Arcam service manual A85, P85, P85/3 Service Guide

Page 8

 

 

 

 

A85, P85, P85/3 Service Guide

Build History

 

 

 

 

 

 

 

 

 

 

 

 

 

ECO

Date

Description of Change

Number

 

 

 

 

 

 

 

00_1089

 

02/10/00

 

A85 – Fascia position changed to prevent display buttons sticking

00_1129

 

01/11/00

 

A85, P85, P85/3 – Improved stability under heavy clipping of amplifier R345,

 

 

 

 

R346, R445, R446 changed from 100R to 0R link

 

 

 

 

C307, C308, C407, C408 changed from 47P to 100P capacitors

00_1138

 

27/11/00

 

A85, P85, P85/3 – C303, C304, C403 changed from 10uF to 100uf capacitors –

 

 

 

 

this prevents protection circuit from operating when driving a 4 ohm load at

 

 

 

 

low frequency

01_1030

 

23/02/01

 

A85, P85, P85/3 – RV300, RV400 changed to 220R presets to make it easier to

 

 

 

 

adjust the bias settings

01_1068

 

11/04/01

 

A85, P85, P85/3 – New output device clamp fitted to heatsink

01_1101

 

04/06/01

 

A85, P85, P85/3 – Sensitivity of DC offset detection circuit reduced – Power

 

 

 

 

amp cct R308, R408 changed to 22K - R314, R414 changed to 10K

 

 

 

 

PSU surface mount fuse F202 up rated from 500mA to 750mA

01_1142

 

22/08/01

 

A85 – Preamp board upgraded from L866 to L937

01_1178

 

12/10/01

 

A85, P85, P85/3 – Speaker terminals changed from Camcon to 4mm binding

 

 

 

 

post

 

 

 

01_E014

28/11/01

 

A85 – Preamp board fuses F300, F301 up rated to 2A surface mount

02_E033

31/01/02

 

A85 – Extra pad F038 fitted under TX to stop TX coming loose in transit

02_E035

04/02/02

 

A85, P85, P85/3 – Main 20mm fuse rating changed to 4AT

Software History

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ECO

 

Date

 

Version

 

Description of Change

Number

 

 

 

 

 

 

 

 

01_1072

 

18/04/01

 

1.1

 

Remote standby action changed from turning unit completely off

 

 

 

 

 

 

to putting unit into standby

01_1095

 

21/05/01

 

1.2

 

Delay added to start H8 start up routine (volume control chip)

01_1167

 

12/09/01

 

1.3

 

Volume chip read/write protocol changed

01_1179

 

26/10/01

 

2.0

 

Added the processor mode option

01_E011

 

23/11/01

 

2.1

 

Corrected the welcome message saving fault. This fault was

 

 

 

 

 

 

introduced with version 2.0 software

02_E048

 

15/02/02

 

2.2

 

Corrected the processor loop volume jump when v/c adjusted

Current Fuse Ratings (20/02/02)

 

 

 

 

 

 

Fuse Position

 

 

 

Fuse Rating

 

Main Supply fuses - A85, P85, P85/3

 

2 x 4AT 20mm (Arcam part number C12406)

 

PSU fuse F202 - A85, P85, P85/3

 

750mA surface mount (Arcam part number C3751)

 

Preamp fuses F300, F301 – A85

 

2A surface mount (Arcam part number C3202)

 

Quiescent Current Setting

 

 

 

 

 

 

 

 

Left channel

 

 

 

Measure points indicated on PCB -

 

 

 

 

 

 

 

 

Adjust RV300 for 8.5mV cold or 12 mV when warm

 

Right channel

 

 

 

Measure points indicated on PCB -

 

 

 

 

 

 

 

 

Adjust RV400 for 8.5mV cold or 12 mV when warm

 

Image 8
Contents A85 Contents List Pre-amplifier circuit description Amplifier & PSU Circuit Description L882 Circuit Sheet PSU Ground naming convention is as follows A85, P85, P85/3 Service Guide Fault Diagnostics A85 amplifier and PSU top sheet Circuit Diagram A85 amplifier power supply and microcontroller interface A85 amplifier power output stage left A85 amplifier power output stage right DVD Display PCB USE Exclude NF When Using Runout Sheet Program Integrated amplifier preamp main signal path Integrated amplifier preamp power supply A85 Display PCB Circuit Diagram A85 Phono Stage TOP Level A85 Phono Stage Left Channel A85 Phono Stage Right Channel AP85 third channel top level 23425 P85 microcontroller and switch Page Page Page Page Page Page Page Arcam 220NF Class X2 CAP 275VRMS IC Vreg POS Wima FKP2 Ppro Obsolete, absent, redundant, or incorrect issue in PDM Part Qty Iss Description Designators Phono SKT 4-WAY EMC Gold SK2 SK3 SK4 SK5 WAF MN12818A VFD Itron DISP1 Title A85 Phono PCB Title RES SM Phono SKT 2-WAY EMC Gold Title P85 Switch Board Tact Switch 2-PIN LOW Prof SW1 SW2 A85 General Assembly Parts List Silver Black Description Where Used QTY P85 General Assembly A85P Transformer P85/3 General Assembly Clamp E912MC to E804HK ST=L
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Manual 14 pages 30.61 Kb

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.