So I have a Nobles ODR-1 and I like the sound. My only complaint is that it feels a tiny bit stuffed... If it were an amp I would think it had too much negative feedback.
Being proficient with working on and tweaking amps I figured I would have a look at the schematic... Yeah, pedals are a different ball game. The one thing I did notice was an area of negative feedback near the output. I have a schematic below and I highlighted the area that I am looking at. Would adding a trim pot in the looped area below be the same as reducing the negative feedback? My goal is to have a more open, less compressed ODR-1.
Thanks!
(http://i180.photobucket.com/albums/x96/oc2tennessee/nobels_odr1_overdrive_schpdf_1_zps80afc05e.png) (http://s180.photobucket.com/user/oc2tennessee/media/nobels_odr1_overdrive_schpdf_1_zps80afc05e.png.html)
Put 2 diodes instead of one for d1 and d2. Maybe even d3 and d4. Start with that.
+1
Thanks! I will absolutely give that a try this week. For the sake of my own education, what is the reason for adding those diodes?
You are going to love this. This type of document starts a whole bunch of trouble:
Read the first mod:
http://www.diystompboxes.com/wiki/index.php?title=Simple_mods
Quote from: aron on May 12, 2013, 02:12:33 PM
You are going to love this. This type of document starts a whole bunch of trouble:
Read the first mod:
http://www.diystompboxes.com/wiki/index.php?title=Simple_mods
Oh crap... You just opened up a can of worms! ;D
The ODR-1 is a little "cracker" I like it as much as a good TS-9, tone control works better too IMO.
Doubling up the D1-4 with extra 1N4148's helps, IIRC I also reduced the cap to ground around D3/4, which brightens the
"crunch" a little ( to 1nf/1000pf ) and also reduced the small pf cap across D1/2 to 47pf.
There are also a couple of other caps that I changed as i found the pedal a little "dark" sounding, can't remember which and that
schem is a bugger to read !
Welcome to a VERY large can 'o worms :-)
Marty.
I have modded a few of these , they can sound very nice with a few mods !!
here's my suggestions ..
C1 - 1 uf ( less low end from the factory value of .22 uf )
C34 - .047 uf ( also cuts a touch of low end )
D2 - 1N4001 +1N34A germ in series ( far warmer clipping that stock )
D4 - 1N4001 + 1N34A germ in series