True bypass hall of shame
Ever so often, someone claims that such-and-such pedal is true bypass, either having been told so by a salesperson, or having convinced themselves it is, or simply because the manufacturer says so. Quite often, these claims turn out to be untrue. In some cases, it is evident that the manufacturer has tried to use terms that come as close as possible, without actually claiming outright that the product is true bypass. In other cases, they simply don’t seem to care. I decided to make a list of questionable cases I’ve come across, simply because I can. So here goes:
They’ve never before earned a place here, but now it is time. The stupendously large and expensive TU-1000 stage tuner has a ”parallel” output jack (sitting in parallel to the input jack) which in the official Boss marketing video is said to output a ”true bypass signal”. Unless Boss has gone out of their way to make the electronic switching system also physically disconnect the tuner input from this jack when the pedal is inactive (which would be highly unlikely), it can simply not be true. Using this jack will place the same impedance load on the guitar signal as connecting the tuner to the ”tuner out” jack on a volume pedal.
When Maxon released their ”nine” series pedals – reissues of the classic Ibanez 9 series pedals from the early ’80s – they claimed that they featured true bypass switching. They do now – all pedals produced after the early 2004 release of the second series pedals (AD-9, CS-9pro and FL-9) are indeed true bypass. But the ones made before that point in time wasn’t. The ones that are have a 4PDT switch, which is also noted on the box the pedal comes in. Could be good to know…
In the ”Vintage” series (the large box pedals reminiscent of mid-to-late 70s Ibanez pedals), Maxon now distinguishes between ”Mechanical bypass switching” (the ”hardwire” system) and ”Mechanical true bypass switching”, which is another good step.
In the past, I’ve been quite frank and upfront with the way Maxon handled the bypass issue, and it seems they’ve listened. Thumbs up!
In the manual for the WD-7 ”Weeping Demon” wah pedal, they claim it to be true bypass. This made me quite suspiscious, mainly because that would mean a big and expensive step away from the tried and proven electronic bypass system they’ve used for over 25 years now. Also, the pedal has an auto on/off function, which can’t be combined with a true bypass system without the use of logic controlled relays to switch the audio. That would be even more expensive… Naturally, I had to check this out, so I headed for the music shop. To make a long story short, the WD-7 turned out to be fully buffered. Of course, that doesn’t make it a bad wah pedal per se – if anything, when placed first in the chain, the fully buffered electronic bypass system it has is definitely preferable to the crappy hardwire bypass system in a Dunlop GCB-95 Crybaby… But what it does mean is that Ibanez is misusing the term ”true bypass”.
Also, the LU20 pedal tuner is advertised as having true bypass. Now, I haven’t seen this one in person yet (and probably won’t, as my local dealer didn’t think it looked solid enough to bother carrying) but I did take a quick peek in the manual. The only time the footswitch is mentioned is as a means to mute the signal, should you want to. IF the LU20 is true bypass, the tuner won’t work at all unless you step on the switch – and if so, the first line in the operating instructions would read something to the effect of ”to activate the tuner, step on the footswitch”… So, until I’ve been proven wrong, I’m going to declare this one most probably not true bypass.
The term ”hardwire bypass” can be a little misleading, but in short it is the same thing that causes old Vox wah pedals to suck tone. The signal is simply split at the input, leaving the circuit constantly connected (”hardwired”), which places the circuit’s input impedance in parallel to the input impedance of the next pedal, bringing the total down.
Lately, Dunlop has started using the term ”true hardwire bypass” to denote pedals that are actually true bypass (not just ”hardwire”), which is good. Some of the newer designs (Carbon Copy etc) are proper true bypass (using a variant on the Millennium circuit to control the LED), while the older ones tend to stay ”hardwire” until they are due for a redesign for other reasons.
- The Fuzz Face reissue has always been TB, as was the original. The input impedance of the fuzz face circuit is so low, that it created tone loss that was unacceptable even by 60′s standards.
- The single-battery 535Q wah is wired for true bypass, but has a couple of misplaced pulldown resistors (sitting on the input/output jack, rather than the input/output of the circuit) which causes it to lose tone the same way a stock GCB-95 does. Dunlop may have removed those resistors in later revisions, though.
- The GCB-95F Crybaby Classic seems to be better built – it has a 2.2M pulldown resistor on the circuit input (where it is supposed to go), but nothing at all that affects the bypass line. So it is proper true bypass, thus (at least Revision A, which was the one I had on the bench).
They’ve never officially used the term ”true bypass” in the advertising for their line of pedals. However, some dealers have taken it on themselves to add the word ”true” to the official Marshall term ”passive bypass”. Inspections of both the pedals and the schematics prove that these pedals have the same bypass system as MXR/Dunlop and the others – the effect input is hardwired to the main input, and the switch only selects which signal to send to the output. The only difference is that some of them (mainly the distortion/overdrive pedals) have an extra feature that mutes the input to the distortion circuit, to avoid crosstalk in the switch (a common complaint with the output switching only system). Some confusion arose when people started finding 3PDT switches (normally associated with true bypass switching) in some of the newer pedals, but it turned out to be a red herring, as the pedals in question had stereo outputs. To do the ”output only” style of switching on a pedal with stereo outputs, you need an extra set of poles – hence the 3PDT instead of a DPDT (as the mono output Marshall pedals have).
Hughes & Kettner
In the specifications for the ”Tube tools” pedals, they use the term ”Real bypass” for three of the four pedals (the fourth pedal is a recording preamp that can’t be bypassed). Now, I know for a fact that at least one of them is buffered – on the Tube Rotosphere, the preamp section is always active, regardless of bypass state. At the same time, in the manual for the Replex (an awesome Echoplex simulator, by the way), they state that the pedal has a ”true hardwire bypass”, where ”the signal at the input is routed directly to the output, absolutely unaffected by the internal circuitry.” Whether that means ”hardwire” in the MXR sense or actual true bypass remains to be seen. But ”Real bypass”??
