andreidaniel
Member
Hello guys! I remembered recently about a Romanian magazine since 1994 where was presented an interesting phono preamplifier based on FET transistors. As previously most listeners preffered to buy or construct either "Le Pacific" or "Boozhound" preamplifier, I decided to come in help for them with this diagram.
Short description:
"The preamplifier for the magnetic cartridge presented can satisfy a series of lately wishes such as:
-very good signal/noise raport thanks to using the FETs;
-very low THD for a high gain and a high output voltage;
-high capacitance for preloading the signal peaks.
Technical characteristics:
-Gain at 1KHz = 40dB;
-V out = 250mV;
-S/N = 82dB;
-overload for the normal output voltage (250mV) = 40dB;
-THD = 0,01%;
-Z in = 220K;
-minimum Z out = 1K.
The preamplifier is built after the pattern of an OA equipped with FETs at the input in a differential mode. The stage mixes or combines the advantages of the BJT (regard frequency and high amplification) with the low noise of the P-channel FETs.
Regarding to the type of cardridge, C1 can vary between 10-90pF.
Here are the diagram, the power supply, the part list and the PCB 45 x 55mm
Short description:
"The preamplifier for the magnetic cartridge presented can satisfy a series of lately wishes such as:
-very good signal/noise raport thanks to using the FETs;
-very low THD for a high gain and a high output voltage;
-high capacitance for preloading the signal peaks.
Technical characteristics:
-Gain at 1KHz = 40dB;
-V out = 250mV;
-S/N = 82dB;
-overload for the normal output voltage (250mV) = 40dB;
-THD = 0,01%;
-Z in = 220K;
-minimum Z out = 1K.
The preamplifier is built after the pattern of an OA equipped with FETs at the input in a differential mode. The stage mixes or combines the advantages of the BJT (regard frequency and high amplification) with the low noise of the P-channel FETs.
Regarding to the type of cardridge, C1 can vary between 10-90pF.
Here are the diagram, the power supply, the part list and the PCB 45 x 55mm
