Simple DIY Mod YJM308 to Gray 250 Overdrive
Posted: Sun Jul 31, 2011 7:57 am
I modded my DOD YJM308 Overdrive to late 70's gray specs. Removed stock KA4558 chip and replaced with socketed LM1458N (dual 741 op amp), removed C2, and replaced the 0.001uF input capacitor C3 with a 0.01uF value per spec. I used fine braid size #2 solder wick and it worked so good de-soldering the parts that they literally fell out of their holes. Simple and done in less than 30 minutes!
I finished off the mod with original DOD style fluted knobs! Sounds freaking great now. I decided not to cut traces and re-route wires just to use a single 741 chip. The 1458 op amp has two 741 circuits inside and using one of them so it is technically still the same. Comparing noise levels to a gray 250 clone I can't hear any difference to make it worth doing the so-called 'mojo' mod.
I've been meaning to do this for some time. Only thing 'optional' I could add is true bypass 3PDT footswitch, LED, and Boss style power jack, and maybe re-decal it to say YJM250.
I finished off the mod with original DOD style fluted knobs! Sounds freaking great now. I decided not to cut traces and re-route wires just to use a single 741 chip. The 1458 op amp has two 741 circuits inside and using one of them so it is technically still the same. Comparing noise levels to a gray 250 clone I can't hear any difference to make it worth doing the so-called 'mojo' mod.
I've been meaning to do this for some time. Only thing 'optional' I could add is true bypass 3PDT footswitch, LED, and Boss style power jack, and maybe re-decal it to say YJM250.
