X-4046 VCO Page is Up

claudiodelcairo · Joined: Dec 13, 2013 Posts: 1 Location: argentina

niiice!! Can you pm me the eagle files please?

fonik · Posted: Sun Apr 27, 2014 12:44 pm Post subject:

[quote="inlifeindeath"]

paulstone · Joined: Apr 14, 2013 Posts: 23 Location: ITA

[quote="fonik"]

fonik · Posted: Sun Apr 27, 2014 10:11 pm Post subject:

just have to order the prototypes...

piter_sensei · Joined: May 15, 2014 Posts: 2 Location: argentina

hello,

i am from argentina, and quite new in this DIY world
my question is about the X4046 tempco resistor.
i cant find here the 2K tempco 3500ppm
but found a TTC 202 that is 4000ppm

i think the 2k2 value is not a problem for calibrate the scalling trime.
my question is about the conversion rate (4000 ppm) of ohms/c°

i test it, and with the tempco in thermal contact (in the middle) of my transistor pair (but not connected yet in the circuit), its go down in 60Ω by C° in the range between 20-25C°

my question of course is to ask if this TTC tempco is admissible in the Thomas Henry designs

thanks !!

Pedro

fonik · Posted: Thu May 15, 2014 10:30 am Post subject:

the TTC 202 is a NTC (negativ going) while you need a PTC (positive going).

check these sellers: synthcube, thonk, bridechamber, or MFOS. they are specialized on synth DIY

piter_sensei · Joined: May 15, 2014 Posts: 2 Location: argentina

ok thanks !!

fonik · Posted: Thu May 22, 2014 10:03 pm Post subject:

fonik · Posted: Tue Jul 08, 2014 3:07 am Post subject: Subject description: FYI

a new run of PCBs (and front panels) will be available soon:

http://electro-music.com/forum/post-401449.html#401449

Colonel Steel Lungs · Joined: Oct 23, 2013 Posts: 2 Location: Blackhill

I wish you would just label things on your schematics, Shoes. Lazy git.

msprigings · Joined: Jan 16, 2012 Posts: 7 Location: Virginia

Has anyone had any issues with hot wave forms? I just tested my saw/tri and i'm getting around 15v p2p with the NXP 4046.

airfrankenstein · Joined: Jan 10, 2010 Posts: 62 Location: france

Could anyone suggest a cap value to make this VCo capable of LFO duties?
I'd like to put in a switch.

fonik · Posted: Tue Oct 20, 2015 5:34 am Post subject:

airfrankenstein · Joined: Jan 10, 2010 Posts: 62 Location: france

Yes I'm aware the feature is available on the new pcbs. I'm just going to try to squeeze in that option on V1, without the led.
Thanks

fonik · Posted: Tue Oct 20, 2015 9:43 am Post subject:

wackelpeter · Posted: Tue Jan 26, 2016 12:51 pm Post subject:

just finished a 4046 VCO on stripboard.

Run's straight coming from the work bench, which is a bit unusual with my building skills... Very Happy

Tracking was a bit tricky thumleft

... had to swap the 4046 for some better results, but the rest is very fine...

will have to twaek the pwm a bit because when turning the pot fully cw or ccw i got either a + or - constant dc Signal... increasing the 330k should solve the Problem i guess....

what i have noticed is that my original triangle out on pin8 Shows some Spikes at the upper and bottom edges... 2-3 Volt more than the Signal itself... anyone with an idea to get rid of them?

well i'm glad with it and guess this week another 4046 will beborn on my workbench...

Thanks a lot Thomas for your very cool designs and your generosity to share your knowledge with the community.
thumleft

wackelpeter · Posted: Thu Aug 24, 2017 7:43 am Post subject:

Don't know if i ever mentioned this before, but the Expo converter from the 4046 VCO works really well (and for me in an astonishing precise way) in the ASM1 VCO... have finished two of them and tuning was very easy, both oscillators track really close, so far my best result regarding tracking of a VCO...
Also i now used LF op amps in the Expo converter and thus slightly changed it a bit and added the positive and negative FM method as used on the buchla 258 VCO's.

