Oct 12 2009

Defining True Bypass and Buffered Bypass

Yesterday, I posted a review of the Boss TU-2 Tuner which I mentioned had buffered bypass. Eric commented and provided a fantastic link to a article by R.G. Keen which works at Visual Sound Pedals. My post about Visual Sound’s Route 808 pedal is what started my tangent / interest in buffered bypass.

Here is a great explanation of the differences between True Bypass and Buffered Bypass:

Once guitarists noticed that their CLEAN sound suffered from having a bypassed effect in the line, they demanded better bypasses. This came in two flavors, true bypass and buffered bypass.

Buffered bypass is the technique of designing a high input impedance amplifier to go ahead of the actual effect circuitry. The input impedance of this buffer is high enough to avoid tone sucking, and it has an output impedance low enough to drive the rest of the effect with no loading even if the effect proper has a low input impedance. This also allowed electronic switching from dry to effected signals, and became a favorite of several Japanese electronic companies. The best example is probably the Ibanez xx-9 series, which includes the fabled Tube Screamer 808 and 9. These effects do not get a lot of reports of tone sucking, although purists sometimes demand that they be converted to true bypass.

True bypass is the standard of clean signal quality against which all other bypasses are measured. True bypass means that when the bypass switch is in the bypass position, the effect circuit is entirely disconnected, input and output, from the guitar’s signal, and that the signal passes from the effect input to its output going only through wire and switch contacts. To see how a true bypass works, we can make up a hypothetical set of single pole, single throw (also know as simple make/break) switches and concoct a true bypass. For this, we only need three simple switches and some timing. Clearly we need two switches to break the path from the input jack to the effect input and from the effect output to the output jack. If these two are simultaneously opened or closed, they connect or disconnect the effect from the jacks.

I’m going to do some personal experiments with true bypassing and adding a buffered item in line. I’ve been so use to my tone, that I need to shake things up a bit and see I hear a difference with my current set up. Or at the very least, if I can replicate a complete true-bypass signal path to see if things darken.

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Oct 11 2009

Boss TU-2 Tuner – Must Have

I picked up the Boss TU-2 Chromatic Stomp Box Tuner about 10 years ago. Prior to that, I owned a series of digital tuners that I would include with a various looper pedals to keep the tuning on the ground. I remember how much I appreciated the quality and effectiveness of the Boss Tu-2 tuner immediately.

It is incredibly easy to view under various types of stage lighting and conditions, and is versatile in the sense that you can use it as a kill switch or mute while switching guitars, etc. It can also be used a power supply to power up your other pedals via daisy chain power cable.

Here are the official features for this pedal from Boss.

  • BOSS world-renowned TU-Series tuner accuracy in a convenient stompbox design
  • Mute/Bypass select for silent tuning with a single stomp
  • 11-point LED indicators and new “stream” meter display tuning discrepancy via speed and direction of LEDs (speed of LED movement gets slower as pitch becomes more accurate)
  • 7-segment LED displays string and note names, easily visible on dark stages
  • Seven easy tuning modes include Chromatic, Guitar Regular, Guitar Flat, Guitar Double Flat, Bass Regular, Bass Flat, Bass Double Flat
  • Tuning mode setting and display style choice stored in memory
  • Adjustable reference pitch from 438 to 445Hz
  • 8-octave tuning range—the widest in its class
  • Footswitchable Tuner Off mode preserves battery life by disabling LEDs

Now, if you’ve been following this blog, and you haven’t please do (you can follow me by subscribing to our RSS and receive updates via email or follow me on Twitter), you’ll remember a post a few days ago where I discuss buffered bypass. Many of the pedals today are true-bypass, and that is always listed as a ‘feature’ of the pedal, but if you’re signal has nothing but true-bypass, you could be experiencing some potential tone issues.

I’m still trying to put the pieces together and there is a lot of debate and discussion out there on the topic, but by having a completely true-bypass line, you’ll be converting your cables into capacitors, basically darkening your tone due to the length of the signal path. One way to correct this is by adding a couple of buffered bypass items in the chain to alter the impedance of the guitar signal.

I’m mentioning this because the Boss TU-2 has buffered input/output stages to achieve this. If you have many pedals and good cable length, you might want to try to add the pedal as the first thing or last thing depending cable lengths and number of pedals, etc. Some guys like to have a buffer at the front and the end of their line.

Bottom line, the Boss TU-2 Chromatic Stomp Box Pedal is a must-have for any guitarist pedal board out there. They’re built to last and just plain work.. forever. I’ve had mine for 10 years now and it works like the day I got it with countless stomps on it.

You can pick up the TU-2 at Musician’s Friend for $99.

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Oct 8 2009

Visual Sound (buffered bypass) and Route 808

Lastnight’s band practice we had our general gear tear-down, which always leads to gear talk. The interesting topic lastnight was about true bypass vs. buffered bypass. Many of the pedals promote they offer true bypass, and there are various loopers/switches that indicate buffered.  I wanted to learn more about this, and specifically about cable impedance and how it can dull your tone with true bypass pedals in your line.

So this morning, I started searching for some sound clips or videos related to the subject, and I came across this great video by Visual Sound that clearly describes the differences.

As you can see and hear that the buffered bypass provided a brighter tone vs. the true bypass pedal. It totally makes sense that the amount of cables (guitar to pedal and pedal to amp) can add large amount of capacitance to the signal.

I wasn’t too familiar with the Visual Sound stuff, and noticed that it was a Route 808 pedal in that demo. Since I just recently wrote a post about the TS9 which included a TS808 in there, I wanted to learn more, and found another video by Visual Sound (same demo) but a shoot out between the following pedals (TS808 TS original, Klon Centaur, Keeley Mod’d TS9, Fulltone Fulldrive 2 MosFet, Visual Sound Route 808). I thought how they did the shoot out was great, played the same piece, each pedal configured to be generally the same tone settings and drive.

I was quite impressed with the video. You can pick up a Visual Sound Route 808 on Musician’s Friend for $99.95 (list price is $148.00.. so that’s a 32% savings over list).

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