This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Thursday, November 21, 2019

Revv G4

This one was actually pretty easy to knock out after doing the G3. Slightly simpler and with less clipping than the G3, it's got loads of gain on tap. This also has the same pot layout as the the G3, so just use that drill template.



55 comments:

  1. Fantástico! Obrigado por seu trabalho e paciência você e o melhor!

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  2. You can build the G2 on the G4 board. Change the following C3 47p, C11 120p, C13 120p, C21 10n, C26 47p; R13 82K, R14 22K, R18 22K, R29 22K, R31 15K, R31 jumper. Double check the schematic on the forum but this is what I had written down.

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    1. That info is verified?You have the schematic of g2?

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  3. Quick question about the caps just below the voltage and ground inputs
    Are they 100nf or 100pf?
    Only ask because they are coloured as ceramics ?

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    1. I'm seeing 100nf on the Sanguine schematic. He may have drawn them in as multilayer ceramic 100nf for the sake of using small caps in a tight space.

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    2. Those caps are for power filtering and I've read a few places that ceramic is better for this application than film. Hence the ceramic package instead of the film. And yes they're supposed to be 100nF.

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    3. Thanks for the info, D... Good to know.

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  4. Verified. Now enjoying the difference b/w G3 and this one. Can't decide which one my favorite is. I like both.
    Again thank you very much for sharing!!

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  5. Hi.
    If I don't have all the values ​​of the "green" capacitors, what material would be better to replace them? Polypropylene would be effective, or is better ceramic.

    I'm new to this, sorry for the inconvenience. Thank you

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    1. A lot of people will choose film or polypropylene over ceramic because it is generally believed that they are better quality when used in the signal path.

      Other times I choose based on what might fit best in the layout. Poly caps in higher values can often be too large to fit well in a pedal.

      Sometimes it just comes down to what you have available (or how much you want to spend).

      Here is some good, basic info that might help you out:

      http://www.byocelectronics.com/capcodes.pdf

      Otherwise, doing a Google search on this subject will bring up tons of chat threads and you can dig through all sorts of opinions and ideas. It can become a mind-boggling discussion topic.

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    2. No problem! Here's another good link with lots of basic info for beginners:

      http://www.generalguitargadgets.com/how-to-build-it/technical-help/

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  7. I can't buy 5517 anywhere. Can I use 5817 ??

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    1. It's supposed to be a 5817. 5517 is a typo

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    2. Well, first things first... Thanks for all your effort on bringing us those amazing layouts. Really really appreciated!

      On that note, would the 5819 diode do the trick?

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  8. hello, first of all, this circuit is confirmed it works like a bomb... but i have a question... the 2 leds should light up when playing? because they're not lighting at all, thanks

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    1. yes, they light up, i was just dumb and solder one the wrong way, it's fixed now and has more gain.. just smashing!

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  9. Hi, where did you get the schematic? I have a Revv G4 on my hands now. I opened it but it seems to have some more parts than in the layout, like a capacitor, transistor and a coupple of resistors going from volume's pin 2. Plus this one have 3 units of tl072 instead. Thanks!

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    1. Hi Fabian
      I think TL074 just has two TL072 in one chip. So in total there should be (and actually are) 3 TL072 in the circuit.

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    2. Fabian, do you have internal pictures of your unit?

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    3. I've been wondering this as well! I have the revv pedals and also built the pedalpcb clones of all 3. The originals sound much clearer while the clones just sound kind of stale in comparison. Recently noticed the q6 transistor on all of the revv boards at volume pin 2 that isnt on any of the clone schematics but cant find any info on this

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  10. Also, is the diode a 5817? I can't find 5517... Thanks!

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  11. Hi.
    I have questions regarding the DPDT switch. According to the scheme, pins 4 and 6 connect to the same pad? According to a diagram that I have seen on the web, pin 4 would connect with the 82k resistor and pin 6 should remain without connecting to anything. How are you doing those who work the pedal? Thank you all!!

