What is stereo?

There are now two system of high fidelity, monophonic (monaural) and stereophonic. Monophonic is a system that starts from one microphone and is fed through a single high fidelity set. Stereophonic is a double system. Two separate microphones are placed at different sides of the orchestra and two different systems are used to keep the two signals or channels separated. Two separate speakers are used, placed on different sides of you room. Stereo is much like 3-D photography, two slightly different sound reach your ears giving you a new dimension in sound.

H.H. Scott '59

Denon PMA-850

Solid State Stereo Integrated Amplifier
A new series of Denon amplifiers, incorporating a wide dynamic range, low noise MC amplifier. It reaches the highest class in the most fundamental characteristic of amplifiers both in distortion factor and Signal-to-Noise  separation. By coupling all stages with a pure complementary circuit from MC amplifier to power amplifier using both PNP, NPN transistors, an ultra low distortion rate of 85 W +85 W was achieved.
An DC power amplifier placing importance on a quick build-up characteristic by incorporating, a new amplifying element. Distortion factor less than 0,01% (20 Hz - 20 kHz).
Torodial core power transformer which has an independent coil for left and right channels for exceptional regulation.
Employment of an ultra low noise transistor permits a high Signal-to-Noise  ratio, head amplifier for MC type cartridge (74 dn IHF-A), and equalizer amplifier (89 dB IHF-A)
Provided with direct couple switch for direct connection of equalizer amplifier and power amplifier
A unique design of two tone color, imparting a sense of high class structural grace.

Type Amplifier:  All stage pure complementary pushpull system DC circuit
Power Amp Section
Rated Output (Both channel driven):
110 W RMS (at each channel) : 1 kHz (T.H.D. 0,05%, 4 Ω)
85 W RMS (at each channel) :  20 Hz to 20 kHz (T.H.D. 0,01%, 8 Ω)
Total Harmonic Distortion (at rated output, 20 Hz to 20 kHz):  less than 0,01%
Intermodulation Distortion (60 Hz : 7 kHz = 4 : 1)a rated output:  less than 0,02%
Power Bandwidth (both channels driven, 8 Ω):  5 Hz to 100 kHz
Transmission Characteristic:  DC to 100 kHz +0 dB, -1 dB (at 1 watta output)
Frequency Response (at 0,5 W output, -1 dB):  5 Hz - 100 kHz +0 dB -1 dB
Input Sensitivity/Impedance (20 Hz - 20 kHz):  1 V RMS/50 k Ω  ±10 %
Output Impedance:  less than 0,16 Ω
Signal-to-Noise  Ratio (IHF, A network at input terminal Shorted):  122 dB
Output Terminals:
Speaker :  A & B = 4 - 16 Ω load; A + B = 8 - 16 Ω load
Headphone :  for stereo headphone
Pre Amplifier Section
Pre Amp Output:
Max. Output :  25 V at 50 k Ω
Rated Output :  1 V
T.H.D. :  0,003% at 3 V output
Equalizer Amp Output:
Max. Output :  25 V at 50 k Ω load (T.H.D. 0,01%)
Rated Output :  320 mV
Input Sensitivity/Impedancce
Phono MM 1, 2  :  2,5 mV RMS/ 50 k Ω
Phono MC 3 :  0,37 mV (cartridge impedance 40 Ω)
Tuner :  320 mV / 40 k Ω
Aux, Tape :  320 mV / 40 k Ω
RIAA Deviation (20 Hz to 20 kHz):  ±0,2 dB
Signal-to-Noise Ratio (IHF, A network)
Maximum Allowable Input Phono:  200 mV RMS (1 kHz)
Phono MM :  better than 89 dB (input terminal shorted)
Phono MC :  better than 74 dB (input terminal 40 Ω)
Tuner, Aux, Tape :  better than 105 dB (input terminal shorted)
Aux to pre Out Frequency Response Tone Defeat:  5 Hz to 100 kHz +0 dB, -1 db
Tone Control Frequency Response:
Bass :  100 Hz ±8 dB
Treble :  10 kHz ±8 dB
Filter Characteristic:
Subsonic  :  20 Hz  at 12 dB/oct
High Cut :  9 kHz at 12 dB/oct
Loudness Control Characteristic:
Low Range :  100 Hz +7 dB
High Range :  10 kHz +6 dB
Muting level:  -20 dB
Power Source:  AC 120 V 60 Hz, AC 220/240 V 50/60 Hz
Dimensions (W x H x D):  434 x 164 x 400 mm (17-5/64" x 6-29/64" x 15-3/4")
Weigh:  17 kg (37,5 lbs)

