Best simple clean boost?

[oczad]

I say simple because i don't want to waste a lot of time on building a pedal that i end up trashing. Just wanna try some quick simple circuits. i use a TS5 now with the distortion at zero and the level at 10 for a clean boost. i've been happy with that for years, tho i often wonder if there is something that would improve my hi gain tone. But others i've tried or build have not done so. Two i found that did nothing for me just so you don't mention them are the LP1 or whatever thats called and the MXR micro amp. Those aside, what do you think actually improves the tone of a boosted front end? Something that actually thickens the tone would be great. Thanks.

[Mark Hammer]

If you want "thicken" then you don't want "clean".

Here is the lesson that seems to escape the thinking of tens of thousands of players.  I mean no disrespect by it, and my fatigue is not directed at you in particular.  I'm simply pointing out something that just hasn't sunk into the public consciousness enough, maybe because advertising copy misleads, maybe misdirecting interview quotes from big name musicians who should have directed the question to their tech instead of answering it themselves, or maybe because it requires more systems knowledge than prospective buyers have by the time they get interested in one.

So....

ALL electronic circuits are predicated on some anticipated input signal.  That is, they are designed to do what they do when they get an input that is approximately like "this".  If you exceed that anticipated amplitude range, the circuit misbehaves.  Fifty+ years of rock and roll tells us that that amplifiers can "misbehave" in some interesting and pleasing when we exceed the expected input amplitude.  Some amplifiers (most, these days) have gone so far as to build in extra gain stages that can force "misbehaviour".

At the same time, all amplifiers and audio circuits have a certan amount of "headroom".  That is, the range of signals they anticipate is wide enough that many which fall within the acceptable window can even be a bit louder without disturbing anything.  People who work in professional audio, sound reinforcement, or simply "golden ears" audiophiles, know that one generally aims for optimum S/N ratio throughout a system by aiming for the highest amplitude signal that falls within the headroom of each stage in the sound reproduction process.  If the mic preamp can take 80mv without breaking up, then a mic which delivers 70mv is a better choice from a S/N perspective, than one providing a mere 40mv.  And so on.

So, when there is an external gain stage somewhere in a musician's signal path, that gain stage can do a few different things, depending on where it is and how the person uses it.  If I have an amp that is expecting pickup outputs in the 150mv range (on average), and I have a Danelectro with underwound coils and/or weakened magnets, then the output of my guitar will be well below what the amp is expecting.  The amp can tolerate - without altering the tone in any way - a signal that is perhaps 2-3 times greater average amplitude than what my puny pickups aqnd hand-flailing can generate.  In a world where that measly guitar signal has to fight for attention with whatever the cord does or picks up from the outside, a "hotter" signal is better and lets me hear the guitar more than the other stuff.  BUT IT DOES NOT IMPACT ON TONE at the amp.  It can impact on tone from the guitar by "protecting" the signal on the way to the amp.

The moment that the extra gain results in a signal level which exceeds what the amp (or anything just ahead of the amp) is expecting, then those circuits will misbehave and sound different, because you are not letting them behave.  The "cleanliness" of the boost will NOT be reflected in the cleanliness of the amplified tone.  Indeed, the resulting tone will be dirtier and full of more harmonics when you exceed the amp's headroom, no matter HOW pristine the gain stage is.  It could be something that has received the highest accolades from Absolute Sound  as a "clean" boost for 20 years running and would still make the amp do stupid stuff, simply because the amp was designed to remain clean only if the average signal level was below some amount.

The critical question is whether the misbehaviour elicited from the amp/speakers is something you like or something you don't like.  If it is something you don't like, then clearly you have to boost the signal in a manner that is tailored to anticipate the way the amp will misbehave.  And THAT, my friend, is where the definition of "clean" starts to change.  It is also likely why you have expressed dissatisfaction with several named commercial boosters.  All of them obviously make the signal have a higher average amplitude, but the way they push the amp does not please you.

For some people, the clean boost they REALLY want, is something that is not clean at all.  That is, it predistorts the signal a bit.  That is the secret of the Klon Centaur, and increasingly a number of competing pedals.  In other cases, the boost IS clean, but the output is not full bandwidth.  Some frequencies are tapered off a bit in anticipation of what the amp will do.  In still other cases, what the user really wants is a compressor set for modest compression and hot output.  That is, the amp misbehaves inpleasing ways if the level is increased up to such and such a point, but not beyond.  The compressor sets the limit on that maximum output and the amp misbehaves in the desired fashion.  In still other cases, what the person wants is a graphic EQ that allows the user to tailor what gets boosted and what doesn't, so as to elicit specific behaviour out of the amp.

