Circuit Atlas · HUSH M4 · Rev 2027.4 draft
1 Safety
Safety notes for a product in development. This draft is not a licence to build mains-powered equipment without a qualified review.
IN DEVELOPMENT · REV 2027.4 (DRAFT) · DESIGN TARGETS, NOT MEASUREMENTS
HUSH M4 is in development. This draft is published on zakkhutoretsky.com; it has no price and no ordering. Figures marked design target are goals for the finished product. Figures marked calculated come from the published formulas. No value on these pages was measured on a built unit. Interviews are cited as the design brief, not as an endorsement.
See this control Status on the mixer page
1 Safety
This is a draft document for a product in development. Do not build mains-powered equipment from it without a qualified engineer’s review and the safety approvals your country requires.
| Hazard | What to know | Design response (draft) |
|---|---|---|
| Mains voltage | Lethal. The primary side (inlet, fuse, switch, transformer) is the only part connected to mains. | Class I (earthed) enclosure; protective earth bonded to chassis and transformer core; fused live; double-insulated transformer; no user-accessible primary wiring. Design review against IEC 62368-1R10 before any build. |
| Stored energy | The 4700 µF reservoirs hold charge after power-off. | Bleeder resistors across each reservoir (value to be set at prototype); wait and measure before opening. |
| Hot parts | Each regulator dissipates about 5.7 W. | Heatsinks inside the chassis, away from user access; vented enclosure. |
| Hearing | The headphone stage can deliver 2.83 Vrms into 32 Ω, far louder than comfortable. | Start with the PHONES knob at minimum. Do not wear headphones when connecting or powering up. Limit exposure. |
| Speaker damage | A DC fault or switch-on thump into a club system can damage drivers. | Series coupling capacitors on outputs, muting relay on the master outputs (prototype task), always power the mixer before the amplifiers. |
| Handling | A four-channel, transformer-powered mixer is heavy. | Lift with two people; a mass target is not set in this draft. |
Safety standards are cited by title and catalogue page only; this draft does not claim compliance with any of them.