I found the audio quality on my Degen 1103 to be not nearly
as good as that of my 1102, which is actually smaller.
So when Kiwa (www.kiwa.com) announced an audio upgrade for
the 1103, I ordered the parts and instructions kit for $17
including shipping. The package arrived in about a week.

The 1103 employs a commonly used audio output chip (CXA1622P)
and a popular Toshiba chip for the IF, AM/FM detector, and
stereo demodulator (TA2057N). Radios with these chips are
capable of quite good audio quality. Yet I found the 1103
to be thin, tinny, and showing overload distortion,
particularly with strong MW signals.

Kiwa provides very clear instructions for the mod. But doing
it is somewhat involved, as you must disconnect all leads which
attach to the main board, including the four fine wires to
the ferrite loop antenna, and remove the main board. This is
a mod to be done only by those comfortable with soldering
and de-soldering in small spaces, and willing to risk potential
catastrophe with their radio. Re-attaching the ferrite loop
is probably more difficult than unattaching it.

The Kiwa mod replaces several capacitors associated with the
CXA1622P audio output chip, with better quality capacitors,
of higher values. It also adds one capacitor. Comparison of
the schematic at:

http://lab.radioscanner.ru/schematics/de1103_main.jpg

with the datasheet for the CXA1622P shows that the makers
of the 1103 saved a few cents by using smaller capacitors in
several places in the circuit than what is recommended by
the chip manufacturers.

The Kiwa mod improved the sound somewhat. Now instead of thin,
tinny, distorted audio, I was hearing rich, warm, distorted audio!
The overload distortion that troubled me was still there,
apparently a separate issue from the compromised capacitors.

There is a resistor network which feeds the audio output from
the TA2057N to the CXA1622P. It forms a voltage divider which
attenuates the signal entering the CXA1622P.

Part numbers are printed on the board, to easily match them to
the schematic. I discovered that R223 and R224, which are part
of this voltage divider, have the value 1K on the schematic,
but my radio had 2.2K resistors soldered onto the board. (these
surface-mount resistors say "222"). This error results in
less attenuation, apparently overloading the CXA1622P,
driving it to distortion on strong signals. The presence of
2.2K resistors is probably a parts substitution that was
made during certain production periods, perhaps by mistake.
I have no way of knowing how many 1103 units are like this.

I soldered 2K resistors across R223 and R224 to bring the
effective resistance to approx 1K. I'll call this the "KD1TE"
mod, for my ham radio call sign. The result, combined with
the Kiwa audio mod, is a very nice sounding radio. Of course,
you don't need the KD1TE mod if you have the correct resistors
already. The Kiwa mod alone will sound just fine.

After completing the Kiwa mod, the KD1TE mod is very easy to
do. Remember, only do this if you can determine that R223 and
R224 have the wrong values. And of course, you do this mod
entirely at your own risk. Here's the procedure:

Do the Kiwa mod first. When you remove the main board
for the Kiwa mod, look for R223 and R224 on the underside.
These are tiny surface-mount resistors in the corner of
the board near S2 (the "news-music" switch). If they
have the marking "222", consider doing the KD1TE mod.
If they have the value "102", they are correct, and
the KD1TE mod should not be done.

When done with the Kiwa mod, re-install the main board.
The work for the KD1TE mod is done entirely on the
topside of the main board, after the Kiwa mod is complete.
The Kiwa mod includes replacing C224 and C225, and
installing the new caps laying on their sides, leaving
their leads partially accessible. We will take advantage
of these exposed leads. Obtain two 2K, 1/8 watt resistors.
Tack solder one end of one resistor to the lead of C224
which is closest to S2. Tack solder one end of the
other resistor to the lead of C225 which is closest
to S2. Then solder the free ends of both resistors to
the frame of S2. You will see that S2 is soldered into the
board at one corner; this is a good point to solder to.
If you later change your mind about this mod, you can easily
snip out these resistors without removing the board.

CONCLUSION: I recommend the Kiwa audio upgrade mod for the
1103. The Kiwa instructions are good, but do this yourself
only if you are comfortable with the soldering techniques
involved, and are willing to take a risk with your radio.
When doing the Kiwa mod, check to see if your unit is
supplied with incorrect values of R223 and R224. If so,
consider doing the KD1TE mod after completing the Kiwa mod.

Gary W Thorburn
KD1TE
18 January 2006.