On my two 4046 VCO it is limited somehow at higher range or at lower range which i had to make some compromises to handle both...

First of i think it has something to do with my CD4046, still managed it to get another brand, and also i finally decided to order a lot of polysterene caps which i can Exchange for the Polypropylene caps build in there, might improve things a bit i hope...

fonik · Posted: Thu Aug 24, 2017 8:00 am Post subject:

you could subsitute polysterene with C0G ceramic. at reichelt they would be found under "NP0".

wackelpeter · Posted: Thu Aug 24, 2017 8:34 am Post subject:

Sorry got it the wrong way around... too much poly's left me poly-confused Smile

After reading a guide, regarding caps and their use in audio circuits, i don't know exactly what web site it was, but it was from one of the more known guys (Marc Bareille perhaps) active in the DIY scene, who compared the different cap types and their use, giving a rough guide for their use.

For a long time i used polysterene (wima MKS) caps in most circuits, which seem not as useful in VCO's or VCF's. So from that list one of the closest replacements for silver mica were polypropylene caps (in my case Wima FKP2 and MKP2) from which i now ordered a few of some values to exchange them.

So those COG ceramics are better suited for audio applications than FKP2 or MKP2?

fonik · Posted: Thu Aug 24, 2017 9:25 am Post subject:

WIMA MKS is polyester NOT polysterene.
polypropylen is good for s/h applications IIRC.

the best choice for timing caps is polysterene (i.e. styroflex) or ceramic C0G/NP0. polysterene is THE classic VCO cap, however, meanwhile the new C0G appeared and they have a much more civil footprint.

at least thats what i learned from different sources.

wackelpeter · Posted: Thu Aug 24, 2017 9:46 am Post subject:

Yes Matthias, you're right... i'm mixing up these different types of poly-whatever caps again...

Well next time i'll order some components i'll give those NPO-caps a try, perhaps the better alternative as MKP2 or FKP2 as they're cheaper and relatively small compared to those.

As per Wima web site those FKP2 are well suited for Timing, filter, s&h and audio circuits in general.
https://www.wima.de/de/produkte/filmfolien-kondensatoren-im-rm-7-5-15-mm/fkp-2/

Seems as i have to search for some more informations about those COG/NPO caps and were they better suit in audio circuits as polypropylene would do.

Paradigm X · Posted: Sat May 16, 2020 6:24 am Post subject:

Hi Thomas, Mattias and Scott

I finally after many years got round to finishing and calibrating this VCO - it really does sound awesome, better than all my others i would say. I used the expensive MAT02 matched pairs for this, which i dont know if it affects anything other the v/oct, but theres something realoly unique to this VCO.

I must admit I always though a VCO was a VCO, a squarewave a squarewave etc, but happy to be proved wrong.

SO many thanks my Henry for your generosity in sharing an innovative design using cheap parts, and Mattias for the PCBs, and Scott for his usual input and very helpful details on his website.

Ben

injektilo001 · Joined: Aug 21, 2020 Posts: 10 Location: Chile

Hello Everyone, I'm Jean Paul from Chile
I was wondering if somebody has a working single sided PCB and layout from this beautifull VCO for etching myself?
I've been looking like crazy everywhere.
(If somebody has the same kind of files for the Thomas Henry 555 VCO it will be wonderfull too).
Hope somebody can help
Cheers from Chile

JimRead · Joined: Nov 07, 2021 Posts: 9 Location: uk

Please ignore I worked out what I wanted to know from the previous posts.
Silly me!

Cheers

JimRead · Joined: Nov 07, 2021 Posts: 9 Location: uk

Hello Thomas, Hello Scott, Hello Ryk, Hello Robert and Hello all,

I found the single sided PCB layout and looking through the thread the feedback modification;
Posted Image, might have been reduced in size. Click Image to view fullscreen.

I also altered the transistor layouts so they meet face to face
Posted Image, might have been reduced in size. Click Image to view fullscreen.

The PDF layout on Page 3 is too big so I had to reduce it proportionally by using Ps CS2 to measure and resize it. Not a problem so many are like that, I've done a how to video about it.

But this one is too wide in one direction most unusual but again easy to fix by un-constraining the proportions.

Cheers