, that connects pin 10 of fv1), when on, working normally (but whistle is Here if module powered)   so... But the 15p is totally omited when un module mode (so was said un this forum, and not told in the build doc ? Is it necesary for the module too ?

I don't see any more lead on this one, IC seems correct, Wiring is too... 

I can deal with it with a grounded switch that cut the module power but meh... It would still whistle when I use it... 

Any clue ? 

Thx !


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## Nostradoomus (Dec 31, 2019)

Do you have some pictures of your build?


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## arkhhh (Dec 31, 2019)

Since it is full of mods it will Be unreadable (and suprisingly enough, it is working despite the spaghetti Nexus !), i have taken a photo of the module part, but Here again i doubt it will help but Here it is... 
I'm 100% sûre now that my wiring is correct and I have controlled the components (except the 4049,don't know how to control this one).
The vcc of the module is now disconnected (i just finished the wiring and wanted deep test without whistle). Everything's going smoothly without this little Guy...


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## Nostradoomus (Dec 31, 2019)

Yeaaahhhh... I got nothin for ya haha. Maybe turn it on and move some of the boards and wiring around, could be something making contact.


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## arkhhh (Dec 31, 2019)

Yes, it could be, except that I first tested it unboxed and clearly isolated. Same result... 
I'll go for another IC, could be à fake... 
Well, i'll go without for now !


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## arkhhh (Jan 3, 2020)

Hi again,

With reflexion and re-reading the build doc of the module clock and forum threads previously published, i'm questionning myself about the wiring (i know my spaghetti incident doesn't allow to see clearly things, but in fact only the wiring module / PCB is questionning).

One (forum) said to "omit cristal and 15p capacitor", other (build doc) doesn't say to, only to "connect X to pin 10 of the FV1".

Question : is the module clock doc is saying that we may let cristal and capacitor in place AND connect directly the module to pin 10 ? or omitting totally the 2 components AND no bridge instead ? 

As i have mounted this on switch to keep the 2 options for driving the clock, my schematic is on the photo attached (sorry it's sketched really fast, but i think it represents what i've done, except i don't have a perfect idea of the pcb's pads corresponding to the schem of arachnid, but i have simply took pads and connect them to input pins of the switch).

When i omit capacitor as said and switch to module clock, it seems to me there's no more connexion beetween 9 and 12 of the fv1 (except if there's a connexion in parrallel to the capacitor in the pcb ?).

Is it not a (the ?) problem here ? "omit capacitor" did you mean "bridge the pads" ?

Thx !

Note : don't bother the clock module schematic, it's probably wrong as i d'ont know what the little squares mean on the build doc schematic for the 6, 10, 12 and 15 of the 4049)


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## arkhhh (Jan 16, 2020)

Hi guys ! 

Closing this case : really stupid Noob error, following bad IC classic.

Installed new 4049 from tayda : no More whistle but LOT of noise. 

Deep inspection... Doubt.... Look at my capacitor stash... No 1.5n... Weird... Look at the module capacitor... Fuuuuuu****** ! 15n ! 

*growl*

Testing 1.8n (well you Know... No 1.5n around), 1.7n... Will do the job ! 

Breathe, solder, test... 

It's alive and No noise  

Nice add to this fascinating FV1 !

Well then, I'm really confused ! 

Thx for the help and indulgence ! 

End of this dumb story.


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## Nostradoomus (Jan 16, 2020)

That’s good to hear! So that spaghetti box works now? You should definitely post a demo


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## arkhhh (Jan 17, 2020)

Ahah yeah spaghetti box, it's exactly how I presented it ! Do i know you ? 

Well yes, surprisingly it works like a charm (at first start, was reaaaaally surprised myself)

Not sure demo needed, everyone here should know it already, it's only a full modded arachnid.

Well a fat modded one with 32 patches but simply modded 

But I'll see that if it's a demand!


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