Thomas Henry's X-4046 VCO - New Edition

fonik · Last edited by fonik on Fri Mar 09, 2018 4:30 am; edited 2 times in total

from time to time people ask me about the Thomas Henry X-4046 VCO and if i would do another run. I think this is due to the fact that this VCO is rather unique. Thomas did an awesome job in utilizing this 4046 IC for a musical VCO with 1V/oct response - something this IC has not been designed for. and the result is a VCO with great features and character.

back in 2012 thomas approached me to try and test a VCO design using this chip. a design that he had developed, and worked on together with scott stites, who did a great job on the documentation fo this design. you will find all necessary information about this VCO here:
http://www.birthofasynth.com/Thomas_Henry/Pages/X-4046.html

i sold PCBs for this project in the past. however, there had been two PCBs, one for the actual VCO core, and another for the waveshaper (sine and pulse). these PCBs were a leftover from the breadboarding/testing. i sold them as they where...

now i decided to do a new design. the prototype PCBs came in recently, i assembled them and they work perfectly. if there was enough interest i would offer them together with a top notch front panel in professional quality, as i did for the 555-VCO.
there will be one PCB containing the actual VCO circuitry, providing MTA-100 footprints for easy manual wiring (if needed/desired), a combined footprint for super matched pairs or your hand matched 2N3904, and another additional adapter PCB carrying the front panel components (eurorack form factor), which could be mounted piggyback to the VCO PCB. the adapter PCB provides an LFO modification as well (mode switch, bi-color LED and LFO timing cap).
____

documentation could be found here:
X-4046-VCO_V2
(if you feel something is missing, just let me know...)
____

pricing:
Bare Main VCO PCB, 7.-EUR/ea
Bare Eurorack Adapter PCB, 7.-EUR/ea
Eurorack Front Panel, 15.-EUR/ea

shipping
international 4.-EUR
deutschland 2.-EUR
(you will pay half the shipping cost when ordering just a single PCB)

i am taking orders until 17 JUL 14
PCBs and panels will be ready for delivery early AUG then.
i am taking no money u ntil the boards/panels are in. i will then contact all who indicated serious interest.

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StormB · Joined: Aug 15, 2013 Posts: 18 Location: Germany

Hi,
I´m want 2 PCB
Thank you

feggster · Joined: Sep 12, 2011 Posts: 52 Location: uk

great stuff!
I would like :
1x vco pcb
1x euro adapter
1x front panel

thanks. Very Happy

dwhacks · Joined: Jul 18, 2014 Posts: 2 Location: montreal, CANADA

Great!

I too would take:
1x main PCB
1x Euro adapter board
1x front panel

AlasdairMoons · Joined: Dec 03, 2011 Posts: 105 Location: East-Belgium

Damn mist the timeline ....

if still possible 1 pcb and euro pcb for me .. please

greetings .. sascha

ioannis taf · Joined: Sep 19, 2013 Posts: 5 Location: GREECE

I am late.again.
Sorry, but if it's possible,
please send me
3 x bare main vco pcb and
3 x bare eurorack adapter pcb (international shipping).
Thank you,
Ioannis T.

Sony Crocket · Joined: Sep 27, 2010 Posts: 13 Location: Madrid, Spain

Went out for holidays and missed that one. Crying or Very sad

I know it´s too late, but if you order extra/spare pcb´s, I´d like a pair of main pcbs if possible.

Thanks a lot.

David

drapdap · Posted: Sat Aug 09, 2014 3:24 am Post subject:

We ALL missed it Matthias! Very Happy

would have taken 4 or so... did you close down the order for this?
did this happen? Very Happy

robert

fonik · Posted: Mon Aug 11, 2014 1:04 am Post subject:

there will be an option for you all, soon. stay tuned.

aerogramma · Posted: Mon Aug 18, 2014 9:00 pm Post subject:

I've missed it too! Crying or Very sad

hodad · Joined: Jul 31, 2007 Posts: 41 Location: atlanta

Just got my boards today--thanks!!

I'm wondering if you have docs for this revision yet. A BOM would be very helpful--or do all the parts/part numbers correspond to the parts list at scott stites's site?

Tom

fonik · Posted: Fri Aug 22, 2014 12:15 pm Post subject:

documentation could be found here:
X-4046-VCO_V2
(if you feel something is missing, just let me know...)

fonik · Posted: Fri Aug 22, 2014 12:17 pm Post subject:

you missed the boat?

no problem:
http://www.thonk.co.uk/shop/fonitronik-th-x-4046-vco/

fonik · Posted: Mon Jan 04, 2016 5:03 am Post subject: Subject description: HOT FIX

ATTENTION

today i learned that the main board layout exceeds the manufacturers tolerances. my fault.

so by now one case has been reported where this led to an actual problem. the middle pin of the coarse pot connector is not only connected to the 100k input resistor (R29), but to the 2k PTC as well (at the opamps output node).

if this happens, everything but the coarse pot will work fine.

my proposal fo an easy fix (also see picture below):
- cut the trace from the middle pin of the coarse pot connector to R29 on the top layer.
- for R29 solder only the leg towards the IC to the board.
- solder a wire from the middle pin of the coarse pot connector to the unsoldered leg of R29.

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