Stumbled across this one and it seems pretty cool. It's like an Escobedo Punch-in-the-Face sandwiched between two opamp gain stages, and is very similar to the Carl Martin Crush Zone. Wide range of gain and tones on tap as well. Pots are board mounted and it'll fit in a 1590B.
This is a nice, focused, mid-rangey OD. I was surprised that it sounded good with the 220pF input cap, but I preferred 2.2nF or 4.7nF for a slightly fuller sound.
Some of the demos for the Om and the similar Carl Martin Crush Zone have noticeable background hum, and mine does as well. I tried a few easy fixes (small caps off the input or between Q1 collector and base, disconnecting the 2.2uF cap off Q2), but those all muffled the sound too much. The noise floor is not too bad with the gain set under 10:00 or 11:00, which is enough drive for me.
If I wanted to build a similar effect again, I might try building a tweaked version of the Punch-in-the-Face, since the op-amp in the Om is not adding much with the gain set low.
Will common dual opamp do?
ReplyDeleteAny suggestion to replace Q1?
Yeah TL072, JRC4558, etc will be fine. 2N3904 or 5088 for Q1. Sockets are your friend ;)
DeleteGoing to start building very soon.
DeleteHow about the q2 sir? Can we replace it with 2N5088?
DeleteNo that needs to be a n-channel JFET
DeleteCan i use non polar elco for 1uf caps?
ReplyDeleteItu memang non polar mas
DeleteOk. Ngaruh ga mas kalo saya pake elco bipolar dibanding sama kapasitor mkm
DeleteKe hasil sound? Rasanya ga ngaruh mas
DeleteOk sipp. Ntar saya coba. Makasih mas
DeleteVerified.
ReplyDeleteThis is a nice, focused, mid-rangey OD. I was surprised that it sounded good with the 220pF input cap, but I preferred 2.2nF or 4.7nF for a slightly fuller sound.
Some of the demos for the Om and the similar Carl Martin Crush Zone have noticeable background hum, and mine does as well. I tried a few easy fixes (small caps off the input or between Q1 collector and base, disconnecting the 2.2uF cap off Q2), but those all muffled the sound too much. The noise floor is not too bad with the gain set under 10:00 or 11:00, which is enough drive for me.
If I wanted to build a similar effect again, I might try building a tweaked version of the Punch-in-the-Face, since the op-amp in the Om is not adding much with the gain set low.