Tuners and true bypass?


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Tuners and true bypass?

Several manufacturers have tried their hand at marketing their pedals as being true bypass, either by stating it straight out or by implying it through clever use of "close-but-not-quite" language. Very few actually do produce any tuners with a true bypass arrangement. The only two I have confirmed to be true bypass are the Peterson StroboStomp and the Korg PitchBlack. As for the others... in many cases, I know they aren't, and in others it hasn't been confirmed to be either way.

First, let's quickly go over the true bypass thing again, just to get our bearings straight:

True bypass

This means that the signal passes straight through the box - directly from input to output jack, touching only the switch/relay - when the effect is bypassed. This kind of bypass arrangement is only possible to create with some sort of mechanical switching - either with a good old stompswitch, or with an audio relay. The switching is done simultaneously at the input and the output, to route the signal around the electronics in the effect, and when bypassed, the effect/tuner is completely disconnected from the input signal. This is important, because as we will see later, this is a simple way of knowing if the claim that a certain pedal tuner is true bypass, is true or not.

True bypass switching can be wired inside a pedal, or inside a separate true bypass box which the pedal connects to. In that case, the pedal is kept constantly active, and the signal gets routed through or around it from the box.

A solid rule

Look at the true bypass graphic again. Remember what I said about this type of wiring requiring the effects circuit to be completely disconnected from the signal, in order to actually be a true bypass? Alas, when the tuner is (true) bypassed, it shouldn't receive any signal. Which leads us to the following rule:

A pedal tuner that senses the pitch constantly, even when the stomp (mute) switch isn't activated, simply can't be true bypass.

It really is as simple as that, and no amount of marketing or clever use of words by the manufacturer can change that fact. Plug it in, and if it tunes regardless of what you do with the switch, it isn't true bypass. Of course, this rule doesn't work the other way - it can't tell you if a pedal really is TB. It will only help you find those that are definitely not.

And the tuners?

With all that under our belts, it's time to look at some of the tuners available.

Non-pedal tuners: Here we have all those that you can plug your guitar into, but don't have a switch and/or come in pedal form. These tuners ofthen has an output jack, for sending the signal on to the amp/pedals. They can be buffered (with vayring buffer quality, of course) or use the simpler technology of simply splitting the signal to tuner and output jack. The Boss TU-12 is a prime example of this type of tuner (it is buffered, btw).

Boss TU-2: This is more or less the industry standard pedal tuner - even though I've seen too many reports of erratic tuning behaviour from it to feel comfortable recommending it. Like any other Boss pedal, it uses FET (electronic) switching, and shouldn't affect the sound any more or less than any other Boss pedal does. It is most definitely not true bypass, in any case.

Korg DT-10: This one has the legendary Korg tuner preciseness about it, and a large mute switch. There are two output jacks - the one labeled "output" mutes when you press the switch, and the one labeled "bypass" is always active, regardless of the switch (in essence, it is bypassing the mute switch). The signal passes through a buffer amp before it splits to the "bypass" jack and tuner section/"output" jack. No true bypass here, then, but a great tuner nonetheless (if possibly a bit big). Also, it is possible to modify it for true bypass, if you should want to.

AKAI DT-1: Originally advertised as a true bypass tuner, AKAI has now pulled all ads using that terminology and rewritten the manual. Like the Sabine, the tuner is constantly active, regardless of the mute switch, and therefore it has the same system as the Sabine. No true bypass there either...

Guyatone MT-3: Easily the smallest of the pedalboard tuners out there. It has a buffered system with electronic muting, and the tuner is constantly active. No true bypass, but a neat little tuner that can be modified for true bypass. Not that I'd recommend anyone to try it - I did mine, and still can't believe how much problems I had with wires coming loose. This pedal is quite fragile...

Fender PT-10: Like the Korg, this one also has two output jacks. One is affected by the mute switch, while the other isn't. But I don't know if the mute switch does anything else - if it switches the tuner in or out as well, or if the tuner is constantly active. So this is in fact the one tuner I'm not 100% sure isn't true bypass - I'd have to check the manual, or try it out in person, to know for sure. But I'd hedge a bet that it isn't - if it was, they would definitely advertise it...

