Best Boost for onboard?

[DanielWong]

What's the best boost I could put in my guitar or frequency to specifically target? I'm guessing it has to be something useful for being the first in the effects chain.

If I make a good boost at the end of the chain, what will the difference as opposed to before? More distortion/effect or the same amount of effect, just louder? Would this be overkill to have two boosts?

Now that we're on the topic of boosts, perhaps I make two outputs so I get the option of sending one boost through the entire fx chain or just sending it directly to the amp, after the last effect. Will this work and how can I build this (I'm new to electronics) and how shall I set up my effects chain with this?

like Guitar to input 1 of  boost, then output 1 to effects chain and output 2 two amp, then have end of effects chain to input 2?

And most importantly, is this really all worth it?

[Mark Hammer]

Read my 1979 article here: http://hammer.ampage.org/files/Device1-12.PDF

I haven't really changed my mind since then (though thankfully my writing has improved).  Certainly feel free to experiment but be VERY mindful of the many ways in which an onboard booster can restrict your choices.  Personally, I think an onboard buffer is almost always a good thing to have, but any boost beyond that is a strategic decision that requires some deep thought about how YOU play.

Years after I wrote the article, I made myself a Tube Screamer clone, and just hated hated hated it. Couldn't understand what the fuss was all about.  Then I got another guitar that DIDN'T have an onboard booster, the clouds parted and the tone finally arrived.  Some pedals really need to have the lower and tamer levels of a passive pickup to sound at their best, and are essentially designed on that basis.  Keep that in mind.  On the other hand, a  x4 or x5 booster in the guitar and going straight into the amp has yielded up some of my best tones ever.

[oldrocker]

Obviously go with whatever Mark Hammer suggest for sure. 
I just wanted add that the first DIY circuit that I ever built which got me started on stompbox building in the first place is this one from DIYguitarist.com (Paul Marossy's website).
It fit great into my Flying V.  The stratoblaster was cool too.  Just a thought.
http://www.till.com/articles/GuitarPreamp/
http://www.generalguitargadgets.com/diagrams/asb_sc_i.gif

[Dragonfly]

The Tillman preamp is good for this....about 3dB's of boost, so not tons of output, but keeps your signal integrity in tact and just gooses the signal a little.

Also, the Alembic Stratoblaster, if you want more "boost."

A quick search for either "Tillman" or "Stratoblaster" should give you more than enough info about each circuit.

[Mark Hammer]

You can use the onboard circuit to do a number of different tasks.  I think the one it does best is to assure that the signal reaching the first pedal is the best possible quality signal you can manage.  Anything related to boosting and overdrive, however, is probably best done OFF the guitar, where you can do it to your taste, add controls, tweak, play with supply voltage, etc.

One of the pivotal questions is how much additional gain you can tolerate and still have it be a "guitar level" signal.  Most pickups can comfortably manage being amplified by 2-3x without turning into an overdrive, though obviously highly overwound ones want less gain.  The simple JFET circuits referred to by Dragonfly and oldrocker will permit very modest gain, so you don't HAVE to think of them as heavy-duty boosters (even though they can be used that way).

To get back to the rest of your questions, a boost at the end of your chain will simply make everything preceding it louder, and make that output more likely to overdrive the amp.  The same boost applied earlier in the chain will increase the likelihood of the effects themselves being overdriven.  Whether that output in turn overdrives the amp will depend on how you set the output level of the effects chain.

Finally, note that gain is multiplicative.  One device with a gain of 5, followed by another device with a gain of 5 gets you a combined gain of 25.  So, while each alone may seem modest, their combined effect can be quite severe.  Keep that in mind when inserting more gain here and more gain there.

[goosonique]

I find a guitar volume knob makes a good booster as well .... i get my amp & dirt pedal pumpin at guitar volume set abt 7 ish ...then full throttle for boost