AS3340 VCO Square output help needed

Okay had some time to rest on this project, gonna go buy new components and try again, will try to do as best as possible and as slow as I can so I would not make any mistakes. Maybe some resistors could have an impact ? I don’t know

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Hi klimashere I checked my harddrive again and found the layout of the alfa4 VCO. maybe that will help you too. Greetings THOGRE


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And they shipped today, after three days. I’ll see how long the post takes this time.

Edit: it’s now September 7th and I still haven’t got the chips after nearly two weeks. The delay is clearly in the postal journey from Portugal to Britain.

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September 10th and the second lot of Electric Druid chips arrived. Not prompt delivery but not exceptionally slow either. It’s worth the wait in my opinion. Taking into account the glacial rate of my synth work this is lightning fast. It could well be months before I get around to playing with any of these chips.

The items I ordered are 2 of VCLFO10, and one each of ONESHOT Event Generator, AS3310 VCADSR Envelope Generator, AS2164 Quad VCA and AS3046 Transistor Array.

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I’m excited to see what you can do with it! Tomorrow I will finally get my IDC sockets and can finally power my case and play with the modules for the first time

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This looks like something I could just breadboard in an idle moment. Fun to play with.

https://electricdruid.net/one-shot-event-generator/

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Looks like a nice toy, definitely comes on my shopping list!

Some time ago I built a simple busboard 1.0


Today my IDC sockets arrived I was finally able to build Busboard 2.0 today.

Version 2.0 has filter caps a red LED for + 12V and a blue LED for -12V. It also has pin headers to make it easy to expand. Let’s be honest, it’s just a stupid busboard, but I’m still really happy and proud of myself.

Now I can finally supply the modules in my first case with power and then play with them for the first time.

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Have you folks mixed this up with the mail and build threads, or is discourse being flaky?

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I think I started with a comment about the stripboard design and let it morph into a diary about obtaining the synth chips. In retrospect I should have made a new thread.

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I had the same problem I’ve been checking my circuit over for days with circuit tester checking all the values are right was proper scratching my nut over it but in the end turned out to be one of my potentiometers were faulty took me ages to even think of checking them, so I changed the pulse width potentiometer and it works perfect now, if your chip is getting hot there’s a problem with circuit and also probably fried the chip as I’ve also done the same thing I bought 5 as I thought I’d end up buggering a few so wasn’t a big problem lol if there’s nothing wrong with the circuit it shouldn’t get hot even if the chip is faulty so I’d make sure your faulty chip isn’t getting hot before inserting a new 1

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I have found that once you get them hot its best just to bin them [ ic’s ] , damage is done and they won’t last even if they seem to be working .

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Hey, did you find what your issue was? I have exactly the same problem with a Pulse out, checked everything and nothing comes out. Tested two IC’s, it doesn’t get hot but yet no Pulse output :/// Thanks

welcome !
maybe some answers here

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Which schematic/layout are you working with? Simple or performance? Stripboard or PCB? I would triple check your connections as that has been the primary cause for many of my issues (including the pulse output of the 3340 VCO where the solder I was initially using was worse than anything). If it is just the pulse output that isn’t working - your issue obviously lies among the PW, PWM, or Pulse pathing, so check there first!

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Thank you and apologies for the lack of info.
I use slightly modified (more compact) LMNC vero layout. Been checking everything for a whole day, but i understand that the mistake is somewhere in the wiring. I have two question, that i think will help me:

  1. Should i get a Pulse output (pin 4) without using PW to Pin 5?
  2. Is it possible to damage the IC in a way that only a Pulse part will stop working?

Thank you!

No worries, I was literally in the same boat of a messed up square wave like a week ago! Are you able to send pictures/layouts/schematics of the circuit?

  1. As far as I can tell, I’ve always seen pulse outputs on the as3340 with PW control. However, that I am not too sure about, so someone else might be better suited to answer that question. Are you using PW control in your circuit?

  2. It’s not likely to have just damaged the pulse output, unless there has been some sort of physical damage to it such as breaking the leg of the IC itself.

Have you tested the triangle and sawtooth outputs? If those are good, then that narrows the scope like I mentioned earlier.

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From datasheet:

0 V gets you 0% pulse width. You need +2.5 V for a square wave. (That’s with Vcc = +15 V, I think it’s +2 V with Vcc = +12 V.)

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Great. Really helpful. So i do need to feed a PW voltages in order to get something from pin 4. Will investigate further. Thanks :slight_smile:

I fried a couple of these chips in a similar way. I found that when it gets hot, that’s usually because there’s something wrong with the negative voltage on pin 3. I found the best way to fix this issue is applying -5v to pin 3, instead of -12 through a resistor.

I was getting discouraged too, I’m still having trouble getting it working how I want, but keep at it! You’ll get there!

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