True Bypass switching: myths, pro's, cons, alternatives...

All frequent questions on switching: true or not true bypass, transistor-based or mechanical.

Moderators: Greg, RnFR, moderators

  • Advertisement

Postby bajaman » 07 Nov 2007, 11:42

if you have a buffer in a circuit does this make everything after it in the signal chaning buffered?


NO

Think of the buffer as a way of isolating whatever is plugged in to it from whatever it is plugged in to - kinda like a firewall :lol: :wink:
If you plug a high impedance guitar directly into an effects pedal which has a low impedance input, then you are going to get some damping ,tone sucking, whatever you like to call it happening - sometimes this is desirable, as with the fuzz face, but most often it tends to take the sparkle or edge off your guitar sound because of the damping of the resonant peak inherent in all high impedance pickups.

The buffer (if it is a jfet or jfet input op amp) provides a very high input impedance to the guitar pickup and consequently has very little sound degrading effect - it will not dampen the resonant peak etc.
The output of a buffer can be made very low in impedance, and this will better match up to the input of the effects unit it feeds the guitar signal to.
Another advantage is that now you can take a further feed off the buffer output to send a low impedance buffered bypass signal to either the bypass switch or another effects pedal input , WITHOUT interfering with the guitar pickup response OR the original effect input it is also feeding.

Some of the best sounding circuits I have heard make extensive use of buffers - some have 3 or 4 within them at critical points in the circuit to effectively isolate the action of the individual processes from interacting with each successive section.

Stephen Moellers Vox AC30 simulator is a very good example of this approach.

Regarding BOSS effects pedals - many have buffers at the input, BUT many of them use bipolar transistors as emiter following buffer stages. IMHO these pedals suck tone big time, and YES, the CE-2 has a bipolar buffer. BUT, you can dramatically improve any of these pedals by replacing the bipolar transistor with the n channel JFET, AND, you do not have to change anything else, the jfet will give you a much better sound on bypass - try it and you will see what I mean.

Finally, check out my simple buffer design in the DIY Projects section - some kind forum member even contributed a vero board layout too. :wink: :wink:
cheers
bajaman
User avatar
bajaman
Old Solderhand
 
Posts: 3840
Joined: 26 Jun 2007, 22:18
Location: New Brighton, Christchurch, NZ
Has thanked: 201 times
Have thanks: 479 times

Postby R.G. » 08 Nov 2007, 14:17

guiltyspark wrote:I have about 6 TB pedals in series on my board. I've been thinking about measuring the capacitance and resistance of the chain when off. This should tell me something, not sure what though.

It will tell you how much loading is placed on your guitar signal. If it's wired right, you should get 1.068M resistance (assuming a typical tube amp input) and some number for capacitance. The capacitance is how much total capacitance is added by all the cables and wires on the way to the amp.

If you had a good electrical model of your guitar, you could then compute the amount of signal lost. However, no one has that. But you can realize that all capacitive loading on the raw guitar is bad, so the less the better.

There is an outfit called Creation Audio Labs that sells a box called The Redeemer. It's a very high class buffer. If you run your guitar into it and then into the rest of the signal chain, you'd be amazed at the added clarity of the bypassed sound. Other simple buffers get you most of the way there.

Buffers do this by making the sum of cable and wiring capacitance not matter. The guitar sees only the buffer input loading, which can be very, very small.
R.G.
Resistor Ronker
 
Posts: 312
Joined: 22 Sep 2007, 03:24
Has thanked: 0 time
Have thanks: 26 times

Postby R.G. » 08 Nov 2007, 14:23

solderboy wrote:does it count, where in the FX Chain a Buffer is placed?

Yes, big time. You get 95% of the value by making the buffer the first thing the guitar touches, and another few percent if it's on the guitar.
solderboy wrote:Yesterday i tried out the A/B comparisation by plugging the Guitar directly into the Amp and... wow.wow.wow... YES... better Signal !!!

