JJJelectronics- SSB/CW audio filter/amplifier

*Improve selectivity for speech mode (SSB, AM) and CW mode* Output power: 1.0w AF.* Pre-amplifier stage * CW center frequency is about 850Hz, Band width about 300Hz *SSB roll off about -50dB at 3.4KHz*4 way switch for /on off, CW mode, SSB mode and AM mode (no filter)* Voltage 11v-13.5v * LED power indicator* LM380 (1w) audio power amplifier*sound level control (volume)

Tool required.Soldering iron (25w-40w), small cutter, trimming tool

Now let’s build the audio filter

I would recommend fitting the parts in the order they appear in the part list.Resistor first, then semiconductors, coils and Capacitors.Make sure you put the electrolytic capacitors and diodes in the right way round .keep all components leads as short as possible.

When you have finished assembly of the board, check all the parts are in the right places.The soldering looks bright and good. Re-solder any suspect joints with a little fresh solder, check that there are no short or splashes of solder between tracks.

Resistors

R1, R14, R15, R16, R21, R34, R38 4k7 7

R2, R3, R24, R25, R41 10k 4

R4, R5, R10, R12, R29, R30 8k2 6

R6, R17, R19, R13 22k 4

R7, R26 5k 2

R8, R27 3.9k 2

R9, R11 82k 2

R18, R22, R23, R28 100k 4

R20 47R 1

R31 560R 1

R32 1k8 1

R33 47k 1

R35 2k2 1

R36 150R 1

R37 390R 1

R39 10R 1

R40 100R 1

VR1 10k 1

Transistor, Diode and IC

IC1 TL074 1

IC2 LM380 1

Q1 2N3904 1

LED 3mm 1

Capacitors

NOTE: You will find some of the capacitors values on a paper with your order

C1, C7, C8, c25, C28 See note above 5 C25, C28, see note 1

C2, C14, C17, C30 See note above 4

C3 C34, C35 100uf /25v 3

C4, C5, C6, C9, C10, C11, C16 See note above 7

C12 220pf 1

C13, C26, C27, C29 100nf 4

C15, C22 47nf 2

C19, C20, C21, C23, green See note above 4 Green capacitor

C32, C36, C37 22uf/25v 3

C18 1uf 1

C24 22nf 1

C3, C32, C34,C36, C37 and C35 are electrolytic capacitors and must be installed the correct way round. The Longest lead is normally positive; this lead should go to the hole marked“+“ on the circuit board.

Note 1Please check the photo for capacitor C25 and C28You need to solder resistors in parallel with C28 and C25.

For C28 solder 10k resistor 1/8wFor C25 solder 3.9k resistor 1/8w

10k resistor 1/8w with C28

3.9k resistor with C25

Solder 3 wires as shown below1: from J1 to J22: from J3 to J43: from J5 to J6

CW position SSB position Normal position OFF position

Miscellanies

Wires4 way switch

Testing *Connect a power supply to +12v and GND *connect speaker (not included) to Sp1 and Sp2 holes (speaker should be 1w or higher) *put the 4 way switch on normal position (no CW/SSB filter) * Connect the radio receiver to the input of the filter (you should take signal from the radio (from product detector or from the diode detector or from the mixer directly (of the direct conversion receiver)