Sunday, 22 April 2012

Catalinbread Heliotrope

Info from Catalinbread about the original:

What do you call an effect that isn’t quite a Bit Crusher, or an Octave, or a Harmonizer, or a Ring Modulator, or a Lo-Fi dirt box/fuzz – but a bit of a blend of each?

Yeah – we don’t know either, so we came up with “Harmonic Pixelator”.

The Heliotrope is an "analog bit crusher" of sorts. Since there is no analog to digital conversion happening it isn't a true bit crusher, hence the name "Harmonic Pixelator". It works with guitar, bass, keyboards, etc. We designed the pedal to be intuitive and easy to use even though what it is capable of sonically is actually quite complex and varied.
         
The Heliotrope can be powered from a 9v-18v adapter or a 9v battery. At 18v you’ll notice more output volume and headroom is available.

The controls work like this:

Your instrument of choice (aka: Program Frequency) feeds the Heliotrope an input signal. From it is subtracted the Carrier Frequency. The Carrier Frequency is set by the Hi/Lo switch and the Sample Rate knob.

These are the rough ranges of the frequencies governed by the Hi/Lo switch:
Hi: 1.44kHz - 6.66kHz
Lo: 333Hz - 1.58kHz

So if the Carrier Frequency is tuned using the Hi/Lo switch and the Sample Rate knob to around 440Hz and you play a high E string at around 320Hz the output is roughly 110Hz or an A String. With a little thinking you can break down all these intervals and harmonize with the pedal - or you can just have fun and set it to an interesting resonant sound and see where it takes you.

The Resolution control determines the duty cycle or the ratio of on to off time of the Carrier Frequency. The effect of this control is somewhat like focusing the lens on a camera, you can make it as sharp or as blurry as you’d like.

Volume makes it go loud.

Gain distorts and compresses the signal. You can get a decent amount of grit and fuzz out of it for more squarewave synthy type stuff.

Enough math – let’s rock this thing!






65 comments:

  1. The SPDT will be on-off-on? thought I'd make sure before I buy a handful.

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    1. 2 position, the centre is the common

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  2. Absolutely Gutted..It took me effing ages and nothing :0( lol. All I get is a VERY low sounding 'whine' that changes pitch with the res and gain...

    The only thing I'm not certian of is my grounding so thought I'd ask where you would ground it using skreddy method before I bin it.

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    1. Have you connected both ground points on the board?

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    2. Yes, I ground mine like your off board wiring. I took each ground from the board to each of the in/out jacks..I have tried grouping them all together into one place. I've tried placing them all in random ground places with no luck.

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    3. Post a front and back pic mate, and just check with your multimeter that you're getting continuity between all ground points. Don't bin it!

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    4. I haven't soldered the grounds as I wasn't positive where to send them but here's a couple of pics anyway,

      Back; http://imageshack.us/f/99/dsc001383.jpg/

      Front; http://imageshack.us/f/225/dsc001374.jpg/

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    5. Well that all looks good to me. So how are you connecting the grounds if it's not soldered yet?

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    6. I'm bending the wires and clamping them tight with pliers. The best I can explain my grounding is show you... please excuse my laughable diagram

      I have moved the grounding wires around but I get the same results. My multi meter 'beeps' between grounding points?

      http://imageshack.us/f/822/grounding.jpg/

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    7. That looks ok, but it is relying on the input and output sockets both making a good ground connection by just touching the box. That CAN be ok, but if one of the connections isn't great or intermittent, then it can cause noise. Just take a wire from the input to output sleeves, then you know that connection is solid. I'll go over the layout again just to make sure it is right.

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    8. I thought that and ran a wire between jacks, no change. I don't think I can cram it into the box anyway lol... tried different IC's etc... I'll try and squeeze the pots for a Distorus in there :)

      Nevermind. hopefully someone else will have better luck.

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    9. Don't bin it! I've found a mistake mate and a couple of things will need moving but it's not a biggy.

      1) Swap the positions of the 2K and D2
      2) The top connection of the left hand link needs dropping a row.
      3) Add that 1M resistor between 1C1 pin 3 and the 7th row.

      That should do it and I've updated the layout.

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    10. I'm a man on the edge! haha..

      Nice one Mark.. I'll try and get that done later and report back. So glad I didn't start hacking at it with a screwdriver now :o)

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    11. Ok I've done that and it's exactly the same. Your layout must be ok now so it's probably my error or a fault somewhere... I'm not a 'debugger' so I'll pilfer parts from it..