Denon TU-850

 FM Stereo Tuner TU-850
5-gang variable capacitor, a complete front-end incorporating MOS-FET
Low-distortion, high-selectivity 2 system IF Section
PLL IC stereo demodualtor circuit
Unique design and high precision tuning system
Incorporates a recording level check
Equipped 2 large size multi-functioning level meters capable of mesuring amplifier output.

FM Section
Tuning Frequency:  88 to 108 MHz
Usable Sensitivity (IHF):  1,7 µV (9,9 dBf)
Effective Selectivity:  65 dB
Signal-to-Noise Ratio:  84 dB
Total Harmonic Distortion: 
Mono :  0,05%
Stereo :  0,08%
Capture Ratio:  0,8 dB
AM Suppression:  65 dB
Image Rejection:  120 dB
IF Rejection:  110 dB
Separation:  50 dB (1 kHz)
Level Meters Indicaton Error:  ±0,2 dB (Ext. Aft. -10 to +30 dB) 1khz
Frequency Response:  20 Hz - 15 kHz +0,2 dB -1 dB
Power Source:  AC 120 V 60 Hz; AC 220 / 240 V 50/60 Hz
Power Consumption:  13 W
Dimensions (W x H x D):  434 x 164 x 400 mm
Weight:  8,9 kg

Technics SL-1200GAE

 Due to the widespread use of CDs, turntable systems disappeared briefly from the market, but their warm sound quality is bringing them back. The direct-drive turntable invented by Technics is still highly acclaimed by audiophiles and DJs in the form of the SL-1200 Series, and there have been many requests to revive the turntable system. As such, we decided to develop a new system for Hi-Fi use. Here we provide an outline of our intent in this development.

Direct-drive is generally considered to be for DJ use, and belt drive is for Hi-Fi use. In the 1970s, when Technics invented direct-drive turntables, their performance and reliability were first recognised by broadcast stations. High acclaim was then received by audiophiles. The high-precision rotation and absence of S/N ratio degradation were particularly attractive to these users. The high torque and reliability of direct-drive were recognised by DJs, and direct-drive turntables became the standard in the club scene.

When developing a direct-drive motor, considerable capital investment is required for large-scale production equipment. In contrast, belt drives can be made with a little cost. Also, compared with direct-drive, belt drive was designed with the latest technology. The view remains that direct-drive is for DJ use and belt drive is for Hi-Fi use. Originally, direct-drive offered superior sound quality. If we redesign the direct-drive motor and control circuitry, we will be able to create a turntable that is superior to other systems.
Technics was also a leader in incorporating innovations, such as vibration-damping materials, cabinet construction, and insulators. Having inherited the DNA of Technics, we do not wish to merely make a replica of the SL-1200.
In other words, our intent in this development is to redefine the direct-drive turntable reference.
The coreless direct drive eliminates cogging and achieves smooth rotation
The twin-rotor construction reduces minute vibration during rotation while maintaining high torque.
The high-precision motor control technology switches the drive mode depending on the operational status of the motor. This technology combines high torque with high stability.The tone arm with high-precision bearings achieves high initial-motion sensitivity

The tone arm pipe employs magnesium which provides high rigidity.
The use of traditional Technics gimbal suspension construction and high-precision bearings attains high initial-motion sensitivity.

