Sony STR-DE485

The STR-DE485 is a high-specification Audio/Video receiver with surround sound manufactured by the Sony Corporation in 2002. It is one in a series of AM/FM receivers consisting of STR-DE585, STR-DE485, and STR-DE485E, all of which had surround sound capability. The STR-DE585 was 100-watts per channel for all channels, whilst the other two models were 80-watts per channel for all the channels. These amplifiers have Dolby Pro Logic, and DTS Digital Surround decoder built-in to provide a fully realised home theatre system. The speaker outputs are for the front, centre, and surround channels. In addition, an RCA socket provides signal to an external amplified subwoofer speaker. The built-in FM tuner has Radio Data System (RDS) facility, which displays the names of the stations. For the sockets, it has optical and coaxial inputs for decoding 5.1-channel DTS signals. There is no phono input for a record player and therefore you will need to use an external RIAA preamplifier if you wish to connect a record player. The standard remote control for this amplifier is RM-U306. This amplifier is 430 mm × 145 mm × 298 mm in dimensions, and mass 7.0 kg. The full specifications, for all the model variations, and regions, are in the user manual.

Review

The STR-DE485 is a wonderful piece of audio electronic engineering, which the engineers at Sony Laboratories have intelligently designed. If you use this amplifier with the correct Sony speakers, then the sound quality is excellent and you will enjoy the surround sound produced in DVDs. A great advantage of this amplifier is that all the channels are of equal power and therefore the surround channels are noticeable when they kick-in. This amplifier has a huge number of functions for setting the correct sound fields and it certainly gives you the impression that the engineers have thought of everything so that you can enjoy the best sound quality possible.

To give the amplifier a clean and minimalistic look, they are using the M61511FP IC, which performs the input switching function. You will find many Sony amplifiers using this at the input end and consequently they tend to sound the same. The power output transistors are MN2488 and its complementary pair MP1620 in a symmetrical push-pull configuration, for all the channels. The µPC2581V-S integrated circuits perform the pre-driver function to drive these transistors.

In this amplifier, there are transistor-based circuits in each channel to detect an overload condition. The speaker protection is by way of a relay that engages only when there is no short in the audio power transistors. If there is a short, then the relay does not engage, and the amplifier flashes "PROTECT" to inform the user.

Price/eBay

The STR-DE485 is becoming a bit of a classic amplifier, and it is often for sale at places such as eBay. A unit in mint condition together with the remote control and original packaging can fetch over one hundred pounds. A pre-owned unit with scratches and missing remote could fetch around fifty pounds, and a burnt amplifier that flashes "PROTECT" on the display would cost around the ten pounds region. The audio power output transistors are still readily and cheaply available and therefore a unit in good condition may be a cost-effective repair to qualified engineers.

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