Valvecaster - Tube Overdrive / Boost Pedal


While I know we've posted this previously, I found this layout to be one of the more useful ones. Look into our archives / previous posts for more Valvecaster layouts. Power source I was getting better results with 12v 1A, see Garth's 24v version below.  -K

Another idea is to incorporate a boost of your own choice (i prefer the alembic stratoblaster) and hook that up before C1 .  This gives the pedal an extra boost to the circuit so it distorts more.  I would use separate pots for this, not a dual pot. 

 WIRING DIAGRAM w/ LED  & True Bypass Footswitch

GARTH's VALVECASTER w/ MODS @ 24V
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20 comments:

  1. AnonymousAugust 30, 2019 at 4:23 PM

    is the blue thing in the third schematic the foot switch?
    I know nothing about this

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    1. Kyle O'HareAugust 30, 2019 at 4:25 PM

      Yes, the blue box with wires represented by colors is a 3PDT (three pole double terminal) stomp switch (on/off, latching)

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  2. AnonymousAugust 30, 2019 at 4:27 PM

    thank you

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    1. Kyle O'HareAugust 30, 2019 at 4:28 PM

      no problemo, also see "switch / effect wiring" under the quick links for more info

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  3. AnonymousOctober 20, 2019 at 3:39 PM

    Is it ok to use a different value potentiometer?
    if so what value would it have to be?

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    1. Kyle O'HareOctober 20, 2019 at 3:48 PM

      You can always try different values, but a couple of 100k (audio) is pretty common, and 50K B (Linear) is also pretty common. I've tried different values for the gain pot, with varied results ; The 50k Gain pot is the tube cathode resistor on the first stage. Cathode resistance (@10k) is only likely to give low gain, and eliminate much of the tube overdrive effect. A 1M gain pot allows for a lot more gain, and you can always find that 50k sweet spot by simply turning the gain pot down.

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    2. Kyle O'HareOctober 20, 2019 at 3:53 PM

      Also see: http://cdn.instructables.com/ORIG/FXM/9B6H/IK1FLK5B/FXM9B6HIK1FLK5B.pdf

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    3. AnonymousOctober 20, 2019 at 4:03 PM

      Where is the best place to get these parts?

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    4. Kyle O'HareOctober 20, 2019 at 4:06 PM

      Well, I would suggest Small Bear and Tayda electronics (the later being often your cheapest option) but those are just suggestions. You can also shop with mouser, antique electronics supply, etc...

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  4. AnonymousOctober 20, 2019 at 3:58 PM

    thanks

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  5. AnonymousOctober 20, 2019 at 4:24 PM

    lots of them just say K after the number. not KA or KB. on the schematic it specified the KA and KB. does that matter?

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  6. UnknownApril 13, 2020 at 3:40 PM

    Is it possible to wire a dpdt switch to this instead. I'm planning on building this without an led. If so, could you shed some light on how to wire that switch? Thanks for anything you can tell me.

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  7. plamssMay 12, 2020 at 11:49 PM

    Excellent!

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  8. UnknownJuly 5, 2020 at 11:03 AM

    In the first layout, is the jumper from volume lug 3 and c3 supposed to be wired to lug 1 of tone pot?

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  9. Fretty krugerAugust 25, 2020 at 9:17 AM

    Noob question: does it matter/what should the capacitor voltages be,

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    1. Kyle O'HareAugust 25, 2020 at 5:35 PM

      Yes it matters, I usually go for higher rated voltage caps (20v) if running a 12v power supply but it's overkill ;technically you could use anything over 12v of voltage rating and it will be fine. I just like to think it makes sense, longevity wise.

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    2. Fretty KrugerAugust 25, 2020 at 9:22 PM

      Awesome thanks! For 12v (opposed to the 9v schematic), I reckon the component values change?

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    3. Kyle O'HareAugust 26, 2020 at 6:54 AM

      Nope, not really just the voltage rating... I ran mine at 12V 1A , and 12V 1.5a, and to my ear it sounded better than 9v.

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  10. JhonsJune 1, 2021 at 2:11 AM

    Amazing "caster" sound..

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