Saturday, 26 September 2015

Keeley Oxblood

Info about the original:
The Keeley Oxblood Overdrive is our response to everyone kloning pedals.
We wanted to build a new circuit that let players blend from perfectly clean to amp-crushing roar.
We wanted that impossibly huge and focused midrange that makes any guitar… Strat, Paul, Tele, sound incredible.  We knew we could do it our way and offer you more tone.
So we designed this pedal over the course of a few days to outdo the klones.

With the Keeley Oxblood Overdrive you roll off the Drive Control down and get a perfectly clean sound, you can dial in any amount of distortion and volume to stomp an amp into pure tonal nirvana.  The Keeley Oxblood Overdrive offers you two ways to clip and saturate your signal with overtones by selecting carefully chosen diodes.  Magical and Mythical, Monstrous and Most Satisfying they are indeed.



  1. Wow awesome! I am definitely taking a shot at this one this week!

  2. This is pure gold, thank you!

  3. Thank you so much! If you could post the BOM on this one, it would help a lot.

  4. How do you make your electrolytic capacitors look like that?

  5. I use DIY Layout V.2 with Mark's updated library.
    Regarding the BOM, I won't be able to post it cause I must have misplaced some of the original files by moving them from one computer to another.
    I'll do it as soon as I find them.

    1. Hi Alex, can you tell me where can I download the DIY Layout V.2 and the Mark's updated library so I can try to collaborate with some vero's for the blog? :D

  6. would this fit into a a 125 box ?

    1. Definitely, it could even fit into a 1590b with careful measuring (and no battery).

  7. You can find V.2 here:

    I've downloaded Mark's library here:

  8. Hello,
    As I cannot get hold of any MAX1044, may I use a ICL7660CPAZ instead and if so, without any change in the vero?
    Thanks in advance for your support.

    1. First of all - thank you Alex for this awesome layout. @Frederic - ICL7660 should work as a voltage doubler, but may cause high pitched whine. I've built oxblood yesterday using 7660 and the whine appeared. Today I ordered MAX1044 and i'll let you know if it helped :) Sorry for my poor english :)

    2. Hi Macko, against all odds, I built this pedal with an ICL7660S (I insist on the version S). The pedal works. It began whistling when cranked all the way up the same way my other high gain pedals did. I then soldered shielded cable from the input jack chassis to the vero. It drastically reduces this flaw. Apart from that, I have the feeling my pedal doesn't actually sound like the genuine Robert Keeley's Oxblood recorded on uTube. Life seems so hard sometimes!

    3. What did you use for Q1 (Hfe?) and Schottky? Did you experiment?
      Robert Keeley has posted the schematic but didn't mention the final diodes he used.

    4. Today I recieved MAX and the whine is still there. I have the same problem as Frederic. The higher the gain the higher the volume of the whine. It also turns up when I switch to normal diodes or add more treble. For Q1 i've used BC550C(about 450 Hfe) and a 2SK117 for fet. My Shottkys are BAT41. Any thoughts? BTW, Alex, have you built it?

    5. @Frederic - one more question. How does your whistle sounded? Was it about 4.5 kHz frequency changing slightly with turning of volume knob and switching phat switch? I'm just asking, cause maybe it's me, who screwed up something :)

    6. Haven't built it but Hozy31 did in the Forum section.
      He used a J201 (original JFet), a 2n5089 for Q1 (Hfe must be higher than 500) and BAT85s for D4 & D5.
      He didn't mention any whining in his circuit.

    7. You MUST use the 7660S - ENSURE that there is an S because that denotes the frequency boost which will put the whine out of an audible range.

    8. @Alex,
      I swapped the J201 for one 2N5457 without any noticeable difference. AS far as Q1 is concerned, I couldn't get hold of any MMBT6429. Complying with Mark's advice, I bought one NPN BJT delivering 500Hfe, more specifically BC549C. I also swapped it for one MPSA14 (Hfe 20,000) to check out. It didn't alter the sound, not drastically in any case. And as for D4 and D5, I soldered BAT41s. They sound darker than the 1N4148s in D2 and D3.

  9. Hello Macko, after enquiring, there's no difference between ICL7660S and MAX1044 in our case. You can use one or the other. Its purpose in the Oxblood pedal is not to double the voltage but to invert it into negative. It has then no link with any whining, whistling, microphonic problem. You have to use shielded components from the input to the veroboard, more specifically one shielded 6.35 mm jack chassis socket and shielded wires from the input chassis to the 3PDT stompswitch and from the 3PDT stompswitch to the stripboard. This is mandatory for reducing, killing this whistling when all the pots are all the way up.

