Articles > Kchibo KK-E350 radio review
Introduction
The KK-E350 is a pocket-sized portable receiver with PLL tuning. The unit has a 1.5" LCD display; depending on the mode of operation, it will display the time, current frequency, reception band, preset number and/or other indicators. With its built-in whip antenna and speaker, the unit is a versatile unit for casual FM/MW/SW listening. Its size also makes it ideal for travelling.
It is powered by a pair of AA cells. The KK-E350 was intended for the Chinese market. All the labels are in Simplified Chinese, however with icons and symbols on some buttons, the unit can be operated by non-Chinese speaking users.
Specifications:
Coverage bands:
- MW: 522 - 1611 KHz (9KHz steps)
- SW: 5.95 - 17.9 MHz (5KHz steps)
- FM: 64.0 - 108.0 MHz (100KHz steps)
Tuner IC: SA2104CS
Power source: 2 x 1.5v AA cells or external 3 volt supply
Features:
- 24-hour clock
- Alarm (switches on radio for 90 minutes)
- 10 preset memories per band (30 total)
- Auto scan-to-memory function
- Backlighting (with light sensor)
- FM stereo (always activated)
- Stereo 3.5mm headphone socket
- Built-in swivel extendable whip antenna
- External antenna 3.5mm socket (for FM and SW only)
- DX/Local sensitivity switch
- Manual volume control
- Built-in 2.5" speaker
- Optional external 3V DC adapter
- Keylock
- Accessories: stereo earbud headphones, external antenna cable
- Dimensions: 118 x 72 x 25 mm
Operation
Power: The top pushbutton acts as both the power switch and also the sleep timer selection. Pushing it briefly will turn the unit on indefinitely (until it is manually turned off or the cells run flat). Holding it down for more than one second will activate the sleep timer menu, where it will display "90". Subsequent presses within 5 seconds will lower the sleep timer by 10 minute increments. After 5 seconds, the sleep timer selection will dissapear, a sleep icon appears and the radio will run until the timer expires.
Volume: Volume control is provided by a knob on the right hand side of the unit.
Keylock: A dedicated button is used to activate and deactivate the keylock. A single press will toggle the lock. The keylock prevents accidental operation of the other buttons on the radio. This feature is useful when carrying the unit in a pocket or packing into a bag with other items that could unintentionally push the unit's buttons.
Band Selection / Clock set button: When the radio is switched on, the band selection button will cycle through the FM, MW and SW bands. The radio will remember the frequency that was last listed to on each band.
When the radio is off, the button will cycle through the hour and minute settings, first for the clock, then for the alarm time. The hour or minute digits will start flashing when they are selected for adjustment. To set the time, press the Up/Down buttons.
Frequency Up/Down buttons: A momemtary press of these buttons will either increment or decrement the frequency on the current band. On MW, the step is 9KHz, SW is 5KHz and FM is 100KHz. Holding the button down for at least a second will activate scan mode. The radio will stop at the frequency of the next or previous strong station.
Preset +/- buttons: These will cycle through the presets, from 1 through 10 for the current band.
Memory button: The memory button is used to store a frequency into a preset slot. To store the current frequency, press the memory button. Then choose a preset slot by pressing the +/- keys. Press the Memory butotn again to store the frequency into the selected preset slot.
Auto scan-to-memory and alarm on/off button: When the radio is on, a press of the scan-to-memory button will start the radio scanning. It will store each station found into the each of the 10 preset locations until they fill up. The only time this feature would be remotely useful is when visiting a foreign country, and it would be desireable for the first 10 stations to be stored for easy review at a later stage.
When the radio is off, the button will toggle the alarm. When the alarm activates, the radio is turned on in 'sleep mode' for 90 minutes. The sleep timer is not configurable. A drawback is if the volume control is not set to a reasonable level, the alarm may be too soft or be unpleasantly loud - not the best way to wake up in the morning.
