DIY True-Bypass-Strip Project

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After I decided to go all "true-bypass" with my setup, I checked out the different ways to do so. The first way would be to convert all stompboxes to true bypass. On some of them like the EH stuff it is not a big thing to do and the Boutique-stuff is true bypass anyway but I also use some "normal", non-boutique stompboxes from Boss, Ibanez, Danelectro and Nobels and converting them is a lot of hassle and fumbling. You have to drill a big hole in the box to load it with the new switch, you have to block the stock switch, bypass the buffer system and you have to work with a lot of flimsy cables in small areas - sounds like it is not much fun ;-) Anyway, if someone is interested in such massive operations you should contact the "FX Doctor" Josh (NS). The second way would be to buy or build a true-bypass box. This is a fine solution if you donīt need many loops - you simply connect the non-true bypass pedal to this box and youīre done ! But I love it to be flexible on my board and I donīt want to have big chains of several pedals on the individual loops and an increased number of loops in a true-bypass box also means an increased amount of cable mess on the board, difficult to control. So I decided that the best solution for me is a true-bypass strip !!! Easy to stomp on, easy to control and a higher number of loops is possible without converting the whole board into the cable mess from hell. I checked out all the commercial offers for such strips, but the perfect solution for me means nine independent loops - sure, itīs possible to order such a beast as a custom order, but the prices are similar to that of a good tube amp. So I decided to build a true-bypass strip myself.
Before you start to do the same, decide if you really need one !!!! If you need a maximum of 3 to 4 loops, get a true-bypass box and thatīs it. There are plenty of good offers out there for such boxes and you will find one for you for sure. If you really want a multi loop true-bypass strip, go on reading ;-)

First of all I would like to thank those people who helped me a lot with this project - without them this project would never took place:

  • Andi Allan (dot-dot-dot)
    He is the mastermind behind this project and provided me with the circuit and a lot of technical help and explanations. Visit his own pedal-factory and click here or send him an email

  • Andreas Möller (andreas)
    Andreas taught me the basics of the whole true-bypass subject and some more electronical stuff. So donīt miss to see his great stompbox related StinkFoot Electronics webpage by clicking here or send him an email

    The Details

    Here you can see the very first pattern for the strip made out of cardboard. This is very useful to determine the final dimensions of the complete thing. There are a lot of parameters you have to think of, eg. the depth of the jacks, switches, LEDīs etc. So donīt think this is obsolete, it will protect you from a lot of troubles later. As mentioned before, I decided to build a 9-loop true bypass strip with LED indicator for each loop and some additional gimmicks like stereo out, wet/dry out, tuner out etc. Isnīt the cardboard pattern wild looking ?!? Iīm sure you all know the fairytales about german engineering ;-) If you want to enlarge a photo, simply click on it and it will open in a new window.

    cardboard pattern
    cardboard pattern
    cardboard pattern

    The next step was to get a custom enclosure for the specific measurements. I found a local stainless steel company who was willing to do it for me for a very decent price and after only a few days it was finished and I picked it up. Itīs a two-piece enclosure out of SS304 stainless steel, very solid and easy to work with. I covered it with masking tape and transfered the measurements from the cardboard pattern to mark the drilling holes.

    the stainless steel enclosure, ready to drill
    the stainless steel enclosure, ready to drill

    For drilling stainless steel you should use a very good drilling-machine and a high-tech drill bit like a titanium bit. I used a permanently installed drilling machine and a unibit and the whole job was done within 30 minutes without any damages or injuries ;-) Here you can see the drilled enclosure without the masking tape.

    the drilled stainless steel enclosure
    the drilled stainless steel enclosure

    I was not sure to leave the enclosure the way it was high-polished or to paint it. Sure, high-polished stainless steel looks cool but you can see each and every fingerprint on it and it will cause a lot of serious reflections when gigging outside in the direct sunlight. So I decided to paint it black. Painting stainless steel is a science of its own and requires a lot of individual steps to look good. Try it with your kitchen-sink at home (or a DeLorean car if you have access to one) .... it will not last long and will come off after a short time. After several attempts I sandblasted the complete enclosure and brought it to another local company to get it black powder coated. This is very durable and looks great. Have a look at the finished enclosure.

