Apologies if there's an answer to this question already buried in the cupboard somwhere, but I was wondering what the circuit differences were between the original (A & B) quad op-amp OD-1, and the dual op-amp versions.
I don't know about circuit differences, but this inspired me to compare the models. So I just A/B'd two of my OD-1s for the first time: #7900 with the Raytheon, and #9200 with the 4558. There's actually a quite noticeable difference between the two, but it might be chalked up to component drift or other variances..
#7900 was much thinner sounding, to my ears more like a piercing, loud Plexi (although I've only played a few plexis in my life)
#9200 had a thicker tone, but ended up sounding much more nasal. I sounded like some kind of low-mid freq. being boosted. It was also nice but I preferred the clarity in the older pedal.
I have another with the NEC chip, but I'll save that test for another day (maybe for a day when I can record the differences).
@nathanscribe: Hope somebody can shine a light on your inquiry!!
The 3403 is used in the PH-1 as well (and probably others). My guess is that they bought a container full of the 3403 chips cheap from Raytheon and when they ran out changed the design.
OD-1 changes from quad to dual op-amp
Posted - 05/27/2009 : 17:07:21
