Baja BBE Sonic Stomp

bajaman · Post by **bajaman** » 19 Aug 2007, 02:49

Hi guys and gals
Just a short note to let you know, I have designed a BBE Sonic Stomp circuit board etc. using easily obtainable TL071, TL072, And TL074 ICs
I have also designed a replacement daughter board for a Sonic Stomp repair - Too hard to get an NJM2150AD chip locally, so necessity being the mother of invention, I designed and built a working replacement - just installed and tested it too!! Works a treat

Stay tuned - a complete project will be posted in the coming week

Cheers
bajaman

MoreCowbell · Post by **MoreCowbell** » 19 Aug 2007, 03:04

I"m looking forward to it !

markm · Post by **markm** » 19 Aug 2007, 05:37

Very Cool baja, can't wait!!

grolschie · Post by **grolschie** » 19 Aug 2007, 06:01

See ya tomorrow bajaman! I can't wait to hear this!

bajaman · Post by **bajaman** » 19 Aug 2007, 12:33

The wait is over - here it is

Baja Sonic Stump and replacement daughter board for BBE Sonic Stomp NJM2150AD
A full explanation and schematic will follow - must sleep now though 12:30 am here

The first image and layout is true to the original BBE Sonic Stomp
The second image is a verified working daughterboard - in case you have a Sonic Stomp that has a buggered NJM2150AD chip (like I did with a recent repair).
The third image is a DIY Sonic Stomp utilising the same components used on the daughterboard - I rotated one of the pots by 180 degrees to allow for a stable and easy mounting in a box - I got this idea from the Demeter tremulator mounting system, which I used on the Baja Trembulator also. I left the circuit traces for a dc printed circuit board mounting socket (same as the BBE) but I would recommend using a chassis mounted dc socket - I have seen far too many dry joints / loose sockets with PC mounted sockets

For your information - The NJM2150AD is a two channel processor, with built in electronically activated process, lo contour and mixing stages. In the Sonic stomp only one channel is used and all the electronic control and mixing stages are ignored. my daughterboard uses an input buffer, and a modified state variable filter, with a precision buffered v/2 supply rail, and the outputs are sent to the existing process and lo contour controls and the existing TL072 input and output mixing IC.
enjoy

bajaman

Kaos · Post by **Kaos** » 19 Aug 2007, 12:40

baja you're the real tone god

grolschie · Post by **grolschie** » 20 Aug 2007, 02:58

And it sounds GOOD! I heard it today. I can definitely see a use for this pedal to cut through the mix. Excellent work.

bajaman · Post by **bajaman** » 20 Aug 2007, 03:11

UPDATE - my layouts contain a small error for the daughterboard and BAJA versions - I mistakenly assumed that the first stage of the TL074 was a unity gain buffer - it is NOT, it is a 6db non inverting gain stage

I could modify the board layout BUT, there is an easier work around - change the 27k resistor around the TL072 to a 56k (27k + 27k in series), then the effect level will better match the bypass level and be almost 100% the same as the BBE unit level.

MODS - change the 39k resistor to a 10k + 50k lin potentiometer in series, for a midrange cut or boost control

. AND change the 47n capacitor for changing the lo contour turnover (try 33n - 100n), OR change the 3n3 ( try 2n2 - 10n) capacitor for changing the process (high frequency) turnover point.
Cheers
bajaman

bajaman · Post by **bajaman** » 20 Aug 2007, 06:32

I "found this" - it was a great help in reverse engineering the BBE Sonic Stomp - credit where credit is due

bajaman
BBE chip internals exposed

bajaman · Post by **bajaman** » 21 Aug 2007, 09:42

Here is the schematic - i am not sure about the 10uf polarised electrolytic coupling capacitor - a bipolar ( or two 22uf electros back to back) would probably be a better choice, but it does work okay!
cheers
bajaman
Baja Sonic Stump schematic

bouli · Post by **bouli** » 21 Aug 2007, 14:23

Hello !

Is somebody could explain to me ( with simple words if possible ) what's the utility of this circuit ?

i would like to now , what's going to happen to my sound when i m going to push the footswitch

thanks

ps : i'm really sorry for my dreadful english

krome_magnon · Post by **krome_magnon** » 21 Aug 2007, 20:06

bajaman wrote:Here is the schematic - i am not sure about the 10uf polarised electrolytic coupling capacitor - a bipolar ( or two 22uf electros back to back) would probably be a better choice, but it does work okay!
cheers
bajaman
Baja Sonic Stump schematic

So is this the schem for the whole thing or just the daughter board?