The boosters you mention, and many of the boosters out there, do exactly what they purport to do: they reproduce the signal coming from the pickups exactly, with full bandwidth.  This performs a vital and important function in many contexts, but it is often NOT what people want in their context.  They want the amp to distort, to distort in a certain way, and to do that requires a booster which DOES alter the sound in a deliberate way.  That deliberate pre-conditioning of the signal could be reason to buy/build a different circuit, but it could also be reason to simply mod an existing circuit in a certain strategic way.  For example, it may be that you want/need an MXR Micro-amp to roll off the highs whenever you add more gain.  The Klon Centaur includes a treble control expressly for that purpose, so that users can tame the highs when applying boost, so that whatever distortion/harmonics the amp adds are of a more musical nature, and not just fizz.

[Jason M.]

Most clean boosts aim to leave the signal uncolored, but if you are looking for a boost with some fat and girth, try Jack Orman's minibooster. Simple, low parts count build. Built stock, it has some distortion, but in his newsletter he has a gain mod that works great! It is very clean with the gain pot all the way down and you can add some distortion if you want. Check out his site AMZ.

[Caferacernoc]

Ditto on what Mark and Jason said. The Tubescreamer you have been using has a huge mid boost and bass rolloff built in. So a LPB or Microamp is probably way too "full range" even if it is a clean boost. It will certainly sound different to what you are used to. Sounds like you might like something in between. A mild or "transparent" overdrive with mild tone shaping. Or maybe a treble booster. A sparkledrive might be interesting. It's a tubescreamer with the added option of blending in a fullrange clean sound "underneath" your overdrive.

[Gus]

oczad
You kind of gave a design you would want with your TS setting.

  You like the TS dist at 0 and the volume at 10 (10 o clock)  You did not post the tone setting If I read you post correctly. 

You are operating the TS noinverting opamp so that is a gain of 1 until about 1 /(2*pi*4.7k *.047uf) and above that it it goes to  51K /4.7K +1 gain(about X12 gain with the dist at 0).  Next you would need to measure the voltage divider the volume contol is wiper to each end.  The TS has a lowpass after the distortion that cuts the highs above 720hz.  You are not maxing the gain so you mid boost is at a min setting and you are rolling off the gain after about 720 due to the lowpass.


So maybe you would like something like a noninverting opamp set at maybe a design range of x5 for more volume control range or up to X10.  I would make it flat with a lowpass set to take the edge off.  Adjust the RC time constant in the - leg to ground gain setting part for the change from gain of one to were the  boost frequency starts.  Adjust the input resistance for the pickup loading you want (I would start about 470K).  Calculate tha gain setting resistors. Caps to taste.   


You MIGHT like this circuit.     http://www.diystompboxes.com/pedals/gusOverdrive.gif    Gain about x4.7 till about 720hz then a boost to just under X9.4 and a lowpass filter on the end.   Works it's best going into a input resistance of 1 meg like some tube amps.

[MikeH]

Well put Mark.  I'm going to bookmark this page so i can post it whenever anyone asks what the best "clean" booster is.

[suprleed]

Great thread!  Although boosters are often relatively simple circuits, as Mark and Gus point out, there's actually a lot going on.  Especially when you think of it in relation to your existing pedal chain and amp and the resulting "tone."

[petemoore]

  When I want clean as in 'clean' as I can get, I plug the pickups into a TubePRE into the Mack-ie [3 way powered SpK's].
  Wide frequency response/decent SPL's, the closest I can get to clean-clean.
  Great for listening to the sound of 'bare pickups' or as close as I can get to no other coloration.
  Totally clean is unforgiving, and not so much fun to play on after a while, the sounds just don't tend to grow the same way without some dirt.

[m-theory]

After having built about 30 different circuits and experimenting with numerous different boosts and overdrives over the past year or so, my advice would be to just start building and auditioning various circuits.  You'll not only eventually find your "perfect" circuit(s), but you'll gain a whole lot of knowledge along the way. 

