Xotic - BB Preamp  [traced]

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Re: Xotic - BB Preamp

Postby ballfire » 21 Feb 2014, 04:26

hello everybody..

i build this pedal but there is a problem there is a craclikg crickling noise from the output but the output of the pedal .. the knobs is functioning well ic and transistors are okey..but there is a crackling in the background of the the effect when it bypass.. :(

any suggestions or advice?
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Re: Xotic - BB Preamp

Postby andregarcia57 » 09 Mar 2015, 06:20

OSHPark Xotic - BB Preamp (basead Madbeans)

https://oshpark.com/shared_projects/guCDvUnz
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Re: Xotic - BB Preamp

Postby Frabbio » 01 Oct 2017, 15:19

Here is my single sided layout for the BB Preamp, it's verified.
This version includes all the latest modifications to the schematic (stereo volume control, 4 clipping diodes), and was designed to fit board mounted pot, including the stereo pot for volume control.
Board dimensions are 5.5cmx5.5cm, should fit in a hammond b enclosure.
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Re: Xotic - BB Preamp

Postby rafikian » Yesterday, 21:53

special thanks to Frabbio for the great artwork :applause:
worked perfectly and sound amazing, this one is smoother than the first version, the gain is more linear, and the bass response is awesome !
here's some guts :D
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Re: Xotic - BB Preamp

Postby Intripped » Today, 09:32

Freppo,
In your schematic the first half of the dual gang pot (the half acting as a filter) is connected in a strange way:
Is it a mistake or made on purpose?
In this way you have changed the frequencies of the filter to 15.8/40Hz (in all other schematics the frequencies are 40/160Hz)

And by the way: at the bottom end of the previous page of this topic, Frabbio (...are you two relatives?) said that the filter should work in the opposite way, making the filter add bass freqs while you turn the pot cw.
...I still haven't understood if he is right or not.

Cheers,
Cristiano
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Re: Xotic - BB Preamp

Postby Frabbio » Today, 12:25

Hi Intripped, i think you messed up with the names, there is no Freppo!
I tried both arrangements and i liked it better this way.
However if you want to try it by yourself give me your email in pvt and i'll send you the eagle files.
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Re: Xotic - BB Preamp

Postby Intripped » Today, 13:49

Haha! :slap:
I definitely messed up with the names, sorry for that!

Thanks for your offer Frabbio, but I don't need the eagle files.
I have already built a clone, and I can easily modify it, since the pots are not board mounted.
I was just curious about this variant that you've made.

However: Do you know how this pot is wired in the original pedal? Is it as you said in your post in the previous page?
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Re: Xotic - BB Preamp

Postby Frabbio » Today, 16:04

I can't say for sure because i have never opened a real BB preamp, but with this configuration it sounds pretty good and really similar to the samples, give it a try ;)
The biggest difference however are the 4 clipping diodes.
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Re: Xotic - BB Preamp

Postby Intripped » Today, 16:22

Ok, thanks!
I'll give it a try for sure

Cheers
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