Modding a LPB-1 for more transparency?

[skiraly017]

I built a LPB-1 after my original EH one had gotten too fragile to use. I love this pedal and the fact that it adds some "girth" to my sound. Now I'd like to build another one that's totally transparent. Is it as simple as changing the cap values? Any suggestions? Thanks.

[Mark Hammer]

Um, I guess you didn't read, or perhaps agree with, the recent thread on "transparency" in effects?

My own feeling is that if you want "transparency", then you want: a) less maximum gain than the LPB-1 provides, and 2) a much higher input impedance than the LPB-1 provides.

"Better quality" components will only take you so far.  High gain always compromises retaining the original tone since it introduces distortion in subsequent stages.  If that's what you *want*, fine, but don't call it "transparent" or you'll have a bunch of folks here all over you like a cheap suit..

[skiraly017]

I didn't read the transparency thread. Hopefully I'll get a little amnesty for being honest. Should I go back and read it? Will I find the answer there or am I looking for the unobtanium?

[aron]

What value resistor from base to ground does yours have?

You can try building it with all metal film resistors and film caps as well as raising the value of the base resistors.

[moosapotamus]

... or, you could build a stratoblaster, or a utility boost instead.

~ Charlie

[aron]

Yes, very true.

[Mark Hammer]

You've got total and unqualified amnesty, my friend.

What you want to get is fine and dandy and musically valid.  Rather, it's the use of the term "transparent" that tends to evoke debate.  R.G. asked the question a little ways back about what "transparent" means to people, since it seemed like an almost inconceivable entity to him, though mostly he was just perplexed about how it gets used.

Read the thread and you'll see there were a variety of views.  All valid, but certainly different meanings of the same term.

There is certainly no reason to scold anyone for asking the question you did.  Rather, because the term "transparent" has so many possible meanings, don't be surprised if the suggestions you get don't seem to be on track with what you're aiming for.  My own suggestions are based on one particularview of what "transparent" is.

[skiraly017]

The LPB-1 adds girth/bass/width/call it what you will to my tone. I would like to build one that doesn't add anything tonally and just "boosts" sound. I'm using the GGG layout. Can this be done by changing some parts values or should I look to another type of booster? Thanks.

[AL]

You may want to try the AMZ mini-booster or Mosfet Boost. I think these may get you where you want.

http://www.muzique.com/schem/mosfet.htm
http://www.muzique.com/amz/mini.htm

Great sounding circuits.

AL

[petemoore]

  Terminology again, as always...
   ITCase of 'Transparent', the 'horsense' of it led me to 'not colored' as a possible applicable definition.
  EE's wanted the most accurate amp. For Hi Fi, it is unobtainable, but you can get close. A whole ream of technical terminology sprang up, for simplesake, I'll choose 'distortion' example. Some of the derivitaves of this term still get used and the definitions, though applied to different texts, the texts of Hifi and Guitar nuts...such as crossover distortion, intermodulation distortion, etc.
  When the Hifi EE's spoke of distortion, most of the time it is just 'bad', something to bother you and something you want to get rid of if at all possible.
  When guitarnuts Speak 'Distortion', it is of an amount that would make Hifi engineers puke, they would tell you to shut the amp down immediately until you can find the problem, even if it is a brand new amp, just 'broken in'. Really most of the difference in the way the term Was used to how it IS used is amount. Hifi-ers want none, or very small percentage, enough maybe to fatten up the bass or something like that.
  The 'Distortion' we as guitarists speak of, crosses the line, fits into, or is completely out of..the realm of the old, or hifi use of it. The term Distortion has become Distorted in meaning.
  There's plenty more like that too.
  Guitarists slang has no regard for bastardization of terminology. true meanings are bent, folded, and often mangulated beyond reason.
  I wrote a long post, something like the content in this one, long ago...IIRC it was titled Definition of Terminology.
  To be stickly, one could say there Is no 'clean', no 'transparent', only facsimiles of, and 'relative closeness to' perfect electronic audio. Your pickup distorts. The string mostly puts out less than 'perfect' waves. Cables distort. This is to be assumed: 'Transparency' can't be had, so the use of the term is meaning 'closer to 'transparent'...IWCase I'd recommend trying an FET or Tube device.

[moosapotamus]

You may want to try the AMZ mini-booster or Mosfet Boost.

Careful, Al. You might be treading on "transparent" ice, there.

Seriously, tho... My experience with the mini and the mos are that they do "color" the sound of my instrument. While I agree that that "color" is pleasing to my ears, it does not conform to my personal definition of "transparent", which, to me, means no coloration at all. For that kind of "transparent" boost, I'll stick with my previous recommendations, above.

~ Charlie

[aron]

I would like to build one that doesn't add anything tonally and just "boosts" sound

As soon as I hear that I think op amp booster.

[TheBigMan]

I would tend to agree with Aron.  The AMZ mini-booster definitely adds some colour, at least for me, whilst the MOSFET boost is seems pretty much like "me only louder" but some people find different.  Maybe a Micro Amp type circuit?

[vanhansen]

Mark and or Aron, would an LPB-1 type running off higher voltage, say 12 volts be more transparent (in the sense of not adding color to the sound)?  I drew up a schematic for one not too long ago.  Still needs to be verified though.  Some component values change to compensate for the higher voltage to maintain bias.

[TheBigMan]

Doesn't that just give you more headroom because there's more voltage to swing before you max out?

[vanhansen]

Yes, it does give more headroom but what I'm curious about is if increased headroom decreases how much it colors the tone.  I guess I might need to read that thread Mark mentioned.  I don't have a 12 volt adapter handy to try it.  I used Joe Davisson's bias calculator to come up with the values.

[aron]

Without trying it, I would have to say yes. It has much less chance to distort.