Three-layered turntable that delivers smooth rotational stability
The turntable has a three-layered construction with a rigidly combined brass and aluminium diecast platter, and a rubber covering its rear surface to eliminate unnecessary resonance. With this construction, high rigidity and vibration damping are achieved.
The use of a heavyweight-class turntable that generates a large inertial mass.  It delivers smooth rotational stability.

Four-layered cabinet construction and insulators based on thorough anti-vibration design
The top panel of immaculate aluminum has been added to the three-layered construction of aluminum diecast, BMC, and heavyweight-class rubber. This four-layered construction combines high rigidity with a high quality finish and feel.
The insulators employ special silicon rubber to ensure high vibration damping and long-term reliability. They completely dampen external vibration and suppress howling noise.

High-quality terminals
The use of brass-milled and gold-plated terminals prevents degradation in sound quality.
Inside the case, the metal shielding construction is used to diminish the effects of external noise.

Highly accurate turntable speed maintained with the pitch control
The digital control method is adopted to achieve constant pitch control.
The pitch variable range select button (×2) is provided. The pitch control with the range up to ±16 % is possible
 Coreless Direct Drive Motor
Conventional analogue turntables have problems with degradation in sound quality caused by factors such as minute speed vibration during rotation and rotation irregularity called "cogging." In the SL-1200GAE, the use of a newly developed coreless direct-drive motor with no iron core eliminates cogging. Also, the twin-rotor construction reduces the bearing load while maintaining high torque, and also reduces minute vibration during rotation. These factors enable reproduction of the warm, exquisitely detailed sound etched on analogue records.
High-Precision Motor Control Technology
The application of motor control technology developed for Blu-ray devices, and switching the drive mode depending on the operational status of the motor achieve a high starting torque and high speed stability.
Four-layered Cabinet Construction
A hairline-processed, 10-mm-thick top panel of immaculate aluminium has been added to the previous three-layered construction of aluminium diecast, BMC, and heavyweight-class rubber on the SL-1200MK5. This four-layered construction combines high rigidity with a high quality finish and feel.
 High Sensitive Tonearm
The tonearm employs lightweight magnesium which has a high damping effect, with cold drawing improving the characteristics of the material and achieving the high-precision required. In addition, high initial-motion sensitivity is attained by employing the traditional Technics gimbal suspension construction with horizontal rotation axis and the vertical rotation axis intersecting at a single central point, as well as high-precision bearings using a cut-processed housing.
Three-layered Turntable Platter
The turntable has a three-layered construction with a rigidly combined brass and aluminium diecast platter. With a deadening rubber covering its entire rear surface to eliminate unnecessary resonance, thereby achieving high rigidity and vibration damping. This delivers smooth rotational stability and inertial mass surpassing the SP-10MK2, the direct-drive turntable standard used by broadcast stations worldwide, as well as having more than twice the inertial mass of the SL-1200MK5.
 High-Quality Terminals
The use of brass-milled and gold-plated phono terminals and ground terminals prevents degradation in sound quality while enabling the easy attaching and detaching of cables. Also theuse of metal shielding construction inside the case reduces the effects of external noise.
 High-level Balance Adjustment
When the weight distribution of the turntable is uneven, excess vibration or noise occurs during rotation, which causes degradation in sound quality. Therefore, the balance of the turntable is adjusted at the factory by using specialised high-precision balance adjustment equipment for each and every item after the turntable is assembled. Turntables that have undergone adjustment are labelled with a sticker reading "BALANCED" to indicate that adjustment has been done.
Turntable Section
Type:  Direct drive manual turntable
Drive Method:  Direct drive
Motor:  Brushless DC motor
Turntable:  Brass and aluminum diecast combined
Diameter:  332 mm (13-5/64“)
Mass:  Approx. 3.6 kg (7 15/16 lbs) (including a rubber sheet)
Turntable Speeds:  33-1/3, 45 and 78 rpm
Variable Range Pitch:  ±8 % and ±16 %
Starting Torque:  3.3 kg-cm (2.8 lb-in)
Build-up Characteristics:  0.7 s. from standstill to 33-1/3 rpm
Braking System:  Electronic brake
Wow and Flutter:  0.025 % W.R.M.S. (JIS C5521)
Rumble:  78 dB (IEC 98A weighted)
Tone Arm Section
Type:  Static Balance
Effective Length:  230 mm (9-1/16“)
Overhang:  15 mm (19/32“)
Tracking Error Angle:
Within 2° 32' (at the outer groove of 30 cm (12“) record)
Within 0° 32' (at the inner groove of 30 cm (12“) record)
Offset Angle:  22°
Arm-height Adjustment Range:  0 – 6 mm (0“ - 15/64“)
Stylus Pressure Adjustment Range:  0 – 4 g (direct reading)
Head Shell Weight:  Approx. 7.6 g
Applicable  Cartridge Weight Range:
Without the auxiliary weight :  5.6 to 12.0 g; 14.3 to 20.7 g (including the  head shell)
With the small auxiliary weight :  10.0 to 16.4 g; 18.7 to 25.1 g (including the head shell)
With the big auxiliary weight :  14.3 to 19.8 g; 23.0 to 28.5 g  (including the head shell)
Head Shell Terminal Lug:   1.2 mm Φ  4-pin terminal lug
Power Supply:  AC 120V, 60 Hz
Power Consumption:
Power ON :  14 W
Power OFF :  0,2 W
Dimensions (W×H×D):  453 x 173 x 372 mm (17-27/32“ × 6-13/16“ × 14-21/32“)
Mass Approx. 18.0 kg (39.7 lbs)

