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Circuit Atlas · HUSH M4 · Rev 2027.4 draft

S9 Power supply

Schematic for S9 Power supply. Design targets and calculations, no measurements.

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 Power on the specification

S9 Power supply

Power supplyA 2 by 22 volt AC toroid transformer feeds a bridge rectifier and 4700 microfarad reservoirs. An LM317 regulates the positive rail and an LM337 the negative rail to plus and minus 18 volts. The mains side has a fuse, switch and protective earth.S9 POWER SUPPLY — ±18 V linearMAINS: HAZARDOUS VOLTAGE. Build only to a qualified engineer's design review and the local safety standard.LF1T 630 mASW3NPEchassis; bond T1 core and enclosureT1 toroid2 × 22 Vac 50 VAdouble insulated0 VBridgeD1–D4 3 A+C14700 µFLM317+18.3 V+Co110 µF+18 VR1240R23.24k+C24700 µFLM337−18.3 V+Co210 µF−18 VR1240R23.24kVout = 1.25 V × (1 + R2/R1) + Iadj·R2 = 18.29 V (LM317 datasheet, Rev Z); the LM337 mirrors it with reversed diodesand capacitors.Ripple = I/(f·C) = 1.06 V pp at 0.5 A, 100 Hz, 4700 µF. Input 29.7 V DC nominal, 28.6 V at the trough, 25.5 V at −10%mains: headroom over Vout 10.4 V (7.3 V low line); each regulator dissipates about 5.7 W: heatsink.Also: 5.0 V precision shunt reference for the VCA control scaler; every op-amp pair decoupled with 100 nF + 10 µF perrail; star ground at the supply.
S9 Power supply (schematic) Swipe sideways to pan on a phone.
ItemValue / formula
Rails±18 V, LM317 / LM337: Vout = 1.25 × (1 + R2/R1) = 1.25 × (1 + 3240/240) = 18.29 VR5
Rectifier2 × 22 Vac, 50 VA toroid, bridge, 29.7 V DC nominal; 4700 µF reservoirs, ripple = I/(f·C) = 1.06 V pp at 0.5 A, 100 Hz
Headroom10.4 V above the regulated output at the ripple trough, 7.3 V with mains −10% (LM317 asks for 3 V)R5
HeatEach regulator dissipates about 5.7 W at 0.5 A: needs a heatsink
BudgetEstimated 124 op-amp sections (62 dual packages) × about 8 mA = 0.53 A per rail against the 0.5 A design current. An estimate, not a measurement

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