It gets even better if you can buffer at the guitar, before loading it with that cable that goes to the amp.
solderboy wrote:But in my FX Chain are Buffers....
My FX Chain is as follows:
Guitar -> WahWah(TrueBypass) -> DIYOverdrive (TrueBypass) -> ZoomUltraFuzz (has Buffer(s)) -> Boss CE-3 Chorus (Buffer) -> Boutique Phaser MEK (Millenium Bypass) -> Amp
After the Zoom there was placed a RogerMayerClassicFuzz (DIY), but i didnt need it anymore, so it flow out of the Chain..
The Zoom seem to have quite good Buffers, because there is no hearable influence to the Signal...
But i think the Boss is sucking Signal ... I tried some changes
and throw out the Boss, than the Zoom and at least the Phaser..

The Tone only with the Wah and DIY Overdrive was than the same as it is with guitar directly into the Amp.. no Buffers... (but only few TB Effects)

makes it a difference, where a Buffer or good buffered Pedal is placed into the Chain??

Yes, it does. The earlier, the better.

N.B.
There are a few effects, like germanium fuzz faces, that need an unbuffered signal to produce the sound you expect from them. These can still be used buffered by placing some resistance (10K - 50K) in series with their inputs.
R.G.
Resistor Ronker
 
Posts: 312
Joined: 22 Sep 2007, 03:24
Has thanked: 0 time
Have thanks: 26 times

Postby CS Jones » 22 Nov 2007, 23:31

There is an outfit called Creation Audio Labs that sells a box called The Redeemer. It's a very high class buffer. If you run your guitar into it and then into the rest of the signal chain, you'd be amazed at the added clarity of the bypassed sound.


So you've played that then? I ragged on it pretty hard a couple of years ago. I figured it was just more of the same old boutique GASCAP (guess and swap, cut and paste) bullcrap. These guys are legit, engineering wise? I might need something like this as I'm moving over into playing celtic music at acoustic gigs.
CS Jones
 
Posts: 44
Joined: 05 Jul 2007, 07:31
Has thanked: 0 time
Have thanks: 0 time

Postby Redhouse » 30 Nov 2007, 04:52

bajaman wrote:Here is something for you true bypass fans to try - connect 3 true bypass pedals together in a chain, then play your guitar through them, with them all set to bypass - OKAY.
NEXT, plug your guitar straight in to your amp (no pedals) :wink:
Well - i bet you heard the loss of tone :wink: :(

...give it a try :wink:
Cheers
bajaman


Well I'm of a different opinion, not only have I tried it, but as for myself (and others who've attended our "blind" testing-for-fun) I tend to disagree somewhat.

When listening without knowing which-was-which (no visual clues) no one, could repeatedly tell the difference between a straight guitar cable and the 6-effect (big-test-box ala Cornish style) unit in true bypass we were listening to. I'm reminded of the literally miles of cable in a quality mixing desk as opposed to his (Pete C) essay on true bypass...hmmm.

Ok so say what you like (I'm nobody, what does he know etc.) but I disagree alot with the Cornish explanation of the sum of the bypass cable thing he wrote-up, most internal bypass wiring is not high capacitance cable and anyway a few pF at 8k-10k isn't a real big deal if anything it is often percieved as a benefit, lower noise as hiss is often associated with the silibacnce levels which might be effected with even 100pF@100k).

Another thing to consider, which is a totally Cornish-free thought (and quite argueable I suppose) is that most of the best recorded guitar tone's in History have come through high capacitance, not-expensive, long >10', non audiophile, >20pF/10ft, cables (well maybe except D Gilmore)

Look at Hendrix, Nugent, Betts and many more used those coily-cords which are beyond arguement as the epitome of capacative cables, more than most normal cables of their day, and definately more than any modern (1/2 decent meaning like $25/25ft) cable of today.

IMHO, buffers are ok, they do a job, but they can also interfere with the interaction between the guitar pickup's and the input of the first effect they hit.

Case in point (excluding transistor mojo and lore) many prefer the FuzzFace to the Tonebender MKII. To the novice they sound very much the same, to the musician they sound very much the same BUT "react" different to their playing style and dynamics, hence players with more finger control prefer FuzzFace's, and players with more percussive attack prefer the Tonebender. The buffer in the front of the Tonebender absorbs much of the (to some) annoying qualities of the FF, while to others it robs the nuances of their style and makes them play less "in touch".

