DIYstompboxes.com

DIY Stompboxes => Building your own stompbox => Topic started by: lightningfingers on March 29, 2005, 01:34:28 PM

Title: My vanishing point has some ISSUES
Post by: lightningfingers on March 29, 2005, 01:34:28 PM
the clock will not, well, clock. The output stays constantly high. I have checked with a meter, all positions of the 100K pot it stays the same (I'm usinng a 4049 BTW).

Schematic Here: http://www.geocities.com/thetonegod/vanpoint2/van_point2.html

Anyone have any suggestions? I know the clock is simple enough....I have tried a different 4049 (in fact, tried 3 different 4049's)
Title: My vanishing point has some ISSUES
Post by: Arno van der Heijden on March 29, 2005, 01:42:17 PM
I don't know whether this can be checked with a meter.
Instead, you can also try to hook it up to an LED (in series with a resistor) and check whether the LED will pulse.
Title: My vanishing point has some ISSUES
Post by: lightningfingers on March 29, 2005, 01:45:13 PM
I tried that just now but it the led stays on, just as if i hooked it to the +VE rail.......
Title: My vanishing point has some ISSUES
Post by: The Tone God on March 29, 2005, 01:45:25 PM
The circuit uses 4093s not 4049s. The 4093 is a schmitt trigger NAND gate. The 4049 is an inverter gate without the schmitt trigger inpuit so that particular clock circuit will not work.

There are other common clock circuits that the 4049 can use to drive the 4017 with.

Andrew
Title: My vanishing point has some ISSUES
Post by: lightningfingers on March 29, 2005, 03:16:15 PM
I see. Now i'm completely f  :D  cked. Oh well. One more quick Q, with the 4093, do I still need to ground the in/outputs of the unused gates?
Title: My vanishing point has some ISSUES
Post by: The Tone God on March 29, 2005, 03:35:48 PM
Quote from: lightningfingersI see. Now i'm completely f  :D  cked. Oh well.

If your using the PCB that I offer then yeah your screwed. If you are doing your own board or breadboarding it then just use the common two gate clock circuit you see everywhere with the 4049. You'll have to retweak everything to work to your tastes.

I also have an untested layout for the 40106. It includes an LED output for the sequencer clock so you can see the speed of the even in bypass.

Did you do a look up for a post I made awhile ago concerning a collection of changes to improve the performance of the VP ? I haven't updated the article with the changes yet.

Check out my post in this thread:

http://www.diystompboxes.com/sboxforum/viewtopic.php?t=28396

QuoteOne more quick Q, with the 4093, do I still need to ground the in/outputs of the unused gates?

Yes. As with all unused logic gates in ANY circuit tie the inputs to either ground or V+but only the input. Leave the output unconnected.

Andrew
Title: My vanishing point has some ISSUES
Post by: Arno van der Heijden on March 29, 2005, 03:59:03 PM
Andrew,

I (STILL) have my VP2 on the breadboard (the logic part that is), tweaking it for perfection.
I'm trying to replace the optocoupler that changes the frequency of the RF clock with a transistor (à la zvex  8) ), because the use of diy optocouplers on the breadboard really annoys me. I'm using this (http://www.geofex.com/Article_Folders/LFOs/psuedorandom.htm) as a guideline.

Right now, I have the transistor in the feedback loop of the second clock. The base is connected to the clock via a 100k resistor, and to ground via a 1M resistor. I'm getting reasonable results this way, but still not perfect.
Have you tried something like this? Do you have some tips?
Title: My vanishing point has some ISSUES
Post by: The Tone God on March 29, 2005, 04:13:23 PM
Quote from: Arno van der HeijdenI (STILL) have my VP2 on the breadboard (the logic part that is), tweaking it for perfection.
I'm trying to replace the optocoupler that changes the frequency of the RF clock with a transistor (à la zvex  8) ), because the use of diy optocouplers on the breadboard really annoys me. I'm using this (http://www.geofex.com/Article_Folders/LFOs/psuedorandom.htm) as a guideline.

Right now, I have the transistor in the feedback loop of the second clock. The base is connected to the clock via a 100k resistor, and to ground via a 1M resistor. I'm getting reasonable results this way, but still not perfect.
Have you tried something like this? Do you have some tips?

