Pedal Tone Suck

[rgorke]

I did a little experiment to see if and how much some of my pedal suck the high end off. I was noticing a bit of high end loss but was wondering if it was just my ears. So, I put 5 pedals in a loop, two of which are true bypass (Joyo tube screamer, modded MXR blue 6 band EQ), I also have a Boss EQ, a vintage MXR Flanger and a script logo MXR Phase 90.

So the chain is guitar > loop (Above pedals) > into Echoplex true bypass switcher to amp.

Holy Smokes....switching the loop off and on is like taking 40 of grandma's quilts off the cabinet.

Has anyone else tried this with their pedals? Would a buffer help the most? Or just have a loop with stuff in it? I'll see if I can post a clip, the difference is striking.

Thanks

EDIT: So, 2 1/2 hours later and another experiment is putting my Boss TU2 tuner pedal (with what ever buffer Boss puts in those) the improvement is dramatic. Is it perfect? Almost. There is just an ever so slight high end roll off but frankly it is nearly identical.

Thanks for your attention.

[Haze13]

Boss EQ is not True Bypass, but it has a buffer in it (tone sucking one ) than there is that thing that MXR pedals use - Millennium Bypass. Half of your signal goes to the pedal, half to the bypass.
To be honest even if all of your pedals were true bypass you will hear a difference. Short good cable effects the sound much less than a long one, and if you have 3pdt switches in between it's even worse.
True bypass prevents you from using the switching transistors in your pedal, by doing that it's improves the tone/sound (less components in the signal path). Effect bypass is just a bonus.

[Haze13]

Problem with buffer is that you don't need in every pedal, only one! A very good one before all your pedals. Maybe another one between wah and fuzz if you use that combination. But another problem that you will face is that almost every pedal use a buffer, a very cheap and a very bad one. So if you will use a good one and lots of bad ones it will make unwanted noise. Good thing is to remove all buffers from these pedals and to live a happy life with only one.

BUFFER: The whole point in this thing is not to hear it. It's has to as transparent as possible and to leave all the coloration of the sound to pedals/effects that were made to make that very thing.
As you know the most famous one is CR high pass filter in to BJT cathode follower and CR high pass filter as an output and of course with a reference to the voltage divider (Vb). And don't forget the cheap components. This thing by default can't sound good!

[rgorke]

Yeah, I knew all that intellectually (short cables, true bypass, etc) but had never really heard it as bad in my rig.

I had in the past looked into building a buffer, maybe the one by Pete Cornish.

[JimiJames]

Hey guys.... there are plenty of pedals that when even when "on" and not true Bypass are not actually low (enough) impedance. Active when off does not automatically = low output impedance. Some have a level pot as the last component leaving you with a variable output impedance, If they do I would find out what the value of the pot is and the worst case will usually be that /4. So a 50K pot could be a 12.5K output impedance, not such a great number. There are many pedals around that are not great buffers. There is also the ability to drive which matters in conjunction with the output impedance. The buffer can run out of steam so to speak even being a low output impedance it may not have the current drive capability to get the job done. All buffers are NOT created equally and you will find tonal differences between them. I would suggest finding out the actual worst case specs of the device instead of guessing on the need or not. It also helps to actually measure the capacitance of the chain if you have a good LCR meter. Pedal board cabling and wiring inside the pedals can add up to considerable capacitance.
This is all easy to hear if you have the buffer of course. If there is no change with the buffer in that position you didn't need it there. Ideally you should not hear any difference with the whole pedal board in or out.- TGP -Husky- aka Suhr-
05-28-2013

[Haze13]

For transparent buffer I'll go to the world of Hi-Fi.
First one is designed by Nelson Pass called "Pass Labs B1 Buffer" it's far more superior than Pete Cornish buffer.
It uses more voltage, better components, 2 x 2sk170BL matched transistors.

Another buffer, that I would use is an IC type buffer. Opa627, lme49710, AD797 - Unity Gain Stable Audio grade op-amps.
With dual power supply +/- 15v, bypassed with 0.1uf and 10uf (4.7uf if datasheet calls for it) with DC servo for zero DC offset or very good audio grade capacitor in the output. In the input I don't think that you need one. Last time I checked Sound was far more better without one.
Large Electrolytics on the power rail with good filtration... And That's it!
Better than that can be only discrete Matched Jefets in a Single Ended mode with Current mirror in the input bla bla bla... To Expensive, to complex...