Monday, 5 July 2010

Guitar and Bass Paralooper

From Moosapotamus:

The ParaLooper is something every effects-using Bass player should have, because it will 'Bassify' any bottom sucking, high-passing guitar pedal out there. And, it's pretty simple to build, too. Instead of just an effect loop pedal, this is actually a little mixer that blends your straight signal with whatever effect (or chain of effects) you plug into the send & return jacks. There are controls for wet/dry balance and overal output level (boost & cut).

Experimenting with parallel effects chains a snap, in mono or stereo. For example, you can plug whatever effect(s) you have connected to the send into a second amplifier or mixer/recorder channel. It can also be used just like a two-channel mixer itself by plugging a second source into the return jack. There is also a low-pass filter (capacitor to ground) on the clean signal that can be switched in for even more low end.

Pots are 100K lin for Blend and 100K log for Volume.

Full Range version


Bass version


55 comments:

  1. I'd be interested in this but what IC is that??

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  2. Something like the TL074 would be perfect for it

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  3. Replies
    1. Doh! Yes linear for Blend, log for Volume. I'd better put a note in the post.

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    2. cool. i haven't started building it yet, but i ntend to in about a week or so.

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    3. to make it even more versatile, i'd like to add a phase reverse switch for pedals like the Marshall Guv'nor and others that reverse the signal's phase. i know that the xotic b.blender and the guitarpcb.com 'paramix' (of which this vero is very similar to), both have phase reverse switches. i'm just wondering how to incorporate one into this vero?

      here's the schematic for the paramix:
      http://www.guitarpcb.com/PDF%20Files/ParaMix.pdf

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  4. Looks to be ok, but i'm not dead sure:
    http://mirosol.kapsi.fi/varasto/boxes_other/paralooper_gtr_bass_switch.png

    If those two changes on the two versions are the only ones, then that should make the full range version switchable to bass version with single 3 pole switch..

    I'm contemplating about building this with simple transformer DI at the output... Now if i just had the time to do everything i wanted :)
    +m

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    1. Yes if you omit both parts and the link that would be it exactly. The full range version is just supposed to be the same but with that low pass filter removed.

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    2. Is that possible to also add a indicator LED to the bass/guitar switch? Can I do that using the 3PDT or I will need a 4PDT? Thanks.

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  5. I need to buy more vero. Once I do that, I'll have a crack at the bass version. This will be useful for my chorus, which does some really nasty things to the low end.

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  6. Replies
    1. Yup. I thought about building this, but couldn't find any use for it... Maybe someday.
      +m

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    2. I'll be getting to it, one of the following days. One question (be prepared, this might be the stupidest question you've ever had); will there be a problem using a 16 pin socket for a 14 pin IC? I will be placing the socket one row up and placing the TL074 according to the layout, so not using the two uppermost socketholes. Make sense?

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    3. That answer saves me a lot of re ordering. On the other hand... I'm running out of excuses fast... I need to heat that iron.

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  7. Just put this together and I'm getting nothing but hum. I've uploaded some pics to Photobucket for anyone that cares to take a look.
    The whole shebang; [IMG]http://i271.photobucket.com/albums/jj138/saintOlav/Guitars%20and%20stuff/Rehousing%20Ibanez%20FL5/20121213_135929.jpg[/IMG]
    The board; [IMG]http://i271.photobucket.com/albums/jj138/saintOlav/Guitars%20and%20stuff/Rehousing%20Ibanez%20FL5/20121213_135929.jpg[/IMG]
    TL074 for IC. 100KA for Volume and 100KB for blend. I have Volume lug 2 on tip.
    I'm not seeing what went wrong...

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    1. Hit enter too soon.

      I'm not seeing where I went wrong... Any help would be much appreciated.

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    2. Nothing seems to be working for me today... Pasted the same image code twice...
      Here's the board wired up;
      [IMG]http://i271.photobucket.com/albums/jj138/saintOlav/Guitars%20and%20stuff/Rehousing%20Ibanez%20FL5/20121213_140000.jpg[/IMG]

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    3. The 100u cap is the wrong way round, and you missed out the 10u at Blend 3

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    4. Thanks for that ultra quick reply Mark! I don't think I have to tell you I feel like a complete clown at the moment... Been staring at it for an hour. You'd think I'd at least have seen the missing elco...
      I'll fix that tomorrow, probably will have to change out that reversed elco?

      Now, to get me a pair of glasses I go... :(

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    5. Probably. Electrolytics don't usually like having the polarity reversed, but just add the 10u first and see, you may have been lucky

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    6. Changed 100u for a new one, right polarity this time. 10u is in. Still nothing.
      I decided to redo the grounding as it looked a bit raggety. No change.
      New 074. No change.

      My amp reacts to me touching the guitar strings. But that's about it.

      Here's my soldering; [IMG]http://i271.photobucket.com/albums/jj138/saintOlav/Guitars%20and%20stuff/Rehousing%20Ibanez%20FL5/20121214_100818.jpg[/IMG]
      Not too hideous is it? I cut between tracks before, during and after soldering. I checked the cuts with a DMM. They were all good.

      Here's the board as it sits now; [IMG]http://i271.photobucket.com/albums/jj138/saintOlav/Guitars%20and%20stuff/Rehousing%20Ibanez%20FL5/20121214_100930.jpg[/IMG]

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    7. Can you measure the voltages you're getting at all the IC pins. There is always the chance that reversing the polarity has damaged one or more of the other electrolytics but the voltages should give us a clue where the issue is.

