SK103 connects to the micro controller and display PCB.

The 14 pin connector is numbered as follows:

No

Name

Type

Description

 

 

 

 

 

1

+5V_D

O/P

5 volt digital supply (for micro)

 

 

 

 

 

2

0V_D

O/P

Digital ground

 

 

 

 

 

3

+49V

O/P

Main power supply for VFD (via fusible resistor)

 

 

 

 

 

4

STANDBY

I/P

Mains relay control signal

(HIGH = ON)

 

 

 

 

 

5

SPKR1 ON

I/P

Speaker 1 relay control signal

(HIGH = ON)

 

 

 

 

 

6

SPKR2 ON

I/P

Speaker 2 relay control signal

(HIGH = ON)

 

 

 

 

 

7

THERMPROT

O/P

Over temperature protect

(HIGH = FAULT)

 

 

 

 

 

8

VIPROT

O/P

Short circuit protect

(HIGH = FAULT)

 

 

 

 

 

9

DCPROT

O/P

DC offset protect

(HIGH = FAULT)

 

 

 

 

10

AC PRESENT

O/P

Indicates AC mains is plugged in (HIGH = ON)

 

 

 

 

 

11

TRIGGER

O/P

12V DC trigger input

(HIGH = ON)

 

 

 

 

12

REMOTE

O/P

Demodulated RC5 remote input from rear panel

 

 

 

 

 

13

0V_D

O/P

Spare digital ground pin

 

 

 

 

 

14

+5V_D

O/P

Spare 5 volt digital supply pin

 

 

 

 

 

The ground naming convention is as follows:

Name

Description

 

 

0V_D

Digital ground (used for micro processor circuitry, display and interface)

 

 

0V_LS_R

Right channel loudspeaker ground return

 

 

0V_SIG

Signal ground (this is the ‘clean’ precision reference ground)

 

 

0V_PSU

Power supply ground (high current pulses for the large reservoir caps)

 

 

0V_TRIG

Ground return for the jack socket trigger and remote control circuit

 

 

0V_HF_R

Decoupling ‘noisy’ ground for the right channel power amp

 

 

0V_LS_L

Left channel loudspeaker ground return

 

 

0V_HF_L

Decoupling ‘noisy’ ground for the left channel power amp

 

 

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Image 7
Arcam A85 service manual Ground naming convention is as follows

A85 specifications

The Arcam P85 and A85 amplifiers are a testament to Arcam's commitment to high-quality audio performance. These components are well-known in the audiophile community for their unique blend of state-of-the-art technology and superior sound quality, catering to discerning listeners who value fidelity and craftsmanship.

The Arcam A85 is a high-performance integrated amplifier that features a robust design and advanced circuitry. It offers a powerful 85 watts per channel output, which is more than sufficient to drive a wide range of speakers with clarity and precision. The A85 incorporates a dual mono design with separate power supplies for the left and right channels, ensuring low crosstalk and high channel separation. This design choice also enhances the amplifier’s dynamic response, allowing it to handle complex musical passages with ease.

One of the standout features of the A85 is its use of high-quality components, including low-noise transistors and capacitors that are specifically chosen to minimize distortion. The amplifier exhibits an impressive signal-to-noise ratio, contributing to a clean audio signal that preserves the nuances of the music.

On the other hand, the Arcam P85 is a powerful, dedicated power amplifier that pairs perfectly with the A85. It utilizes a Class G amplification technology, which provides significant power efficiency. This means that the P85 can deliver peak power output without generating excessive heat, making it an ideal choice for long listening sessions.

The P85 offers 85 watts per channel into 8 ohms but can also deliver 140 watts into 4 ohms, allowing it to drive even the most demanding loudspeakers with authority. Its balanced XLR inputs, alongside standard RCA inputs, ensure compatibility with various audio sources, while the sturdy construction ensures durability and performance.

Both the A85 and P85 feature a simple yet elegant design, characterized by a sleek chassis that minimizes resonances and maximizes aesthetic appeal. They also come equipped with a variety of connection options, including multiple line-level inputs and outputs, making integration into an existing audio system straightforward.

In summary, the Arcam P85 and A85 amplifiers represent a harmonious fusion of innovative technology, impeccable sound quality, and user-friendly design. Their powerful performance, combined with high efficiency and low distortion, makes them a prized possession for any audiophile seeking to enhance their listening experience. Whether used in a stereo setup or as part of a more extensive home theater system, the A85 and P85 deliver exceptional audio performance that stands the test of time.