Fender DPT-100: Another offering from Fender, this time with a detachable tuner. The idea is simple - the pedal base can stay on the pedalboard, while the actual tuner can be detached for tuning up in the dressing room before the gig. I had a quick look at the bypass system in this pedal, and while the switching is passive, the tuner is permanently connected to the input jack. In other words, it has the "half-arsed" or "hard-wire" bypass system. With a twist... in bypass mode, the switch actually cuts the power to the tuner, saving battery life (because it can't keep sensing pitch when you don't want it to). No true bypass, though.

Peterson StroboStomp: The first true bypass pedal tuner available! For those who don't know what "strobe" means in the world of tuners, let me just briefly say that it is a completely different method of measuring pitch, compared to "regular" tuners, and that it is a lot more accurate. This particular specimen is of the "virtual" strobe variety, which means that it doesn't use the actual moving parts a real strobe tuner has, but the readout (which is what we're tuning to) works the same way. As if that weren't enough, this puppy has true bypass switching too (although you have to select "true bypass" mode using DIP switches in the battery compartment, as it ships in buffered mode).

Planet Waves has a pedal tuner which has the words "true hard bypass" attached to it. In my experience, every time a manufacturer has stuck something in between the words "true" and "bypass", the pedal has turned out not to be TB... I have dissected one, and even though the switch disconnects the tuner circuit in bypass mode (the first rule of TB), the wiring leaves about 680Kohm between hot and ground on the bypass line. It really should be infinite, if I'd be entirely pleased. I can't really call it true bypass, as it breaks the second rule (about there being nothing at all in the bypass path, except a connection straight through). Full writeup with pics here.

Dean Markley PT-13: Advertised as having "input, output and true bypass 1/4" jacks", which I assume means that the output jack is constantly active, while the other is muted when the tuner is active. Wether or not this means actual true bypass is of course another matter. I have no timetable for when I might be able to get into one of these to find out, as I'm not even sure they have distribution here in Sweden.

Ibanez LU20: Another pedal tuner offering, which is advertised as having true bypass. This is another one I doubt I will actually get to see in person, as its price point here in Sweden puts it way too close to the Korg DT-10 to be able to compete. Also, it doesn't really look sturdy enough to survive, with its unsupported pcb-mounted jacks... My local store will most likely not even carry it, for those reasons. So I'm not too likely to get to see one in person, to verify or disprove the "true bypass" claim. I did, however, take a peek in the manual, and the operating instructions only mentions the footswitch as something which will let you mute the signal when tuning. If the LU-20 were true bypass, I'd expect the first thing in the operating instructions to be "activate the tuner, by stepping on the footswitch"... So until proven otherwise, I'm going to declare this one not true bypass.

Artec Big Dots Matrix (or "SE-PTN", if you like): it sure looks like the real deal. Hammond box, big footswitch. Two things caught my eye in their ad: firstly, when the tuner is active, the output is apparently not only muted, but a "low impedance mute" is applied. It might mean nothing, but if I were to interpret that, the output jack gets connected to an output buffer stage which is muted (instead of simply shorting the output to ground). The other thing I noticed was that the switch apparently also turns the power off in bypass mode (like the Fender DPT-100). Like the other contenders, I'd of course love to peek inside one of these...

Korg PitchBlack is a new tuner that seems to be intended to replace the DT-10, and not only is it smaller (although the jacks are located on the sides, so you don't get to use all the saved pedalboard space), it is also true bypass. I have peeked inside one of these, and confirmed this to be true. It uses a signal relay to control the bypass, and even shorts the output jack to ground when the tuner is active - I doubt we'll hear any reports of noise and bleed-through with this one (like the Planet Waves). Pics of the PitchBlack guts here.
a stompswitch.

