3TrinsRGB-1c Triple CV Comparators - kits available

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FetidEye
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Post by FetidEye » Sat May 06, 2017 3:02 am

:sb: a modded one, cool!

I could have made that cascading function with the jack switches on the pcb.
Is that an option you use often?
I find that I use single comparators more. (different color routings)

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sebiiksbcs
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Post by sebiiksbcs » Sun May 07, 2017 8:54 pm

I haven't played with it enough to figure out a preferred config, what I do use is CV attenuation because it lets you find the one or other sweet spot.
And I like the input cascading simply because I'm lazy and try to utilize a single patch wire for multiple things. This takes you somewhere else with the flip of a switch.
Also I found you can create a kind of edge effect by slightly detuning two cascaded comparators against each other, for what it's worth.

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Post by queensescort » Thu Jun 08, 2017 2:47 pm

Is it possible to order a kit for Denmark? First time posting here :)

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FetidEye
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Post by FetidEye » Thu Jun 08, 2017 4:53 pm

no problem

pm me for details

or see my Etsy store:
https://www.etsy.com/shop/ReverseLandfill

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diodes?

Post by leolodreamland » Wed Jul 05, 2017 11:41 am

why no diodes in the BOM, they are on the pcb!

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FetidEye
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Post by FetidEye » Wed Jul 05, 2017 4:58 pm

em..

see bom? (from build package in 1st post)

BOM cv comparators

1x pcb "3x comparator" v3 2016

Resistors: (metal film 1% or carbon 5%)
r1: 5k1
r2: 5k1
r3: 5k1

r4: 1k
r5: 1k
r6: 1k
r7: 1k
r8: 1k
r9: 1k

r10: 10k
r11: 10k
r12: 10k

r13: 10r

r14: 10k
r15: 10k
r16: 10k

r17: 100k
r18: 47k
r19: 100k
r20: 47k
r21: 100k
r22: 47k

Capacitors:
c1: 100nf 5mm film
c2: 47uF 2.5mm electro 16v

Diodes:
d1: 1n914 or 1n4148
d2: 1n914 or 1n4148
d3: 1n914 or 1n4148


Transistors:
t1: 2n3904
t2: 2n3904
t3: 2n3904

IC1: 14pin socket + CD74hc14

Potmeters:
pot1: 20k lin 9mm alpha vertical
pot2: 20k lin 9mm alpha vertical
pot3: 20k lin 9mm alpha vertical

Connectors:
in1 cv1: thonkiconn jack
in2 cv2: thonkiconn jack
in3 cv3: thonkiconn jack

Pinheaders:
11way pinheader (10pin + 1pin)

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Post by Branko » Tue May 29, 2018 9:06 pm

Just built mine, but the 1st input doesn't behave the same as 2 and 3. Turning the knob has almost no effect. Running the same patch through 2 and 3 replicate the effect correctly. (VID to input, output to R-) I checked my soldering and everything seems good, and I reflowed solder everywhere.

Could I have burned out one of the transistors?

Or the module may be ok and I just don't understand what the ins/outs do exactly!

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FetidEye
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Post by FetidEye » Wed May 30, 2018 12:34 pm

make sure you don't solder r23, r24 and r25! (you have v4 right?)

all 3 comparators act the same, so something is wrong.

you can make a picture of both sides and post it here. Then I can give you tips!
It is possible to blow a transistor, if you hold the solder iron on it for too long.

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Post by Branko » Wed May 30, 2018 1:38 pm

V4, yeah. I omitted those resistors as per the instructions. I'll take a pic today when I get home. Thanks!

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Post by Branko » Wed May 30, 2018 1:47 pm

Question: Is each transistor tied to a specific comparator circuit?

Actually turns out I did take photos!

High res:
https://s15.postimg.cc/d9ht41wqh/20180530_011507.jpg
https://s15.postimg.cc/xtmn2jk7f/20180530_011516.jpg
https://s15.postimg.cc/pbd6y6qjf/20180530_012422.jpg


Image
Image
Image


Looking at them, a couple of resistors might need some extra solder. My gut tells me I burned out a transistor as I was overconfident and going fast.

Also I slightly damaged the plastic on the input jacks after trying to screw on some nuts, unscrewing them made the plastic crack. (I should have sanded the panel as you instructed.)

Also to note, the undamaged jack is the one I am having issues with.

And inspecting the photos at high res, I may have doubts about my soldering. I'll look it over closely when I get home.

Also one resistor looks like it has a weird hole on it.
I don't recall touching it with my soldering iron but I'm curious about it.

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FetidEye
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Post by FetidEye » Wed May 30, 2018 5:50 pm

on the first pic, the right potmeter looks badly soldered.
and the leftmost pin of the left jack socket looks weird (solderblob?)

reflow all IC pins

what resistor looks weird?

and if you solder the "link" holes, the CV signal of input jack 1 gets carried over to jack 2 & 3

I'll check the schematic tomorrow, for which transistor belongs to ch 1

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Post by Branko » Wed May 30, 2018 6:59 pm

I followed your instructions and still have the same issue. I've made sure to improve the soldering, but the module functions exactly the same as before.

I tried inputting CV instead of turning the pots and 2 and 3 behaved the same way. The pot with the issue (to be clear it is the pot closest to the input/output headers) had no effect.

Appreciate the help!

Let me know which transistor is connected to that circuit with the problem. (I think T3?)

Thanks!

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FetidEye
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Post by FetidEye » Thu May 31, 2018 4:10 am

hmm.. that is strange.

T3 is indeed the transistor for ch. 1
(the markings are switched around a bit, because of the flipped pcb
(header on top instead of below, like in the previous version)

you can try switching this for another 2n3904

also check R3, R8, R9, R12, R16, R21 and R22 and the pinheader
(the pcb picture is in the build manual, or I can send you one)

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Post by Branko » Thu May 31, 2018 8:09 am

I'll have to order some 2n3904s and I'll get back to ya. Would a BC547 flipped around work as well? I have a ton of those.

Cheers!

b

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FetidEye
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Post by FetidEye » Thu May 31, 2018 3:04 pm

yeah, try it! (the BC547 I mean_)

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Post by Branko » Thu May 31, 2018 3:25 pm

Can't see the PCB photo in the manual PDFs for some reason. I'll PM ya.

Thanks!

Also I replaced the transistor, and while I did get a better response, it still isn't too similar to the other 2 circuits. Especially noticeable when I try any keying effects. I'll check over the resistors you mentioned and see what that does.

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Post by pisrecords » Tue Jul 02, 2019 11:09 pm

hell o .
Can I use 10k pots ? i dont have 20k .
thanks. :sb: :sb: :sb: :sb:

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sorry 4 my poor English words.

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FetidEye
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Post by FetidEye » Wed Jul 03, 2019 3:22 am

you can, but the range might be different
try it and see if you like it?

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