Making M7 Preamp

[jerrylong]

The tubes I will used for this preamp, from left to right V1（EH 12AX7), V2(GE 5751), V3(EH 12AT7)

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[jerrylong]

My power transformer has two independent AC 0～140V/100ma outputs, and the SPU have two independent high voltage circuits

Purple wire is for left channel and brown one is for right


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[jerrylong]

Connected the inductors to the PSU PCB


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[jerrylong]

Connected the shields of power transform to the E connector of power socket


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[jerrylong]

Connected the AC 15V/1.5A wire(BLUE) to the filament PCB, and connected two wires(RED/WHITE) with the to light up the LED of the power switch

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[jerrylong]

The PSU is nearly finished

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[jerrylong]

The low voltage socket is finished

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[William Wallace]

Hi Jerry,

Where is the best place to earth the chassis?... IEC mains AC power input connector?.. and congratulations on what looks like a very satisfying time for you.

Cheers,
Shane

 

[jerrylong]

The RCA input "-" is the best place to earth the chassis, you can see the way I arranged the GND of different parts of this circuit, I have put the illustration picture on


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[jerrylong]

I have connected the GND of filament PCB to PSU PCB

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[jerrylong]

The PSU case is finished

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[jerrylong]

Begin the installation of AMP case, connected the "-"of input and output of RCA

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[jerrylong]

Connected the filament power wire, I use 6.3V for the filaments

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[William Wallace]

The RCA input "-" is the best place to earth the chassis, you can see the way I arranged the GND of different parts of this circuit, I have put the illustration picture on


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Hi Jerry, - so mains earth is connected to the RCA connector which is directly electrically connected to the chassis itself?. Thanks.

 

[jerrylong]

Hi Jerry, - so mains earth is connected to the RCA connector which is directly electrically connected to the chassis itself?. Thanks.

No connected one 100R res and 3n3 capacity then to the chassis


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[jerrylong]

The V1(12AX7) res connection


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[jerrylong]

The power supply of each stage

And the wire used to connected to PCB


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[jerrylong]

The output RCA connection


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[jerrylong]

The feedback res and cap


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[jerrylong]

Nearly finished


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