Sobbat - DB-1 Drivebreaker

Chugs · Post by **Chugs** » 25 Jan 2010, 22:23

I can label up the parts on the layout tomorrow night. I don't have the pedal with me today.

himister · Post by **himister** » 25 Jan 2010, 22:40

Tomorrow is fine!

Thanks for the effort Chugs.
Cheers

Chugs · Post by **Chugs** » 26 Jan 2010, 23:00

I have figured out what all the components are and will post tomorrow. I don't have a paint or draw program on my mac so I had to do it old style and get my girlfriend to print the layout so I could write the values on it. She is going to scan it tomorrow at work and email me it to me so I can upload it. I am feel so technologically backwards! I'm all 20th century, not 21st century!

mictester · Post by **mictester** » 27 Jan 2010, 02:59

Chugs wrote:I haven't played a DB-1 but apparently the DB-2 is slightly less saturated and a little more overdrive orientated compared to the DB-1.

I may be wrong (I often am!) but the difference between the DB 1 and 2 sounds like it's just the diode configurations in the distortion stage. The one I built tonight is as drawn above (mostly), with the diodes to ground. I'm going to modify the board tomorrow, so that I can switch between diodes to ground and diodes in the op-amp feedback loop (like a Tubescreamer). I have a strange feeling that I will have build a switchable DB 1 & 2 clone. It may be worth including a "mode" stomp switch as well as the bypass.

I like the tone circuits, using the gyrators, which seem like an obvious solution to me. I've tried the transistor gyrators sometimes found in some of the Japanese pedals, but they don't really cut it - they have limited boost and cut, and the Q is poor. The op-amp method is far superior, and voiced apart as these are gives a very wide range of tonal colours.

The version I constructed earlier is just lashed together on a piece of Veroboard, but I really like the way I can make this sound, so I'm going to do a PCB, probably using a 4558 in the distortion circuit and the gain stage just before it, and I'll use 5532s or TL072s for the others. I may experiment with CMOS switching for the circuit, as I can't find any really good quality multi-pole stomp switches at sensible prices. However, I can get a really good single pole switch for almost nothing.

When the PCB is finally done, I'll post it here. This is a damn good pedal, and is well worth building!

Chugs · Post by **Chugs** » 27 Jan 2010, 14:54

Here's the layout with the components labelled. It's a bit of a mess so any questions regarding my crappy handwriting will be answered promptly.

I'm not sure what the clipping diodes are. They look similar to 1N1418 or 1N1914 but are a slightly different colour.

Also, there is a blue capaciator of some sort directly above the point where most of the leads connect to the board. It has a positive labelled facing towards the lugs connections and is labelled thusly...

1
25
N

mictester · Post by **mictester** » 27 Jan 2010, 15:12

Chugs wrote:Here's the layout with the components labelled. It's a bit of a mess so any questions regarding my crappy handwriting will be answered promptly.

I'm not sure what the clipping diodes are. They look similar to 1N1418 or 1N1914 but are a slightly different colour.

Also, there is a blue capaciator of some sort directly above the point where most of the leads connect to the board. It has a positive labelled facing towards the lugs connections and is labelled thusly...

1
25
N

Your mystery capacitor is a 1 µF 25V Tantalum type.

himister · Post by **himister** » 27 Jan 2010, 15:23

Well done Chugs...

I believe diodes are 1N4148-914 type, no mistery there. Protection diode could be any 1N400X, like on the ver.1 4002 will suffice. Led polarity diode could be easily 4148 too.
I just wonder where the big top side points are connected...

and where the mistery cap is connected?

mictester, any work and mods you do is more then welcome here and I really can't wait for your updates.

I'm also working on the layout for the version 1 from the Japanese site so I'll include that one too.
Also I've seen the "mini" version for B enclosure of version 2 but I'll need some help with tracing that layout with components values...later on with that one.

Great job.

Cheers fellas.

mini B pcb:

: db2-mini-dual-opaque.gif (70.07 KiB) Viewed 2103 times

himister · Post by **himister** » 27 Jan 2010, 15:34

Sorry fellas...shitting with blue cap..

I've misunderstood that one..
Chugs you missed one resistor, it's above 2k2 resistor, TL074 is below it.

