Tag Archives: stompbox

sqrt() reverb…

sqrt_reverb4

this was the final build before it shipped out. circuit is a simple MOSFET (BS170) driver stage followed by two JFET (J201) recovery stages. i’ve included a sound sample of a similar reverb i built later without the second recovery stage and clipping diodes. it makes for a much more subtle reverb, but also tames the noise floor from the Belton module.

[audio:http://abrammorphew.com/notes/wp-content/uploads/2013/02/sqrt_reverb_demo_02.mp3|titles=sqrt() reverb demo #01]

this is the actual first build. the “dirty verb” comes in towards the end which just switching on a pair of germanium clipping diodes. you get more reverb for your buck with the second JFET stage, but i haven’t found a way to cool down the noise just yet. that’ll be revision 5… maybe 7. [audio:http://abrammorphew.com/notes/wp-content/uploads/2013/02/reverb-test02.mp3|titles=sqrt reverb demo #02]

Mistumin Valve Caster build…

a tube overdrive build for Anthony of the The New Diet and The Regular Fucked Up People. it’s my take on the Mitsumin valve caster with the values i tend to use and a Telefunken 12AX7. excuse the ugliness for this one is just the prototype.

four sections of clean vs. effected total.
[audio:http://abrammorphew.com/notes/wp-content/uploads/2013/02/tube_overdrive_sample_long_02.mp3|titles=Tube Overdrive sound sample]
1) high volume, no tone roll-off, and low gain
2) mid volume, high tone roll-off, and mid gain
3) mid volume, mid tone, mid gain
4) high volume, low tone, high gain

tube_od_proto_02

tube_od_proto_03

tube_od_proto_04

PT2399 build…

this is an older build now, but i wanted to post it while i’ve been on the subject to record the process. believe it or not, i still have some work to do on this one. i used a TL082 as a buffer for the mixing circuit. getting the gain set to my taste has been the toughest part. this one (unlike the last) is a bit low. it will all come in due time though. i’ve produced two solid builds this week (though really just debugging this one and one from scratch), and i’ll consider that a productive week.


MOSFET overdrive…

a forced contract job for Ryan of Falcon Scott. he’s been having some issues finding an overdrive suitable to his hollow-body guitar. i just got a lot of BS170s and thought this might do the trick. the distortion is pretty squared off on the oscilloscope and crunchy. the left pot is post volume while the right biases the BS170. overall, it sounds pretty good and that’s saying a lot coming from someone who isn’t much into “distortion” (personal bias does make a difference. hah).

a big thanks to Jack Orman at Musique.com for laying out the basis. i modified his schematic a bit to get the “best” results for my ear, but i couldn’t have done it without his work.