Akai BT-500

 The Akai Professional  belt-drive turntable BT-500 is an exquisitely crafted, premium performance turntable that extracts every musical detail and subtle nuance from your beloved record collection.
All the must-have features audiophiles demand for top-flight musical reproduction are here: a quiet belt-drive system with a mechanically-isolated motor that eliminates any residual motor noise and vibration, a heavy die-cast aluminum platter that ensures an exemplary signal-to-noise ratio, a rubber non-slip mat so there’s no record slippage, imperceptible wow and flutter and a low-mass straight tonearm with adjustable counterweight and precision damped cueing. Our unique leveling bubble with adjustable feet ensures a perfectly level needle drop.  A high-quality pre-mounted Audio-Technica magnetic cartridge with elliptical stylus in removable headshell completes the package.
Luxurious walnut finish with brushed aluminum controls
Low-mass straight aluminum tonearm with adjustable counterweight for precise tracking
Leveling bubble with adjustable feet
Die-cast anti-resonance aluminum platter and non-slip rubber mat
Built-in switchable phono pre-amplified
Gold-plated RCA jacks
Streams music wirelessly to any Bluetooth speaker (not included)
 In addition, the Akai's BT-500 has many new school flourishes that make it even more enjoyable and convenient, such as a built-in switchable phono pre-amp so you can use it with a traditional stereo or connect it directly to powered speakers. The BT-500 is also a wireless streaming turntable, so you can stream your vinyl to any Bluetooth® enabled speaker (not included). The BT-500 also boasts the ability to convert your analog records into digital files using the included software and USB port for quick computer connectivity.
System:  Belt Drive Turntable
Speed:  33-1/3 RPM and 45 RPM)
Motor:  Isolated DC
Signal-to-Noise Ratio:  67 dB (A-weighted)
Wow and Flutter:  Less than 0.2%
Output Level:
Pre-amp "OFF”:  2.5 mV
Pre-amp "ON”:  155 mV
Dimensions (W x H x D):  444 x 123 x 347 mm (17.5" x 4.84" x 13.7")
Weight: 14 lbs. (6.4kg)
USB Function:  A/D 16-bit 44.1 kHz or 48kHz selectable
Computer Interface:  USB 1.1 Compliant Windows 10/8/7/Vista/XP, Universal Binary for OS X 10.5 to 10.10.x