Abmient light sensor
A novelty feature on the KK-E350 is the automatic backlight with sensor. The unit will illuminate the LCD for approximately 15 seconds whenever a key is pressed whilst the unit is in a relatively dark location. When in bright light (such as a bightly illuminated room or in daylight) the backlighting will not activate. At night, or in a darker room without direct sunlight, the green backlight will activate. Unfortunately the buttons on the front of the unit are not illuminated, but the unit is simple enough that after a while, users will 'know by feel' of which button is which.
Performance
Electrical performance
Out of the box, the KK-E350 has average performance for almost all local broadcast signals on the MW and FM bands. With its built-in 18-inch whip fully extended, the weaker FM stations can be picked up with acceptable clarity.
The circuitry for AM is single conversion, and uses an IF of 455KHz. On the MW band, tuning is fixed to 9 KHz steps, making this unit only suitable for Asia, Australia/NZ and European areas (Canada/US uses 10 KHz channel spacing on MW).
Although the KK-E350 can tune down to 65.0 MHz on the FM band, it suffers from poor image rejection. Local stations from 88 MHz and above can be heard 21.4MHz below their frequency, rendering the 64 to 88 MHz range useless for all but the strongest signals. This is due to the units' use of the popular FM IF frequency of 10.7MHz (2 x 10.7 MHz = 21.4 MHz).
The KK-E350 has a good AGC, and connecting an external antenna (either to the whip or the dedicated antenna socket) does not cause distortion. However, with a long random wire antenna attached, the front end of the receiver can become slightly overloaded, causing images of strong MW stations to appear on the SW band. The unit does provide a DX/Local switch, which helps a little with attenuating some of the unwanted frequencies. The DX/Local switch is more effective when the built-in whip is used alone.
SW performance is on par with most other pocket receivers of this size. The passband filter in the KK-E350 is fairly wide - giving it low selectivity - and splatter will be heard from closely spaced adjacent stations. As a result of the wide filter, the KK-E350 will stuggle to hear distant stations with clarity due to the noise.
Battery life is average. With alkaline dry cells, the unit can be used for an hour a day for two to three weeks at a time between battery changes (at a low-moderate volume level). Using rechargeables is more varied; NiCads will last about a week and a half at most due to their high internal discharge, and NiMh cells will go for just under two weeks.
Physical performance
There is an aluminium speaker grille covering most of the front of the unit, of which is made from paint-coated ABS plastic - the paint will wear off over time. The headphone and external antenna sockets are made of steel, so should endure many plug insertion cycles. The protective faux leather case protects the unit well, and only slightly muffles the speaker when in use.
The speaker provides adequete volume for a radio of this size. The speaker uses a mylar cone, giving the sound a tinny feel. Once the volume control is set to the halfway mark, the maximum volume is reached. Pushing it any higher results in clipping and bad distortion, with little increase in perceived volume.
The buttons use PCB mounted tactile switches. Their performance and positive tactile feel can degrade with use over time. The switches can start 'bouncing' or require harder presses to register when worn out.
Problems and quirks
Unintentional button presses: If the scan-to-memory button is unintentionally pressed, it will start to scan for stations and over-write the pre-sets that already exist. If frequently used stations are programmed into the preset slots, a press of the autoscan button will mean you'll have to re-enter all the frequencies again. The fact that the only way of tuning the radio is by the up/down buttons makes it all the more time consuming - especially on SW - it takes the radio some time to scan through the band to your required station, and the radio stops scanning when it reaches any station in between.
Loss of power: The KK-E350 will loose all presets, current frequencies and clock/alarm settings when power is lost. This can occur when the radio is accidentally left on long term; there is no built-in low-battery cutoff to prevent this.
There is a built-in capacitor which will retain the clock and preset frequencies for about 30 seconds when the batteries are removed. If the battery replacement is quick enough, no memories will be lost. This time can be extended to three minutes by a modification which entails adding a 1000uF 6.3v capacitor in parallel with the battery supply rails.
Also, when plugging in external power, ensure the adaptor is powered. Connecting an external source will automatically disconnect the batteries in the KK-E350, so if the external adapter is unpowered, memory loss will occur.
