comradehoser
Well-known member
Just built the Aion Diezel DZ4 and have a whistling problem when the gain pot is above 1:00 and strings are muted or not playing. Changes sound depending on guitar and pickup type/selection. Very loud when cable unplugged. I know I probably have to get down and do an audio probe, but I had a similar problem with the Aion Sunn Beta build (only with gain and treble at close to full, though), and I never did manage to get rid of it. Don't know if there are standard things to try, because I can't think of any currently.
One other user on reddit mentioned that they had the same issue with their build.
Installed everything to spec here: https://aionfx.com/app/files/docs/dz4_preamp_documentation.pdf including offboard wiring. Socketed the suggested presence cap substitution.
Troubleshooting to date: tried removing either ground on the board in case of ground loop since it doesn't follow Aion's SOP, reflowed all points, tried different signal-in cable. I can do multimeter readings, but the effect is doing what it's supposed to do up to 12:00/1:00 on the dial and then it whistles when you stop playing. My multimeter also might be not the most reliable at this point
This is a very odd one, as it is extremely inconsistent so it's hard to pin anything down--it disappears in some conditions and then seems to pop back up, thus the provisional language to follow. Seems to lessen when the board is moved away from the offboard wiring. Played with a yamaha revstar RSS020T and Ibanez AR325QA. The revstar has a mid boost switch (via transformer) and that changes the pitch of the whistle. The Ibanez has toggles that select for humbucker parallel, single coil, and humbucker series. When the pickup selector is both humbuckers, seems to be less whistle and I can push the gain to about 3:00. When out of phase humbuckers are selected (parallel neck and series bridge), it seemed to almost go away and then came back.
Rolling back volume makes it disappear.
Build pics:
One other user on reddit mentioned that they had the same issue with their build.
Installed everything to spec here: https://aionfx.com/app/files/docs/dz4_preamp_documentation.pdf including offboard wiring. Socketed the suggested presence cap substitution.
Troubleshooting to date: tried removing either ground on the board in case of ground loop since it doesn't follow Aion's SOP, reflowed all points, tried different signal-in cable. I can do multimeter readings, but the effect is doing what it's supposed to do up to 12:00/1:00 on the dial and then it whistles when you stop playing. My multimeter also might be not the most reliable at this point
This is a very odd one, as it is extremely inconsistent so it's hard to pin anything down--it disappears in some conditions and then seems to pop back up, thus the provisional language to follow. Seems to lessen when the board is moved away from the offboard wiring. Played with a yamaha revstar RSS020T and Ibanez AR325QA. The revstar has a mid boost switch (via transformer) and that changes the pitch of the whistle. The Ibanez has toggles that select for humbucker parallel, single coil, and humbucker series. When the pickup selector is both humbuckers, seems to be less whistle and I can push the gain to about 3:00. When out of phase humbuckers are selected (parallel neck and series bridge), it seemed to almost go away and then came back.
Rolling back volume makes it disappear.
Build pics:
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