Sunday, 17 April 2011

Skreddy Mayo

I've done a few Skreddy layouts, but to be fair to the man here's one of his discontinued effects to start off with.  If you want to build an authentic one using the original transistors you'll need to find some high gain 2N5133s to use.  You do find them on eBay but the last seller I questioned said the hfe was about half what you really need for a good muff and he was charging a fortune, so buyers beware of eBay mojo.

If you're not bothered about the transistors, just use 2N5088s or 5089s and enjoy! :o)


  1. how close to the pumpkins sound does this go dyou reckon? Is it based on any particular muff variant?

  2. I've no idea about the Pumpkins mate, I'm definitely the wrong person to advise on that although I've seen it described as Smashing-Pumpkins-in-a-box on one of the testimonials on the Skreddy site. I believe it's based on the triangle, and you can find a few sample vids here:

  3. is the DPDT an ON-ON-ON or ON-OFF-ON.
    Also, how are you wiring the switch? does each terminal connect on each side of the 4n7 and 10n caps?(sorry, im still catching on)

  4. The switch will be an on/off/on because it's simply choosing between two caps or neither. If you imagine the switch lugs being like this:

    1 _ 4
    2 _ 5
    3 _ 6

    with the first pole being 1,2 and 3 (2 is the common) and the second pole being 4,5 and 6 (5 as the common).

    The the first cap is soldered in between 1 and 4, the second cap is soldered between 3 and 6.

  5. thanks for the info man! I just ordered these parts, im excited to build this one.

  6. Ok I have one more question... I have already build the circuit, so what I need to know now is how do I wire in the sustain, volume, and tone?

    Am I wiring like...sustain 1 to terminal 1... sus 2 to term 2... etc? I just want to be sure?
    If this is right, am I just leaving the middle terminal blank on the volume?

    thanks for the help and putting up with my ignorance!

  7. Yes, sustain 1 would be soldered to lug 1 of the sustain pot, as per this lug numbering:

    Volume 2 will go to the stomp switch and is the circuits main output (after attenuation by the volume pot).

    Let me know how you get on.

  8. Ok so I wired everything up and Im not getting a signal. I checked my solder connections, checked in/out lines, knob wiring, layout placement, cuts and links, diode orientation... Im stumped on this one. Is there a way to fix this? I did this on perf board instead of vero but that shouldnt matter as long as I connected the leads, right?

    any suggestions?

  9. Can you post a high res front and back pic, or email them to turretboard at hotmail dot co dot uk and I'll see if anything jumps out at me.


  11. there is one more thing... just to be sure...

    I am running tone3 to the on-off-on switch, then running a wire from the switch to the tone pot. is that proper?

  12. I'll see if anything is obvious in the pics, but one of the switches commons (centre lug) goes to Tone 3 as you say, the other goes to the collector of Q3, marked Sw1 in the layout. So yes if you've just daisy chained one side of the switch and Tone 3 that is fine.

  13. I know ive done the layout properly, if you can find something, let me know. Ive checked it almost 50 times. Was the schematic confirmed that you got it from?

    Im not ruling out its something I didnt do though, but im pretty sure Ive got everything. :/

  14. Hey mark, sent you a pm over at FSB when you get 5 mins. Thanks so much.

  15. this is a beautiful effect, I built one using this layout so it's verified. My favorite of a few transistor swaps was the phillips BC550C. the flat resistors really makes this look nice when it's all built up. I posted more comments on freestompboxes

  16. Just finished this build and it sounds great! Much "tighter" tonal feel than the russian muff I just built, and great sustain and compression. I love the three way mid switch!

    One side note: I used 5088s and had to reverse the top left transistor...any idea why?

    Mark, I read your blog every day and have built several effects from your layouts. I am excited to see that you have been really active with the postings lately and can't wait to build some more. Thanks!

  17. Thanks for your comments Kellet and I'm glad you're so happy with your build. I have absolutely no idea why your last transistor needs reversing, and am quite surprised by that. The layout definitely requires E-B-C top to bottom so I'm flummoxed why that would happen unless the manufacturer somehow managed to ship out transistors with the case on upside down?! Very weird indeed. I must admit I do prefer my 3 way mid switch to the one you normally find. I don't often use a scooped muff setting but it's nice to have the option as well as flat and boosted mids. Covers more bases that way.

    I have been quite active recently. I had quite a quiet year last year and decided I wanted to get into this again to get my brain working a bit. Some people do sudoku, I like doing vero layouts! :o)

    If you've built any which aren't currently being shown as verified then please let me know which ones and I'll update the tags. Cheers.

  18. I love your site!

    I do have a question on this layout. What do the red thick horizontal lines represent? Sorry for noob question, but I haven't come across it before. Thanks!

    1. It's something that I do as a guide when I'm putting together the layouts and usually delete after I've finished, but didn't for some reason with this one. It's just a guide for me to show clearly where the 9V rail is so when I need to make any connections to it, I don't have to look very hard to work it out, which helps speed things up and also helps avoid misplaced connections. I do similar lines to show the ground and half-voltage rails as well with some opamp circuits.

      So you can just ignore it! :o)

  19. Here is where I am at with this project. This has been a fun one and its only my second pedal. I think I am hooked on this.

    1. Great job Cody. Nothing better than a build with some big ass caps! :o)

    2. Great! Where did you get the 5133's?

    3. I got them from a vintage pedal pull from eBay.

  20. I seem to be having a problem with this one.. I have been troubleshooting it for 2 days and can't seem to get it to work. Im sure its something dumb on my part. I have check for shorts and also recheck the layout to make sure all cuts were correct and part placement was correct. I also soldered the SW1 directly to the Tone 3 pot since I did not want the switch in the equation yet. Could that be an issue?

    Here is the voltages from my transistors.

    Transistors are 5133's




    Does this look normal?

    Im really new to this. I come from a game console modder so I know basics of soldiering but I have no idea how to use a multimeter correctly.

    1. The Sw1 wire shouldn't be soldered to Tone 3. That switch is used to put a cap in parallel with the 4n7 but tying it directly to Tone 3 creates a connection between the tone pot and the collector of Q3 which you don't want. If you don't want to use the switch just ignore the Sw1 wire completely.

    2. Thanks I sniped the SW1 to Tone 3 and I still do not get signal through the pedal. I can hear the volume pot "turning up", I mean I can here low noise getting louder, if that makes sense. I can hear the Tone pot working by the cut of highs I hear on the "noise" previously explained. But still no guitar sound. Any other hints? Did the voltages look ok on the transistors? Sorry for the dumb questions, this is just a pedal I really wanted to make so bad. Thanks

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  22. Modern production 2N5133 produce hiss and they are expensive. I use 2N2484. Electricaly similar, with a hair more gain.