I'm reminded of the last time friends and I did blind-testing at my friends home studio (he has a 30k Speck board, 3x24 ADAT's, Blue/Senheiser/Shure mikes[/i] etc lives a long way away, don't get to hang out very often) we were listening to 3 wah's, two of which I had modified for folks and one was a fairly stock GCB-95 with a switchable input buffer. The long-and-short of it was, all (present were 7 musicians, 3 were electronics related) agreed that the buffer in the Dunlop sounded better, more clear, no grit, less variance from low-to-high in the sweep, but ruined the way the wah interacted with the guitar pickups.

The buffer specifically lost the growl the wah had at the low-mid point of travel (think opening riffs of Hear My Train A Comin, or Money For Nothing) at the end of the day all agreed that better overall sound was achieved with a buffer ...but also... all agreed that better overall "character" was achieved with the guitar straight in to a normal VOX/Thomas type wah (with no input buffer) wah.

So in my mind while buffers do help things, in a way, and have measurable value, to the musicians ear (which is THE litmas test really) the character of the tone is more significant and buffering can flatten the character of the effect.


R.G. wrote:...you can realize that all capacitive loading on the raw guitar is bad, so the less the better....


I would disagree, too sweeping a statement (it's only my opinion, don't get upset) and considering music more with the mind and less with the ears. Was it not capacative loading that allowed Hendrix to live on the verge of feedback, without killing people (dogs, birds, plant life, single cell ameaba etc.) before you answer read on...

I'm reminded of the EMP Museum in Seattle (I live in the area) where his white Woodstock Strat currently resides, Fender asked EMP if they could come up and open it up to profile it for a special Hendrix model they were doing back in 2002 or '03, and they found a.... whoa!.... yep a .1uF tone cap, yep, not a .022 or .047 or an old Tele .056, nope the Godfather of feedback had a .1uF tone cap (on a 250k pot), geez, talk about capacitive loading! no room for argument here, all one needs to hear how much non-treble loss 'ol Hendrix had is to just pop-in a copy of the Woodstock Tape/DVD and let 'er (him) rip....(or R.I.P. as it were)

Just for kicks, just try this at home, if you have a Strat drop a .1uF cap in there and see what your sound does (I did, it came right back out) nope it takes a special man with a full-blast 1959SLP and a .1uF tone cap (and a old funky coily-cord) to rip the paint off the walls with non-loss-o-treble like that man did.

Anyway, food for thought, buffers definately have a place in electronics, but, not always in a musican's tone character, and it isn't always automatically about capacitance or treble loss issues IMHO.
(YMMV)

-Brad
(Redhouse)
User avatar
Redhouse
Breadboard Brother
 
Posts: 92
Joined: 29 Nov 2007, 15:34
Location: Sammamish, USA
Has thanked: 2 times
Have thanks: 0 time

Postby bajaman » 30 Nov 2007, 09:11

Brad - very interesting points - thanks for raising them and sharing them with us all here :)
bajaman
User avatar
bajaman
Old Solderhand
 
Posts: 3840
Joined: 26 Jun 2007, 22:18
Location: New Brighton, Christchurch, NZ
Has thanked: 201 times
Have thanks: 479 times

Postby R.G. » 01 Dec 2007, 04:28

Redhouse wrote:I'm reminded of the literally miles of cable in a quality mixing desk as opposed to his (Pete C) essay on true bypass...hmmm.

It matters a great deal what impedance is driving the capacitance of the miles of cable. Those miles in a quality mixing desk are largely driven by impedances well under 10K, probably well under 1K. A guitar pickup's few Henries of inductance has a source impedance well into the megohms out in the treble region, so capacitance affects it proportionately.

Redhouse wrote:IMHO, buffers are ok, they do a job, but they can also interfere with the interaction between the guitar pickup's and the input of the first effect they hit.

They do, and do so in a calculable way. There isn't any magic there, just the numbers.

Redhouse wrote:Case in point (excluding transistor mojo and lore) many prefer the FuzzFace to the Tonebender MKII. To the novice they sound very much the same, to the musician they sound very much the same BUT "react" different to their playing style and dynamics, hence players with more finger control prefer FuzzFace's, and players with more percussive attack prefer the Tonebender. The buffer in the front of the Tonebender absorbs much of the (to some) annoying qualities of the FF, while to others it robs the nuances of their style and makes them play less "in touch".

