HI All,
Here is more info on the new Pass Labs HPA-1 headphone amp...
Basic Operation
· The unit is designed to stay on at all times. The power switch is located in the rear.
· When the power is turned on the unit goes into a mute state for twenty seconds, this is to allow the circuitry to stabilize. During this period no functions are available. During the mute period the power led will flash. When the unit goes out of mute into operate mode the power led will stop flashing and stay on.
· The unit has two inputs that can be selected from the front panel.
· The unit also has a preamp function, which is selected from the button on the front panel. When the preamp function is engaged the headphone output is disconnected, only one output either headphone or preamp is available at any one time.
· The unit gets to optimum performance after about one hour after turn on.
· In the event of a power loss the unit shuts off and upon restoration of power the unit will go through the mute cycle and return to the state it was in prior to the loss of power. It will remember the last input and function and will return to that setting before the loss of power.
This is also true when the unit is switched off with the power switch.
· It is recommended that the unit stay on at all times, if you are away for an extended period of time you could shut the unit off.
Features
· Works with headphones with impedances of 15 ohms to 600 ohms
· Designed as a power amplifier rather than a typical headphone amplifier to be able to drive low impedance planar phones.
· Low feedback wide bandwidth discreet design.
· Class A direct coupled Mosfet output stage.
· Custom built low noise Torodial power transformer with a Farady shield and peripheral magnetic shield
· Discreet regulated power supply for audio circuits.
· J-Fet input stage
Pass HPA-1 Specs:
Output Power into 20 ohms 3500mW
Output Power into 300 ohms 200 mW
Frequency Response 10hz -100k -1dB
Gain 8 dB
THD + Noise < 0.005 at 1V out
Input Impedance 50K Ohm
Output Impedance < 2 ohms
Power Consumption 6 Watts
