DENON PMA-830

Commentary

A pre-main amplifier using a symmetrical push-pull system.

The symmetrical push-pull circuit, which was adopted for all stages for the first time in the PMA 850, is also adopted in the PMA 830.
In order to make the most of the features of this circuit, a class A operation DC amplifier has been newly added to the class B operation DC amplifier configuration in the power amplifier section to realize low distortion characteristics over an ultra-wide band.

The first stage of the symmetrical class A push-pull circuit in the equalizer amplifier section employs a newly developed ultra-low-noise transistor to reduce the noise level to -142dBV (0.079 μ V), which is close to the limit.
In addition, the gain of the equalizer amplifier has been increased to 42 dB (1 kHz, 126 times) so that even when the output of the equalizer amplifier is directly connected to is directly connected to the power amplifier.

A direct coupling method is adopted, and when the control function is not required, it can be switched to a simpler circuit configuration.

The intermediate amplifier section, which serves as both a tone amplifier and a flat amplifier, uses a symmetrical class A push-pull circuit similar to the equalizer amplifier to achieve low distortion over a wide range.
In addition, the tone control has a structure in which the control element is detached at the Defeat position, so that flat characteristics can be obtained.

The power supply section uses an ultra-large toroidal transformer with an emphasis on S/N and voltage regulation. Together with the parallel use of large-capacity block capacitors, it forms a powerful power supply section. In particular, in order to prevent leakage flux (leakage flux), which is harmful to high S/N, strict multiple shielding is applied to suppress leakage flux of the power supply transformer.

Equipped with a subsonic filter.

Continuously variable volume is used for volume adjustment.
By using a special curve for the balance volume, it is possible to finely adjust the volume balance of the left and right channels.

Model Rating

Type	Pre-main amplifier
Power Amplifier Unit
Circuit system	All-stage pure complimentary service push-pull circuit
Rated Output (Both channel drive)	Class A operation : 15W + 15W (8 Ω, 20 hz to 20 khz, THD 0.005%) Class B operation : 65W + 65W (8 Ω, 20 hz to 20 khz, THD 0.01%) 90W + 90W (4 ω, 1 kHz, 0.02% THD)
Total harmonic distortion factor	Class A operation : 0.005% or less Class B operation : 0.01% or less
Intermodulation distortion factor (60 hz : 7 khz = 4 : 1)	0.01% or Less (at Rated Output Equivalent Amplitude Output) 0.01% or Less (Sine Wave 1W Equivalent Amplitude Output)
Output Bandwidth (IHF, THD 0.05%)	Class B operation : 5 Hz to 80 kHz Class A operation : 5 Hz to 100 kHz
Transmission Characteristics (at 1W output)	DC ~ 100 kHz + 0 -1dB
Input Sensitivity / Impedance	1V/50k Ω
Output impedance	0.16 Ω or less
Signal-to-noise ratio	122dB
Output terminal	Speaker AORb : 4 Ω ~ 16 Ω Speaker A + B : 8 Ω ~ 16 Ω Headphone port
Preamplifier Section
Maximum Output / Rated Output	Pre-out : 25V/1V (at 50k Ω load) Rec out:25V/320mV(THD 0.01%)
Total harmonic distortion factor	0.03% (at 3 V output)
Input Sensitivity / Impedance	Phono1, 2 : 2.5mV/50k Ω Tuner, Aux, Tape : 320mv/40k Ω
Maximum Allowable Input (1 kHz)	Phono:200mV
RIAA deviation	20 Hz to 20 kHz ± 0.2 dB or less
Signal-to-noise ratio (IHF, A-network Input short)	Phono : 90 dB or more Tuner, Aux, Tape : 100 dB or more
Frequency Response (Aux → Pre out)	5 Hz to 100 kHz + 0 -1dB
Tone Control Variable Range	Bass : ± 8 dB (100 Hz) Treble : ± 8 dB (10 kHz)
Filter characteristic	Subsonic filter : 20 Hz, 6dB/oct.
Loudness control	Low frequency : + 7 dB (100 Hz) High frequency : + 6 dB (10 kHz)
Muting	-20dB
<General>
Power outlet	Switched : 1 system, 100W Unswitched-2, 250W (total)
Pwer	100 VAC, 50Hz/60Hz
Power consumption	170W (Electrical Appliance and Material Control Law)
External dimensions	Width 434x Height 164x Depth 400 mm (including leg, knob, terminal)
Weight	16.5kg