: resun.gif (30.27 KiB) Viewed 2103 times

Chugs · Post by **Chugs** » 27 Jan 2010, 22:28

The missing resistor is a 100K.

himister · Post by **himister** » 27 Jan 2010, 23:20

Once again, thanks for the effort Chugs.

Cheers

SOBBAT_DB2_pcblay.pdf

Chugs · Post by **Chugs** » 27 Jan 2010, 23:25

No problem. This is a really good pedal. I hope you enjoy it. I like the DB-2 so much I brought two!

mictester · Post by **mictester** » 05 Feb 2010, 20:41

himister wrote:Once again, thanks for the effort Chugs.

Cheers

SOBBAT_DB2_pcblay.pdf

Just noticed - pin 6 of the TL074 doesn't go anywhere on the pdf layout.

himister · Post by **himister** » 06 Feb 2010, 01:28

I apologize. I missed that one...pins 5 and 6 are connected.
Thanks mictester!

Fixed project file:

SOBBAT_DB2_pcblay_a.pdf: Updated layout!; (97.81 KiB) Downloaded 473 times

mictester · Post by **mictester** » 06 Feb 2010, 02:48

himister wrote:I apologize. I missed that one...pins 5 and 6 are connected.
Thanks mictester!

Fixed project file:

SOBBAT_DB2_pcblay_a.pdf

You mean 6 & 7!!

himister · Post by **himister** » 06 Feb 2010, 02:59

Yup... it's late here.. almost 4 in the morning, and redrawing schematic for DB-1 to compile whole project...now damn buffer is bugging me, and my eyes kind of tired...blured vision...

Cheers

ryanuk · Post by **ryanuk** » 24 Feb 2010, 14:20

Guys

Stumbled on this thread - great progress being made on reversing the DB-2

I was drawing up a schem based upon the layout provided by himinster, and the pics from Chugs. Whilst tracing, I have spotted some errors in the layout.

1. Pin 3 of the 4558 (IC1A +) is shown to connect to a 1uf cap that follows IC2d OUT i.e. 2 traces have been joined in error. Check the PCB pic.

2. The layout has pads for the pots - BASS 1 and 2, TREBLE 1 and 2 - however no reference is made to the third terminal of each pot. I could assume that these were not connected, but the DB-1 schem (linked above) shows Bass 3 to connect to Treble 1, and Bass 1 to connect to Treble 3. This can also be seem in the japanese DB-2 schem (if you squint!). I think the answer lies in the offboard wiring of the Bass/Treble pots.

3. Similar to the above, wiring is not clear for DRIVE 3, or VOL 1. I assume VOL 1 is connect to GND, and DRIVE 3 is connected to DRIVE 2.

Chugs - I see the images are from your original unit. Could you make some notes or take pics of the pots to clarify??

Once I finished my schem I will post it on the forum.

regards

RyUK

Chugs · Post by **Chugs** » 25 Feb 2010, 06:55

I away from home traveling for the next month and I don't have the pedal with me unfortunately. From memory, two of the pots definitely did not have their third terminals connected. I'll be sure to check the pots when I return.

himister · Post by **himister** » 25 Feb 2010, 12:40

Thanks ryanuk... Good for spotting mistakes. Must say that working on several layouts made lot of confusion for me.
As for the DB1 layout, I redraw that one from Japanese site photos but didn't posted yet!
These days I'm very busy so not much time to finish it. I hope Chugs will help us here again with pot wiring.
Apologies for the errors. I'll wait for your schematic and made changes to the layout and post it after.
Cheers to you lads!

himister · Post by **himister** » 25 Feb 2010, 13:22

Ok guys. I just included redrawn schematic from this thread into project pdf for DB1.
Small thing that's not included on the layout is the buffer out point pad and it can be easily soldered between the 100k resistor and 1uF cap on the left of the board, just below 10k res and 22n cap.
This is the unverified layout so if anyone spots any mistakes, shoot here. I've also included the wiring diagram into pdf.
Enjoy!

Ver. A - Unverified

SOBBAT DB1-Project_a.pdf: (387.29 KiB) Downloaded 445 times

Dimitree · Post by **Dimitree** » 07 Mar 2010, 14:04

great..I really appreciate it!!