Buffer in Pedal Chain?

chunkmonk

I'm looking to add a true bypass looper ( the pedal switch variety, not the recording type) to tidy up my new pedalboard setup, and wondering if I need to add a buffer to the looper.

The 1st two pedals are a Wah and Fuzz and the remaining are true bypass pedals, a combination of Compressor, OD (x2) and Delay. I'm aware that a buffer is always placed after Wah and Fuzz, but rather than place a buffer mid-looper, post Wah and Fuzz, can it be placed at the end of the looper and still have the required functionality or it it better placed mid-looper

Any advice greatly received.....

simonk

I'd stick it as near to the front of the chain as the fuzz and wah will allow.

english_bob

My understanding is that a buffer's job is to convert the high impedance signal from your guitar to a low impedance signal that is not affected by cable capacitance- most noticeably, cable capacitance results in loss of high end, and the effect increases the more cable your signal has to travel through.

By that logic, you should put the buffer as early in your signal chain as you can, since it'll only eliminate the capacitance effect from the cable between the buffer and the amp, not before that point. 

Of course, it's not quite that simple. Cable capacitance can affect midrange gain as well as high end loss, so some players actually like the effect of a long cable run on their sound. Not all fuzz pedals get upset after a buffer either- Fuzz Faces certainly do, but I don't think Big Muff type fuzzes or other more modern designs do. It might be worth trying your board with a buffer in different locations if you're unsure. Or the person making your TB looper (assuming it's not you of course) might be able to offer some advice.

ICBM

It's usually OK to put the buffer much later in the pedal chain, or even at the end. In an all-true-bypass board, the biggest problem is the capacitance of the long cable to the amp, which is only loading the guitar when all the pedals are off - as soon as even one pedal is on, there is a buffer of sorts and the load doesn't matter, so the sound will be brighter… ie it will make the all-bypass sound seem dull. By comparison, the capacitances of the short patch cables is relatively small, unless you've got dozens of pedals, so the difference between a pedal being on before one is small.

Gassage

First. I am adamant about this.

Gassage

ICBM said:

It's usually OK to put the buffer much later in the pedal chain, or even at the end. In an all-true-bypass board, the biggest problem is the capacitance of the long cable to the amp, which is only loading the guitar when all the pedals are off - as soon as even one pedal is on, there is a buffer of sorts and the load doesn't matter, so the sound will be brighter… ie it will make the all-bypass sound seem dull. By comparison, the capacitances of the short patch cables is relatively small, unless you've got dozens of pedals, so the difference between a pedal being on before one is small.

@icbm

I sort of agree, but I also think you need to understand that every time you blend a lot of different pedals, so the impedence changes hugely- so a combo of a, b and f may be wholly diff to b, c and g. If that makes sense.

ICBM

Gassage said:

@icbm ;

I sort of agree, but I also think you need to understand that every time you blend a lot of different pedals, so the impedence changes hugely- so a combo of a, b and f may be wholly diff to b, c and g. If that makes sense.

The output impedance - and hence how well it drives the following cable - is only dependent on the last pedal which is on. The preceding ones have no effect because they are not driving anything more than the patch cable(s) after them. Each pedal completely blocks the impedance characteristics of any preceding ones when it's on.

Of course if you use proper pedals like Pete Cornish or Boss then you don't need to worry anyway because each is identically buffered .

chunkmonk

Cheers guys.....

dindude

ICBM said:

It's usually OK to put the buffer much later in the pedal chain, or even at the end. In an all-true-bypass board, the biggest problem is the capacitance of the long cable to the amp, which is only loading the guitar when all the pedals are off - as soon as even one pedal is on, there is a buffer of sorts and the load doesn't matter, so the sound will be brighter… ie it will make the all-bypass sound seem dull. By comparison, the capacitances of the short patch cables is relatively small, unless you've got dozens of pedals, so the difference between a pedal being on before one is small.

Kind of the principle I've always worked with. I find anything up to 4 or possibly 5 TB pedals and a good buffer at the end is sufficient. The way I get round more
these days is I always have at least one pedal on, my core "no effects" clean tone still has a very mild compressor kicked in. 

Don't agree with the slap one at the front ethos, I've found it to make my drives sound shrill.

ecc83

ICBM is on the money but I don't agree with the other comment that cable capacitance can affect mid range frequencies* (it forms a "first order filter with whatever the source impedance is and the function is well known nay, caste in stone!) .

The sole exception is where a capacitance is directly connected to passive guitar pickups, i.e. pots at max. Then it forms a resonant system and the response will have a "hump", possibly at some mid range frequency. The resonance will vary hugely for different pups and to a lesser degree the loading by following circuits. The whole resonance/cable/Z in/Zout/pedal characteristic and WIDDLE factor is SO complex it can only be understood by the most systematic of operations (any activity with more than 7 variables becomes "art" not science!)

*Of course, IF you had an absolutely huge cable many tens of mtrs long and of several nFs of capacitance you would start to get a roll off around 1-2kHz but I bet you would be more worried about hum!

Dave.

Gassage

ICBM said:

Gassage said:

@icbm ;

I sort of agree, but I also think you need to understand that every time you blend a lot of different pedals, so the impedence changes hugely- so a combo of a, b and f may be wholly diff to b, c and g. If that makes sense.

The output impedance - and hence how well it drives the following cable - is only dependent on the last pedal which is on. The preceding ones have no effect because they are not driving anything more than the patch cable(s) after them. Each pedal completely blocks the impedance characteristics of any preceding ones when it's on.