Depends on the musician, as you note.
Redhouse wrote:I'm reminded of the last time friends and I did blind-testing at my friends home studio (he has a 30k Speck board, 3x24 ADAT's, Blue/Senheiser/Shure mikes[/i] etc lives a long way away, don't get to hang out very often) we were listening to 3 wah's, two of which I had modified for folks and one was a fairly stock GCB-95 with a switchable input buffer. The long-and-short of it was, all (present were 7 musicians, 3 were electronics related) agreed that the buffer in the Dunlop sounded better, more clear, no grit, less variance from low-to-high in the sweep, but ruined the way the wah interacted with the guitar pickups.


Redhouse wrote:The buffer specifically lost the growl the wah had at the low-mid point of travel (think opening riffs of Hear My Train A Comin, or Money For Nothing) at the end of the day all agreed that better overall sound was achieved with a buffer ...but also... all agreed that better overall "character" was achieved with the guitar straight in to a normal VOX/Thomas type wah (with no input buffer) wah.

So in my mind while buffers do help things, in a way, and have measurable value, to the musicians ear (which is THE litmas test really) the character of the tone is more significant and buffering can flatten the character of the effect.

I'd say that a different way. Keep reading.

Redhouse wrote:I would disagree, too sweeping a statement (it's only my opinion, don't get upset) and considering music more with the mind and less with the ears. Was it not capacative loading that allowed Hendrix to live on the verge of feedback, without killing people (dogs, birds, plant life, single cell ameaba etc.) before you answer read on...

I'm reminded of the EMP Museum in Seattle (I live in the area) where his white Woodstock Strat currently resides, Fender asked EMP if they could come up and open it up to profile it for a special Hendrix model they were doing back in 2002 or '03, and they found a.... whoa!.... yep a .1uF tone cap, yep, not a .022 or .047 or an old Tele .056, nope the Godfather of feedback had a .1uF tone cap (on a 250k pot), geez, talk about capacitive loading! ...
Anyway, food for thought, buffers definately have a place in electronics, but, not always in a musican's tone character, and it isn't always automatically about capacitance or treble loss issues IMHO.

No, it's not always about capacitance or treble loss. To the musician, it's about control - the ability to coax those nuances out of whatever they're playing on. Historically, musicianship and technical understanding were on the opposite sides of the world. Musicians had to find out how to hold and move their hands, haul around on the instruments, abuse the amplifiers, the speakers, everything to find some nuance they could control. Woodwind players get downright abusive to reeds. Guitarists abuse strings, bridges, necks fretboards, etc, etc.

Jimi and the other mega-loud players had to cut treble to live in a 140db world on stage. He (and the others) affected that change where he could control it, on the guitar. I suspect he may have liked experimenting with a well-buffered guitar, considering what his performances had to do his hearing.

At the bottom of the pile of reasoning is this business about nuances. When you do something to remove them, they're gone. Your concern is about nuances of effect interaction with an effect input. That's OK, but a well buffered signal preserves the treble nuances that are flatly removed by loading. Not all musicians like that.

When the treble is gone, it's gone. No amount of treble boost later will put it back without incredible hiss as well.

On the other hand, you CAN put impedance back. I've had a few test sessions with people trying a fuzz face with an inductor/resistor in front of it. They found little issue with the inductor/resistors supplying the impedance after a buffer.

There isn't any one answer. Knowing all the possible things to do lets a techno-musician adapt his answers to where he needs them.
R.G.
Resistor Ronker
 
Posts: 312
Joined: 22 Sep 2007, 03:24
Has thanked: 0 time
Have thanks: 26 times

Postby Redhouse » 03 Dec 2007, 00:57

R.G. wrote:At the bottom of the pile of reasoning is this business about nuances. When you do something to remove them, they're gone. Your concern is about nuances of effect interaction with an effect input. That's OK, but a well buffered signal preserves the treble nuances that are flatly removed by loading. Not all musicians like that.

When the treble is gone, it's gone. No amount of treble boost later will put it back without incredible hiss as well.


Yep, so often in life artistic ability flies in the face of intellectual reasoning but we can leave that for another subject/thread just now I would think.

It's undeniable that impedance can effect things as you say RG, most certainly, but luckily for us most effects (and amps) are in fact in the ballpark if not right where they need to be, sure some may be a little high, some a little low, but none are so off-base that the "treble nuances that are flatly removed by loading" that's a little bit of a stretch.

