Buffered pedals, True Bypass Pedals and Long Leads

[ratman]

I found an interesting video on Pete Thorns You Tube page. (He's well worth checking out, a great player) It's a quick demo on how very long leads kill your tone, and how a buffered pedal put in the signal path can bring back the lost tone. I am no expert but I'm sure somebody here can enlighten us all with the physics as to how this works.
I have gone down the true bypass route in recent years like a lot of us have. At the June BC bash in Hatfield, Sibob gave an interesting chat on pedals where he touched on this subject. It was the first time I had heard about this, and It's got me thinking. Now I've found this video I'm sold.
I want to know why a signal going through true bypass pedals suffers without a buffer in the chain? What exactly does a buffer do?

http://www.youtube.com/watch?v=YOWeoizp4y0

[ratman]

Seriously, someone here has got to know something about impedance and buffering.....

[Count Bassy]

I think there's a thread about lead length & tone in the technical forum.

Basically the 'Buffer', as in most active basses, will have low output impedance, so any capacitance in the lead after the buffer will have little filtering effect. With a passive bass the output impedance is far higher and the combination of resistance and cable capacitance acts like a low pass filter. Good cables have very low capacitance anyway and so are less affected.

Edited August 27, 2013 by Count Bassy

[Mr. Foxen]

Short version is 'True bypass' is much cheaper to implement than a buffer. Then you call it a 'feature' and people don't twig they are getting stiffed. For consistent tone, you want a stable impedance on you pickups, as they are an inductor in a circuit with a resistor (the impedance) they act as a bandpass filter, if you constantly change the value of the resistor the tone changes with it (like turning a tone control), if you have a buffer, the impedance (the hypothetical resistor) stays the same, and the changes happen isolated from the circuit with the pickup in it.

Edit: another write up for reference: http://www.tech21nyc.com/technotes/

Edited August 27, 2013 by Mr. Foxen

[TimR]

As the video suggests. True bypass is what you want for short lengths of cable as the buffer built into the pedal can/will alter the tone.

If the cable length is very long, in the video they mention over 18ft and on a big stage could be 100m. Then, as the previos posters have said, the increased capacitance of the cable togther with the impedance of the bass acts as a filter. The longer the cable the lower the high frequency cutoff point. ie long cables lose treble.

Buffers will affect your tone so when playing with short cables you don't want them. IMO 18ft for bass isn't long!

It's a trade off.

Edited August 27, 2013 by TimR

[Silvia Bluejay]

Calling Sibob, Calling Sibob...

[dincz]

[quote name='TimR' timestamp='1377609240' post='2189330']
As the video suggests. True bypass is what you want for short lengths of cable as the buffer built into the pedal can/will alter the tone.[/quote]

There's no reason this should be so. It's dead easy to design/build small signal amplification stages that are dead flat from DC to hundreds of kilohertz, if not megahertz. There are more good reasons for including a buffer stage than there are for "true bypass" and its frequency-dependent loading effects on pickups.

If a buffer alters the tone, it's not a good buffer.

Edited August 27, 2013 by dincz

[Mr. Foxen]

Buffer will alter the tone from running unbuffered, suddenly you don't have chunks of it scooped out. Running into a high impedance can make quite a lot of difference.

[dincz]

[quote name='Mr. Foxen' timestamp='1377629124' post='2189684']
Buffer will alter the tone from running unbuffered, suddenly you don't have chunks of it scooped out. Running into a high impedance can make quite a lot of difference.
[/quote]

Point taken. I should have said "If a buffer degrades the tone ...."

[paul_5]

[quote name='dincz' timestamp='1377622680' post='2189557']
If a buffer alters the tone, it's not a good buffer.
[/quote]

How 'bout this one...
[url="http://s1221.photobucket.com/user/paul_510/media/cornish_buffer_zps9ba31ef1.png.html"][/url]

You could get away with a 2N5088 if you haven't got a BC549, or probably a 2N3904 would do just as well.

Edited August 27, 2013 by paul_5

[dincz]

[quote name='paul_5' timestamp='1377629673' post='2189695']
You could get away with a 2N5088 if you haven't got a BC549, or probably a 2N3904 would do just as well.
[/quote]

I think I've still got some BC109's. Not bad for an old buffer.

[thisnameistaken]

To be fair, the 'true bypass' thing got popular because there were so many poor buffers around. Most people have got a Boss pedal or three on their boards, and you can hear the effect a bypassed Boss box has on your signal.

But yeah, one good buffer permanently in your signal path, preferably as the first pedal your signal hits (so long as you don't have any pedals that require a high impedance at the input), is the way to go. I got Max at SFX to make me one.

[LukeFRC]

worth pointing out to folk who don't know but this is less relevant if playing an active bass...

[paul_5]

[quote name='LukeFRC' timestamp='1377633798' post='2189770']
worth pointing out to folk who don't know but this is less relevant if playing an active bass...
[/quote]

True dat. I've also found that certain pedals and headphone amps work better with a buffer to [i]lower[/i] the impedance of my active bass; EHX headphone amp sounds clearer after the buffer (High input impedance, low output impedance) than going straight in. My bass fuzzes in particular sound better like this also.

