Crackle sound from amplifier

A K Bhattacharjee

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I own a Philips 900 series, FA 930 integrated amplifier. I observe that a crackle sound developes whenever I want to use the amplifier. It happens in all the options, i.e in tape, cd, phono etc. The sound is so loud sometimes, it makes me worried for my speakers.This peculiar phenomenon remains for a quite long time. After that it becomes normal. I have shown it to some of my known technicians but without any result. Can any fm suggest any solution?
 
Is it only from one channel...
Is there any crackling even when fully muted...
Does it goes up when you turn up the volume?



Is this the model you are referring to?

philips_900_series_integrated_stereo_control_hifi_amplifier_fa_930_10471856.jpg
 
Last edited:
Is it only from one channel...
Is there any crackling even when fully muted...
Does it goes up when you turn up the volume?



Is this the model you are referring to?

philips_900_series_integrated_stereo_control_hifi_amplifier_fa_930_10471856.jpg
Yes, this is the model. You are right it goes up with the volume. No crackling when it is muted. The sound is mainly from left channel.
 
Service the amp....it could be the volume pod issues or some caps on the board are nearing end of life and hence this challenge....this is indeed a good amp!
 
It could be attributed to following reasons :

1. Moisture in the PCBs : One of friends also suffers from similar thing in his Sansui AU317. It goes away randomly and comes back on it's own will.
A senior technician told him it's due to moisture in PCB. It has corroded some miniscule joint or copper paths. It is suggested that if possible you
give a very through look over at boards in amp. Specially Power amp section. Look for some cracked or dry solder.

2. It could be oxidized contact issue. You may use contact cleaners like Deoxit at places like soruce selector switch, speaker selections switches.

3. You may look for swollen or burst capacitors on the diff. PCBs, specially in power supply, preamp and power amp section.

Hope this helps
 
From my experience if the "death" crackle or what we call, static appears, its not an easy fix and can be due to several reasons, starting from faulty cabling to oxidized input, speaker terminals to noisy pots and switches, capacitors, dry solder, breaks in wiring, PCB problems and failing semiconductors. From this list itself, it is evident that there is not a single cause of this issue and troubleshooting has to be done in sequence using the elimination method. The source of the static has to be identified, isolated and then rectified. Honestly for someone who does not know the inside, only superficial checks like input and speaker wiring, etc are possible. Only a skilled tech or experienced tech will be able to fix these problems. Sometime ago, I came across this challenge with a vintage Sony amplifier. It took nearly a month to find out what the issue was, in this case it was a faulty silicon transistor.
 
I had the exact same problem a few years back. Was a leaky capacitor and dry solder. Easy fix with a qualified technician:)
 
My amp still suffers with this issue intermittently despite multiple check ups by a tech guy. The left channel crackles loudly irrespective of the volume knob position. I am sure its not the volume pot. It's definitely related to the electronics. Goes away itself. This is happening for more than 3 years now. :(
 
Almost after 8 months, one of my known techs started searching the culprit. After two days of marathon search he noticed that the analog switch/selector ic (LC 7821)is the reason of noise. But the ic is not available in the local market. I request the fellow members to help me in getting the ic.
 
Congrats at least you know which part is causing the issue. Possibly the electronics market (spare parts) may have this. Have you checked online?

It would help to post a pic of the part if some FM can source it for you
 
Hi all, I have a Sansui AU 317 amplifier and I am experiencing almost similar problem of "Crackle sound". But in my case it is from Right Channel only when Phono input is selected. With other inputs like Tuner & Aux, both channels are working fine, no such "crackle" sound. Can any one suggest what could be the problem.
 
Hi all, I have a Sansui AU 317 amplifier and I am experiencing almost similar problem of "Crackle sound". But in my case it is from Right Channel only when Phono input is selected. With other inputs like Tuner & Aux, both channels are working fine, no such "crackle" sound. Can any one suggest what could be the problem.
It is the pre amp section which is creating the problem. Just check.
 
Hi all, I have a Sansui AU 317 amplifier and I am experiencing almost similar problem of "Crackle sound". But in my case it is from Right Channel only when Phono input is selected. With other inputs like Tuner & Aux, both channels are working fine, no such "crackle" sound. Can any one suggest what could be the problem.

If you unplug your turntable from the amplifier and still hear the crackles while the phono input is selected, its got to be the phonostage chain (from the phono sockets, right through to the output of the phonostage. If your amplifier is silent with the phono input selected, but without the turntable plugged in to the phono input, then you'd have to check your tonearm circuit from the cartridge pins to the phono plugs. Trying a cart mounted to a different headshell can help confirm that the cart is ok. If its the amplifier, then start with cleaning the phono jacks, check for dry solder and broken wiring, faulty electrolytic caps and even in some rare cases, a faulty semiconductor. All the very best.
 
I too had the same problem,went off after keeping the amp under direct sunlight for 1/2 hr.Advice was given by a very old man Who repairs vintage amps.The sound slowly disappeared.
 
If you unplug your turntable from the amplifier and still hear the crackles while the phono input is selected, its got to be the phonostage chain (from the phono sockets, right through to the output of the phonostage. If your amplifier is silent with the phono input selected, but without the turntable plugged in to the phono input, then you'd have to check your tonearm circuit from the cartridge pins to the phono plugs. Trying a cart mounted to a different headshell can help confirm that the cart is ok. If its the amplifier, then start with cleaning the phono jacks, check for dry solder and broken wiring, faulty electrolytic caps and even in some rare cases, a faulty semiconductor. All the very best.
I have tested by unplugging the TT and it stil gives the crackle sound. So, I too think it is in Phono Section only. The TT is Ok as I tested by interchanging the inputs and found it is not giving the crackle sound. Anyway, thank u so much for your valuable suggestion.
 
If its the phonostage, start with checking the phono sockets, the wiring, selector switch (if the amp has push button selector switches, this can be a key suspect), then the wiring, capacitors and check for dry solder. If all this is ok, you may need to check the transistors.
 
If its the phonostage, start with checking the phono sockets, the wiring, selector switch (if the amp has push button selector switches, this can be a key suspect), then the wiring, capacitors and check for dry solder. If all this is ok, you may need to check the transistors.
Thank u for ur suggestion, will check all those.
 
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