Hi,
How can it work either from 7 to 12V DC or 9 to 12V AC ?
The wall wart they supply is 9V AC and 1000mA
Why AC ?
Maximum input level is 40mVrms @ 1kHz
Maximum gain is 45db @ 1kHz
Maximum Output level is +6dBu (1.4Vrms)
They don't mention input sensitivity.
I assume the nominal level is -10dBu or less since the max output is only +6dBu.
I don't have schematic yet , I hope they say yes.
Thank You
How can it work either from 7 to 12V DC or 9 to 12V AC ?
The wall wart they supply is 9V AC and 1000mA
Why AC ?
Maximum input level is 40mVrms @ 1kHz
Maximum gain is 45db @ 1kHz
Maximum Output level is +6dBu (1.4Vrms)
They don't mention input sensitivity.
I assume the nominal level is -10dBu or less since the max output is only +6dBu.
I don't have schematic yet , I hope they say yes.
Thank You
I do not know the circuit so I will take a guess...
If the first component on the circuit board is a diode then it will flow DC or rectify the AC. If so the next component is likely to be an electrolytic capacitor and then some form of voltage regulator with a minimum input requirement of 7 Volts.
Still guessing... if it requires about 7 Volts then the regulator is likely to be something like a 7805 which has an output voltage of 5 Volts and requires an input of at least 7 Volts.
If the circuit runs from a single 5 Volt supply then it will need to be offset / biased around half of that Voltage (i.e. 2.5 Volts DC) to give equal positive and negative swings. If it is operating on an offset of 2.5 Volts DC it will need a capacitor at the input and the output to block the flow of the DC Voltage, allowing only the required alternating voltage signal to enter and leave the circuit.
Just a guess.
If the first component on the circuit board is a diode then it will flow DC or rectify the AC. If so the next component is likely to be an electrolytic capacitor and then some form of voltage regulator with a minimum input requirement of 7 Volts.
Still guessing... if it requires about 7 Volts then the regulator is likely to be something like a 7805 which has an output voltage of 5 Volts and requires an input of at least 7 Volts.
If the circuit runs from a single 5 Volt supply then it will need to be offset / biased around half of that Voltage (i.e. 2.5 Volts DC) to give equal positive and negative swings. If it is operating on an offset of 2.5 Volts DC it will need a capacitor at the input and the output to block the flow of the DC Voltage, allowing only the required alternating voltage signal to enter and leave the circuit.
Just a guess.
I'm with Gordy. I think they have a diode inside, filtering and a voltage regulator to give the final DC voltage required by the circuit.
Bottom line though is that it is an extremely good phono pre for the price. Adjustable gain, adjustable input capacitance and good sound. I use one with a passive pre to control a variety of amps and output level is definitely sufficient.
Bottom line though is that it is an extremely good phono pre for the price. Adjustable gain, adjustable input capacitance and good sound. I use one with a passive pre to control a variety of amps and output level is definitely sufficient.
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