[Mr. Foxen]

Boss pedal buffered bypass is fine, some aren't bypassed though, ones that parallel process, digital ones and pitch shift ones can potentially not be buffered. It was the old wahs that really tone sucked due to having no bypass, meaning the signal always passed through the input circuitry even when the effect was off, those really improved with a true bypass switch, but a buffered one would have been even better.

[thisnameistaken]

[quote name='Mr. Foxen' timestamp='1377636551' post='2189820']
Boss pedal buffered bypass is fine,
[/quote]

It depends how much of your top end you really want. I could hear it on my OC-2s and on my LS-2. The LS-2 was the one pedal that was always in my signal path - I was using it as a buffer - and that's the one I asked Max at SFX to replace.

After I received the pedal from Max I A/Bed it in the same position against the LS-2 and, bypassed, there was a big difference. With the SFX pedal it's practically the same as running one cable direct to the amp. With the Boss there's a noticeable difference - the bass just doesn't sound as lively or present. Of course the Boss is better still than no buffer at all, but it's still not good enough IMO.

[Mr. Foxen]

Don't assume a cable straight to the amp is better. It may be different, but often a buffer will have higher impedance, and thus less tone effect than an amp input. The true bypass fallacy is all about the assumption cable straight to amp is better, regardless of lead length. A buffer removes lead length as a variable.

[TimR]

I leave all that top end to the guitarists.

Active bass into a 30m lead has been fine for me to go out front during sound check.

Keeping time with the drummer at that distance though...

[molan]

Pleased this rhread was started. It reminded me that I've got a stack of ludicrously expensive Analysis Plus cables sitting around doing nothing. All brand new and never used.

Must stick them up in the for sale section

[ratman]

Thanks to you all for your answers. I understand this a lot better now

[Telebass]

[quote name='LukeFRC' timestamp='1377633798' post='2189770']
worth pointing out to folk who don't know but this is less relevant if playing an active bass...
[/quote]
It's one of the reasons active instruments were invented.

[Happy Jack]

[quote name='Mr. Foxen' timestamp='1377638858' post='2189861']
Don't assume a cable straight to the amp is better. It may be different, but often a buffer will have higher impedance, and thus less tone effect than an amp input. The true bypass fallacy is all about the assumption cable straight to amp is better, regardless of lead length. A buffer removes lead length as a variable.
[/quote]

It's posts like this that serve to remind me just how little I understand about electrickery.

Increasingly, I give up on trying to understand WHY things sound better or worse (cos I can't, see?) and focus instead on how they sound to my ears, using nothing more sophisticated than trial & error.

I really would love to know what I'm doing, but I spend enough time learning to play bass without starting Electronics 101 at the same time ...

[uncle psychosis]

[quote name='Happy Jack' timestamp='1377851216' post='2192627']
It's posts like this that serve to remind me just how little I understand about electrickery.

Increasingly, I give up on trying to understand WHY things sound better or worse (cos I can't, see?) and focus instead on how they sound to my ears, using nothing more sophisticated than trial & error.

I really would love to know what I'm doing, but I spend enough time learning to play bass without starting Electronics 101 at the same time ...
[/quote]

This is definitely a good attitude to have! Most people's favourite records were all recorded by artists using gear that was riddled with electrical imperfections. Much better to spend your time practicing and writing music than worrying about whether or not the bypass on some boutique overdrive is buffered or not...

However, the basic principles of electical impedance aren't *that* complicated. Impedance is basically resistance, but for AC current. When you connect two electronic circuits together (eg an amp to a cab, or a guitar to an amp) you really want to match (confusingly this doesn't always mean "equal" either, but that doesn't matter) the impedances of the two circuits---if you don't then the signal doesn't pass as efficiently as it could (other things happen too, but I'm simplifying). This is why you need to be careful when matching cabs and amps. To think of an analogy thats easy to visualise---imagine light travelling through the air (circuit 1) and then striking a window (circuit 2). The impedance matching (or mismatching) between the window and the air govern how much light is reflected by the window and how much passes straight through. Simples

[BassTractor]

[quote name='uncle psychosis' timestamp='1377853341' post='2192675']
Simples
[/quote]


But at any rate, it's threads like this that make me grateful that BC exists.

[TimR]

[quote name='Happy Jack' timestamp='1377851216' post='2192627']


It's posts like this that serve to remind me just how little I understand about electrickery.

Increasingly, I give up on trying to understand WHY things sound better or worse (cos I can't, see?) and focus instead on how they sound to my ears, using nothing more sophisticated than trial & error.

I really would love to know what I'm doing, but I spend enough time learning to play bass without starting Electronics 101 at the same time ...
[/quote]

As things become more complicated and more varied. Trial and error becomes a very long process.

So you buy a long lead and your guitar sounds bad. You assume it's the new lead. What process of trial and error would then lead you to buying a buffer?

You don't need to understand how the buffer works, just what it does.

It stops the cable acting like a filter. It appears to act like a signal booster. Technically it is but doesn't boost the signal, just stops it from degrading.