Erica Synths DIY Bundle II Part 1 : The VCO

Part 1 of my series on the Polivoks Inspired complete 84hp DIY Eurorack System by Erica Synths. This is an introduction to the whole project as well as an in depth look at the VCO specifically.
PDF: Suggested Method for building the Bundle: www.dropbox.co...
Music and Video by Quincas Moreira
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[@paulbergel9191]

I could listen to you FM those 2 VCOs all day!!

[@QuincasMoreira]

Hahaha, thanks :) This might be my favorite thing to do with modular synths, lol

[@synthsocialist]

I bought two of these recently and love them! The build was less difficult than other VCOs because the entire kit is really well designed. I opted to reduce the range on the tune knobs personally, made them easier to tame. Erica have really done well!

[@slmodeformat]

How did you do that?

[@YoYoYo]

This is so cool that they send you the polivoks modules to build them. Great vids man.

[@QuincasMoreira]

I'm a lucky guy! Thanks :)

[@robertsyrett1992]

That is a beautiful oscilloscope!

[@QuincasMoreira]

Thanks! This Rigol is special to me because it was once Ray Wilson's

[@XYtoTheDoubleG]

The DIY Ray Wilson? Man... He has quite the catalog! I can't believe I have been interested in creating a modular synth for so long, but have yet to do so. I remember looking at Ray Wilson's complete systems so long ago! I am only finally feeling quite confident in my soon to be endeavor. been wondering if you are able to supplement your building with built modules. Are u able to make money selling assembled kits? I could see this being a way of affording a modular synth or creating a separate income. I do own a dual cabinet ROLAND 100m but I feel the extreme urge to create "my" own sound. The DIY aspect of modular is so enticing! What's more enticing than modular? A handbuilt modular!!!

[@devtank]

Very pretty oscilloscoping!

[@jumptoit3812]

This sounds so good.

[@QuincasMoreira]

Thanks :)

[@MrStanley85]

This is so great, thank you for doing this in such a great detail!

[@QuincasMoreira]

My pleasure!

[@sneakyfatcat]

I just finished building one but I can't recommend it. My kit was missing parts so I hard to order the missing components. Tracking isn't perfect either across more than one octave unless I manually choose the octave with the switch and don't feed it multiple octave changes on the v/oct in. That being said it still sounds like a beast and might be my current favorite vco!

[@jokkemartens8065]

Oh damn.. Same here.. Thought I was doing something wrong. Tracking Just isnt usable. Unless its fixable.

[@ludotex]

Great video as always. These whole systems look and sound nice. Looking forward to the Polyvoks VCF :)

[@QuincasMoreira]

ludotex thanks! VCF next week!

[@jamesbaynton1881]

Great video, exactly what I need right now, thank you.

[@QuincasMoreira]

James Baynton cool, thanks!

[@simonburns1055]

Use a socket to tighten the pots

[@simonburns1055]

Sounds like the synth from DOGs in Space !

[@retsukage]

thank you for these videos !

[@QuincasMoreira]

absolutely, my pleasure :)

[@simonburns1055]

Its a forest of leads

[@plasmativa6089]

Wowsome!!!

[@JustWickedSwede]

at 8:20 the themesong of my life is played

[@QuincasMoreira]

Hahahahahahaha

[@gorillaau]

3:20 or so.... I adore the wind sound. I didn't notice it at first.

[@QuincasMoreira]

filtered white noise :) I like having that as a layer in my drones !

[@gorillaau]

Quincas Moreira Thanks for the reply. These videos are awesome.

[@wackenthaljef]

My problem is that its more expensive in Diy than a Doepfer bundle already made...but its cool,Erica synths is cool.

[@QuincasMoreira]

jeff wackenthal sooo sexy though :)

[@sofiaurquiza2074]

hola podrias hecharme una mano con el vco polivoks 3 ? tengo un pico negativo en la onda triangular como puedo corregirlo ? y la calibracion no es precisa aun siguiendo al detalle todos sus componentes incluidos en el bom ?

[@shinrinyoku69]

Hey Quincas--I am so happy to hear from you! I had a hard time calibrating my VCO, but it must be due to an assembly error somewhere along the way. Any pointers on calibrating analog VCOs?

[@QuincasMoreira]

Hi Brian! Just saw this. The main thing for having well tuned analog VCOs is a very stable, preferably linear PSU. Once you have clean power it should be just a matter of careful adjustment. What is a bit counterintuitive is that normally when the top octave is sharp you trim it even sharper, and when it's flat you trim flatter. Other than that I can't think of anything, if you still haver trouble feel free to message me privately!

[@capacitoresdetantalio]

lovely

[@QuincasMoreira]

Thanks!

[@analog_output]

Looks pretty nice... wonder what ever happened with those two builders who had tracking trouble.

[@QuincasMoreira]

good question! Mine track well, as long as I give them linear power :)

[@liamsparling]

hi im planning on getting the panels and pcbs's for this kit. any reccomendations on what supplies i need besides a soldering iron.

[@QuincasMoreira]

Soldering STATION, with temperature control, Solder, wire cutters, tweezers, desoldering braid, desoldering pump, helping hands, multimeter, magnifier. That should do to start!

[@lucfiumara]

Hola! estoy tratando de calibrar este gran vco con un beastep pro. El unico problema lo tengo cuando una vez calibrado cambio las octavas con la llave octavadora, cambian las frecuencias a medida que bajo la llave se va desafinando cada vez mas. Como corrijo esto? Y otra pregunta. Es normal cuando entro en modo sync con otro vco como master y el polivoks como esclavo al mover el tune del esclavo en las zonas altas se interrumpe abruptamente la señal? Muchas gracias!!

