Xotic - BB Preamp  [traced]

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Re: Xotic - BB Preamp

Postby Orkspalter » 28 Aug 2009, 22:57

Heres a photo of the limited edition copper version of the xotic bb preamp. The website doesn´t say anything if its an improved version or only the same circuit in a different shiny box
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Re: Xotic - BB Preamp

Postby elrengofa » 25 Sep 2009, 23:16

hi, i never post here, but i get this layout from a brazillian forum
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Re: Xotic - BB Preamp

Postby batteryacidtea » 26 Sep 2009, 00:01

This layout by GuitarHero is verified, there's lots of working builds (i've made 3 using this layout). Pretty big, but sounds gorgeous.
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Re: Xotic - BB Preamp

Postby Chris_mt » 26 Sep 2009, 19:36

The Schematics are not correct!, none of them!, the clipping diodes are across pins 6 and 7 with the cap, take a look at a degooped BB preamp pic i got of the net, I can not find the correct schematic anywhere on the net for this pedal......


Image
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Re: Xotic - BB Preamp

Postby Silent Fly » 26 Sep 2009, 22:13

Chris_mt wrote:The Schematics are not correct!, none of them!, the clipping diodes are across pins 6 and 7 with the cap, take a look at a degooped BB preamp pic i got of the net, I can not find the correct schematic anywhere on the net for this pedal......

(...)


:hmmm: I may be wrong but probably it just means that the the two sections of the op-amp are not in the same order. From the sound viewpoint, it shouldn't make any difference.
"Remember - all I am offering is the truth, nothing more". Morpheus
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Re: Xotic - BB Preamp

Postby TheNixonWayne » 29 Oct 2009, 11:13

Yes I agree. Diodes are connected to pin 6 and 7... and this really not neccesary mean that these two stages are in different order. I believe clipping stage is stil the first but with second part of opamp. Sometimes is easier to make layout to use second gate in opamp instead of first gates (to avoid vias etc).

I attached a modified part of schematics (Douglas Castro's schematics) regarding screenshot and comments mentioned before. However as mentioned before this doesn't make any audiable differences (only layout purpose)

Image

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Re: Xotic - BB Preamp

Postby kram888 » 09 Nov 2009, 10:58

batteryacidtea wrote:This layout by GuitarHero is verified, there's lots of working builds (i've made 3 using this layout). Pretty big, but sounds gorgeous.

I've just finished building this and it sure sounds close to the real thing but with more mids.
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Re: Xotic - BB Preamp

Postby Danch » 18 Nov 2009, 09:27

Hello,
yesterday I was looking at bb preamp guts, it has 4x1n4148 in the loop just added one in each direction on kusi schematic, C1815Y transistors, and IC was JRC for sure, but I could not see the numbers clearly, 4558BD maybe. This is just different version than before, probably less compressed because of two added diodes.
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Re: Xotic - BB Preamp

Postby TheNixonWayne » 18 Nov 2009, 09:57

Has anybody found out which circuit is in BB plus for second channel (B channel)? I have BB plus but it is hard to find out, it has something to do with green LED (for clipping) and transistors mentioned in earlier post. Channel A is BB preamp with only Tone knobe (withoud baxandall tonestack), but channel B has Mid, Bas, Tre.
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Re: Xotic - BB Preamp

Postby TheNixonWayne » 18 Nov 2009, 09:59

Oh I forgot there are two pushbuttons for hard/soft compression. I believe this switch only adds more clipping (sounds like that when pressing).
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Re: Xotic - BB Preamp

Postby mrkaploca » 15 Dec 2009, 12:04

elrengofa wrote:hi, i never post here, but i get this layout from a brazillian forum

This is not completely correct and pins 2 and 3 of the first half of IC1 need to be swaped because the input signal meets first half of IC1 in an inverting input (pin 2)!
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Re: Xotic - BB Preamp

Postby kram888 » 19 Dec 2009, 11:26

mrkaploca wrote:
elrengofa wrote:hi, i never post here, but i get this layout from a brazillian forum

This is not completely correct and pins 2 and 3 of the first half of IC1 need to be swaped because the input signal meets first half of IC1 in an inverting input (pin 2)!
Have you breadboarded this? I've already made a pcb version and it works tremendously close to the real thing.FYI, i have the real thing.
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Re: Xotic - BB Preamp

Postby separanets » 11 Jan 2010, 19:11

I designed a veroboard, but I'm so perplexed by loads of different schematics provided in this discussion that I can't be sure I've choosen a right one for veroboarding.
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Re: Xotic - BB Preamp

Postby separanets » 12 Jan 2010, 18:17

Here is my layout.

Image
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Re: BB Preamp, new layout!

Postby MRobi777 » 20 Jan 2010, 21:59

Hi!

Just one question:
R23 resistance=? Ω


THX
Robert
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Re: BB Preamp, new layout!

Postby MRobi777 » 20 Jan 2010, 22:01

Hi!

Just one question:
R23 resistance=? Ω

http://darkfinn.googlepages.com/BBSchem.jpg

THX
Robert
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Re: Xotic - BB Preamp

Postby SPeter » 21 Jan 2010, 02:44

MRobi777 wrote:Hi!

Just one question:
R23 resistance=? Ω

http://darkfinn.googlepages.com/BBSchem.jpg

THX
Robert


47K!
:)
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Re: Xotic - BB Preamp

Postby MRobi777 » 22 Jan 2010, 10:49

THX :D
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Re: Xotic - BB Preamp

Postby extremist » 28 Feb 2010, 12:28

Hello guys! Does anybody knows what potentiometers used in xotic effects for tone controls (the ones with "middle point")? Brand/type?
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Re: Xotic - BB Preamp

Postby stoske87 » 15 Mar 2010, 02:35

I used layout from a brazillian forum and it is working... I still need to find the way to get rid of hummmmmmm but it sound Andy Timmonish :mrgreen:
Pics tomorrow!

Thanks!!! (4 layout, support etc.......)
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