    the black powder coated stainless steel enclosure

    During the time I spent on the enclosure, I collected all the parts for the strip. I decided to use the 3PDT switches from BANZAI (thanks Olaf !) and the rest (Switchcraft jacks, LEDīs, chrome bezels, limiting resistors, DC jack) from Smallbear Electronics. For the internal wiring I choose two different cables. For all the ground and power connections (= all non-signal feeding connections) I used the pre-bonded hookup wire (stranded / AWG 24 / PVC insulated) from Smallbear Electronics. This wire is easy to use, routes perfectly and is available in a lot of different colors. I highly recommend this one. For all the signal-feeding connections I used a high-quality AWG 22 teflon insulated cable with pure silver cores (0.38/AWG 22-19). This is the military specs cable which is also common for use in airplanes and similar applications. This cable offers the lowest capacitance and most transparent tone you can imagine. If you also want to use such cable, have a look at our SINGLECOIL Webshop. Have a look at all the goodies, ready to rockīn roll .....

    wow, a lot of parts :-)

    The next step was to install all the hardware. Because of the two-piece design of the enclosure, I decided to first install everything and to hook up the loops in this condition. Everything was easy to access so I choose this way. In a more tighter enclosure I highly recommend to hook up everything outside the enclosure and install the hardware afterwards.

    installed hardware
    installed hardware
    installed hardware

    After stripping a lot of cables I soldered everything in place. I started to hook up the limiting resistors for the LEDīs. Afterwards I soldered all the power and ground connections (black for power & brown for ground), followed by the signal-feeding connections (white) and the switches. At the end I set up all the additional features like the stereo out, wet/dry out, tuner out, tuner mute and power switching. I used a standard 30 watt soldering iron from ERSA, nothing special about it. Use a good solder for electronics, not the crazy stuff for eaves, tiffany-arts or other twaddle. I used high-grade silver solder for this job, but only because I had access to this stuff for free. I would not buy it (itīs VERY expensive) if I had to and I doubt that it will have an influence on the sound ...... but you never know and using it will protect your true-bypass strip from any werewolf attacks for sure ;-)

    the hooked-up strip
    the hooked-up strip

    The True-Bypass Strip FAQ

    Whatīs the deal with true-bypass ?

    If you need it or not depends on your gear and is also a matter of individual taste. It can help you to get rid of all the tone-sucking within a fx-chain, but it can also cause new problems (read more about this later). To teach yourself about the true-bypass subject, read the fantastic article from Andreas Möller by clicking here

    Is there a special wiring scheme you use ?

    I used the wiring-scheme from Andi Allan (dot-dot-dot). Most of the true-bypass wiring schemes out there are switching inputs, not outputs. In engineering that's regarded as a bad thing. When the loop is engaged, all schematics are essentially the same; the input jack is connected to the Send and the output jack is connected to the Return. But when the loop is bypassed things are different. In the common schematics, the input to the pedal is left unconnected. If you had a high-gain pedal in the loop you could then get all sorts of squealing, or if there was a delay pedal you'd be filling the delay line with noise. In Andis diagram, when the loop is bypassed the input to the pedal is grounded. No noise, no hum, no squealing. With well designed pedals in the loop, the difference is negligible, but you may get popping and extra noise when switching the loop in and out (more about this later). You can have a look at the diagram I used by clicking here. Please keep in mind that this diagram belongs to Andi Allan and if you like to use it in any way, you have to ask him beforehand !!!

    Some more technical specs available ?

    Yeppp, here you go

    How do I orientate the 3PDT switch correctly ?

    Thatīs really important to know, because it makes all the work a lot easier. For the more technical way by using a DMM please click here (provided by Andreas Möller). For a very simple way you just have to look on which side of your switch the logo is printed. X-check it with this diagram and there you are ;-)

    How do I cascade the loops ?

    Thatīs very simple - The first switch takes the input jack as its input, the second takes the output of the first 3PDT stage as its input and so on. The last 3PDT stage output goes to the output jack. The green wire (OUT) from each stage goes to the next stage's purple (IN) wire. For the first stage, the purple (IN) wire comes from the Input jack. For the last stage the green wire goes to the Output jack. Ground needs to go to each ground point and to the sleeve on each jack ! For a diagram please click here

    Can I also use DPDT switches ?