Not to be a smart-ass, but I just can't think of any pedals off hand that we deal with in the DIY effects that are that far-out of the impedance ballpark that they flatly remove treble by their loading effects, maybe you could help me out here and tell me what effects we're talking about that automatically benefit from additional buffering to stop the treble nuances from being flatly removed by loading?

Usually effects that are close to that are the unique sounding ones (FF, Wah etc.) that kinda need the weird interaction (loading) with the guitar.

Anyway, mine is just an opposing opinion to the better living through buffers crowd, no need to get yer nickers in a twist. I think buffers have a place, have value, have merit, but I just don't think they're as needed as the DIY community tends to make them seem, and 'ol Cornish likes to make additional buffering sound like a mandatory part of modern effects implementations.

Just my opinion, ...to add to all the rest.
User avatar
Redhouse
Breadboard Brother
 
Posts: 92
Joined: 29 Nov 2007, 15:34
Location: Sammamish, USA
Has thanked: 2 times
Have thanks: 0 time

Postby Coony » 03 Dec 2007, 12:20

Jack Orman has a nice article in his lab notebook about TB...
Another opinion?

Best Regards,
Koen
Coony
 
Posts: 1
Joined: 03 Dec 2007, 10:47
Has thanked: 0 time
Have thanks: 0 time

Postby Redhouse » 07 Dec 2007, 02:45

Coony wrote:Jack Orman has a nice article in his lab notebook about TB...
Another opinion?

Best Regards,
Koen


I would agree with Jack's observations. In particular "measurements that were made for this article have revealed that it is not problem in practice to chain together numerous true bypass pedals...and....Buy true bypass when you can. Always use good quality cables and go ahead and chain your pedals together. Then, don't worry any more about it and just start jammin'!"

http://www.muzique.com/lab/truebypass.htm

Jack knows what time it is, and when it's time to let the brain rest, let the talent rip.

Sometimes we beat things to death on the DIY boards, and to the noob's sometimes we make some things sound mandatory which aren't necessarily so.
User avatar
Redhouse
Breadboard Brother
 
Posts: 92
Joined: 29 Nov 2007, 15:34
Location: Sammamish, USA
Has thanked: 2 times
Have thanks: 0 time

Postby jrc4558 » 21 Dec 2007, 23:29

I personally have more issues with electronic switching than with a bypass being buffered. Especially Boss/Ibanez discrete Flip-Flop. On distortion pedals, the dirty signal leaks through fets back into the clean bypass signal line. Fets are never perfectly off, and with such a wide tolerance range as fets have, there's no surprise that sometimes there's some distortion audible in the clean signal.
My pedalboard is buffered, but all the switching is done mechanically.
jrc4558
Solder Soldier
 
Posts: 172
Joined: 25 Aug 2007, 08:13
Location: Toronto, Canada
Has thanked: 1 time
Have thanks: 1 time

Postby vhollund » 12 Jan 2008, 15:36

...
Vaughn Hollund
vhollund
 
Posts: 34
Joined: 09 Jan 2008, 01:20
Has thanked: 0 time
Have thanks: 0 time

Postby R.G. » 14 Jan 2008, 15:45

jrc4558 wrote:I personally have more issues with electronic switching than with a bypass being buffered. Especially Boss/Ibanez discrete Flip-Flop. On distortion pedals, the dirty signal leaks through fets back into the clean bypass signal line. Fets are never perfectly off, and with such a wide tolerance range as fets have, there's no surprise that sometimes there's some distortion audible in the clean signal.

I believe you're generalizing from a few bad cases.

Fact is, NO switch is ever perfectly off. The attenuation of signal is something that can be directly measured, given suitable instrumentation. A **properly designed** FET switch can be very 'off', at least as 'off' as a mechanical switch. What FETS suffer from in comparison to mechanical switches is that their resistance is never as low as a hard-contact switch.

