madbeanpedals::forum

Projects => Build Reports => Topic started by: RonaldB on June 06, 2012, 09:39:35 PM

Title: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: RonaldB on June 06, 2012, 09:39:35 PM
Hi,
After building the dirtbag with the V3205 chips I wasn't really happy with the sound.
So I purchased the MN3005 fakes from smallbear (2 sets). I made a little prefboard layout and changed the circuit to the MN3005 standard. Now the echo is beautifull.
What I did changed was for R11 and R12 39K instead of 68K. Somhow I liked it better with those values.

And after reading this post last night:
http://www.madbeanpedals.com/forum/index.php?topic=5090.0 (http://www.madbeanpedals.com/forum/index.php?topic=5090.0)
I added a 100R resistor after C32. I will be trying a 1K potentiometer in the future.


Looks haven't changed, sound Oh yes. THANKS MADBEAN.
(http://i1237.photobucket.com/albums/ff467/ronaldvdboon1/SAM_1491.jpg)
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: njkke on June 07, 2012, 12:59:53 AM
Can you tell me more about your mods? I've built a dirtbag with MN3205 that works one day at week! Probably the MN3205 from Hong Kong are instable in some way I don't know... I'd like to switch it to a MN3008 version, simplier to find in europe...
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: RonaldB on June 07, 2012, 03:47:04 AM
I used the schematic Small bear added in his shop:
http://www.smallbearelec.com/servlet/Detail?no=247 (http://www.smallbearelec.com/servlet/Detail?no=247)

And followed Madbean documentation to redo all the changes made for the V3205 version.

I'm also in europe (the Netherlands) to be exact. But ordering from Small Bear was easy and cheap.
Got them send in a week for 33 euro's.

best of luck
RonaldB
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: gtr2 on June 07, 2012, 04:07:12 AM
Nice build.

Gut pics are required  ;D

Josh
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: the3secondrule on June 07, 2012, 05:02:22 AM
Quote from: RonaldB on June 06, 2012, 09:39:35 PM
What I did changed was for R11 and R12 39K instead of 68K. Somhow I liked it better with those values.

What effect did/would this have?

cheers,

J
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: RonaldB on June 07, 2012, 05:23:24 AM
They will follow  ;)
But because of the prefboard there is lots of spagetti in there (16 wires) ;D

RonaldB
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: madbean on June 07, 2012, 05:55:10 AM
Quote from: the3secondrule on June 07, 2012, 05:02:22 AM
Quote from: RonaldB on June 06, 2012, 09:39:35 PM
What I did changed was for R11 and R12 39K instead of 68K. Somhow I liked it better with those values.

What effect did/would this have?

cheers,

J

It reduces the output of the compressor portion of the compander. IIRC, 39k is the value used on the Memory Boy which uses 4x BL3208a.
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: LaceSensor on June 07, 2012, 07:05:13 AM
Quote from: RonaldB on June 07, 2012, 05:23:24 AM
They will follow  ;)
But because of the prefboard there is lots of spagetti in there (16 wires) ;D

RonaldB

please consider to post your doubledelay board layouts ? thanks
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: RonaldB on June 07, 2012, 10:41:38 AM
Lacesensor:
I will draw one up tommorow. I did this one out of the top of my head.

Madbean:
I Think the 68K would work also but i'm happy with the 39K for now.
Will the dirtbag delay PCB's be stocked again soon?

RonaldB
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: sgmezei on June 07, 2012, 02:03:47 PM
I would consider putting in a bypass switch. That way it isn't always on...... ;D
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: RonaldB on June 07, 2012, 09:40:09 PM
i have all my effects routed through a bypass looper, no need for a switch in pedals then. ;D
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: RonaldB on June 08, 2012, 01:45:18 AM
Here is the pref layout I would use the next time I will make these double delay boards.
Mine are a mess now but they work ;D
(http://i1237.photobucket.com/albums/ff467/ronaldvdboon1/TraceDoubledelayboard.png)
(http://i1237.photobucket.com/albums/ff467/ronaldvdboon1/Doubledelayboard.png)
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: LaceSensor on June 08, 2012, 04:41:01 AM
thanks
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: pickdropper on June 08, 2012, 05:18:35 AM
I think a layout that used PCB mount pin headers could clean up the wiring quite a lot.

After I finish up a few other things, I may make a go at it.

[EDIT] - Nevermind, I see that Smallbear has the PCB layout for this already on their site.
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: LaceSensor on June 08, 2012, 10:26:26 AM
HI

This also works (at least in an aqua puss build)

http://www.sabrotone.com/?p=698
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: gitaar0 on June 08, 2012, 11:38:12 PM
Nice dirtbag build.

Lacesensor: i am wondering if those values will work in the dirtbag as well? The values for the double delay that smallbear has posted are different.
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: LaceSensor on June 11, 2012, 05:16:17 AM
I can try it, I guess.

Anyone know if cascading 2x mn3008, then 1 x mn3008 on the board should work?

Any reason not to / any damage can be done?
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: RonaldB on June 11, 2012, 05:53:19 AM
This will defenatly work.
Just see every MN3008 as a stage.

RonaldB
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: LaceSensor on June 11, 2012, 07:40:21 AM
It does indeed work.

Whats interesting now, is some bloke sent me a double delay fabbed board, but its not one of the red ones. Im puzzled as to what it is or what the resitor values are :)
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: gtr2 on June 11, 2012, 10:18:07 AM
Does it have 8 header pins on one side  ::)
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: LaceSensor on June 11, 2012, 10:23:34 AM
Quote from: gtr2 on June 11, 2012, 10:18:07 AM
Does it have 8 header pins on one side  ::)

Yes
Its a green PCB. I can take a pic and upload it.
has space for one trim and 5 resistors.
Title: Re: Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)
Post by: the3secondrule on July 06, 2012, 06:45:43 PM
FWIW, I swapped out r11 and r12 for 39k on my 3005 build, and it DRASTICALLY improved the headroom, without losing any of that dirtbag character  ;D

Quote from: the3secondrule on June 07, 2012, 05:02:22 AM
Quote from: RonaldB on June 06, 2012, 09:39:35 PM
What I did changed was for R11 and R12 39K instead of 68K. Somhow I liked it better with those values.

What effect did/would this have?

cheers,

J