The middle switch is for a low level crossfeed filter.
See also an audio RMAA tests here.
- IC1-IC4 - LM6171 (High speed unity-gain stable voltage feedback amplifier)
- IC5-IC6 - BUF634T (250mA high-speed buffer)
- IC7-IC8 - DB107 (Bridge rectifier)
- IC9 - LM7815 (Voltage regulator)
- IC10 - LM7915 (Voltage regulator)
Schematic of the amp is similar to that shown below are taken from earler article of Jan Meier named "A DIY Headphone Amplifier With Natural Crossfeed by Jan Meier".
|A DIY Headphone Amplifier|
With Natural Crossfeed
Some info from Meier's site:
- $240,- outside EC.
- The CORDA ARIETTA is a small budget-amp with a big sound. It has a detailed and natural sound. There is a touch of warmth that makes this amp slightly forgiving. A very nice entry amp for a really nice price!
- Maximum amplification factor 3.0 (+ 10 dB).
- Maximum output voltage 13V.
- Maximum peak output current 250 mA.
- Crossfeed filter (stereo, low).
- Gold-plated input jacks.
- Silver plated headphone jack (Neutrik).
- Silver plated heavy duty switch.
- Alps Blue Potentiometer.
- 3.2 Watts toroidal transformer.
- 110V and 220V selectable.
- Power uptake 2 Watts.
- Built-in groundloop breaker.
- Low impedance electrolytic buffer capacitors. Total Buffer capacity 28.000 uF.
- Ceramic bypass capacitors in the power supply.
- Polystyrol and polypropylen capacitors in the signal path.
- Metalfilm resistors in the signal path.
- Double sided PCB.
- LM6171 opamps biased into class-A.
- BUF634 buffer amplifiers at each output channel.
- Star-ground and ultra short signal paths.
- Signal paths and signal path components at the bottom side of the PCB for maximal shielding.
- Sturdy aluminium enclosure.
- Weight: 0.8 kg.
- Size: 18.0 x 10.7 x 6.1 cm.