PMA – 655R
Integrated Stereo Amplifier (2000-06)
Dimensions: 434 x 121 x 338mm
Power output: 50 watts per channel into 8Ω (stereo)
Frequency response: 20Hz to 20kHz
Total harmonic distortion: 0.01%
Input sensitivity: 2.5mV (MM), 150mV (line)
Signal to noise ratio: 86dB (MM), 107dB (line)
Output: 150mV (line)
Common problems that occur in PMA 655R
Problem: Distorted audio from amplifiers
How do you feel if you cannot hear any audio from your speaker or amplifier, all you can hear is distorted sound with sizzle and pops?
(a) Amplifier or Home theatre is damaged or blemished.
Solution: If the speaker gets damaged or blemished, the best way is to let the Professional Audio Engineers handle it. They will fix the cables and wires that depend on plugs and jacks which can get faulted over time. Sometimes there may be carbon deposits stucked inside the amplifier. They will clean that also with the relevant chemicals and make your amplifier up to the mark and delightful for you.
Solution: Clipping means issues in power supply voltage in speakers. This problem can be corrected by the professional engineers. They will fix the clipping with specified technicalities.
Problem: Amplifiers sputter periodically
The reason for sputtering of amplifiers could be faulty or loose wires or there would be some internal issues. It can also happen because of the high volume. Sputtering usually occurs during the loudest parts of the songs.
There is a specified saturation level to which volume can be raised. If sputtering occurs eventually, it will ruin your amplifier.
Solution: This problem could be cured by the professional only. So go to the authorized service centre near you for this.
Problem: Music lacks Treble or Bass
When your music system doesn’t sounds good, the issue is the lack of treble or bass in the amplifier.
Cause (a): Inappropriate setting of Equalizer
Solution: The inappropriate setting of equalizer could be the major possibility of treble or bass in amplifier. This could be corrected by the applying correct technicalities by the professionals.
Cause(b): Faulty wires
Solution: This is also a very common issue which can be corrected by changing damaged for faulty wires.
Cause(c): Damages with Tweters and Woofers
Solution: Sometimes there are damages with tweeters and woofers of the amplifiers because of which the music system does not sounds good and lacks treble or bass. This should be corrected by the professionals.
Problem: Humming audio/sound in the amplifiers
Isn’t that annoying, when you aren’t playing any sound still your amplifier is buzzing like a bee. This is not distortion, it’s humming. Humming and distortion are two different concepts. It usually happens with older models.
Causes & Solutions:
(a) Most of the time the humming sound comes from power supply section of amplifier. Generally it comes from Power transformer, main filter condenser in the AC to DC converting circuit.
(b) Humming sound also comes from a faulty pre amplifier section. Pre amplifier stage need to be checked when the pre stage transistor, capacitor is on the coupling circuit.
(c) Sometimes humming sound also originates from defective input source which should be corrected.
Problem: Volume keeps getting too loud
This is a common issue that we all have experienced one’s in a life. It usually happens when we are listening to our favourite songs, watching our favourite movies and all of the sudden the perfect volume gets very loud.
Cause & Solution:
It is because of the fault in Automatic Volume Control Feature. This fault will be corrected by the professional audio engineers by using specified components.