    Yes you can and you have two choices. If you want to use DPDT switches and also want the LEDīs, you should use Mr. R.G.Keenīs "Millenium Bypass". For further information, have a look at his GEOFEX webpage. If you want your true bypass strip totally passive without any LEDīs you can also use DPDT switches. For this passive design you also donīt need the DC jack. For a diagram how to wire a DPDT switch for true bypass please click here to have a look at Andi Allanīs circuit. You can always use a 3PDT switch instead of a DPDT switch but not vice versa. To use a 3PDT like a DPDT switch you just have to leave one row of the lugs unconnected.

    What are all this terms like send and return ?

    In a single true bypass loop you have a total of 4 jacks. IN - guitar input / OUT - to amp. Then one SEND and one RETURN. SEND sends your signal to the pedals in that loop, RETURN takes the output of those pedals.

    What about the measurements of your strip ?

    The overall measurements of my 9-loop strip are 62 x 7 cm with a height of 6 cm. Finding a case for such a strip can be difficult, try to find the HAMMOND cases. If you are living inside the USA you are lucky, you can buy the HAMMOND cases in almost every homestore. A good HAMMOND case for such a project are the T and W models as shown on the LOOOPER homepage - the 1411T model is my favourite, check it out. If you want to make your own housing, I recommend the measurements as shown on my cardboard pattern here on the webpage, there you can see all dimensions in metric. For each loop I choose a with of 6 cm and a height of 3 cm and a depth of 6 cm. From there you have plenty of room for all kinds of switches, LEDīs, bezels, jacks etc. The rest of the measurements are more or less individual and are coresponding to the choosen parts. I highly recommend that you also make such a cardboard pattern for your personal strip to make sure that everything will fit perfectly !!!!!! For my parts I used 2,2 cm for the top hole (switch) and 1,4 cm for the side holes for the jacks. To convert all the metric stuff into american standard, please have a look here. As for the two parts of the casing, yes I joined the parts together after everything was finished, otherwise the complete procedure would be VERY fumbly. You can use almost every material for a case, wood, aluminum, plastic, sheet-metal ..... but if you use a non-metal case, I highly recommend to use self-sticking copper-foil for the inside to shield the case, itīs the same stuff you can use for the inside of any electric guitar.

    I donīt need a big TB strip, how can I make a single-loop TB box ?

    If you only need a single-loop true-bypass box you can also use the scheme from the strip and simply take out the additional loops you donīt need. Here is the drawing from the strip, as well as more "beginner friendly" version with only one loop for you.

    I want to add a master-bypass switch, how can I do this ?

    A master-bypass switch is a good idea if you want to completely remove the true-bypass strip from your signal chain with only one step. In general you only need an additional 3PDT switch and to know how to wire it up ;-) Here is how to do to it.

    I also want a tuner out with muting option, how can I do this ?

    This is another very popular option for true-bypass strips and boxes. When you engage this option, your signal is routed to the tuner while the rest of the true-bypass strip is muted. So you can tune silently without hearing the signal in your amp. You need an additional 3PDT switch for this and here is how to wire it up. Here is another, more complexe diagram where you can see how to wire this option together with a "master bypass" function. There is also an alternative way to do a tuner-mute output with a 2PDT switch instead of the 3PDT, this can save you some bucks when buying the parts. This way of wiring is from Mr. Ashok Fernandez from New Zealand and he was so kind to do a custom drawing for us. Itīs a kind of special A/B function, muting the wet-output and routing the signal to only the tuner-out jack. Here is his tuner-out option.

    Is it possible to reverse the order of two loops ?

    Reversing the order of two loops can be a very helpful feature to create some new sounds with the flip of a switch, eg. Iīm sure you all know the "Jimi Hendrix debate" and the question what sounds better - to play the Wah-Wah pedal into the fuzz-box or to play the fuzz-box into the Wah-Wah pedal. With the "loop reversing" option you can realize both possibilities without changing your stompbox order. You will need an additional 4PDT switch for this, this switches are available as a toggle switch or a footswitch. Place this new switch between two loops and connect it like this. Now you can play loop A into loop B or vice versa by simply using this new switch. If you want to dip much deeper into this option, please visit this webpage.

    Can I build A/B and A/B/Y switching options into my true bypass strip ?

