freestompboxes.org

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?

OSHPark Xotic - BB Preamp (basead Madbeans)

https://oshpark.com/shared_projects/guCDvUnz

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.

special thanks to Frabbio for the great artwork
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

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

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.

Haha!
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?

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.

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

Cheers

Frabbio wrote: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.

hello sir..

is your bb clone suffer from noise and squelling noise at the volume when max??? i build the this bb preamp from madbean pedal and suffers much on noise and squelling im disappointed..

is your clone behaving like this??

im confused which is the right one schematic that no noise or squelling..

thanks...

Hi, this layout works perfectly, i have had no problem whatsoever.

can someone come in handy)

Don't drink and autoroute, stay safe bro.

oooh this is the original BB Layout with two boards and the BS250 etc.
but this one has got 22k resistor insteade of 47k between lug 1 and 3 of the dual gang pot !
I will try this to see (hear) how it sounds

In case that someone has any doubt about the resistor in parallel with the pot... yes, it's 22K.

Gutshot: Dave

Hi everyone

I have tried the 22k resistor in the dual gang volume pot version, and this has bring the overall output up to the same level as the madbean version (with normal volume pot),assuming that there's two versions on the market, I think that the guys from exotic wanted to make them @ the same output level . using 4 diode make the BB has less (but still enough) gain than with 2 diodes, IMO it's smoother.

Rafik.

hello diy muscians..


i built this bb preamp and box it already ..but when i laid it down on the floor there is a noise in the audio background i check all the parts for ground loose but nothing i can find, the noise is like a shhh..noise..then when i lift it up just i 1 feet on the ground the noise disappear..what is this??
anybody advice?? thanks

Is the box connected to ground? If you are using isolated jacks try soldering a ground wire on the backside of one of the pots.

Frabbio wrote:Is the box connected to ground? If you are using isolated jacks try soldering a ground wire on the backside of one of the pots.

good day diy musicians

thanks for reply Mr. Frabbio
i already grounded the back of one of the pot to the jacks but still the hissing
still there..

theres also a another problem my bb preamp has a low gain when i max the gain pot..
i just have only 1MB pot and it has a low resistance can i have a substitiute for
1MB pot for gain knob what other potentiometer value can i used for gain knob??

any advice thanks..