Описание
It can be said that most of the audio enthusiasts had situations with failed amplifiers, where high DC voltages appeared in the outputs. Such voltages can severely damage the precious speaker systems, sometimes worth much more than the amplifier itself. And in the recent days, where almost all audio gear connected in series – from sole DAC to the power amplifier’s output is DC coupled, the damage to the speakers in case of an amplifier’s failure could be devastating. Even the fastest DC servo circuits, implemented into the modern power amplifiers, may be neither fast enough nor capable to withheld the amplifier’s output around the safely zero-DC voltage.
That’s why, the speaker protection board is still almost mandatory as a part of every Hi-Fi amplifier.
Of course, its presence introduces an additionally chain in the signal path, so that the Speaker protection circuit must be carefully designed in order to not only successfully protects the speakers but also to not deteriorate the sound quality.
The Speaker protection board offered here was designed with all these considerations taken into account – it is very fast, very sensitive and with carefully chosen relays, which do not alter the sound reproduction.
Physical characteristics:
– Dimensions: 70x50x35 mm. (WxDxH);
– Weight: 100 gr.
– PCB design: The board is TWO-layered which allows the power traces to be doubled on the TOP and BOTTOM layers thus lowering their resistances and doubling the current handling capabilities of the board. All current conducting traces are shortened and widened as much as possible for additional conductance enhancement.
The PCB has solder mask coating on top and bottom layers for better durability.
На горната страна на платката е нанесен бял печат с означенията на елементите и техните контури.
Electrical parameters:
– Initial time delay of the board: approx. 8 sec.
– Min. DC trigger voltage: +/- 2.5V
– Time delay for protection engagement: 400 ms.
– Time delay for output disconnection after Power OFF – less than 20 ms.
– Relay’s max. handled current (for each channel): 15A
– Power supply voltage: 85 – 265V (AC or DC)
As you can see from the picture, the DC voltage for powering the logic circuitry and the relay is ensured by a versatile Zettler ZP03SXX00WE series AC/DC converter, which can work in wide range of AC Mains voltages (85 – 265V AC or DC). This way the problem with the various AC Mains voltages available all over the world is elegantly solved.
The Output relays are Finder 40.52 series which is well adopted in the audio society.
The circuit for initial time delay and protection is arranged as a small standalone board soldered to the main board.
Connection to the amplifier’s outputs and to the speakers’ terminals is implemented by a terminal row, placed on the short side of the board.
The AC Power voltage is applied to the circuit via dedicated connector, placed on the opposite side of the board.
Although its relative simplicity, the wiring of the board is shown on the picture below.
Какво получава купувачът:
Пакетът ще съдържа 1 pcs. Fully Assembled and tested Speaker Protection Board
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