Behringer - BDI-21 (TB+Mids Control+ Blend Control)

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goaltoday
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Post by goaltoday »

This is my modded Behringer BDI21. It's a clone of the sansamp bassdriver.

Outside

Ugly Inside :oops:

Besides the true bypass I've added a mids control ( the one STM published on diystompboxes) and a new blend control. I didn't like the old blend control because the clean signal was mixed before the EQ and I want my signal unaffected.

I'll add this mods to my DIY sansamp too. So I'm going to have the behringer clone and my own clone. :lol:

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soulsonic
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Post by soulsonic »

Cool.
You should post up those mods here.

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Harold
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Post by Harold »

goaltoday,

I can't seem to find the mid control mod you're talking about! Could you explain what to do and/or point us to the post on diystompboxes?

-tnx!-
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goaltoday
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Post by goaltoday »

I used this schematic

Just changed some cap values to taste.

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Harold
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Post by Harold »

goaltoday wrote:I used this schematic

Just changed some cap values to taste.
The Bass and treble control on my Sansamp Bass Driver are quite all right as is, but I'm really interested in the mid control.

Could you post a picture of how you've implemented this schema? I'm not quite a schematics expert (yet), so I'm not quite sure what X5 is, and where to put the mid section in the sound path...

Would it also be possible to add a second potentiometer to change the freq of the mids? (semi-parametric)

-H-
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samurai1993
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Post by samurai1993 »

Sorry for bothering you buds, but I'm in a hurry. Last week I lend my BDI21 to a friend, and he connected it to a 9v source, but with inversed polarity. The thing heated and after a while he said it smelled like something was burnt. I checked the circuitry and all that I could found was a blowed up resistor. All in all, the pedal itself it's ok, if you use the battery input, it works ok. The problem is, I couldn't find the value of the resistor, nothing indicated on the pcb and the resistor itself was lacking any colored band coding. Could you help me? In the pcb is indicated as the R37, just at the side of the 9v input.

Thanks for your time!

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Harold
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Post by Harold »

samurai1993 wrote:The problem is, I couldn't find the value of the resistor, nothing indicated on the pcb and the resistor itself was lacking any colored band coding.
If it's used as polarity protection (in series with +9v), my uneducated guess is that it's only 47R or 100R.

Check this topic for more info: https://www.freestompboxes.org/viewtopic ... 79#p109979
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yiye777
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Post by yiye777 »

R37=330 ohm

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alanamps
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Post by alanamps »

I had the same problem - burnt out R37. The markings on the pcb said 330R but that didn't work - too much voltage drop across it (6.5V). I read elsewhere it should be 12R which seems a bit low. My guess it's supposed to be 33R and the pcb is marked wrongly. I put in a 22R (didn't have a 33..) and it works fine. :D

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gerodoth
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Post by gerodoth »

in my rev.1 pcb r37 is black and i can't see colors, but it works and tester shows 50 Ohms straight.

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bdp32
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Post by bdp32 »

Ancient thread I know, but R37 in my unit is a 5% 12R 1/2W easy to read the bands on that resistor even with my eyes.

Just making a note for when someone fries mine for me :) :slap:

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Post by reddesert »

I also had a BDI21 (bought used) that worked on battery but not wall-wart, found that burnt component, and jumpered it with a parallel replacement. I can't remember if I used a low-value resistor or a series diode, but anything that works out to a relatively low voltage drop across it should work.

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