where to put buffer and preamp in a chain

[GibsonGM]

Great discussion on buffers, guys.  Ben hit the nail on the head about the difference between buffers & preamps...I'd add that a preamp, in addition to amplifying your signal by a small amount, is also where a lot of tone shaping generally occurs.  Usually you'll have a tone stack in there, and the preamp provides recovery for it at the same time it is amplifying your signal.  This is to optimize the signal level hitting the power amp so that it performs its window-shattering amplification role the right way    Often they're used to overdrive a signal and create an input rich in harmonics (overdrive).   A buffer isn't designed to do this (very well).

If  you go guitar >fuzz face > amp, you'll get a really nice fuzz sound like you remember from the '60's.  If you go guitar>buffer>fuzz>amp or sometimes guitar>wah>fuzz>amp, you're likely to get a very weak, dark-sounding fuzz.  This is because the fuzz face (and a few other ckts) has a very low input impedance.  Its nature is to "pull" your signal out of your pickups (tone sucking)...placing a buffer before it prevents this (by the definition of a buffer - high input/low output impedance!), so it can't "do its job" the way it was designed.   If a wah does this, sometimes a 1 to 10K resistor in series with the wah output or fuzz input minimizes the effect enough to be acceptable.   It's just part of the character of a fuzz face; read up on input impedance to find out about the voltage division effect of this, which is why the phenomenon occurs!  Mark Hammer has gone thru the math on that one very well in the forum...

As has been said, if you don't need it, you probably don't want it...by all means, make a simple buffer and play with it to see what happens.  Most are low parts count and easy to assemble.  I don't like the almost "compressed" way they operate - I lose dynamics with them - but then, I don't use more than 2 or 3 true bypassed pedals so I don't need them!   If you DO need one, you'll probably know it - your signal will become dark, lifeless and weak with all the unbuffered effects you're going thru. 

[seanm]

Why is it that certain fuzzes don't get along with buffers?

Some older fuzzes rely on loading down the guitar pickup with a low impedance to get their sound. If you put a buffer in front of them, you isolate the pickup from that loading.

[bent]

wow....thank's to all the reply-explanation.....very helpfull....

Ben N,
here's what i have, and the order in the chain is not fix, it can be change to my taste:
all made by me....ALL TRUE-BY-PASS...
BSIAB2, shematic from GGG
BLUE MAGIC, schematic from GGG
BIG MUFF, schematic from GGG with some mod and fuzz
EQ 10 band, schematic from GGG (6 band modified)
ROSS/DYNACOMP compressor, shcematic from GGG
SHECHO, schematic from GGG
and to be finish:
ELECTRIC MISTRESS 18V(NON-DELUX), schematic from free-info-society
CORRRRAL CHORUS (boss ce2), schematic from tonepad
and i'm thinking of building a volume pedal, but i'm not certain, since they tcheap to buy....
has you see, i'm a fan of pink floyd...
my guitar is a Godin sdxt, my amp is Marshall valstate avt2000 ( BTW i don't really recommend this amp)

but i didn't finish my board, and my friend maybe want one....so i want to make it versatile, so if a change guitar or amp, i don't have to change everything...
and it have to be usefull on stage and studio, cause me and my friends might be doing some show and make some record in studio...

so Ben N, what is your opinion , should i put a buffer at the main-input and a preamp/opamp at the end, i'm thinking on putting the preamp/opamp on somekind of switch to by-pass the preamp if not needed....
what do you think?

bent

[Ben N]

It looks like being verbose has gotten me tagged as some kind of expert.    That is not even close to being true; I was just trying to share some general guidelines that might help you. 

I can only suggest that, since all your pedals are TBP, and as far as I can see all of them are pretty well-behaved designs, you may not want or need anything in front of them.  In fact, buffering the input of something like a Big Muff may change its tone (not sure).  You might want to read that Cornish article for a different opinion.

However,  there is a matter of the added capacitance that your cables, as well as all those jacks and possibly interior wiring and pcb traces in all those pedals, may add, which may also be robbing you of highs.  Mark Hammer has often suggested this test for cable/pedal capacitance:  Play your guitar through the shortest cord ssible straight into the amp, the, without changing anything on the guitar or amp, run it through your pedalboard (everything bypassed) and normal length cables.  Chances are there is a difference.  A preamp at the beginning of the pedalboard to boost your signal may help reduce the effect of cable capacitance; just make sure it is low noise (because all your gain devices, especially the compressor, will boost noise), and carefully calibrate the level so that you don't end up ovrdriving your chorus and EM.

As for a preamp at the end, it depends on how you play.  You certainly have enough boost built into your other pedals (fuzz, overdrive, eq, compressor are all specialized preamps, after all) for soloing, but you may want JUST a flat boost in addition.  As a Gilmour fan, you may want some kind of a tone-shaping boost, similar to his Rangemaster, Orange Treble&Bass boost or on-board EMG mid-boost (different periods, I know), but you can probably approximate those with the equalizer.  Some boosters are especially good at slamming the input of a tube amp (like DG's Alembic preamp), but I don't know if that is something you want with your Valvestate.

But you know what?  These things are so simple that you ought to just try them out, and TYE (trust your ears).

Ben

[bent]

But you know what?  These things are so simple that you ought to just try them out, and TYE (trust your ears).

Ben

i think i will do that, i'll build both and try it at different place.....i'll post the result when done...

thank's

bent