    Yes, this is possible and easy to do. You can build this switchers as a stand-alone box or simply integrate them into your true bypass strip. An A/B switch will route the signal to either output A or B, very similar to the "tuner-mute output" option from above. This is very helpful, when you have two different amps. An A/B/Y switcher is basically an A/B switcher with added "Y" function which will route the signal to either output "A" or "B" or to both outputs at the same time ("Y"). Keep in mind that using such a standard passive A/B/Y switch to switch to dual amp outputs can probably cause noticable hum in the signal to one or both amps. If you want to be save from this problem, you will need an A/B/Y box with isolated outputs, you will find such a project H E R E. If you want a top-notch ready-to-rock A/B/Y box without any noise and hum, have a look at the german LEHLE Switchers, they are built like a tank and will last forever. For the A/B schematic please click H E R E (used with permission from Mr. Mike Fuller - FULLTONE company) or H E R E to download the A/B/Y switching option

    Whatīs the deal with power switching ?

    You may also want to implement power switching when you insert a jack into the input socket. Do that by using a stereo jack in that location; wire the black lead from the battery clip to the Ring connection, then ground the other jacks together. Power is only then connected when a mono jack is inserted into the input jack.

    What about stereo and pseudo-stereo (wet/dry) outputs ?

    Adding pseudo-stereo options to your strip is very easy. Your "normal" output at the end of the strip is always your mono-output, but it can also act as the "wet" output on a pseudo-stereo setup. To implementate an additional "dry" output, simply run a wire in parallel from the main input jack to the additional output jack and youīre done. The main output is the "wet" and the new additional jack is the "dry" output (similar to the "stereo" option on most chorus stompboxes). I recommend to use a shielded wire for this, because it has to cross the complete length of the strip. You can see this additional wiring on the photos of my strip. Real stereo options are a little bit more complicated .... Basically, for each send/return you add to a loop, you need another pole on the switch. So for a mono send/stereo return loop, you need a 4PDT. For a stereo send/stereo return loop, you'd need a 5PDT - something I've never even seen. You can save one pole if you use the Millenium wiring for the LED, but with the regular wiring style, you need switches that big. A mono send/stereo return loop would be wired as your regular 3PDT mono/mono loop, but with a second "return" pole. For the bypass mode, simply extend the jumper (the one that carries the dry signal to the output side of the switch) to the next pole as well, making the dry mono signal feed both jacks. In the active mode, each return jack is switched to its respective output jack. This assumes that a mono/stereo loop will always be the last loop in the box - there's no point in having more than one of these loops in the chain, since the last loop is the only one where you will be able to hear the stereo effect. As soon as you go stereo, you can't go back to mono again, or you will lose the stereo effect. If you were to find a 5PDT switch, you could wire a stereo/stereo loop (which, to make itself useful at all, would be placed dead last, after a mono/stereo loop). In that case, simply treat them as two separate loops, with the LED portion in between them on the switch (to help keep them separate). But the only time such a loop would ever be useful is if you already have a stereo signal (from a mono/stereo loop) and a true stereo effect (where the left/right dry signals pass through without ever being combined). Once again, as soon as you've gone stereo, you can't go back.

    There are additional holes on your strip, what are they for ?

    The additonal holes you can see are a second input jack (simply in parallel to the main input jack), the hole for the 9 volt power input, an extra tuner-out jack (runs in parallel to the main input jack) and the additional stereo "dry" output jack, described above.

    Iīm confused about all the parts, do you have a general parts list ?

    For each loop with LED indiciator you need: 1 x 3PDT switch, 2 x 6.3mm jack, 1 x LED bezel, 1 x LED, 1 x LED limiting resistor. In general you also need 1 x enclosure, 1 x DC jack and/or battery strip, 2 x 6.3mm jack (general in- and output), hookup wire. For a master-bypass you only need one additional 3PDT switch. For a tuner-mute out you also need an additional 3PDT switch and another 6.3mm jack to connect the tuner.

    How do I determine what limiting resistor I need for my LEDīs ?

    To make life easy about this, just click here. I use a 510 ohm resistor for all standard LEDīs of any color (non-superbright LEDīs, non-low current LEDīs) and it works fine. If you like the LED a little bit brighter, use a slightly smaller resistor and vice versa. If you want to go down deeper into the technical things, read this article from Andi Allan.

    Must I use a pulldown-resistor to avoid popping noises when engaging a true-bypass loop ?

