MXR M181 Blow Torch
Posted: 11 Jul 2023, 15:43
Hello everyone!
We still need to clean up drawing and verify stuff and we don't have means to measure caps atm, but long story short the blow torch is an OPA boosted Si NPN fuzz face (q9/10) with some modded values running at 18V. Torch button sets pre boost gain and there's a weird looking double transistor buffer (q7/8) between OPA and FF that we don't quite understand yet, maybe we missed smth or got it wrong? There's also a 2nd order passive filter after the FF/before the active EQ which boosts bass (fg unkown atm) and may or may not cut mids.
Will try to get more data/verification in but pretty sure this isn't worth a complete trace for us. Kinda annoyed at the 18V, we see no good reason other than EQ pad noise but it's an FF in front c'mon it's not like that's the limiting factor there.
Regarding the rumors that this has been used for some Marceline bass lines in Adventure Time: It does a good approximation of I'm just your Problem with some dry blend, but it could use some compression before and maybe a different bass (P maybe? we're using an EB3L). Didn't need the EQ much, and since it doesn't get you all the way anyways we think a vanilla FF with dry blend is a good DIY alternative (reference: watched some bass->FF vids, close enough).
Hope this helps someone!
We still need to clean up drawing and verify stuff and we don't have means to measure caps atm, but long story short the blow torch is an OPA boosted Si NPN fuzz face (q9/10) with some modded values running at 18V. Torch button sets pre boost gain and there's a weird looking double transistor buffer (q7/8) between OPA and FF that we don't quite understand yet, maybe we missed smth or got it wrong? There's also a 2nd order passive filter after the FF/before the active EQ which boosts bass (fg unkown atm) and may or may not cut mids.
Will try to get more data/verification in but pretty sure this isn't worth a complete trace for us. Kinda annoyed at the 18V, we see no good reason other than EQ pad noise but it's an FF in front c'mon it's not like that's the limiting factor there.
Regarding the rumors that this has been used for some Marceline bass lines in Adventure Time: It does a good approximation of I'm just your Problem with some dry blend, but it could use some compression before and maybe a different bass (P maybe? we're using an EB3L). Didn't need the EQ much, and since it doesn't get you all the way anyways we think a vanilla FF with dry blend is a good DIY alternative (reference: watched some bass->FF vids, close enough).
Hope this helps someone!