The EAE Magic Missile is their take on a Devi Ever Hyperion, so expect some fuzz. You can find the schematic here.
Note from EAE: best results were with a 2n2219A/2n2905A pair, which are functionally close to the 2n2222/2n2907
ELECTRONIC AUDIO EXPERIMENTS (EAE) MAGIC MISSILE
The previous layout (V1) was missing the 10k resistor to ground from Gain pin 1. Updated 12 Feb 2026.
9 comments:
Hello, I am trying to get this one going but can't seem to figure out the issue. I first wanted to ask if on row 13 that's a double link on 9?
Yep - that's a double link
There was a 10k resistor missing from pin 1 of the gain pot to ground - layout updated, you can easily add it without making any other changes.
This is not likely to be the cause of your problems.
What have you doe to test it - do you have a multimeter or any test equipment?
I have a multimeter and audio probe but I haven't tried it yet. I get some audio for a brief second when it is first turned on but i get a horrible screech when I touch the depth pot, and regardless of if i touch it the audio cuts off after a few seconds. When I first turned it on I had forgotten to add the 100uf electrolytic, I'm not sure if that could have fried anything. I'll add the resistor and test with the probe now.
I'm noticing in the updated layout there is also a new cut on row 1column 14 (after 9v diode) with a change in how the 47r interacts with the 100uf (i think it is. At least, its different from what I built)
after adding the 10k I'm getting a very quiet signal at full volume but the effect and all the knobs are working. It's just whisper quiet, but when 9v is unplugged it comes up in volume
I moved the 47 ohm resistor and made some adjustment to the power supply.
That change will not relate to your problem & a missing filter cap will not cause damage (the 100uf).
You have some kind of serious problem elsewhere - I'd be looking for shorts and misplaced parts.
I got it working, quite the odd issue. one of the copper strips wasn't maintaining continuity. I took a magnifying glass to it and there were no cuts or anything (row 12 between 8 and 13, connecting the emitter and base of the transistors on the bottom left of the board) so I jumped the row together and voila. after about 15 minutes of playing it cut out again and will only stay on with a slight bit of pressure on the middle of the board. I'm going to remake it, I think the quality of the board I'm using is garbage. Thank you for your help, I probably wouldn't kept checking otherwise!
Glad you stuck with it and worked out what was wrong. I'm sure the rebuild with decent vero will be a better experience.
Post a Comment