Voodoo-LABS TS-950sdx ESSB AM Mods

Disclaimer Notice
These modifications should be accomplished by qualified personnel who
have had enough knowledge and practice in SMD soldering techniques, at the owners risk.

WARNING - YOU DO THE MODIFICATIONS AT YOUR OWN RISK!

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we cannot guarantee that the instructions will work on every radio presented.

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AM Detector Circuitry:

The TS-950sdx uses a Diode Charge Pump (DCP) as an AM Detector located on the Signal Unit.
The demodulated AM signal is then passes thru some RC timing and a Low Pass Filter to shape the Audio.
The First Low Pass Filter consists of R97 and C65. This is a 27K ohm resistor with a .01uF cap to ground.
This creates a center frequency of about 600Hz.
C65 needs to be changed to a 390pf to give a new center freq of 15Kc.
The signal then goes throu C75, a .1uF coupling capacitor that rolls the lows off at about 100Hz.
This capacitor needs to be changed to a 1uF to give a new roll off frequency of about 20Hz.
This opens up the Fidelity of the AM reception a phenomenal amount!
The new AM Frequency Response is from 20Hz to 10Kc.

Now that the AM Receiver is Hi-Fi, you might notice that when you listen wide (10Kc or wider)
You hear a whistle or a whine. This is the heterodyne from the next station over 10Kc.
The older AM receivers came with 10Kc Heterodyne Notch Filters to take out that whine,
But unfortunately the SDX does not have that. It was designed only to receive at 3kc so it didn't need it.
You can use the IF VBT to shift the IF slightly and filter the whine out.
You can also use any of the Analog Filters, then use the IF VBT to shift those filters.
The SDX is a wonderful AM receiver once you learn all the tricks!!

Reference the pictures below to locate and change the capacitors on the Signal Unit.

390pF - You will need 1ea of these 805 SMD Chip Capacitor	Digikey - 478-1323-1-ND ---- 08055A391JAT2A
1uF - You will need 1ea of these 805 SMD Chip Capacitor	Digikey - 490-4736-1-ND ---- GRM21BR71H105KA12L