Tuning chuffing: A problem when trying to 'hunt' down a station is the muting that occurs when tuning. The KK-E350 will mute the audio for one second whenever the frequency is incremented, or when seeking / scanning. This chuff-chuff noise makes it very cumbersome to 'browse' through a band to quickly find something.
Mod to fix chuffing and prevent accidental preset overwriting: A mod can be made to the KK-E350 by unsoldering (or cutting) the green wire on the ribbon able from the main PCB to the control/LCD board. This prevents the controller from muting the audio when performing operations (such as tuning, changing bands, changing presets and seeking). However, as a side effect, it prevents the radio from stopping on a station during a seek. But this side effect also stops the auto-scan-to-memory from storing any stations into the preset, thereby eliminating its ability to accidentally overwrite your presets.
With presets, the need to seek between stations is not as important, which makes it an acceptable compromise. Without chuffing, the radio is more enjoyable and much easier to use when trying to manually scan through for weak channels. It would drive anyone crazy trying to 'browse' through the band, only to have the audio muted for one second every time they changed the 'dial'!
Volume control issues: The volume control uses a small proprietary carbon-track potentiometer. Over time, the track and/or contacts can get dirty or wear out, causing a crackly sound to be heard when the volume is adjusted. The nature of this control makes it difficult to replace or clean.
Great care must be taken with the volume control when using headphones. A volume setting for comfortable listening level with the built-in speaker becomes too loud for earbud headphones. This problem is due to the headphone socket interfacing directly with the audio amplifier's output, which is designed for speaker level output. There is no line or headphone level output, and this is evidenced with a prounounced, incessant hiss from the amplifier even when the volume setting is lowest.
The amplifier also lacks low-end punch, even when using headphones. The lack of low-end is acceptable (and understandable) for driving a simple speaker and also in the interests of reducing power consumption. The sound quality is somewhat tinny when using headphones.
FM stereo issues: FM stereo is available when headphones or external amplified speakers are plugged into the socket. The unit will recognise this, and if tuned to an FM stereo station, will display the stereo indicator on the LCD. However, there is no way to disable FM stereo when headphones are plugged in. If the signal is marginal or noisy, there will be a great deal of FM stereo interference noise, including the unit rapidly switching between mono and stereo as the signal changes. A modification can be made by fitting a switch to selectively disable FM stereo.
Internal interference on MW band: The internal ICs and other circuits appear to 'tick over' at 2 Hz when the radio is idle. This can be heard as quiet 'blips' twice a second on some parts of the MW band. Strong stations will mask it, but the blipping is quite audible on weaker ones, as well as empty frequencies.
Alarm clock shortcomings: Whilst the alarm works as expected (turning the radio on for 90 minutes), there is no way to set it as recurring. So in order for the alarm to go off the next day, the alarm needs to be activated by pressing the alarm button after the radio is off.
Internals
In the first photo, the KK-E350 has been fitted with an additional power supply capacitor. A ferrite bar antenna for MW reception can also be seen. The second photo shows the inside front cover. The 0.5 watt speaker is of the slimline type. The control PCB is connected to the main PCB via a ribbon cable. The rear of the control PCB is shielded with a sheet of copper.
Availability
The KK-E350 is no longer manufactured by Kchibo. As of late 2009, there are still a few new units floating around on Ebay from sellers in China/HK. Because it is more of a 'throwaway' radio, there will not be many secondhand units available.
Conclusion
For the asking price (around US $25) the KK-E350 represents good value. There aren't many places where one can purchase a PLL digital tuning FM/MW/SW pocket radio for that price. Even brand-name pocket radios with an analogue tuning dial and only FM/MW broadcast bands can sometimes cost up to double the price. If you predominately listen to broadcast FM and MW, with an occasional need to listen to SW, this radio is for you.
The radio is excellent for casual listening, and as an occasional alarm clock. If you can put up with the quirks, it is well worth the purchase if you require a portable unit.
Overall rating:
6.5 / 10
Other radio reviews:
Degen DE1105 FM/MW/SW Receiver
Realistic DX-200
JACQUES RAJCHGOD, Wed, 03 Aug 2016 07:42 pm: Reply