Purpose of boosters?

[jimbob]

Im still not quite sure what purposes boosters serve?  To bring up volume and tonal change when playing lead? For more distortion? I know there a lot of them out there and ive made 2 or 3 but i cant really find a place for them. When ever i need to change to lead playing i simply hit channel 2 on my amp  floor chalnell selector. Otherwise, as long as i have 3 channels( 2 dist and one clean) wheres the nead for a boost effect? For those whos smaller amps wont/cant get get louder?

Im sure its a newbish question--But i dont care..Im too tired of wondering. :lol:

[remmelt]

i have a single channel amp, the marshall bluesbreaker.
i set it to a nice punchy rhythm-sound and when i go to lead, i add the boost. it gives me a volume boost and adds some distortion to the signal.

i sometimes use it in front of a distortion or overdrive pedal to make it distort more.

[Narcosynthesis]

boosters are generally used with valve amps, and usually with single channel amps

as you said, when you have three channels, you can set them up for clean/distorted/lead, but with a single channel amp you cant do this, so what is usually done is the amp is set for distortion, then for clean you can roll back on the guitars volume, and for the lead sound, you use a pedal to boost the sound

quite a few people also use a selection of distortions/boosters/fuzz pedals for giving more options tonally, so they can have their amp sound, a fuzz, a distortion etc... all sounding different to suit different songs or whatever

David

[black mariah]

I have a Sunn Beta Lead that sounds quite nice, but doesn't have enough distortion unless the preamp gain is all the way up. Unfortunately, there's enough noise to kill a horse at that level so what I used to do was just drive the front end with a clean boost. +25dB into the input of any amp will give it a nice kick in the arse. Now I use a New Clipper into the front end instead, but I will probably use a boost after the Clipper once I get a good one built (Treble Blaster, here I come...) just for the extra volume.

[bwanasonic]

Certain pickup/amp combinations really benefit from the *interface* of a "booster" for various impedance/ gain-staging reasons.  From a wide range of players from Pedal Steel to Shred Metal, you will find players who use some form of external boost stage in conjunction with their amps. It's nice that you have found an amp that serves your needs, but you will find many players still prefer an older *vintage* style of amp in conjunction with an external boost stage. In fact, many of the most sought-after guitar tones of the last few decades involve an external *boost* stage in front of the amp.

Kerry M

[aron]

I use it to give my output a little more "juice". Almost everything sounds better when you buffer/boost the output of the guitar into the pedals. At least for me.

[petemoore]

Say you had low output pickups...a bootster would increase the output.
 Example:
 My buddies Powerhouse Strat through a Fender Stage 15 setup...we tried the Fuzzs/ODs/Boosters, but none were an improvement [that guitar active pickups [high output]], the amp is very 'hot' to begin with...all the boosters and fuzzez we tried didn't respond well, added noise etc.
 He asked nearly the exact same question you did.
 Phasers and wahs were liked by the setup, anything that boosted was not very well recieved, I theorize that the amp is 'hot to begin with, adding more 'heat' just  'boils it over', even with non-active pickups.

[cd]

Long cable runs.  A booster (or any effect) with a low output impedance will allow long runs of cable without high end loss.

[jimbob]

I theorize that the amp is 'hot to begin with, adding more 'heat' just 'boils it over', even with non-active pickups.

THats what happens with mine--Its really a two trick pony--great tricks though..the 2 channels--ultra and crunch ( awsome distortion sound and and quiet).the clean channel is bland but can be made to sound good in the loop w other effects..But the distiortion channels--.those are great but any kind of added boost boils it over so if and when i test out effects i make i have to do it on the bland clean channel..

[nightingale]

in most situations~
a booster adds a nice little "edge" to the other effects it's used with..
hth,

[Mark Hammer]

Pretty much all of the above.

The fact is that pretty much ALL amps are designed with a certain amount of headroom, based on anticipated input signal levels.  Guitar signal levels, in turn, vary considerably, which means that there is often much more hidden potential in one's amp than you'd think.  It is quite often the case that a bit of boost on the input can provide more *clean* volume without distortion if you set your controls right.

Boosters also usually provide some buffering, which helps to offset the treble loss from cable capacitance over longer cables, especially that first one out of the guitar.