Of course if you use proper pedals like Pete Cornish or Boss then you don't need to worry anyway because each is identically buffered .

Even with the buffers, the 'last on' tends to rule volume.

ICBM

Gassage said:

Even with the buffers, the 'last on' tends to rule volume.

Exactly, for the same reason. The only time you really notice the cumulative effect is if you're using multiple Boss-type buffers, which have very slightly less than unity gain - the level drop from one isn't noticeable, but string up half a dozen together and it is… although it's still so small that it's perceived as a 'tone suck' rather than a volume loss. Still, all you need to fix it is a buffer at the end with a level boost - if you set it back to where it is at the start of the chain the 'tone suck' goes away.

I found that it's very simple to mod a GE-7's pre-emphasis/de-emphasis circuit to do this - which then made me wonder if that's why a certain person has (or did have, I don't know if he still does) a GE-7 at the end of each sub-chain in his set-up...

english_bob

dindude said:

ICBM said:

It's usually OK to put the buffer much later in the pedal chain, or even at the end. In an all-true-bypass board, the biggest problem is the capacitance of the long cable to the amp, which is only loading the guitar when all the pedals are off - as soon as even one pedal is on, there is a buffer of sorts and the load doesn't matter, so the sound will be brighter… ie it will make the all-bypass sound seem dull. By comparison, the capacitances of the short patch cables is relatively small, unless you've got dozens of pedals, so the difference between a pedal being on before one is small.

Kind of the principle I've always worked with. I find anything up to 4 or possibly 5 TB pedals and a good buffer at the end is sufficient. The way I get round more
these days is I always have at least one pedal on, my core "no effects" clean tone still has a very mild compressor kicked in. 

Don't agree with the slap one at the front ethos, I've found it to make my drives sound shrill.

Hmm. You've got me wondering now. I built a buffer in to my pedalboard patchbay and put it first in the signal chain on the assumption that it would be the best position for it. It ain't broke, so I probably shouldn't try to fix it, but I might try moving it later in the chain. 

FWIW, I'm using the four-cable method with 20' cables in each position (overkill for most places, sure, but I've played on a few stages where I've needed it). Everything in front of the amp is TB I think, but I'm guessing I'd want the buffer before the cables running to and from the loop.

chunkmonk

Thanks...interesting to get the thoughts of others.....My initial thoughts were to have a buffer built into the output of the true bypass looper as a way to cover all bases, but now  thinking it maybe wise just run a boost pedal from one of the looper outputs with a built in buffer for versatility.

Lebarque

One buffer after dirt, before modulation etc for me.

ICBM

english_bob said:

FWIW, I'm using the four-cable method with 20' cables in each position (overkill for most places, sure, but I've played on a few stages where I've needed it). Everything in front of the amp is TB I think, but I'm guessing I'd want the buffer before the cables running to and from the loop.

Probably not necessarily if the loop is decent - but it might be if it's not… what's the amp?

english_bob

ICBM said:

english_bob said:

FWIW, I'm using the four-cable method with 20' cables in each position (overkill for most places, sure, but I've played on a few stages where I've needed it). Everything in front of the amp is TB I think, but I'm guessing I'd want the buffer before the cables running to and from the loop.

Probably not necessarily if the loop is decent - but it might be if it's not… what's the amp?

Laney Lionheart. I've modded the loop to series. 

There was definitely an improvement in tone when I added the buffer- I hate to use the old "lifting a blanket off the amp" line, but that's what happened. Now just wondering whether moving the buffer might make any further improvement. 

ICBM

english_bob said:

Laney Lionheart. I've modded the loop to series. 

There was definitely an improvement in tone when I added the buffer- I hate to use the old "lifting a blanket off the amp" line, but that's what happened. Now just wondering whether moving the buffer might make any further improvement. 

Do you have the buffer immediately at the amp's FX send - amp > patch cable > buffer > 20' cable to board - or amp > 20' cable > buffer on board? If the second, try the first. That's probably a pain with power supply cabling though.

english_bob

No, the buffer is built in to a patch box on my pedalboard, which handles all the send/return connections.

So I have four options of where to put it that I can achieve just by swapping connections on the patchbox (externally for now), and don't involve making a new enclosure for it and/or faffing about with sending power to it. Either right at the start of the signal chain (where it is now), or last thing before the amp input (which would put it after my ODs and an analogue octaver that seems to be quite sensitive to input signal), after the effects loop send cable or right before the effects loop return, right at the end of the chain.

Voxman

I have a relatively simple pedal board: Boss Tu12H tuner (not 'true' buffer)>Boss CS3>Behringer To800>Marshall GVII>Marshall EH1> Marshall RG1>Boss GE-7 EQ.  Both the Boss pedals are buffered and although there is a short patch lead connecting the Tu12H to the CS3 its not a long enough cable to make any noticeable difference on tone (ie the buffer starts after the tuner).

But I have a query with regards to my Line 6 G10 Relay which mimics a 10ft guitar cable - it appears to act like a buffer in preserving higher frequencies - but is it actually a buffer?     

ICBM

Voxman said:

Boss Tu12H tuner (not 'true' buffer)>Boss CS3

I think we've mentioned that before - the TU-12H is *not* buffered in the usual sense. The tuner circuit input is so it's not a huge load on the signal path - but the output is just a parallel jack connected to the input, so it makes no difference to the following cable, which is still driven by the guitar. Of course if that goes to a CS-3 it's then buffered from then on.

But it certainly isn't buffered in the sense that the TU-2/TU-3 are, which have a true buffer driving the output.