APC BUILD Help

[Project_2501]

Hello everyone

Just got into soldering and drooling over schematics just weeks ago.

Need some love.

I only have a small sawtooth oscillator working at the moment with a 2n3904 transitor from Lookmumnocomputer, but I'm hungry for more.

Does anyone have a simple layout for an APC, or help understanding layouts google to get my feet more wet.

https://paulinthelab.blogspot.com/2014/02/atari-punk-console-stripboard-veroboard.html

This layout looks fun but vr2-3,3 means what for the pots????? I know the middle leg on a pot is the swiper or (2) but vr??? I don't have a clue to finish the wiring. I did solder together an layout of an APC but I messed up and the source of that layout is meh.

Also, after this, I know I will want more, cause we all do. Does anyone have any recommendations for a VCO this is generally simple and a vcf to get my feet wet. I'm very new to layouts and schematics. At the moment I can only build off a stripboard layout. I'm planning to build a Baby 8 to try everything together for music from outer space... Don't worry I have Ray's book on my night stand.

[PHOBoS]

VR probably stands for Variable Resistor and the numbers are the connections [1,2,3 where 2 is wiper, 1,3 are the two outer connections].
There seems to be an error though: VR1-3 should be VR1-1 and VR2-3 should be VR2-1.

[Grumble]

And one more error: out should be VR4-2
Oh and the components names don't match:
VR1 = R2, VR2 = R3, VR3 = R4
C3 is backwards

[Project_2501]

Oh, I see where some of my confusion is coming from. This design has 3 Potentiometers, 2 for the sound, the other for volume. Can I ignore the the 3rd pot for volume to save parts? I only have (2) 500k's on hand for the build.

How the potentiometers are lined is the only thing stopping me from firing off some sound.

Just to clarify, rows (a,b,c,f,g) are where the leads are going from and to the pots? Is there a simpler way to say how to wire all the pots. I'm lost here :/

[Ayab]

I was confused to start with but it will all make sense soon. Don't worry it is normal to take a little time to understand!

The stripboard drawing you posted just has a,b,c,d,e, etc.. down the side and numbers at the top just as a reference to help you place components on your own stripboard. For instance (yes) you can replace the volume pot with a wire or better a fixed resistor if you have any (say 100K) between I1 and J1.

Pot wiring will be easy if you rename the stripboard picture according to the advice given by Phobos and Grumble. They have compared the schematic diagram (usually accurate) with the stripboard picture and advised you accordingly. Those guys know their stuff and design and build their own original sound circuits so you are really lucky that they are helping you!!

First rename so that the stripboard and the schematic are the same:

"VR1 = R2, VR2 = R3, VR3 = R4"

Then the changes, first "VR1-3 should be VR1-1" = so that is R2-3 should be R2-1 = so just swap the outer connection on R2 keep the wiper the same

Next: "VR2-3 should be VR2-1"

"Out should be VR4-2"

"C3 is backwards" = look at the schematic the plus sign on the capacitor symbol is on the half before the chip (going to IC2 pin 3). The stripboard C3 has a greyed out top half denoting the positive (easy to remember that the long leg, as with led's, is positive) and that is wrong it should be the other way round.

Have a read about pots being set up as either voltage dividers or variable resistors to understand them better. MFOS is a good website for beginner explanations.

post if you need some help (i am not on here every day but should see it soon or someone will help)

[PHOBoS]

[Ayab]

Hi PHOBoS - Oops! That's why help from guys like you is great! Yes MFOS is great, RIP Ray (looks like I should do some more reading there too!!)

That is alot of mistakes for such a small circuit!

Project-2501 - (love the name am a Ghost in the Shell fan too - anime one being the best!!) best to make sure layouts have been verified as built and working.

[PHOBoS]

Hi Ayab
We are all here to help eachother and it always gives me great joy when I see that happening. It's one of the reasons why I love this place.
(I hadn't made the connection with Ghost in the Shell but yeah that's definitely one of the better animes)

[Ayab]

Hi PHOBoS -

+1 on Nicolas circuits

I just got hold of an unused betamax video tape (in the packaging!) to build the ribbon controller.

[Project_2501]

[quote="PHOBoS"]

[Ayab]

Hi Project 2501 - There is some cool "Appleseed" anime too

I regularly listen to John Coltrane and Miles Davis and such but don't know much about jazz especially good newer stuff. Did go to a Snarky Puppy gig not long ago that was really good.

Back to the APC - Soldering a jumper will work to join where you cut the tracks. C3 should be the way PHOBoS points out (and the C3 strip board symbol indicates the negative short leg in grey)

Btw if you only have linear potentiometers "B" you can convert them into pretty ok logarithmic "A" if you put a fixed resistor between the wiper and the pot leg going to ground (in the APC volume control R4 {VR3}, ground is leg 1) This is when the pot is acting as a variable resistor. The fixed resistor should be approx 20% (10-20%) of the value of the pot.

I have picked up a few other tips here such as you can add resistors in series to get a higher value (solder one end together and treat as one resistor in the same space).

Lastly here is a link to the Nicolas circuits suggested by PHOBoS. They are efficient and tried and tested.

http://electro-music.com/forum/topic-34550.html

The Nicolas circuits are v/Hz which is the same voltage control system as early Korg synths such as MS20. Many analog synths use v/oct (1volt per octave). The Nicolas circuits comprise all the necessary main modules for an excellent modular synth.

As a trombonist you may appreciate a ribbon controller. I must build mine!