New project: Dual VCO for Eurorack

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Synthbuilder
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New project: Dual VCO for Eurorack

Post by Synthbuilder » Tue Oct 15, 2019 9:42 am

The ASV's VCO circuitry as a 14HP euro module:

Image

Surface mount for the most part but like my other Eurorack projects it's the larger 0805 and SOIC parts.

Image

Builder's Guide should be online towards the end of the week.

http://www.oakleysound.com/DVCO-e.htm

Tony

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Pav
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Post by Pav » Thu Oct 17, 2019 4:03 pm

I see more smd in my future ... the writing is on the wall :bang: :bang:
Ordered mine though :hihi:
rgds Pav

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Post by Synthbuilder » Fri Oct 18, 2019 5:52 am

Pav wrote:I see more smd in my future ... the writing is on the wall :bang: :bang:
Sadly we are losing quite a few good through hole parts as the world moves towards increasingly smaller electronics. But through hole parts will continue to exist and I'll endeavour to keep the 5U stuff going as long as I can.

That said, I rather enjoy the surface mount assembly process. It takes me about the same time to populate the board. The real bonus though is that the waste is a lot less and there's a lot less solder and flux fumes to deal with. I got Specsavers as part of their get two for one deals to make me a pair of reading specs that are good at four inches distance. These are perfect for SMD assembly. Some folk use these sorts of things:

https://uk.farnell.com/lightcraft/lc177 ... dp/2442795

Probably should try and get some before they sell out.

Tony

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Post by Pav » Fri Oct 18, 2019 7:57 am

I will add these to my next farnell order. With the flanger and sequencer pot board smd work completed i feel I have lost my smd cherry so to speak, and to be fair , confidence has now grown. This is why i was happy to place an additional order.
rgds Pav

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Post by tvh » Sat Oct 19, 2019 5:53 pm

I got a set of those with the interchangeable lenses from Amazon and they replaced my reading glasses when soldering. The little light is very useful.

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Post by Pav » Mon Oct 21, 2019 9:18 am

The led and lenses headset arrived today and I can confirm my ability to inspect my smd ic soldering has improved considerably. It's cheap and I can use with my prescription glasses.
rgds Pav

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Post by Pav » Wed Nov 06, 2019 9:14 am

Hi, Any Hfe value recommendation for BC850 /860 .? .. appears some choices @Farnell
rgds Pav

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Post by Synthbuilder » Wed Nov 06, 2019 11:16 am

Pav wrote:Any Hfe value recommendation for BC850/860
B or C, it doesn't matter in the D-VCO. Just like the BC550/560s used in the through hole Oakley modules, if it doesn't give the suffix in the parts list then the grade should make no difference.

I'll make them C types in the parts list to save any confusion. I used C types in my prototypes.

Tony

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Re: New project: Dual VCO for Eurorack

Post by Pav » Wed Jan 22, 2020 11:25 am

Hi

just to report that I have completed my first build of Dual VCO this afternoon
(1 of 2 pcb sets) and :mrgreen: It has been running for 45mins with an Saw1,Pulse2,Tri patch with and without Sync.

Pleased with sound, and happy to recommend it to others.

My soldering was not the best this time so i expected a few problems, but no, only one, which i hope to find quickly.

I have no pulse1 audio output at the moment. saw1 is fine.
i have perused schematic and can see i need to check soldering of pin7 U9 and upstream on main board.
If pin7 has the signal Ill then check pin6 of CN7 connection and then on to checking pot board.

EDIT -- I have no output from comparator U3 pin 7 where im expecting pulse.
I have saw on input pin 5 . but pins 1,2,3 appear to be ok as we have sync working -
can half a comparator fail ? hmmm.
Resistor reflowed U3 reflowed - no joy
- puzzle continues
END EDIT

Ill post audio/video clip something - after i have :guinness: Is 4.30 too early?
rgds Pav

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Re: New project: Dual VCO for Eurorack

Post by Pav » Thu Jan 23, 2020 6:02 am

It seemsmain board U3 is ok. It is receiving a 10v from the PW circuit to compare with. Turning the PW1 knob has no effect.
Reflowed the Pot Board PW circuit . and I have the Pulse output working now.! :goo:
rgds Pav

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