      Thanks for your help though Mark ;o)

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    12. I've sent you an email Mark, Found another layout that uses a 1N4001? not sure if that makes any difference?

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    13. I always omit parallel protection diodes. Stupid things! :o)

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  3. Phew. There we go. Verified.

    I felt like i should build one more today, and this caught my eye as not yet verified. Took about 2 hours to finish.

    There is piercing oscillation on about 60% of the settings, which went mostly away by "knifing". Some of that oscillation has to be a feature of this circuit.

    Anyway. From VIC20 to literally massive harmonics and from clear silicon fuzz to untolerable racket - Heliotrope is all that... Once again, this is not a circuit for your base tone, but good thing to have.

    (I'm waiting for shipment of 3PDTs and all of my boxing is at halt until then...)
    +m

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    1. Star man! I wish I could spend my Sundays doing that but the kids, dog and missus won't let me :o)

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    2. It was a rare occasion that i had all day - well - i did cook for my missus and took 20km bike ride after finishing The HogBird..

      Anyway. I thought i'd add some evidence (my phone's camera is really crappy and i didn't feel like taking out the real camera):
      http://mirosol.kapsi.fi/varasto/boxes_other/heliotrope.jpeg

      And the testbox:
      http://mirosol.kapsi.fi/varasto/boxes_other/Testbox1.jpeg
      http://mirosol.kapsi.fi/varasto/boxes_other/Testbox2.jpeg

      At work, they were throwing some stuff away and this box was going too. I stripped some sort of RS232/RJ45 contents and added 5 part pcb mountable terminal - plus battery snap and two mono plugs. I have a small rubber mat to test the circuits on, but it's really easy with that box. Finally i can verify and test vero stuff without boxing everything. Not to mention, the debugging and fixing things is a lot easier if the circuit isn't in a box.

      The middle terminal is unused, but i was thinking that maybe i could add a probe to it... :)

      Huge thanks for material that is always painless to verify!
      +m

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    3. http://mirosol.kapsi.fi/varasto/boxes/helio.jpeg
      +m

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  4. Just re built this. The oscillation is not meant to be a normal part of the circuit. I've just been reading that a lot of people are getting the same whine on most of the settings. I tried it a long side an original yesterday and this is not reacting in the same way at all. In fact it's quite far from it..The controls on the original are VERY sensitive while this isn't. And there seems to be a much wider sweep to the original.

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    1. I'm wondering whether there's something wrong on the schematic if a lot of people have experienced the same thing.

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    2. Could well be mate, The sabro comments are saying the same whine and oscillation. While playing the original there is complete silence on all settings and it just seem much clearer with a wider sweep on the resolution and sample.

      I seem to be getting a bleed too into the bypass signal.. the whine/osc is very faint in the bypass too.. I've re soldered all ground etc.. faulty switch?

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    3. How have you wired the bypass? If you've used the method that grounds the input you shouldn't be getting bleed through.

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    4. I wire everything to the Skreddy system so it should all be as you say so that leaves me thinking it must be the switch?

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    5. Don't know about much, but mine has quite wide range on res/sample and oscillation comes in quiet on the background when gain is maxex.. So mine is working very close to original. It could still be some wrong value in the original schem...
      +m

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    6. Cool so you've a/b with an original?

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    7. No i haven't. It's just my best guess/gut feeling, based on comparison to Fuzzboxgirl's demo: http://www.youtube.com/watch?v=4Xdj--K4y4o

      It oscillates with high gain when she starts to fiddle with the controls - just like mine.

      Some other demos are crappy, as they demostrate just one setting.
      +m

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    8. Fuzzboxgirl ......... mmmmmm

      :o)

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    9. hmmm the original I borrowed didn't oscillate at all.

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    10. ^^ :D Next year i'll get a calendar for sure :P

      Could be with a) power source? b) low battery? c) guitar's mics? d) other?

      I've had some pedals oscillate with certain cheap wall warts. And for my succesful fuzz factory, it didn't oscillate nearly as much with cheap guitar with bad mics than with my Viper...

      Plus even some caps 5-10% feature variance could be the difference between osc and no osc.. Go figure...