[@QuincasMoreira]

Hola Luciano, perdón por no haber contestado antes, apenas veo tu comentario. Tienes que afinar las octavas primero, tiene su trimpot, es el de abajo. Ya que esten todas las octavas iguales afinas la escala. luego regresas a las octavas y asi de un trimpot al otro hasta que todo este bien. Lo del Hard sync no se, tratare de replicar el efecto aqui y te digo. Saludos!

[@lucfiumara]

Quincas Moreira muchas gracias con lo que me dijiste mas lo que me respondio erica creo que voy a conseguir calibrarlo bien😊

[@bbartokk]

Do you have a video on how to calibrate? How do you use the multimeter and what exactly do you adjust? I've reached out to Erica Synths for clarification but have not heard back.

[@QuincasMoreira]

Hello Mr Bartok! What an honor :) This VCO needs no calibration of wave forms, the onboard trimpots are there just in case, but the waves look great right away. Check them on an oscilloscope if you want to make sure. You only need a multimeter to check if you have any shorts in the power rails before plugging it in, to avoid accidents, but the resettable fuses and diodes are good protection. And for tuning the 1v/oct tracking all you need is your voltage source (CV keyboard or Midi2CV module), a tuner and a bit of patience. The procedure is detailed in the manual. Let me know if you have any further questions and I'll try to help! Have fun

[@jokkemartens8065]

​@@QuincasMoreirahaving some trouble tuning. I can get 1 octave in tune. Then it starts to deviate 20 cents per octave. So up 2 octaves is in between 2 notes... Adjusting the scale will Always put an octave out of Pitch..

[@vespine]

Hey synth DIY guy! I'm thinking of taking my first plunge into eurorack and i'm keen to start with two identical analogue VCOs. This one is on my shortlist, as is the Befaco Even VCO, the MST from Synthrotek, the zlob dual VCO which is half the price and a quarter of the size of the other options. I am quite experienced with electronics so build complexity is not a factor... Just by aesthetics I think this is the nicest looking one.. Could you please share any thoughts or suggestions? a befaco rampage and ornament and crime are high on my list i'll be mostly experimenting patching ambient noisy glitchy sequences..

[@QuincasMoreira]

Hi! Yeah, these are my favorite for looks and the big knob is super fun. If you have a linear power supply I highly recommend them, but they are fussy inder a switching PSU. The Befaco is more stable but lacks an attenuator for FM and instead of a Big pitch knob you get a big Octave switch. It has two extra waves and is smaller though, so, depends on your preferences and patching style! I can't say anything about the MST or the Zlob since i've never played them. BUT, do stay tuned for the Ian Fritz Teezer, coming soon from Synthcube, it's my favorite analog VCO for noise, glitch and drone!

[@thesolutionband]

Hey, great video. I just finished the VCO and so far so good except when I went to calibrate it, the module isn't tracking at all. It's way off. Do you have any suggestions for what to do next? The octave voltages at TP1 were right on. Thanks for any assistance. -Adam

[@QuincasMoreira]

Hi Adam, sorry you're having trouble. It's hard to troubleshoot at a distance, what voltagesource are you using for calibration? I used my Keystep and it was pretty straightforward. Also, the PSU is very important, I find these VCOs behave well with very stable linear PSUs.

[@thesolutionband]

Synth Diy Guy Thanks for the reply. I’m using my Beatstep Pro. I’ve also tried it with my Pittsburgh Modular MIDI3. For the Power I’ve been using my Synthrotek Super Power. I’m going to try plugging it into my other rack today which is a Tiptop power supply. I’ll let you know what happens. Thanks again.

[@QuincasMoreira]

No problem! If you continue to have problems try reaching out to Erica!

[@thesolutionband]

Synth Diy Guy I wrote to them last night. I know they are a very different time zone than me so I’ll try to be patient. 😀

[@QuincasMoreira]

Yes, Girts is also very busy, but I'm sure they'll help you out!

[@threeinitiates8260]

Where is the link to the pdf? thanks for the video love it

[@QuincasMoreira]

Posting today!

[@Andrewcoughlan1]

Great video. You mentioned a pdf with test point values?

[@QuincasMoreira]

Hi! The PDF is my suggested procedure for building these as well as the optimal order in which to build them. I should post it later today. The test point values are in the Assembly guide, found in the Erica website.

[@Andrewcoughlan1]

Thanks for PDF - Where did you see the test points (1 to 9) on the assembly guide ? I could only find TP1 mentioned in 'calibration steps'.

[@QuincasMoreira]

you're right, I got this confused with another module I think! That's the only test point listed, so don't worry about any of the other ones ;)

[@HansLiu23]

I love how you skip over the most important part which is the tuning.

[@QuincasMoreira]

here' it's pretty much the same kzbin.info/www/bejne/g37Ml2upr8RpecU

[@franzicosmos5966]

Hello. Are your eg II working properly? (looping, inverted envelope) Love your videos! Regards. François.

[@QuincasMoreira]

Hi Thanks! Yes, my EGs are working perfectly! Making a video on them right now, stay tuned :)

[@simonburns1055]

what do the ferrite beads do?

[@QuincasMoreira]

Nobody knows! 😆

[@thatoneweirdkid7385]

Is this analog or digital?

[@QuincasMoreira]

Daniel McIntosh it’s fully analog

[@anthonymiller4703]

strictly fm jam- no subtraction/////

[@QuincasMoreira]

I hadn’t built the filter or VCA yet!

[@CODDKP]

blah blah blah i'm rich and i think poor people must be rich. blah blah blah

[@QuincasMoreira]

What exactly do you mean?