Improve/ Extend Power Supply

[jbeyerstedt]

The electrical circuit needs some voltages to work:

• +15V and -15V for op-amps (~70 mA @ -15V, ~100 mA @+15V) and LEDs (~500 mA)
  • measured on +15V: 290 mA with 2 channels (with vu meter on 15V) -> ~6.5W extrapolated for 3 channels
    ("idle": 60 mA with 2 channels)
  • measured on -15V: 46 mA with 2 channels -> ~1.0W extrapolated for 3 channels
• 48V for phantom power (if this feature is wanted/ needed)

The current prototype uses an off-the-shelf power supply module (MEAN WELL RT-65C), which works just fine without additional filtering. But estimated total power consumption based on measurements with 2 channels is more like 10 W.
But the 48 V phantom power is still an open question. We either need to get it from the +15 V or just do a completely different power supply design. Or the phantom power feature will just be removed all together.

[jbeyerstedt]

To also add 48 V phantom power to the design, it either needs to be produced by a step-up DC/DC converter (which has a quite noisy output) or another power supply:

• Mean Well PT-45C (+15 V, 1.6 A; -15V, 0.3 A; +5 V, 3 A): ~16€ incl. VAT
• Mean Well PS-05-48 (+48 V, 0.11 A): ~8€ incl. VAT

Alternately some voltages can be produced by step-down DC/DC converters.

Two (less oversized) switching power supplies + DC/DC converter

• Mean Well PD-2515 (+15 V, 0.8 A; -15V, 0.8 A): ~15€ incl. VAT
• Mean Well PS-05-48 (+48 V, 0.11 A): ~8€ incl. VAT
• DC/DC from 15 to 5V (400mA): SLC03A-05, SCWN03A-05 (~12€ incl. VAT) or SCWN06A-05

48V wall adaptor + DC/DC converters

• Mean Well NGE30E48-P1J (48 V, 0.63 A): ~17€ incl. VAT
• DC/DC to +-15V (100mA): DPBW03G-15 (ext. EMC req.), DLC03C-15, DCWN03C-15 (~12€ incl. VAT) or DCWN06C-15
• DC/DC to 5V (400mA): SLC03A-05, SCWN03A-05 (~12€ incl. VAT) or SCWN06A-05

[jbeyerstedt]

Options when leaving out 48V (or generating it from +15V somehow):

• Mean Well RT-50C (5V, 4A; +15V, 1.5A; -15V, 0.5A), enclosed type: ~20€ incl. VAT
• 48V wall adaptor + DC/DC (DCWN03C-15) as mentioned above: ~29€ incl. VAT