    Read what Andi Allan has to say: "I'm starting to feel a little doubtful about how much this can help. It works for TBing a pedal by modding it, but may not have such an influence when you're building a bypass strip. The idea is that it prevents a DC offset that could be caused by old or bad decoupling capacitors in the pedal in the loop. It only really works well, though, if you do it physically close to those decoupling caps. I basically do it if and only if I have popping problems, in which case I put a 1M resistor across the sleeve and tip of the return jack. I wouldn't go below 1M". My 2 cents ... on a stompbox you can use a pulldown-resistor to avoid popping noises by simply solder the resistor across the sleeve and tip of the input jack. The value is not very important and everything from 1M to 4.7M will work fine. I use 1M and I canīt hear any influence on the tone.

    Can I use an all metal (uninsulated) standard power jack ?

    No donīt do this ! The DC jack has to be an insualted type, otherwise it will short the power. If you have an uninsulated power jack (like the Switchcraft ones), you must isolate it, eg. with a rubber grommet. The +9V usually arrives on the sleeve connection, which connects to the housing on a metal jack. The only way to use a metal DC jack uninsulated is if the box is plastic, or the jack is wired center positive (requires a special adapter).

    I want fancy LED colors for my strip, but they are very expensive, right ?

    Andi Allan knows how to save a lot of money: If you want an odd coloured LED (purple, turquoise etc), take a normal white LED and dip it in a 2-1 thinner/enamel paint mix. Let it dry and repeat 3-4 times. Purple LEDs are about Ģ8; a white LED and the thinners and paint will cost you about Ģ5, and you'll have enough paint to do something like 40-50 LEDs. It's a nice way to get some unusual colours. I reckon purple LEDs will be the next big thing :) I also found an online-shop with fancy colored LEDīs for reasonable prices. If you want to visit them, please click here

    What are all those switches like 3PDT, DPDT etc. ?

    Here is a good explanation, again from Mr. Andi Allan

    Do I have to use special patch-cables with the strip ?

    No, you can use any patch-cable you want. But I recommend to use a good quality cable with low capacitance to protect your tone from treble loss. And yes, you can use the George Līs in any color and diameter you want - but you should stay away from this solderless plugs !!! Just solder them to high quality plugs and you have a good patch cable. For more details about the "George Līs debate", read what Andreas Möller has to say by clicking here :-) If you like to teach yourself about "urban-legends-cable-mojo", I recommend to read this article.

    Do I have to use a line-driver (buffer) now ?

    Itīs not a must but I highly recommend it to get rid of a whole bunch of problems when using a true-bypass strip. First and foremost the enhancement in tone when using a buffer in front of the strip is awesome and you can use longer cables without a dramatical high-end loss. You can simply connect a buffered stompbox like any Boss or Ibanez pedal in front of the strip or you use a real line-driver (buffer). To start, read Jack Ormanīs article at AMZ. I first decided to build the JFET "Discrete Buffer" from J.D. Sleepīs webpage and this thing works great without any coloration of the tone. But this design is not unity gain and after a while I decided to look for a different solution. I ended up with a simple IC design from Jack Orman, slightly modified by Andreas Möller. It is absolutely unity gain and is also free of any tone coloration. The impedance is really low and I can only encourage everyone to try this design. You can download the project paper as PDF file here. If you want to use a ready-to-solder PCB to build your own buffer, Mr. Jerry Sleep from General Guitar Gadgets would be happy to supply you with such a goodie, please have a look here. If you are an experienced builder, you can also build the IC Buffer on a piece of cardboard or veroboard, here is the layout for you. Keep in mind that most fuzz pedals donīt like to see another pedal in front of them and a Line-Driver is no exeption from this rule ! If you are interested in a ready to drop in populated Buffer board or a custom version, have a look at our SINGLECOIL webshop

    Can you build some more strips or true bypass boxes and sell them ?

    YES, we can !!! We opened the "SINGLECOIL Custom Shop" for exactly such orders. If you are interested, please send us an email with your wishes and one of our Custom Shop builders will come back to you with the details. Please notice that we are a pure Custom Shop, so we do not offer any budget lines or standard factory produced models.

    If you have any further questions, comments, wishes or whatever else, send us an email. This webpage was created as a help for you to build your own true-bypass strip and itīs only allowed to use this content for private purposes. Please keep in mind, that the circuit drawings belong to Andi Allan, so if you like to use them, drop him some lines and ask if he agrees. If you like to establish a link to this page, feel free to do so - please let us know about it.