Xotic - BB Preamp  [traced]

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
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Goop_buster
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Post by Goop_buster »

admin: merged in here from another thread:[/b]
greenskull wrote:I've been trying like hell to figure out what I could contribute here and remembered this from DIYstompboxes:
https://www.diystompboxes.com/smfforum/ ... ic=55014.0

Here's the schematic:


LA Boutique Screamer JPG schematic

I created an image file from the original pdf. Hope it works out!!

And for reference...accordring to JHS that schematic is not an 100% exact copy of the BB.
Is it is a work-a-like design by k*** which is very close and got the same baxandall-EQ and so on.

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modman
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Post by modman »

Maybe all of them are related in design. It's getting boring, all those tubescreamer clones. Somebody want to spice up the Frantone thread? There's a link to a Fran picture!
Goop_buster wrote:And for reference...accordring to JHS that schematic is not an 100% exact copy of the BB.
Is it is a work-a-like design by k*** which is very close and got the same baxandall-EQ and so on.
K.U.S.I. kusi - "kusi" - *kusi*

This guy's name doesn't get past the inherent forum filters. Found something in a page on Finnish profanity :shock:

http://en.wikipedia.org/wiki/Finnish_profanity

"K u s i, pronounced /k u s i/ or like "c o o s y" in English, means "u r in e" with a similar connotation as "p i s s". Used by itself, the word almost always refers to actual u r i ne and is considered only mildly offensive in colloquial language. Compound words, such as "kusipää" (piss head) are very offensive insults. Children often use "pissa" as a tame replacement word. The word pissa has drifted so far into everyday usage that in combined form "pissapoika" (pissing boy) it refers specifically to the squirter on the windshield of cars. Several foreign visitors have been amused by the product "Superpiss" for windshield wiper fluid."

a lot of other words do get through. Why this Finnish word not?
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JHS
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Post by JHS »

kusi is "short" for "Markus" nothing more...
JHS

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JHS
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Post by JHS »

My twist on the X-drive, add an TS-9 O-buffer if you like, to get closer to the original.

https://s206.photobucket.com/albums/bb4 ... XDRIVE.gif

JHS

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Goop_buster
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Post by Goop_buster »

JHS wrote:My twist on the X-drive, add an TS-9 O-buffer if you like, to get closer to the original.

https://s206.photobucket.com/albums/bb4 ... XDRIVE.gif

JHS
Thanks JHS. What software do you use for schematics?

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JHS
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Post by JHS »

MS Paint and copy and paste.

I have the basic symbols as a template (buffers, tonestacks, trannies, R, C ...) so it doesn't take to much time.
It's much faster than generating the schems with my CAD-software.

JHS

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greenskull
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Post by greenskull »

Well at least we've gotten a non-English cuss words lesson from this thread. :oops:

Modman, feel free to move this thread or destroy it.

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gnognofasciani
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Post by gnognofasciani »

Does anybody have a pcb/layout?

Just not to work in vain...

Thanks!

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modman
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Post by modman »

gnognofasciani wrote:Does anybody have a pcb/layout?

Just not to work in vain...

Thanks!
Haven't seen one yet, maybe because of the TS similarity. Do have a look at the similarities between RC/AC/BB, you might be able to make a layout to be used with either of the three.

Haven't looked into this on schematic level yet, sorry. Trying to get some stuff done this week and it's looking bad already :wink:

keep us posted.
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Post by gnognofasciani »

As far as I can see BB uses non inverting input for the clipping stage and AC the inverting one (is the AC the "Japxotic booster"?), so it won't be easy to draw a universal layout...

I'll see what I can do :wink:

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pakalolo
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Post by pakalolo »

Hello,

Never found a layout for this one.
It's quite close to a TS808 so I built mine using the GGG ts808 PCB.
I added an extra veroboard for the active tonestack.

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Post by gnognofasciani »

There's one thing i can't understand: is there any difference between using an inverting or a non inverting input for the clipping stage?

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JHS
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Post by JHS »

There is a slight difference in tone and IMHO the inverting input deliver a better reaction to the guitar vol. and picking nuances.

JHS

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Post by snail »

can you guys count 3 transistors instead of 2 indicated in the current schematic.

on the ungooped gutshot provided by AG there is what apears to be another transistor, or Fet..., the one in the upper left corner left of the electrolitic cap.

any takers???

Played one of these last friday, not very impressed, but I can see why TS players will dig that one.

snail

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sosodef
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Post by sosodef »

I have one of these BB preamps. I was never too too impressed with it. The main reasons are:

Its overly compressed. It doesn't respond well with dynamics of your playing/picking. It never really does that great of a boost a bit too dirty still. Lastly the gain becomes a bit too loose sounding as you get past say 10 oclock.

I have had thoughts of pulling out the heatgun and trying to make it a better pedal. Is this pedal ready for mods?

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modman
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Post by modman »

Schematic links seems to be dead, IIRC this was the schematic being discussed:

Image
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kusi
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Post by kusi »

hi,

the third transistor is a mosfet and it switches the led.

regards, kusi

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snail
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Post by snail »

Thanks Kusi and Modman!

snail

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Post by modman »

snail wrote:Thanks k**i and Modman!

snail
No way, all credit to K u s i , didn't know he drew it.
Replaced the links throughout the thread.
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kusi
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Post by kusi »

the L.A. Boutique-Screamer is a little bit modified...

here you find the original BB:
http://forum.musikding.de/cpg/displayim ... 4&pos=-424

(+ and - inputs of the gainstage are in wrong direction... ;)


regards, ksui

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