is switched off when the current sense level exceeds the level at the output of the error amplifier.

TimeON phase : A drain current will flow from the positive supply at pin 2 of the transformer through the transformer's primary winding, the MOSFET and Rsense to ground. As the positive voltage at pin 2 of the transformer is constant, the current will increase linearly and create a ramp dependent on the mains voltage and the inductance of the primary winding. A certain amount of energy is stored in the transformer in the form of a magnetic field. The polarity of the voltages at the secondary windings is opposite to the primary winding so that the diodes are non-conducting in this phase.

TimeDIODE phase : When the MOSFET is switched off, energy is no longer supplied to the transformer. The inductance of the tranformer now tries to maintain the current which has been flowing through it at a constant level. The polarity of the voltage from the transformer therefore reverses. This results in a current flow through the transformer's secondary winding via the now conducting diodes, electrolytic capacitors and the load. This current is also ramp shaped but decreasing.

TimeDEAD phase : when the stored energy has been supplied to the load, the current in the secondary windings stops flowing. At this point, the drain voltage of the MOSFET will drop to the voltage of C821 with a ringing caused by the drain-source capacitance with the primary inductance.

The oscillator will start a next cycle which consists of the above described three phases. The time of the different phases depends on the mains voltage and the load.

TimeDEAD is maximum with an input of 400VDC and a minimum load. It will be zero with an input of 100VDC and an overload.

V2

Vosc

V1

0

Vcomp

Vsense

Vgate

Vdrain

Idrain

Idiodes

Ton Tdiode Tdead

CL 96532076_034.eps 290799

Figure 8-15 ‘Regulation’

 

 

CH1

2

 

 

CH2

 

 

PM3394B

CH3

2 V~ ALT MTB5.00us- 0.90dv ch1-

ch1

1

 

 

 

 

 

ch3

 

 

 

ch2

T

 

 

 

 

 

 

3

 

 

 

2

 

 

ch1 : Drain voltage

ch2 : Drain current

ch3 : Gate voltage

 

 

CH1

1

 

PM3394B

CH3

50mV~ ALT MTB5.00us- 0.90dv ch1-

ch1

 

 

 

ch3

1

 

 

 

 

 

 

T

 

 

 

3

 

 

ch1 : Drain voltage

ch2 : Oscillator voltage

 

CH1

1

PM3394B

CH3

20mV~ ALT MTB5.00us- 0.90dv ch1-

ch1

 

 

1

 

 

ch3

 

 

T

 

 

3

 

 

ch1 : Drain voltage

ch3 : Sense voltageCL 96532076_033.eps 290799

Figure 8-16 ‘Oscillograms’

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Marantz DR-6000, MAR770, MAR775 service manual Ch1 Drain voltage Ch2 Drain current Ch3 Gate voltage
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MAR770, MAR775, DR-6000 specifications

The Marantz DR-6050 and DR-6000 are revered components in the world of high-fidelity audio systems, reflecting the brand's long-standing commitment to quality and performance. These models have gained popularity among audiophiles for their comprehensive features and advanced technologies, which cater to both casual listeners and serious music enthusiasts.

The Marantz DR-6050 is a CD recorder and player that stands out with its dual functionality. It allows users to enjoy CDs while also having the capability to record directly from various sources, including analog inputs and digital connections. This functionality is essential for those who wish to preserve their vinyl records, cassettes, or other audio formats onto CD. The machine supports CD-R and CD-RW media, providing flexibility for repeated use and recording.

One of the standout technologies in the DR-6050 is its high-quality Digital-to-Analog Converter (DAC), which significantly enhances sound performance by converting digital signals to analog with incredible accuracy. This contributes to the unit's ability to reproduce audio with rich detail and clarity. Additionally, the recorder is equipped with a Microprocessor that ensures precise recording levels and optimizes the quality of the output.

On the other hand, the Marantz DR-6000 offers similar capabilities but with an emphasis on simplicity and ease of use. Designed for users who appreciate an intuitive interface, it features straightforward controls and an ergonomic design. The DR-6000 supports multiple recording formats, including standard audio CDs, making it versatile for various playback systems.

Both models are built with high-grade components that promise longevity and reliability. They feature robust construction, ensuring minimal vibration and interference to enhance playback quality. Integrated analog and digital inputs allow for diverse connectivity options, which is crucial for users with elaborate audio setups.

In terms of audio performance, both the DR-6050 and DR-6000 exhibit impressive frequency response and low distortion levels, characteristics that are vital for a satisfying listening experience. The devices also include features like playback speed control and disc finalization options, providing the user with complete control over their audio sessions.

The Marantz DR-6050 and DR-6000 are ultimate companions for those who appreciate high-quality sound and need versatile recording solutions. With their blend of advanced technologies, clear audio output, and user-friendly designs, they remain solid choices for anyone looking to enhance their audio collection and experience.
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