Finally, in the same way that amps anticipate a certain input signal level, so do distortion or other dynamics-based pedals (which would include limiters, noise gates, compressors, envelope-controlled filters).  You can repair "undersignalitis" in an autowah by tweaking the envelpe-follower gain internally, OR by feeding it a hotter signal.  Similarly, you can get harder squish from a compressor by goosing the signal you feed it, since a hotter signal forces more gain reduction.  

I have been going on ad nauseum for years that the assumed tonal differences between several different distortion pedals are often the result of different amounts of maximum internal gain.  People dime the distortion control, and from the outside it seems like one pedal has more distortion capability than another.  It may well be the case that boosting a signal ahead of the pedal can make pedal X sound exactly as intense as pedal Y.

[tcobretti]

It cannot be overstated that amp choice is critical with a booster; they work great with the tube and modeling amps I tried, but not well with SS amps.  

How good something sounds is entirely dependant on the listener's ear.  If your amp has a crunchy clean channel, the booster might be cool with it.  But it will likely not be a great combination with a super high gain channel.  What kind of amp do you have?

[petemoore]

Driving a TUbe seems to work [extended testing necessary for experienced conclusions aside].
 The theory behind SS Vs Tube articles stating that distortion in tubes is different, seems to play out vividly in reality, it's really a different sound.
 If you have a 30VDC [like printers use] and don't mind having also a 9VDC to power the heater, wiring a 12ax7 gain circuit is about the same as wiring a Jfet.
 So...I don't have typical SS type guitar amps to test with, it would seem that a booster/fuzz into 12ax7 feeding the input would get some cool usable new tones from amps that don't tend to like their inputs juiced up.
 Commerial amps of this nature [input tube] had good popularity, I had a Legend Amp [30w] that used this topology, and it worked well.
 Modding the input section...rip out the factory sound, and instead, used Jfet amp emulators or other input boost/preamp devices....lol...or not...

[R.G.]

There's one more thing that boosters in front of a tube amp do - they not only drive the input tube with a bigger signal, they drive it from a lower impedance source.

It's not widely known, but the reason a tube grid clips when the signal goes positive is not usually because the plate is as low as it can go. It clips because the grid changes from a near-infinite impedance to about 5K ohms (for a 12AX7) because positive voltages on the grid attract electrons from the plate stream, and the come out the grid. So any high impedance source can't pull up on the grid hard enough to make the grid follow, so the grid stays clamped near ground by its current flow. Running "in clamp" is what the designers in the Golden Age called it.

If you drive the grid with a signal source that *can* pull up on the grid compared to a 5K load, then the grid goes positive instead of being tied hard to ground, the grid is pulled up, and this positive voltage pulls even more electrons off the cathode space charge until finally the space charge is depleted or until the plate does finally bottom against the plate resistance and/or plate resistor. That is - pulling the grid positive does cause the plate to go down further.

It's not linear, as in this region all kinds of things that are not wanted in classical triode operation happen, but it's a good, soft landing for a distortion device.

So if you can drive a grid positive with a big enough signal, source impedance matters. A 12AX7 plate with an rp of 66K or so can't do much to pull the grid positive, and the common 100K Rp doesn't help much. But a transistor circuit with a collector load of 10K or less (sniff... sniff... do I smell a Rangemaster?) can do some pullup, so you can not only feed the first tube a bigger signal, you can knock it about harder, and it caves in a bit in response to the harder pull.

So - you can affect the hardness of grid-limit distortion by what source impedance you feed a tube with.

[brett]

Thanks RG.  Suddenly, I don't feel so bad about those noisey LM307 op amps ahead of the 12AX7 in my Musicman.  They DO have a purpose - their ouptut impedance is low.  Thanks again for words from the wise    

[tcobretti]

Since RG didn't say it, I will:

Anyone who hasn't REALLY should read the rangemaster article at GEOFEX.  It has a very detailed explanation of what a treble booster does and how to build/tune one.

Here's the link:

http://www.geofex.com/Article_Folders/Rangemaster/atboost.pdf

RGs site has tons of detailed explanations on how things work, and the "technology of" series is fantastic.