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Dirtbag with 4xMN3008 (MN3005 fakes from smallbear)

Started by RonaldB, June 07, 2012, 04:39:35 AM

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RonaldB

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
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.

njkke

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...

RonaldB

I used the schematic Small bear added in his shop:
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

gtr2

1776 EFFECTS STORE     
Contract PCB designer

the3secondrule

Quote from: RonaldB on June 07, 2012, 04:39:35 AM
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
"I have many leatherbound books, and my apartment smells of rich mahogany"

RonaldB

They will follow  ;)
But because of the prefboard there is lots of spagetti in there (16 wires) ;D

RonaldB

madbean

Quote from: the3secondrule on June 07, 2012, 12:02:22 PM
Quote from: RonaldB on June 07, 2012, 04:39:35 AM
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.

LaceSensor

Quote from: RonaldB on June 07, 2012, 12:23:24 PM
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

RonaldB

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

sgmezei

I would consider putting in a bypass switch. That way it isn't always on...... ;D

RonaldB

i have all my effects routed through a bypass looper, no need for a switch in pedals then. ;D

RonaldB

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


LaceSensor


pickdropper

#13
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.
Function f(x)
Follow me on Instagram as pickdropper

LaceSensor