      All i know for sure is that i like mine :)
      +m

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  5. Built this out of curiosity over the weekend - it works to a degree - i don't get any octave or crazy oscillation like you guys are saying, and the only differences in sounds I hear with mine are the high/low switch in action (change of frequency) and the gain pot - sample and resolution doesn't contribute anything noticable. If I was to not watch the demo and you told me I was building a smooth sounding fuzz with a high/low switch, I would have been happy with the result, because that's all I got from mine..

    I'll go back over my circuit from the layout and see i've i've missed anything - I did sub the 2n5457 with a mpf102 (that's the only sub) if anyone thinks that would make a significant difference..

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  6. Has anyone successful built this? I'm getting alot of background noise as well. Any ideas on how to remedy this?

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  7. Has anyone successful built this? I'm getting alot of background noise as well. Any ideas on how to remedy this?

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  8. Also have issues with whine bleed through when bypassed, if it's a noisy circuit that's not a problem for me because it's supposed to be kinda noisy :p but the bleed through is indeed a bummer... dunno how to solve it, tried with several power supplys now.

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    1. Do you get noise with a battery? And how did you wire the bypass? My offboard layout method would help, but the problem with circuits with an LFO is that even if you ground the input during bypass, the LFO is still cycling, and with an LFO is combined with a noisemaker pedal it is always a possibility. This even has two separate bias networks to keep the LFO IC as far removed from the gain IC as possible, God knows what it would be like with only one if it still suffers with 2. The only other thing I could suggest is maybe replace the lower 100u cap with something bigger, maybe 470u or even 1000u, and try also putting a lower value cap like 100n in parallel with it. Both those measures should help with noise but whether that is enough to cure the issue completely I don't know.

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    2. Never tried it with a battery, theres no space for it. But i know from the past that running on batterys can help sometimes.
      I always use your offboard wiring schematic. Although my ground maybe is faulty. I usually take a long wire and start at the DC jack, further to theoutput jack, to the three lugs on the switch and then to input and so on. This time I hade to take seperate ground wires to the board but i tend to use one cable only for all the ground connections. The bleed sounds more or less depending on the settings on the pedal, the flipswitch makes a huge differance on the two settings. Maybe i should try those caps couse changing the PSU didn't seem to help this time as it usually does. I got three diffrent ones that im always trying and some of them makes more noise then others in terms of whine, noise and ground noise.
      To me it's just wierd that it can even bleed through since the board shouldn't really be in the chain while not activated.

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    3. I think that the filtering mod may be the key. 470µ and 1n in parallel from supply to ground. That could tame it. Other (slightly harsh) "solution" would be to ground the output on the switch when the circuit is off.
      +m

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    4. so basically a power filter? 470uf electrolytic and a box/mylar type 1nf in paralell right over + and - at the dc jack?
      iv'e also read that grounding the input on the IC when it's bypassed could solve the problem but that means using a diffrent offboard wiring and i have no idea how to get an extra pole without omiting the LED.

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    5. Yes it's a power filter but not at the DC jack. The supply branches out on the board via 47R resistors to power the ICs separately and the cap that I suggest you increase is the one attached to the LFO IC to see if that reduces the clock noise. If no difference is noted then we'll have to look for another fix.

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    6. annoying that i glued the board in the box yesterday haha, took a chance and hoped it would work flawless right from the start, which it does besides the background noise. the effect is really cool although. love it!

      Here's some pics of it btw:
      https://dl.dropbox.com/u/2828668/reaperpedals/thepalehorse/box_front.jpg
      https://dl.dropbox.com/u/2828668/reaperpedals/thepalehorse/box_side.jpg
      https://dl.dropbox.com/u/2828668/reaperpedals/thepalehorse/circuit.jpg
      https://dl.dropbox.com/u/2828668/reaperpedals/thepalehorse/gutshot_box.jpg

      and as you can see i can't really make the wires shorter, i've read that somewhere as well that have as short wires as possible on the jacks could help.

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    7. Thanks for the pics mate. One other thing that has occurred to me when talking about a chorus pedal in another thread, is that you should a TL061 instead of the LM741 for the LFO. Low power ICs like that have been known to solve clicking problems in the past.

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    8. so iv'e been working on this, swapped IC for a TL061, it may be some difference but very slight, noise is still there. also changed that 100uf going to pin 6(?) at IC2 for a 470uf, didn't do much either. the issue must lay somewhere else. i can't understand how the signal can bleed through really. the whine changes when it's bypassed if you change settings on the knobs. iv'e read somewhere that grounding the input on the IC while the 3pdt is switched to off might help, but how would one do that?

