Thursday, 4 July 2019

1981 Inventions DRV

PedalPCB's schematic, info and pcb available here.
This is a buffered effect.
For true-bypass, leave out Sw 3 and connect the rest the usual way.


52 comments:

  1. Thanks for posting this one! I've been wondering what all the fuss is about with this pedal. Time to find out...

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  2. Wohoo nice! Adding this one to the build list...

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  3. To use max1044 or 7660s, Do I only need to omit the cut between 1 and 8?

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  4. Awesome. I've been hoping this one would drop!

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    1. I've gotta ask: why make a Vero when PedalPCB boards are so cheap? Not being critical, I've built my share of both and this site is a fantastic resource. but when I can get a PCB for $10, It's a no-brainer for me.

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    2. Veroboard are even cheaper! :D
      Of course we can buy PCBs for our pedals, but using veroboard or protobard layouts, I guess, make the work more "homemade". It's a part I love.
      And with veroboard I can modify easily the layout and add or cut some parts of the circuit. I did it more than once.
      This is my modest opinion.

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    3. I'm with you there. Simple mods I'll make on the PCB, if I can get one. When I want to get more ambitious with the mods, or build an original design, then it's Vero for sure.

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    4. I think most of the fun for me at least is making mods and making the circuit your own! That's what makes vero so great for me at least. That plus the exchange rate + shipping for me to Australia is horrendous haha

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  5. Does anyone know what general design this is based off of, if any?

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    1. Rat-inspired apparently.

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    2. Well, it's and hard clipping, and tone section yes, that is Rat inspired.

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    3. it doesn't have the same slew rate compensation that a RAT has, but the hard clipping and tone control are a lot like it, yeah.

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  6. I've just checked this against the schematic before building, and everything looks good, except for C9 in the schematic, which is written as 22n, but here is 2n2. Also if you're using a MAX1044 or ICL7660 you can just omit the cut between pins 1 and 8 of the LT1054. Thanks!

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    1. I guess you're right about the 22nF. Thanks!

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    2. No worries, I'll wire this one up in the coming days and hopefully we can verify it soon!

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    3. Well spotted! Used the wrong cap. That's been fixed

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  7. you can tag this one. i like it, but think the hype is maybe a little overkill. i'll put it on my board and play a couple hours and i'll know better then!

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  8. you can verify it. sounds pretty good

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  9. Hello I am quite new to this and don't recognize the CLR in the bottom right of the circuit, can you please tell me what that is.
    Thanks

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  10. Hi Steve. The CLR is a current-limiting resistor used to adjust the brightness of your LED. Too small and you'll go blind looking at your pedalboard, too large and you won't be able to tell that your pedal is "on". Depending on the efficiency of your LED, something like 3.3K to 10K should work, but you should try it on a breadboard before soldering the resistor.

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  11. Anyone else had a high pitched whine noise with this effect when switched on? The overdrive itself works, but there's a very high squeal when not playing. Only difference was use of a max1044 (left the cut out between pins 1 and 8) to above. The noise stops when in bypass. This is before I have boxed it using a test box on a 3pdt switch (left the switch 3 connection off too). Any help would be much appreciated. Thanks, Ian.

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    1. hey Ian, Make sure you've got the 'S' variety e.g. 1044scpa or others, as the chips without the 'S' will emit a high pitched noise, as you've described.

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  12. Thanks for that, think that will be my issue, much appreciated.

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  13. if you compare with this scheme there are differences in the operational pins:
    https://effectslayouts.blogspot.com/search?q=1981

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  14. Would the switch 3 on the board be the output if rewiring for true bypass?

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  15. Hey, I am trying to learn a lot, and I'd be stupid to say I'm not scared to ask the basic low-knowledge questions, but:

    I understand the difference between eletrolytic capacitors and the other ones, but, what is the difference between the capacitors with the boxes, and the ones that look round? I am assuming they are made of different materials. My best guess is that some are film and others are not, but, if anyone could help, I am trying to source parts for the first time and really don't want to order the wrong components, as money is tight. I am ordering through Tayda, as they have been very reliable for me with other projects

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  16. The effect works very well! Thank you for posting it!

    But ...
    I'm having a high pitch when there's nothing conncected to the input jack and the effect is even on ON or OFF. That sound appears when the Drive and the Volume are at 12 o'clock and it goes up if I push the volume. So the more Volume I go more "high freq" noise I got.