And am I right in thinking that the "legendary BBE process" is little more than a State Variable Filter based tone control? With the band pass output always on and the low pass (lo-contour) and high pass (process) outputs gain variable by altering the resistance value going into the summing stage?

In the BBE chip internals exposed schem the high pass output would be given some degree of dynamic variation according to the input signal. But... it still seems to be a fancy tone control.

Wonderfully clean and precise artwork on the PCBs by the way.

bajaman · Post by **bajaman** » 21 Aug 2007, 21:29

Is somebody could explain to me ( with simple words if possible ) what's the utility of this circuit ?

It is supposed to sharpen or focus the sound by altering the phase of the high and low frequencies and the controls allow the level of the highs and lows to be adjusted to suit the need.
More information is available on the BBE website - search for Sonic Stomp.

So is this the schem for the whole thing or just the daughter board?

it is the schem for the whole thing

I will draw up a schem for just the daughter board and post it soon

And am I right in thinking that the "legendary BBE process" is little more than a State Variable Filter based tone control? With the band pass output always on and the low pass (lo-contour) and high pass (process) outputs gain variable by altering the resistance value going into the summing stage?

Yes, you are right

Wonderfully clean and precise artwork on the PCBs by the way

Thank you - I am learning from AG

. I use Corel Draw 13 for all my layouts and schematics - takes a little more effort but allows mixing of images for easy cloning - unlike dedicated PCB drawing programs.
I have been using Corel Draw since version 2 - great program

cheers
bajaman[/quote]

krome_magnon · Post by **krome_magnon** » 21 Aug 2007, 21:41

bajaman wrote:Thank you - I am learning from AG . I use Corel Draw 13 for all my layouts and schematics - takes a little more effort but allows mixing of images for easy cloning - unlike dedicated PCB drawing programs.
I have been using Corel Draw since version 2 - great program
cheers
bajaman

I've used Corel Draw 6 for years and only changed to 8 when I got it for peanuts in a clearance sale. I recently moved to 12 for the same reason. But will probably go back to 8 because it seems to "handle better" and does more than I'll ever need anyway.

And going back to the BBE process all the "phase tweaking" blurb kind of looks like crap when you see under the lid. Stick a dual pot in the SVF part and you could make it a little more flexible by having it tuneable.

bajaman · Post by **bajaman** » 21 Aug 2007, 22:00

Stick a dual pot in the SVF part and you could make it a little more flexible by having it tuneable.

Now, that is what this forum is REALLY about - a very good mod

......and , how about a midrange tone control level as well - also, it may be a better choice for a very flexible tone shaping control after a distortion stage too.

Food for Thought here

bajaman

krome_magnon · Post by **krome_magnon** » 21 Aug 2007, 22:20

bajaman wrote:
Stick a dual pot in the SVF part and you could make it a little more flexible by having it tuneable.
Now, that is what this forum is REALLY about - a very good mod
......and , how about a midrange tone control level as well - also, it may be a better choice for a very flexible tone shaping control after a distortion stage too.
Food for Thought here
bajaman

Or insert loops in the outputs of the SVF so you can process the 3 bands individually etc.

Distorted midrange, chorused hi pass, and compressed lows.
A different flavour of distortion on each band.
A different echo on each band.
A different tremolo on each band.
Univibe style vibrato on the highs and lows with the mids cut for a more leslie like swirl.

Endless possibilities

AL · Post by AL » 22 Aug 2007, 17:55

You should be able to do a patent search using "BBE" or something similar.

http://patft.uspto.gov/netacgi/nph-Pars ... BBE&RS=BBE

AL

estragon · Post by **estragon** » 22 Aug 2007, 18:53

Check this three posts by stm in a thread at the DIY forum from 2006:

https://www.diystompboxes.com/smfforum/ ... #msg378161

https://www.diystompboxes.com/smfforum/ ... #msg378276

https://www.diystompboxes.com/smfforum/ ... #msg378369

A good deal of info on the BBE process and the NJM2150 (New Japan Radio) and BA3888S (Rohm) chip implementations, as well as a DIY version.

bajaman · Post by **bajaman** » 22 Aug 2007, 21:04

thanks for the links Estragon - STM has made a good analysis, but could not find any DIY project links - no need though now

, just an endless - try my settings - I use a GE7 etc. bunch of replies

cheers
bajaman

estragon · Post by **estragon** » 22 Aug 2007, 21:32

Bajaman, this is a link to the DIY project. It was submitted for FX-X, so you need to be logged in to have access:

https://www.diystompboxes.com/smfforum/ ... #msg379782

Baja BBE Sonic Stomp [documentation]