This manufacturer has a rather popular line of analog pedals – PD-01 Power Drive; TM-01 Tri Metal; HL-01 Hyper Lead; UF-01 Ultra Fuzz – that among other things has been hailed for having true bypass. It was like a dream come true – great pedals (the PD-01 is sometimes called the poor man’s Klon, and justifiably so), but as so many times before, if it seems too good to be true, it most likely is… I’ve seen a schematic (reverse engineered, though, not factory original) of the Tri Metal that most definitely wasn’t true bypass. These pedals are fully buffered.
One of the selling points for thei Tonebone tube overdrive pedals are that they have true bypass. Here’s a snippet from the Classic/Hot British manual:
FOOTSWITCH: Toggles between effect and True-Bypass. i.e. when the Tonebone is off, the signal passes straight through without any effect.
If only… I recently got my hands on a schematic for the Classic, and it shows the input being hardwired to the circuit input as well as the switch, just like in most wah pedals and the MXR, Marshall etc pedals mentioned above. Half of the DPDT footswitch is used for the audio (selecting either the circuit output or the signal tapped off straight from the input jack), with the other half switching the LED on/off. So as far as that schematic is concerned, no – the Tonebone Classic is definitely not true bypass. The signal passes straight through to the output jack, yes, but it also taps off to the circuit input, which can lead to tone loss. And again – it isn’t true bypass.
…has a nice brochure ready for download about their Whammy pedal (the Whammy 4, to be precise). And lo and behold, here’s what they say:
”Rugged mechanical footswitch takes the Whammy pedal in and out of a true signal bypass”
Um… I can tell you with the utmost certainty that this pedal is fully buffered, and definitely not true bypass. It is interesting to note their choice of words – it seems that every time a manufacturer sticks additional buzzwords in between the words ”true” and ”bypass” (”true hard bypass”, ”true hardwire bypass”, or indeed ”true signal bypass” as used above), the pedal in question turns out to not be TB.
One exception to that rule is the Digitech ”Hardwire” series – despite their name, they are actually true bypass. I haven’t verified it myself, but the Digitech rep I talked to managed to answer all questions to my satisfaction. So they do seem to be the exception, then. They use relays to switch the audio, by the way. Also, the latest Whammy (5) is said to have true bypass, which is a good indication that even the big manufacturers are learning.
Their pedal tuner is advertised with the term ”true hard bypass”. I have taken one apart, and it turned out to be ”not quite” – the switch does disconnect the tuner circuit from the main signal path, but there’s still a 680 or so Kohm path from hot to ground present in the bypass line. That doesn’t qualify as proper true bypass. Sorry.
I did have an interesting e-mail conversation with a D’addario (which owns Planet Waves) representative, who wanted to convince me that I was wrong. He didn’t have much luck Planet Waves has since updated the look of the tuner, so I can’t comment on the new one – maybe they’ve learned their lesson?
The Strobostomp was long hailed as the first (and only) pedal tuner with true bypass. And all the stuff needed for true bypass is there – with the small switches set the right way (it ships in buffered mode) the footswitch does everything right. But… for some reason, Peterson has stuck a 1 megohm resistor from hot to ground in the bypass path, which of course ends up in parallel to the input impedance of the next pedal. As tuners tend to sit first in line, the lowered input impedance ”seen” by the guitar can lead to treble loss.
Peterson claims that resistor is needed to stop the pedal making popping noises when switching – a good old pull-down resistor, thus, just like the Dunlop 535Q wah mentioned earlier. But once again, pulldown resistors should be located on the circuit input (as they’re intended to pull the circuit input to ground during the switching operation), and therefore out of the bypass signal path. Placing them where Peterson did won’t help pulling the circuit input to ground – all it does now is present a constant 1M input impedance in bypass mode. Still, it is entirely possible that Peterson had to do this to stop the popping (and it is also equally possible that removing this resistor, while stopping the treble loss, also makes the pedal ”pop” when switched), but then they shouldn’t have called it ”true bypass”.
This company uses a variety of terms to describe the bypass system in their line of stompboxes, all designed to confuse the customer (if you ask me). Here are a couple of them:
- ”For absolutely noise-free operation, a first-class electronic On/Off switch is integrated.” (BO100)
- ”…a sturdy footswitch which preserves signal integrity in bypass mode.” (UO300)
- ”…a first-class electronic on/off switch for highest signal integrity in bypass mode.” (CC300)
- ”The footswitch is electronic so that it can withstand years of hard use while maintaining straight-wire signal integrity in bypass mode.” (CD400)
- ”The tough metal footswitch maintains straight-wire signal integrity in bypass mode.” (RM600)
- ”And when in bypass mode, it preserves signal integrity by taking all pedal circuitry out of your chain.” (US600)
As you can see, the descriptions range from fully electronic (Boss-style) switching to something that is intended to remind people of true bypass. And as it seems, the newer and more advanced the pedal (the higher the number), the closer to saying ”true bypass” the descriptions seems to get. Now, I have of course not inspected all of the Boss look-alikes, but the ones I have seen have all had a fully buffered electronic bypass system. Nothing wrong with that, so why confuse the issue?
Some of the Behringers use a mechanical stomp switch, and are described as having ”true hardwire bypass”, which seems reasonable. Not true bypass, of course, but they didn’t say that either, did they? By the way, according to one owner of the PH9 (MXR-style phaser also advertised with ”true hardwire bypass”), the switch is actually just an actuator pushing down on a micro switch on the circuit board – to me, that sounds like electronic bypass. Again, nothing wrong with that. But why call it something else?
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