    If I try to connect the guitar (on the input jack) then the noise dissapears even the effect is ON or OFF.

    I'm using a 7660S IC.

    Any suggestions?

    Cheers,
    Jaime

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    Replies
    1. Maybe linking the input jack to ground while nothing is connected.

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    2. Seems normal - mine is the same with LT1054. Its probably the buffered bypass and bleeding noise into the output.

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  17. Hi, thanks for this layout. I have built it, sounds cool!

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    1. [img]https://scontent.flhr4-1.fna.fbcdn.net/v/t1.0-9/70978473_10156258610375870_737583229187391488_n.jpg?_nc_cat=101&_nc_oc=AQmLV0N1zL2kSu4fPCcf4QhrFtsAvSmmibQ00EoXIdq75LeYVZ9d15hwZFqiYDhTHBw&_nc_ht=scontent.flhr4-1.fna&oh=d88d9e4b33e3eecda82fd02b220c9568&oe=5E36D82F[/img]

      [img]https://scontent.flhr4-1.fna.fbcdn.net/v/t1.0-9/69878693_10156258610410870_7961117213400760320_n.jpg?_nc_cat=101&_nc_oc=AQnGBJzRtzxvU9II8S8AU0pMa_NoS6zbd1d3c1URpTXEp7DphUdEt5F8w4lmyKN9tuQ&_nc_ht=scontent.flhr4-1.fna&oh=db36357771410edacf508754cd6f9981&oe=5E01E7F1[/img]

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    2. I can't open your links...

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  18. Is anyone else getting this warning message when they try to access the forums section? I'm using Chrome browser.

    "This server could not prove that it is guitar-fx-layouts.42897.x6.nabble.com; its security certificate is from asciidoctor-discussion.49171.x6.nabble.com. This may be caused by a misconfiguration or an attacker intercepting your connection."

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  19. Where is the OUT on the board if I'm doing it true-bypass? Tried it at Sw 3, but didn't work.

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  20. What is going on with all the spam atm?

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    Replies
    1. Some f'd up flood. I'm cleaning it up as we speak... These come from time to time.
      +m

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    2. Seems the amount of it isn't slowing as i hoped. Did some cleanup and reporting of the user accounts today. Hope i'll find the time to keep the comments clean in the future too.
      +m

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    3. Yes it's gone mad, just found a load more. I'll try to check every couple of days to clean up

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    4. Sorry chaps, meant to reply and say I definitely wasn't having a go, just an observation! You all do such a fantastic job with this site, must be a nightmare to keep on top of. Happy new year by the way!

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  21. This comment has been removed by the author.

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  22. I have a short question: Is this vero powered with 18V like the original, or do I have to stick with 9V?

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    1. With a 1054 chip, you feed it 9V and it gives 18V on the output. So your pedal runs at 18V internally while being powered by a 9V power supply.

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    2. Nice, thank you! And especially for this very quick reply. :-)

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  23. First of all, I just want to thank you for all your effort of putting this up. Thanks!

    The effect works very well at first try. The only thing I find curious is that the DRV Pot isn't doing/changing very much. VOL & CUT are fine and fun to play with. Is this normal or could this be a wiring problem?

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    1. I have an issue where my cut isn't really working. Only suggestion I have is to retrace and track the lines of not check the pot is okay, this is my plan

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  24. Curious issue with this one. Signal passes through clean when the effect is off... and clean when its on. When on, the filter pot still works and the DRV and vol pots change the volume, but the signal is clean and at unity with them both on max. Any ideas on where best to test voltages, etc? If anyone has expected reading from a working one that would be great.

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    1. Got it working (the 22n on pin 1 of IC2 wasn't connected well), however, the charge pump definitely isn't doing its job. All readings indicate a 9V power supply. Tried a second pump, same result. Tried removing the pump entirely, and it still works and sounds the same without it!

      As far as I can tell the vero layout matches the schematic and the schematic matches the required arrangement for a positive doubler as specified in the LT1065 datasheet... so I'm left scratching my head on what's gone wrong with my build.

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    2. Another cap connection broken by a cracked strip. The cheap stripboard on ebay is not worth the hassle :(

      Now we're cooking with 20V. At 7-9V the low end was a bit rubbery, but at 18-20V everything sounds a bit more high fidelity.

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