signal one CX7 Specification sheet

TN11-1
TN11
Rev. C.0
When you add an I.F. filter, occasionally it will have more or less gain than the other filters. To equalize
the audio level, Paul Kollar designed a small amplifier to insert in the signal chain. Here it is:
A schematic follows showing the amplifier in the signal chain.
W8CXS
Step Description
1. Remove coax # 458 from output terminal/ground of filter and install
two connectors.
2. Shorten Wire #353 (output of SSB Filter to 4 switch contacts) by mov-
ing to the closest switch terminal.
3. Remove W-184 (I.F. Board pin #471 to S8G#6) and replace with coax.
Board end has 1 connector and shield is cut off - switch end to #6 term
and adjacent ground lug.
4. Tack solder board to output & ground connector jacks of filter.
5. Install connector on blue wire and connect other end to lug on wafer
"F" that has other blue wires.
6. Plug in 3 connectors to amp and select size of R5 for required gain.
CX7 Filter Amplifier

TN11-2
TN11
Rev. C.0
* Notes: 1. R5 is a ¼ watt resistor with short leads. The value is selected for gain desired to equalize the loss as various filters are
selected. Values of 5 to 50 ohms are common.
2. Resistors are all ¼ watt, 5%. 3. Capacitors are 10 or 20%. C1 is mica; C2, C3, & C4 are ceramic discs. 4. J3 & J4 are foil pads under board.
J5 & J6 are VECTOR pin jacks. J1, J2, &J7 are AMP pins.
5. Two circuit board layouts - right or left cw filter mounting positions. 6. If gain is too low with R5=0 ohms, change C4 to .01 mfd. (From original .001 mfd)
Q1
2N3904
R5* C4*
.001
R6
270
J1
-15v
(blue
wire)
R2
220
C2
.01
R3
10k
J3
J4
C3
.01
R4
5.6
k
J2
J7
C1
100p
f
R1
150 J6
J5
From
Filter
Solder
Pad
Solder
Pad
C72
100p
f
R68
150
C73
.001
C68
82pf
To
I.F.
Amp
To
Meter
Amp
S8G
471
6
8 Pole Filter
CW2 or
CW3
S8-H CW Filter
8815.700 KHz
To
Amplifier
T5
R63
150 C111
120pf
467
12
To I.F.
6
CX7 Filter Amplifier, cont.