    1. So, when you shielded your build, was the whine gone?

  10. @Macko, Hi, shielded wires erased the whistling when this pedal is alone on my board. Putting my pedals side by side may sometimes bing it back. This is due to the well known radiation stemming from the veroboard we've been using in our builds. Indeed, PCBs would annihilate any whistling. That's the real difference between us cloning pedals and the original pedals IMO!

    1. Thanks for info, Frederic :) I think that that's the price we have to pay for pedals 10x cheaper than original :) Maybe some day i'll switch to PCB but for now it isn't worth the time and effort it needs. May our pedals be noiseless and our soldier irons hot! ;)

  11. Hi, for those who would need the voltages. Here are mine. I also tried with a couple of TL072 and they are nearly the same. One thing though on this pedal: the phat toggle switch doesn't drastically alter the sound. This is a bit disappointing.

    IC1 NE5532
    4,50v 9,01v
    4,50v 4,50v
    4,49v 4,50v
    0,00v 4,50v

    IC2 NE5532
    0,00v 9,02v
    0,00v 0,02v
    0,00v 0,00v
    -8,70v 0,00v

    IC3 ICL7660S
    9,02v 9,02v
    4,53v 6,93v
    0,00v 4,60v
    -4,28v -8,70v

    Q02 J201
    G 4,08v
    S 4,45v
    D 9,02v

    Q01 BC549C
    E 3,61v
    B 4,01v
    C 9,02v

  12. And here's the BOM:

    1µ E*1


    8pin IC socket*3
    MAX1044 <=> ICL7660S*1


    BC549C <=> MMBT6429*1

  13. This thing sounds awesome! He's super clean to super dirty! Awesome pedal!

  14. One advice for those who'd find this pedal too honky & bassy. Replace the 100n cap located at the fifth lug of the upper IC NE5532 by a much lower value like 4n7 or 3n3 or even 2n2. This will deliver a clearer signal.

  15. Just built this thing last night... man its loud! Almost too loud as I can barely use the volume without is blowing out my ears. I used 1N456 and Bat41s for my diodes and a 15n cap at C1. I think it sounds great. Can't wait to play it at practice and see if it holds up and a real band situation.

  16. Fredrick, great tip. I was a bit disappointed how muddy this was actually sounding when I played it in my band. I expected it to cut through the mix more. I changed this out and went to 33n. Any lower and it would just squeal at high gain settings. Really brightened the pedal up nicely. Thanks for this.

  17. Hi All,
    I have a bit of a problem with my build of this unit, as Ralf say's it is very, very loud! But no matter how loud I have it or how far the drive is turned up, I can't get it to distort. Have used 1N4148 in D2, D3 and BAT41 in D4, D5.
    I have been over and over the board with magnifying glass and usb microscope and have rectified any mistakes but still no distortion.
    I must have done something wrong as my voltages don't quite match those of Frederic. Can anyone point me in the right direction please?
    Voltages below:

    IC1 (5532)
    4.53v 9.15v
    4.53v 4.53v
    4.52v 4.53v
    0.00v 4.53v

    IC2 (5532)
    0.003v 9.15v
    0.001v 0.21v
    0.00v 0.00v
    -8.93v 0.00v

    IC3 (ICL7660S)
    9.15v 9.15v
    4.54v 6.03v
    0,00v 5,18v
    -4.47v -8.93v

    Q1 (BC549C)
    E 1.262v
    B 1.779v
    C 9.15v

    Q2 (J201)
    G 4.12v
    S 4.79v
    D 9.15v

  18. This is gold, thank you so much for sharing! I'm glad I found this after reading this review and I can't wait to get started on this build. Thanks!

  19. build this and it's too loud...i can't really understand why this has the transistor after volume control.. it sounds fantastic in the first 5% of the volume but after that it gets really loud and starts squeaking
    any ideas?

    1. That transistor after volume control is a buffer. Similar to tubescreamer and others. It's there to keep the output impedance constant, not to add volume.

      You could try logarithmic 100K pot for volume. That may give you more lower volume sweep on the turn. And in many cases, the squeeling goes away once the circuit is boxed, as that gives proper grounded shield around it.

    2. thanks mate.
      actually it's boxed...
      also..the thing that got me confused is the reference to VR of volume pin1, while in original klon it goes to ground...that's why i asked about the transistor. i didn't know if it needed that VR reference to work.
      anyways..tomorrow i'll get a logarithmic pot and report back.

  20. Any chance for a better resolution vero scheme?