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    9. Also been reading on those topics but no one seems to have made a fix for the issue as far as i can see.
      http://freestompboxes.org/viewtopic.php?f=7&t=4008
      http://circuitworkshop.com/forum/index.php?topic=802.0

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  9. the mystery is solved! i got rid of the whine that occurs in bypass.
    im always using Marks offboard wiring which you can find here.
    here's a modified version of it that you will need:
    https://dl.dropbox.com/u/2828668/reaperpedals/the%20pale%20horse/offboard_wiring_heliotrope.jpg
    so basically it's splitting the ground up and just take the lower lug to pin 2 at the LM741 IC to have it's input grounded while the effect is turned of.
    this way you can still have the LED. just tried it and it works flawlessly.
    /jimmie

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  10. and oh, btw, heres a sloppy demo
    http://www.youtube.com/watch?v=cj-fRvIOC2k&feature=youtu.be

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  11. just built this one. it kinda works but not like the original or rudeez demo above. I've checked everything 10 times, knifed the traces, run continuity tests all over it. anyone have some voltages on a working one?

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  12. well, it's working now and I have no idea why. the thing is, I don't like it at all so it'll never get boxed.

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  13. This thing is nuts...

    It is on my pedal board but I don't know if it will be a mainstay. I will use it a lot in a recording situation, but live sound may not be it's best use.

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    1. Okay I found some settings to be amazingly useful, however I really need to fix the constant high pitched whine that seems to be plaguing everyone. I should have read all the comments in here before boxing it up, as I have all the wires in the case bundled and pretty much running parallel. This was a mistake for this circuit.

      Otherwise I love it.

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  14. mine sounds like the original but I find it unusabl,e so it'll never get boxed.

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  15. I used shielded wire for the input/output wires both from the jacks and the board and I am still getting the whine when this unit is on... has anyone solved this?

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  16. rate 1 and gain 3...not conected?

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  17. This comment has been removed by the author.

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  18. working ... but not with 8-bit sound ...my ci2 is ua741cn....transistor bf245c...problem?

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  19. Replies
    1. Mine didn't work at all when I used a 245 -- just a constant oscillation. Switched to a 2n5457 and it works now with no obvious problems.

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  20. would a j201 work instead of the 2n5457

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  21. Hi Mark,
    I've read in FSB that the 3K3 resistor from pin 6 of IC2 should be 22K in the original.
    It should sound less muddy.

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  22. hi mark. i need your opinion on that please. i've triplechecked everything but still no effect. gain and vol work right, but switch, sample and res do nothing at all.i only get a smooth fuzz.voltages look good to me but i need someone to take a look too. i 've only used 2n5458 inplace of 5457 but as i looked at datasheet it seemed ok. the voltages are:

    ic1
    1. 4,53
    2. 4,52
    3. 2,26
    4. 0
    5. 4,5
    6. 4,5
    7. 4,5
    8. 9,0

    ic2

    1. 2,27
    2. 3,57
    3. 3,61
    4. 0
    5. 2,02
    6. 3,61
    7. 7,59
    8. 6,48

    and
    d 4,5
    s 4,5
    g 1,85

    i could use any help....
    thanks...

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    1. agrrrrrrrr...i feel stupid...autohelped myself...for 5 hours yesterday i was trying to find out what's wrong, and today i saw that i've put 2 of tl072.....now it's working as it should..
      if anyone needs the right voltages in the future, it's the same with the previous post for ic1, and the correct for ic2 are:

      1. 0
      2. 7.68
      3. 5.68
      4. 0
      5. 0
      6. 5,96
      7. 9,18
      8. 0
      i know that there are a lot of zero voltages on ic2 but i can't explain it...it works!

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  23. Just built this, worked in one try but as everyone piercing oscillation on almost every setting.

    For the bleedthrough the solution Rudeez posted is perfect. Like alex said, someone on fsb pried open an original and found out the 3k3 is actually a 22k and it sure does sound better that way but it does nothing for the oscillation.

    Some really good sounds but I would never build it again untill someone solves the oscillation. I think it sounds fantastic otherwise and it's worth the money they're asking for it so consider buying this one instead of building it

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  24. can I use tl071 as an equivalent to the lm741
    ?

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