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    8. i'd run an exacto saw in between the rows. look at this pic:

      http://johnkvintageguitars.homestead.com/Effects/misc/20121214_100818.jpg

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    9. Here goes;
      source is a battery, measured at 9.0V
      01; 0
      02; 0
      03; 2.4 (thereabout)
      04; 9
      05; 0
      06; 4.5 slowly dropping to 0
      07; 0
      08; 4.5
      09; 4.5
      10; 2.2 (thereabout)
      11; 0
      12; 1.8
      13; 4.5
      14; 4.5

      These lower results @ 3, 10 & 12 are all shakey on the DMM, going up and down.

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    10. Thanks John, I've cut between row before, during and after soldering. The issues you point at are bent leads (too long perhaps, need better clippers) but I don't believe they short the tracks. I will however run a sawblade through there to make ab-so-lute-ly sure.

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    11. I did find one short. Desoldered, cleaned up and resoldered the parts. No change.

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    12. =sigh= I'll just solder in the two tiny links underneath the IC on pins 1&2 and 6&7 shall I?

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    13. No change.

      I am now at the point where I'll start a completely new board.
      Not until I've built something else though. Need a little distance between me and this project...

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    14. I'll probably rebuild it in a week or so. Right now I'm frustrated with myself. Wrong polarity on elco, leaving out another elco, leaving out two links, a short... That's 5 issues in this build... I need to slow down first.
      Thanks to Mark and John for jumping in right away and offering their assistance. Kudos to you gentlemen, sorry for wasting your time. Next build I promise to take better care.

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  8. Hi guys, putting this one on the breadboard before committing it to vero. I have some 1uf film caps but they are freaking huge. I want to use electros as I have a healthy supply of 1uf ( polar ), but I'm getting confused as how to work out the polarity from the vero. I'm thinking you knowledgeable ones ( grovel ) might just take one look and be able to tell me which way to put them. Cheers, Buzz.

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    1. Well I bread-boarded this and it didn't work. I could have made a stuff-up. It's happened before ;)

      I got essentially the same result as stated above. Amp just responds to me touching the strings. Like a ground noise.

      I used 470 nf film caps instead of 1 uf on the four appropriate caps, I don't think that would stop it from functioning.

      I plugged a (known to work} 2N2222 fuzz board into the send/return loop. The 2N2222 fuzz is definitely there, when I turn both knobs up full it makes a horrible strobing noise, just like it did when I had it in a box. The blend knob has no effect on this.

      No guitar signal whatsoever, but the ground must be attached to react to my fingers touching the strings. I'm going to double check the BB layout tomorrow or sunday. Will post again then.

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    2. Can't find anything wrong with breadboard layout, maybe the chips I used. Found a confirmed layout elsewhere with a schematic attached going to go with that.

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  9. "There is also a low-pass filter (capacitor to ground) on the clean signal that can be switched in for even more low end."

    Is this low-pass filter actually in this version? I'm not sure what I'm looking for to identify it. I'm interested in a blender with a low-pass. any ideas on how to make it switchable?

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    1. In the bass version, the 2k2 resistor followed by 47n cap to ground is the low-pass filter. In the full range version, this RC combination is bypassed with a jumper. You can use a DPDT switch to switch between the R-C combo and the jumper.

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  10. I have built the bass version according to your vero. Works so tag it.
    I am finding some clipping on stronger attack on the clean signal though. Maybe a charge pump to 18V might help.

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  11. Has anyone else ever built this successfully? Is there any consensus if it needs 18v or not?

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  12. Been ages since I've built a pedal. How does the volume pot. wire up?

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    Replies
    1. Volume 1 to ground, volume 2 to output

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    2. Cheers. Another question would this layout work? http://m.imgur.com/CRlUu7h
      It's combining this circuit with the Eric Johnson fuzz face circuit.

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  13. Getting ready to build this but had a question. Can someone please verify the value of the Electrolytic caps? Is it in mfds?

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    1. On all layouts, the electrolytic values are in µF, micro Farads.
      +m

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  14. Thank you mirosol. Could you verify one more thing? The layout shows the electrolytic caps having a grey stripe, is that the negative or positive side?

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    1. That be the negative side yarr

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  15. What's the cut of frequency of the lowpass? Could I replace the 2k2 to ground with a (ie 10K) pot to have control over this cutoff frequency?

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    1. I wanna know too. How to do this?

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    2. Did the pot work?
      I'm also interested in installing a HPF on the effected (return) path.

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  16. I built this last night and it works but it seems to distort the clean signal when engaged. Could this just be the chip? I'm running it after a meathead so I wondered if the input volume could also be affecting it?

    Thanks

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  17. Hi,
    When i was trying to add a phase inverter to it with LTSpice, I saw that the TL074 have a limited output around 3V with a 0-9V power supply. So if your componants are enought rated you can try a higher Power supply. Or you can try to reduce the output stage gain by decreasing the 100K resistor til it stop clipping.
    I didn't built mine yet and i can not verify it, so I'm not 100% sure that it will work...

    Fab

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  18. Hello ! Thanks for sharing this schematic ! it works perfect for blending dry-wet signals and i also get a good amount of boost. this is my dirt cheap version of this pedal housed ina seafood tin ! haha

    http://tinyurl.com/goq8wru

    http://tinyurl.com/joc6g9d

    Connecting an expression pedal to control the blend pot would be a great inspiration for expirementation. just connect the cables from the board to the blend pot on a 1/4 jack like this. http://www.taydaelectronics.com/media/catalog/product/cache/1/image/500x500/9df78eab33525d08d6e5fb8d27136e95/a/-/a-1123.jpg

    when no expression pedal is connected the signal just passes through to the pot. otherwise, you can use the expression pedal to control your blend.

    wonder how this would sound ? awesome ! Check this russian fellow !
    watch?v=gXK6U2aR97E

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    1. Now you can actually "fine-tuna" your tone, lol!
      Ωραίος!

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  19. Noob question: can i use a LME49740 instead of the TL074?

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