Xotic BB Preamp Mid Boost [Suggestions]

[Zipporello]

hi all,

there's anyone who knows how to build this great pedal?

stripboard, schematic, pcb, or any other suggestions?

Really thanks

Stefano

[Gus]

I put the terms "Xotic BB Preamp Mid Boost schematic" in google and found a schematic and layout.  

I don't like the "design" if the schematic I found is correct.

[Zipporello]

I put the terms "Xotic BB Preamp Mid Boost schematic" in google and found a schematic and layout.  

I don't like the "design" if the schematic I found is correct.

sorry, but i don't find anything about the BB preamp Mid Boost.

[duck_arse]

zippo, I was just this eve reading an old thread which I think could apply here.

if you ask "does anyone have a circuit/design/configuration that sounds/acts/looks like an xocet aa pram roost?", someone like gus, for instance, will probably offer you exactly what you want, with circuit, sims and mod suggestions.

then someone else will say "I built one of them, they rock, thanks gus. here is my vero/perf/pcb. any probs, just ask."

and then you can ask "why do people use so many slashes when they talk around here?"

that is probably more than 2 cents worth, you get the reat gratis.

[Zipporello]

zippo, I was just this eve reading an old thread which I think could apply here.

if you ask "does anyone have a circuit/design/configuration that sounds/acts/looks like an xocet aa pram roost?", someone like gus, for instance, will probably offer you exactly what you want, with circuit, sims and mod suggestions.

then someone else will say "I built one of them, they rock, thanks gus. here is my vero/perf/pcb. any probs, just ask."

and then you can ask "why do people use so many slashes when they talk around here?"

that is probably more than 2 cents worth, you get the reat gratis.

i'm not sure i've understand...

[Jopn]

The normal version of the BB Preamp is widely available.  You can find a stripboard layout of it over at tagboardeffects.

Details on the mid boost version, on the other hand, don't seem to be available.  That said, I did find a thread over at that other site where they've added a basic midrange control to the BB Preamp to get similar functionality.

[Zipporello]

The normal version of the BB Preamp is widely available.  You can find a stripboard layout of it over at tagboardeffects.

Details on the mid boost version, on the other hand, don't seem to be available.  That said, I did find a thread over at that other site where they've added a basic midrange control to the BB Preamp to get similar functionality.

really thanks.

Something like that, for the boost? http://diy-layout.com/25

thanks again

[edit] oh sorry, i didn't understand. Maybe in the BB preap MB i have to add a midrange control (passive) like this:

[mmlee]

I'm not entirely sure I know what you're trying to do, but if you're looking for a mid-boost, a passive one isn't going to cut it (see what I did there...?  ) ...  i.e. passive eq's only cut.

[Zipporello]

I'm not entirely sure I know what you're trying to do, but if you're looking for a mid-boost, a passive one isn't going to cut it (see what I did there...?  ) ...  i.e. passive eq's only cut.

i'm try to build a BB Preamp MB version (with midrange control).

so, i'll build a classic BB preamp with an extra midrange control.

I've just found the BB preamp schematic, now i need a verified midrange control

[YouAre]

The BB uses an Baxandall Equalizer, which is pretty much a non-adjustable shelf equalizer for bass/treble.

The mid boost seems like something that could be accomplished with a graphic or fixed parametric equalizer in tandem with the BB's existing preamp.

Take a look at this:
http://www.geofex.com/article_folders/eqs/paramet.htm

There are also articles out there showing how to implement a Mid control in a Baxandall. It requires another op amp and/or re-configuring the existing op amp set up, which would make it difficult to utilize the same layout or vero.

Let's look at the response of a Bax though:
http://headwize.com/images/eq2.gif

Boost treble and bass, you get a mid cut. A mid boost here would just cancel out the mid cut. Cut bass and treble, you get a mid "boost."
A mid boost here would just boost volume. I was also fascinated with the MB BB preamp, but I had trouble justifying the extra work/opamp/real estate for the mid boost after I had learned about the response of the Baxandall EQ.

[Zipporello]

The BB uses an Baxandall Equalizer, which is pretty much a non-adjustable shelf equalizer for bass/treble.

The mid boost seems like something that could be accomplished with a graphic or fixed parametric equalizer in tandem with the BB's existing preamp.

Take a look at this:
http://www.geofex.com/article_folders/eqs/paramet.htm

There are also articles out there showing how to implement a Mid control in a Baxandall. It requires another op amp and/or re-configuring the existing op amp set up, which would make it difficult to utilize the same layout or vero.

Let's look at the response of a Bax though:
http://headwize.com/images/eq2.gif

Boost treble and bass, you get a mid cut. A mid boost here would just cancel out the mid cut. Cut bass and treble, you get a mid "boost."
A mid boost here would just boost volume. I was also fascinated with the MB BB preamp, but I had trouble justifying the extra work/opamp/real estate for the mid boost after I had learned about the response of the Baxandall EQ. ù

really really thanks.

and what about if i build the mid boost on a different veroboard?

i can't find a simple mid boost project on veroboard. Any suggestion?  

[edit] maybe i find it: http://www.diystompboxes.com/smfforum/index.php?topic=96681.0

[YouAre]

really really thanks.

and what about if i build the mid boost on a different veroboard?

i can't find a simple mid boost project on veroboard. Any suggestion? 

I juuuust gave you one, brother! Read that parametric EQ article. There's enough information in there that can satisfy your design criteria, AND hopefully inspire you to build something else as well.

But ok! I did think of something else. Look at this article below. REALLY look at it. Then really look at the Xotic BB Schematic that you have. I can very easily see an "easy" way for you to implement a mid boost into the circuit without a vero. See if you can figure out what it is.

http://www.muzique.com/lab/tstone.htm

[Zipporello]

http://imageshack.com/a/img819/8017/g8mn.png

don't kill me please...

[YouAre]

http://imageshack.com/a/img819/8017/g8mn.png

don't kill me please...

Looks like you found one of the (many) similarities between the BB and the Tubescreamer. But that's not quite the example I was hoping you'd find. Keep reading the article.

Hint: He doesn't call it a "mid boost" in the article, but it's painfully obvious that it is one.

If you have LT Spice, simulate these controls (and Jack Orman's examples) to really understand what these controls are actually doing. You will definitely get a better visual of how the tone controls interact. If you don't have LT Spice, definitely get it. It's been such an invaluable tool in my learning. I've been using it almost daily lately.

[Zipporello]

it's the AMZ tone 6 example right?

i'll simulate it with LT Spice

[YouAre]

it's the AMZ tone 6 example right?

i'll simulate it with LT Spice

Yep. Better not ask for a vero on how to do that, or else...

Caveat: You get your mid boost (and even a cut), at the expense of the filtering done at that stage. That will probably change the tone of the pedal, possibly dramatically. Even then, I'm not sure why they left that Tubescreamer tone stage in there, only to have it essentially hardwired to Max and then put an incredibly powerful filter afterwards anyway. Seems excessive to me.