CS-255 
 
CD Hi-Fi Mini System
 SPECIFICATIONS
CD RECEIVER SECTION
Amplier Section
Power Output  15 W + 15 W (6 Ohms, 1 kHz, 10% THD,  
    2 Channels Driven, FTC)
THD+N (Total Harmonic Distortion + Noise) 
  0.5% (1 kHz, 1 W)
Damping Factor  60 (1 kHz, 8 Ohms)
Input Sensitivity and Impedance  
    1000 mV/47 k-ohms (Line)
Frequency Response  50 Hz–20 kHz/+0 dB, -3 dB
Tone Control  ±10 dB, 100 Hz (Bass) 
    ±10 dB, 10 kHz (Treble) 
    +4 dB, 80 Hz (Super Bass 1) 
    +8 dB, 80 Hz (Super Bass 2)
Signal-to-Noise Ratio  84 dB (Line, IHF-A)
Speaker Impedance  6 Ohms –16 Ohms
Tuner Section
Tuning Frequency Range  
  FM  87.5 MHz–107.9 MHz 
  AM  530 kHz–1710 kHz
FM Preset Memory  30 Stations
AM Preset Memory  30 Stations
General
Power Supply   AC 120 V~, 60 Hz
Power Consumption   30 W 
No-Sound Power Consumption 
   7 W
Standby Power Consumption 
   0.35 W (iPod/iPhone not connected)
Dimensions (W x H x D)  8 
7
/
16
˝ x 3 
15
/
16
˝ x 10 
5
/
8
˝   
    (215 x 100 x 270 mm) 
Weight  5.5 lbs. (2.5 kg) 
SPEAKER SECTION
Speaker Type  2-Way, Bass-Reex
Drivers 
  Woofer  3 
15
/
16
˝ (10 cm) Cone 
  Tweeter  
3
/
4
˝ (2.0 cm) Balanced-Dome 
Frequency Response  55 Hz–50 kHz 
Crossover Frequency  4.5 kHz 
Output Sound Pressure Level 
  82 dB/W/m 
Max. Input Power  30 W
Nominal Impedance
  6 Ohms
 
General
Dimensions (W x H x D) 5 
1
/
8
˝ x 8 
1
/
4
˝ x 6 
3
/
4
˝  
    (130 x 210 x 172 mm) 
Weight  3.5 lbs. (1.6 kg)  
CARTON 
Dimensions (W x H x D)  13 
1
/
16
˝ x 7 
1
/
2
˝ x 16 
7
/
8
˝  
    (332 x 190 x 429 mm) 
Weight  7.5 lbs. (3.4 kg) 
UPC CODE
(B)   751398011368 
Supplied Accessories
• Indoor FM antenna • AM loop antenna  
• Speaker cable and cork spacers • Instruction manual  
• Remote controller
Due to a policy of continuous product improvement, Onkyo reserves the right to change specications and appearance without notice. iPhone, iPod, iPod classic, iPod nano, iPod shufe, and iPod touch are trademarks of Apple Inc., registered in the U.S. and other countries. “Made 
for iPod” and “Made for iPhone” mean that an electronic device has been designed to connect specically to iPod and iPhone respectively, and has been certied by the developer to meet Apple performance standards. Apple is not responsible for the operation of this device or its 
compliance with safety and regulatory standards. Please note that the use of this device with iPod or iPhone may affect wireless performance. All other trademarks and registered trademarks are the property of their respective holders.
NPR No. 13N21  05/13
Direct Digital Charging Dock for iPhone
®
 5
Dock your iPhone 5, iPod touch
®
 (5G), or iPod nano
®
 (7G) 
via the Lightning Connector and recharge the device while 
you listen. The receiver automatically detects your device, 
selects dock input, and allows you to use the system remote 
to quickly navigate to your desired track. Audio signals are 
transported in pure digital form—bypassing the docked 
device’s analog conversion and gain circuits—for noticeably 
clearer, deeper, and more realistic sound.
Connect, Charge, and Play via USB 
Users of legacy iPhone and iPod models can link up in 
moments via the front-panel charging USB port, which 
also enables direct-digital audio transfer on these devices. 
If your smartphone or tablet features a mini-USB port, you 
can access the MP3 les stored on the device as well. You 
can also plug in a ash memory drive and use the system 
remote to select an MP3 library—no hassle, and no fuss.
Clean and Efcient Digital Amplier
As well as being more energy-efcient than Class AB designs, 
digital ampliers are capable of producing remarkably clean, 
detailed sound. Onkyo’s low-noise circuit topology reduces 
distortion across a wide frequency bandwidth, resolving new 
layers of depth and detail in your favorite recordings. 
Compact and Solid Two-Way Speakers 
The CS-255 includes a pair of two-way bass-reex-type 
speakers that incorporate a 3 
15
/
16
˝ (10 cm) woofer and a 
3
/
4
˝ (2 cm) balanced-dome tweeter. The cabinets feature 
stylish rounded edges and a front-to-rear taper that helps 
reduce internal standing waves—an unwanted acoustic 
resonance that can muddy the sound. Compact in size yet 
surprisingly robust, these magnetically shielded speakers t 
comfortably and sound great almost anywhere you choose 
to place them. 
Super Bass Function
Sometimes the music calls for a little extra bass punch. 
The two-mode Super Bass function on the CS-255 gives a 
welcome boost to the low-frequency band, adding just the 
right amount of heft to bass guitar and kick drum without 
sounding distorted, harsh, or boomy.
Smooth Front-Loading CD Player
While there is no shortage of weird and wonderful  
CD-loading designs out there, the novelty wears off after 
yet another scratched disc. The traditional front-loading CD 
player remains the simplest and safest way to enjoy your 
disc-based media. The CS-255 incorporates a smooth front-
loading mechanism, while track- or album-repeat modes—
plus a random playback option—offer greater exibility. And 
it’ll even play your homemade mixes and MP3-encoded 
compilation discs without any bother.
FM/AM Tuner with 60-Station Preset
Browse up to 60 of your favorite preset radio stations 
(with 30 presets for the AM band, and 30 more for FM) at 
the touch of a button, without fear of losing your original 
program. Once you’ve got all your favorites locked in, you’ll 
never be short of something to listen to again.
Black