Don't confuse the cheapest, most haphazardly designed example of a technology with the technology's inherent capabilities. It took a long time to get from the Chinese gunpowder rockets to ICBMs, yes? It took a while to get from Resistor-Transistor-Logic to that computer you're looking at, yes?
R.G.
Resistor Ronker
 
Posts: 312
Joined: 22 Sep 2007, 03:24
Has thanked: 0 time
Have thanks: 26 times

Postby Ronsonic » 10 Feb 2008, 00:22

Here's something I consider important that never seems to get addressed. All the vintage pedals had some amount of tone suck, some were severe. The answer was to simply turn the knobs on the amp. No problem. Now we come along and we take this Fuzz Face (a near perfect example) and we wire in a DPDT and the tone suck is gone and we can turn the treble knob down. Except now our FF sounds like a mudslide because the thing was originally voiced so that the effected tone was well balanced to the tonesucked sound and we got rid of that.

This is something I think we all need to be aware of experimenting with vintage designs and something I'll warn customers about.

For myself, I usually put the pedals that need to see the guitar to sound right like the wah or fuzz first and then something with a buffer to do the line driving. My tuner works great for that but I keep feeling the need to build a special buffer/switcher box, just because.

Ron
Ronsonic
Breadboard Brother
 
Posts: 148
Joined: 07 Feb 2008, 17:56
Location: Sunny Tampa, Florida
Has thanked: 0 time
Have thanks: 0 time

Re:

Postby MKB » 02 Jun 2008, 14:42

R.G. wrote:On the other hand, you CAN put impedance back. I've had a few test sessions with people trying a fuzz face with an inductor/resistor in front of it. They found little issue with the inductor/resistors supplying the impedance after a buffer.

FWIW, I LOVE the sound of a Fuzz Face with a FET buffer in front, with a series resistance restoring the high impedance. I was working with the Fuller mods (namely the 50K series input pot as mentioned in R.G.'s Fuzz Face page), and you get a very interesting tone with that pot turned up and a good FET buffer in front. For one thing, your humbuckers don't turn to mud anymore. Try it if you haven't yet, you'll be surprised.
MKB
Breadboard Brother
 
Posts: 92
Joined: 06 Sep 2007, 13:03
Location: USA
Has thanked: 0 time
Have thanks: 0 time

Re: True Bypass switching: myths, pro's, cons, alternatives...

Postby kurtlives » 24 Aug 2008, 03:27

I need help...I cant decide on something...

Should I TB my BD-2... should TB it and remove the buffers or should I keep it stock?

I already have quite a few TB pedals... I cant decide.
kurtlives
Solder Soldier
 
Posts: 175
Joined: 20 Jan 2008, 03:18
Location: Toronto, Canada.
Has thanked: 0 time
Have thanks: 3 times

Re: True Bypass switching: myths, pro's, cons, alternatives...

Postby jrc4558 » 27 Aug 2008, 19:01

You should short the switching fets and switch the whole thing (input jack to output jack). That is, if you like the way it sounds already.
Good luck, fellow Torontonian!
jrc4558
Solder Soldier
 
Posts: 172
Joined: 25 Aug 2007, 08:13
Location: Toronto, Canada
Has thanked: 1 time
Have thanks: 1 time

Re: True Bypass switching: myths, pro's, cons, alternatives...

Postby kurtlives » 28 Aug 2008, 15:23

Thanks for the advice...

Where are ya in Toronto?
kurtlives
Solder Soldier
 
Posts: 175
Joined: 20 Jan 2008, 03:18
Location: Toronto, Canada.
Has thanked: 0 time
Have thanks: 3 times

Re: True Bypass switching: myths, pro's, cons, alternatives...

Postby jrc4558 » 28 Aug 2008, 18:48

kurtlives wrote:Thanks for the advice...

Where are ya in Toronto?

PM sent
jrc4558
Solder Soldier
 
Posts: 172
Joined: 25 Aug 2007, 08:13
Location: Toronto, Canada
Has thanked: 1 time
Have thanks: 1 time

Re: True Bypass switching: myths, pro's, cons, alternatives...

Postby kurtlives » 28 Aug 2008, 19:24

Didnt get it?
kurtlives
Solder Soldier
 
Posts: 175
Joined: 20 Jan 2008, 03:18
Location: Toronto, Canada.
Has thanked: 0 time
Have thanks: 3 times

PreviousNext

Return to Switching & Wiring

Who is online

Users browsing this forum: No registered users and 3 guests