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    1. Hello, did you find a answer for pin 4 and 6 fo AG SW?

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    2. It's a DPDT switch with a centre off position, so effectively a 3-way. If you use the correct type of switch and wire it as per the diagram it should work fine.
      I don't see the point in having 3 settings so I just used a regular DPDT and wired to be Ag off or Ag red.

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  13. Hi,
    Is this 100% verified to be the same as Revv's own circuit?

    I ask because I built this circuit on a breadboard and found the mid switch position to have rather low gain/distortion. I have gone through the circuit with a scope and confirmed that each stage is working correctly (I'm not an electronics noob, BTW :)

    A couple of notes/observations:
    1. Swapping out the LEDs for 1N4148s helps to achieve the distortion levels I am hearing in the demos.
    2. With LEDs fitted, there is a absolute TON of volume increase through the pedal. This makes me wonder if the final Op-amp stage has too much gain (x47).
    3. With the bass turned up, high notes can sound flubby/gated. I need to check with the scope, but I think this is due to point 2 above and the amount of low frequency content hitting the output stage.

    Admittedly, as I'm using a strat plus through it, I can't expect anywhere near the kind of gain that Ola achieves in the video. Thats said, Rabea's demo with a strat seems to have plenty of distortion on tap!

    Cheers....the experimentation continues.....

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    1. Did you find a solution to the topic 3? I tried some capacitors change and replaced the 4.7uF capacitor. I used 22nF instead. Can you share if tried something more that worked?

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  14. From what I can tell, there is a lot of low frequency content hitting the output op-amp causing it to overload. Try swapping the 470k for something lower like a 220k or even 100k and see how it goes.
    There will be less output level by doing this, but it's a ridiculously high output pedal so you should be fine!

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    2. I tried all of your suggestions and it still doesn't work as I expected.
      After some ideas, I finally found the solution - feed the circuit with more than 9v.
      The 4.7uf was replaced by 22nF capacitor and the result is good enough to reduce 80% of that strange effect on tone.
      12v already eliminate the problem and now I'm planning to attach a voltage doubler inside the pedal to reach 15 or 18v.

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  15. FYI, I built this using a PCB from a seller name dfx_parts on ebay in the UK.

    It's a nicely made, inexpensive and I haven't had any problems such as noise or oscillation.

    imgur.com/a/uxmGarC

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  17. i have built the schematic as in the picture, with the appropriate components, but there is no sound? can anyone help?

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  18. Just built one as my first pedal. it sounds amazing.I Replaced leds with 1n4148. With leds it sounded a little scooped.

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    1. could make a little diode switch to see how that helps... thanks for the idea !

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  19. Hi! I build this pedal and all work fine, but only the gain pot does not work and the pedal sound clean with little crunch. I check many times all the circut and the gain pot wire, but everything is in the right place. I also tried to replace the pot and nothing change. Can someone help me?

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    1. Update: I tried to re-solder all the gain pot connections with new cables and to change the leds with 1n4148, but the situation is always the same, help!

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  20. What types of capacitors are those(the green ones)?

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  21. build this, like howling beast everything works fine, except it's heavy gated, like a note crushed when sustain.
    I'd read a topic about this on FSB, and tried swap the 1M with 1k resistor for better mid-range suggest, it does more loud but do nothing for the gate problem..
    next try to aim for the feedback loop maybe, I'm not sure..
    anyone had a same problem or solution please?
    Thanks for the layout, it so nice and neat..

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  22. Guys tolong saya!! Led cliping tidak dapat menyala,sudah saya solder kembali tapi tetap tidak dapat menyala, tapi jika di test dengan multitester led menyala. Fx yg saya buat berfungsi normal, hanya led yang tidakmau menyala ,ada yg dapat membantu? ?

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  23. Amazing! But don't connect terminals 4 and 6 of the DPDT switch, as it results in a short circuit.

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  24. Hi! Main picture with mistake: 2 pcs yellow cup (on the top) must be 100pf, instead 100nf pls be noted.

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