There's a whole lot to what Mark said.  I started into this process convinced that I'd never want anything beyond a mosfet boost for solos, but have completely changed my thinking along the way.  MY "perfect" dirt/boost circuits are now a fat boostered, a Klon, and a Krunk.  At this point, I'm more than convinced that, the more I build and try, the more this will morph as well. 

There's so much that goes into this, as pointed out.  Your playing style, your amps, how you run them, your guitars, the music you play, what you're hoping to get out of a boost, and the myriad of unique intricacies that each circuit has to offer, and how it interacts with your guitar, amp, playing style, and music.  I do believe, after having done this myself, that the only real way to know for sure, is to try many different circuits and see what really floats your boat.  After auditioning just a few circuits, you'll get a much better feel for what it is you're looking for, specifically, and can then dial in your quest from that point. 

[petemoore]

  Clean boost ? There's technically no such thing, and as far as practically..none either.
  Whether its the circuit itself or something down the line, 'boost' always sounds like boost.
  Same thing for any electronics, that's why we choose favor choosing the components we like the sounds of when combined with others.
  Electronic components sound a little bit like themselves, even in the best case scenarios.

[oczad]

If you want "thicken" then you don't want "clean"

I haven't read this thread since i posted it except your response, but I guess i should have explained it more clearly....you're right....i do NOT want clean. I am playing an already distorted amp and want a signal booster to overdrive the front end even more. I get my clean tones by turning the volume on the guitar down, get dirty by turning it up, and get high gain with a clean boost. So i DO want a clean boost, IE: a clean hot signal to bash the first stage of an already driven tube preamp.

Should have made that more clear, sorry.  But "clean boost" IMO is an accurate description and one i always see mentioned in the context i meant it. So i'm sorta surprised it was seen here as a way to boost a clean sounding amp. Heck, for that all you'd need is any flat response pedal or even just a volume pedal and make your normal volume the pedal rocked back about 1/2 way. But thats not at all what i meant. Anyways, now to read the rest of the thread.

[oczad]

Most clean boosts aim to leave the signal uncolored, but if you are looking for a boost with some fat and girth, try Jack Orman's minibooster. Simple, low parts count build. Built stock, it has some distortion, but in his newsletter he has a gain mod that works great! It is very clean with the gain pot all the way down and you can add some distortion if you want. Check out his site AMZ.

Hmmmm....i may have built one of those a few years back, but i can't say for sure.I'll have a look.

[Mark Hammer]

If you want "thicken" then you don't want "clean"

I haven't read this thread since i posted it except your response, but I guess i should have explained it more clearly....you're right....i do NOT want clean. I am playing an already distorted amp and want a signal booster to overdrive the front end even more. I get my clean tones by turning the volume on the guitar down, get dirty by turning it up, and get high gain with a clean boost. So i DO want a clean boost, IE: a clean hot signal to bash the first stage of an already driven tube preamp.

Should have made that more clear, sorry.  But "clean boost" IMO is an accurate description and one i always see mentioned in the context i meant it. So i'm sorta surprised it was seen here as a way to boost a clean sounding amp. Heck, for that all you'd need is any flat response pedal or even just a volume pedal and make your normal volume the pedal rocked back about 1/2 way. But thats not at all what i meant. Anyways, now to read the rest of the thread.

No problem whatsoever.  I think you'll find as many opinions about what "clean" is as there are members here on some days!!
For many players, "clean" simply means "not obviously distorted on its own".  However, for other players, "clean" means buffered with all of the high and low end inherent in the original signal under the best of circumstances.  That may be exactly what you want if you're playing a Tele into a Twin Reverb and it's your solo now before the pedal steel comes in.  Many players here, though, want a boost to extract something a little dirtier from their amp, so what they really want is a version of clean that is tone-shaped in anticipation of what the amp will do.  That may well include deliberate dulling of the tone....something that wouldn't really sound "clean" (as in crisp) if the amp was turned down.

But like I say, it may well be that what you're looking for is a mod to an existing circuit that accomplishes that pre-shaping.

[dan5150]

Man, I love this board! I learn so much every time I read it! :-)

I have/had the same question as OCZAD. However, my needs are basically (I think) a volume boost, for the leads. I get my tone dialed in, and I just want something to "push" it out front of the mix for those few seconds.

I will take a look at Jack's mini booster first, but like Pete said, I have a feeling that this will lead to much more experimentation than I had originaly planned. :-)

-Dan-

[shredgd]

Electro-Harmonix LPB-2