I just made a post in the "home-made vactrols" thread about my thoughts on why I used optocouplers. I haven't tried using a transistor for the HF clock...YET! It maybe something to play with alittle later. I have so many things on the go right now. I'll see if I can squeeze something in when I'm suppost to blink. :shock:

Atleast using the optocouplers reduce the flaming I get on german forums. ;)

I would still use a optocoupler for the audio/logic interface.

Andrew
Title: My vanishing point has some ISSUES
Post by: Arno van der Heijden on March 29, 2005, 04:21:54 PM
QuoteI just made a post in the "home-made vactrols" thread about my thoughts on why I used optocouplers. I haven't tried using a transistor for the HF clock...YET! It maybe something to play with alittle later. I have so many things on the go right now. I'll see if I can squeeze something in when I'm suppost to blink.  
Yeah, I just read the other thread. A fet doesn't seem to be a good solution here, but a transistor, if I can get it to work, does, as it only needs a couple of extra components.

QuoteI would still use a optocoupler for the audio/logic interface.
Yeah, that was my opinion as well.
Title: My vanishing point has some ISSUES
Post by: The Tone God on March 29, 2005, 04:26:53 PM
Quote from: Arno van der HeijdenYeah, I just read the other thread. A fet doesn't seem to be a good solution here, but a transistor, if I can get it to work, does, as it only needs a couple of extra components..

Cool. I'll play with it maybe later today in between projects. Just off the top of my head it might be possibe to put a transistor in between the timing cap and ground. That might be better then putting the transistor in the loop. Just a thought.

Andrew
Title: My vanishing point has some ISSUES
Post by: Arno van der Heijden on March 29, 2005, 04:36:41 PM
QuoteJust off the top of my head it might be possibe to put a transistor in between the timing cap and ground. That might be better then putting the transistor in the loop. Just a thought.

I really don't know. I have a good basic understanding of how the building blocks of electric circuits work, but I don't have much knowledge regarding the specific workings of transistors or these kind of oscillators.
I seem to remember, however, that zvex put the transistor across the resistor. Right now I don't even have a resistor, only a transistor. I think I'm gonna experiment with a resistor and a transistor in parallel first.
Title: My vanishing point has some ISSUES
Post by: lightningfingers on March 30, 2005, 05:03:38 AM
Thnaks Andrew :) Now if I can just get through the rest of today without being stupid I might have a build report by tomorrow :wink:
Title: My vanishing point has some ISSUES
Post by: The Tone God on March 30, 2005, 01:20:59 PM
Quote from: lightningfingersThnaks Andrew :) Now if I can just get through the rest of today without being stupid I might have a build report by tomorrow :wink:

lol. No prob. I would love to hear/see another build report. :)

Quote from: Arno van der HeijdenI seem to remember, however, that zvex put the transistor across the resistor. Right now I don't even have a resistor, only a transistor. I think I'm gonna experiment with a resistor and a transistor in parallel first.

I don't remember anything like that or know how Mr. Vex does it as I have never looked in one of his boxes and quite frankly I don't care. I have no interest in reverse enginering someone elses stuff. I prefer to find my own way. If it ends up like someone elses product then it shows they have style. My interest is more in making something simple, reliable, cheap, and when making it availible to the public easily reproducable. /rant

I'll post my findings when I play with this.

Andrew
Title: My vanishing point has some ISSUES
Post by: Arno van der Heijden on March 30, 2005, 02:38:56 PM
QuoteI don't remember anything like that or know how Mr. Vex does it as I have never looked in one of his boxes and quite frankly I don't care. I
I have never looked in one of his boxes either, but I seem to remember a comment he made about it on this board.

QuoteMy interest is more in making something simple, reliable, cheap, and when making it availible to the public easily reproducable. /rant
Exactly. This is not meant as critisism on your cool design, but these are all arguments not in favour of a homemade optocoupler.
Title: My vanishing point has some ISSUES
Post by: The Tone God on March 30, 2005, 02:43:45 PM
Quote from: Arno van der HeijdenExactly. This is not meant as critisism on your cool design, but these are all arguments not in favour of a homemade optocoupler.

Agreed which is why I'm willing to play with this some more. That is the fun part about DIY, if you don't like something you can change it.

Andrew