Carver TX-11 Tuner Filter Mod

Carver TX-11 Specifications

Tuning Range................87.5-108mhz
Antenna Terminals........75ohm coaxial input/ 300 ohm balanced input
Intermediate Frequency 10.7 mhz
Frequency Response.....20hz to 15khz +/- 1db
Selectivity....................at 400hz 90db(narrow), 35db(wide)
Capture ratio...............1.0db
AM Suppression Ratio...50db; 65db with CCD
Image Response Ratio..110db
IF response Ratio.........110db
Spurious Response Ratio 110db
Output Level...............(75hz deviation) 700mv, 600 ohms
System.......................PPL crystal-locked digital synthesizer
Dimensions.................17.5 x 3.5 x 12.5 inches
Weight.......................11.25 lbs

Usable sensitivity........mono 75 ohm 11.3 db/f 1.0uv, 300 ohm, 11.3 db/f 2.0uv

-------------------------------------Charged Coupled Detector------------------------------------
stereo sensitivity.......75 ohm.........34 db/f14uv(no stereo).....16.3db/f 1.78uv(with stereo)
...............................300 ohm.......34db/f 28uv(no stereo)......16.3db/f 3.57uv(with stereo)

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CARVER TX-11 FILTER PLACEMENT SPECS

The TX-11 has five ceramic filters. F101, 102 and 103 are 180khz filters. F104 and 105 are 250khz filters.

See this diagram for placement:

An excellent modification is to remove the two wideband filters (F104 and F105) and replace them with either 150khz or 110khz filters (or one 150 and one 110). Doing this will make your wide setting narrower and your narrow setting truly narrow. The wide setting will still be free enough from any distortion to make music listening enjoyable and the narrow setting will give you that FM station on 96.3 and 100 miles away next to your local on 96.5 15 miles away.

The diagram above can be accessed by removing the board that sits on top of it and moving that board to the side while you do the mod. The upper (smaller) board may have a small wafer capacitor soldered from it to the RF section, which you will have to unsolder first. Four screws with spacers secure the top board. Don't break any green wires when you do this.

To add an RDS Decoder to the Carver, find R306 and attach a lead to one side of the resistor. Only one side will work. Try both to find out which one. Connect the other lead to GND.