The trick here is to keep the tuner out of the chain when you're not using it. After all, you're only going to use the tuner when you're not playing, so why let the signal run through it? As we've concluded earlier, running your tuner from the "tuner out" jack on a volume pedal will not keep the tuner out of the way at all (didn't read it? Here's the article again). For true bypass operation, it is much better to use a small tuner/mute box (like a true bypass box, but with output mute). That way, you can choose your favourite tuner and still get true bypass. Either that, or have someone modify one of the pedal tuners for true bypass operation. The Korg DT-10 can be done, and the Guyatone is possible (although it's more than a little fiddly - I've done it, and don't want to do it again), as is the Korg. The AKAI might be a contender, but the others aren't really modifyable. At least not with a stompswitch.

A short bit on tuning accuracy

Some tuners are claimed to have an accuracy of +/- 3 cents. Now, remember that one cent is 1/100th of a seminote - not very much. Other tuners claim to be accurate to the tune of +/- 1 cent, so they must be better, right? Or does it even matter? Yes and no. Of course, a tuner that will potentially end up being 2 cents off the mark will be better than one that can potentially end up being 6 cents wrong...

But with that said, keep in mind that there's a difference between the sensitivity of the tuner's pitch regonition circuit, and the sensitivity of its interface (the display, which you then use to decide how much to turn the tuning pegs). Having a tuner that has a +/- 2 cents more precise processor is of course good, but chances are may not notice it IRL. If the display was that precise, you'd be going nuts trying to keep the little green LED lit. Most tuners will light up the "ok" LED within +/- 5 cents (some are as loose as +/- 10 cents) of the ideal pitch. This is normal, and part of the interface - it helps keep the tuner display reasonably stable, even when the string isn't. Proper strobe tuners are the exception here, as their interfaces actually can display the tuner's sensitivity in any useful fashion.

Strings are moving objects, and will never be 100% stable like a sinus note from a synthesizer. When you hit the string, it goes sharp, and as the note decays, it will become gradually flat. No tuner in the world - no matter how accurate - can tune your guitar so that it stays within one cent that whole time. In fact, the differences incurred by the natural swing of the strings, and your picking/fretting technique, are far, far greater than the difference between +/- 1 and +/- 3 cents...

So, just because your new tuner is more accurately sensing the pitch, that doesn't mean that the readout on it will be more precise. The moral? Don't stare yourself blind on the accuracy figures, and concentrate on finding a tuner that has a display that is as precise (i.e. willing to flicker about) as you can put up with. If you get annoyed that your tuner moves too slowly, you can live with a more precise interface, but if the flickering drives you nuts, you need to find one with a more stabilized (and therefore less precise) display. Obviously, at the end of the day, the tuner will need to help you get your guitar tuned - if your tuner doesn't do that, you need to keep looking...

There are things you can do to help your tuner present a more stable readout (to let you get away with using a more sensitive tuner). There are two schools of thought here, one involving producing an as steady pitch as possible and the other involving removing as many overtones (which can be confusing to the tuner) as possible.

For the first approach, you need to use the bridge pickup and pick near the bridge. The idea is that since the string moves less near the bridge, the pitch will be more stable.
The second approach is completely the opposite - go to the neck pickup and turn the tone control all the way down. The idea is to produce an as "flute-y" tone as possible (making the fundamental the most prominent, in relation to the overtones).
Which one to use? Well, simply try both approaches and see which one works best for you. If you experiment a bit, you will also find that your playing style plays a great part here. Some tune to the attack (adjusting so the string is in tune when you hit it with the pick), while others tune to the decay (letting the string be sharp when hit, and drift down to correct pitch as it rings out. Tuning to the attack works great if you usually hit the strings hard, with heavy picks. If you're a soft picker, tuning to the decay might work better for you.

Credits to:
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wrote yourself one? or from elsewhere?

Do pardon me if its own written with hands on experience. Was just wondering coz some of the info seem similar to stinkfoot or some other sites online
yup yup. those infos are great. But do quote the origin when sharing the info though.

heh, must give them credit mah(by quoting stinkfoot in this case), small gesture perhaps, but its a form of courtesy to the source, imho.

on stinkfoot, i like the portion where he mentioned bout how to measure the current drawn for pedals. Its definitely a useful thing to know