Question Crackling marantz SR5008 - who’s better than my Shop?

Olivier816

Novice Member
Hi,

I was hoping one of the many gurus out here could solve what my local hifi shop and Marantz couldn’t:

The problem:
  • The first 2 years of my marantz sr5008 were perfectly smooth, no issues to report. Out of the blue, it started to make a crackling noise, initially it was just a small crack ever 15 minutes or so, then, a few days later it became a continuous crackling
  • I returned the amp to marantz under warranty, when it came back it was on for 6 months (of moderate use, maybe 5-10h/ week), then the noise came back with exactly the same pattern
  • Since then, the amp has been 2 times to the local store and 2 times to marantz, where none of them found anything that needed fixing !! Either the receiver didn’t show the same symptoms there, or they have a reason not to help me


The noise:
  • Is a crackling noise
  • gradually increases (over a few minutes), until reaching a stable, annoying level. Impossible to listen to anything
  • Noise is on all channels
  • Noise in not volume dependent
  • Noise is not input dependent; once the noise is there, it continues even if all inputs are disconnected
  • When, while the amp is on, I push against the back panel or its connectors, the noise changes and sometimes even stops. When I release the pressure, the noise comes back
  • If I turn the amp off and unplug it for a longer period (hours or days), the noise doesn’t come back right at startup but only after 10-20 minutes


Hypothesis and Troubleshooting attempts:
  • initially I thought about a solder issue, because the noise disappears when a lot of pressure is applied to the back of the casing. But this was debunked by the local store, all screws are tight and no soldering issue found
  • Then I hunted for ground loops, but some of the tricks found online (same power outlet, no grounding,...) but they didn’t help
  • Then I thought about dirty power (the house is quite old) and tries my setup in a different house. The noise still appeared
  • Then I thought about input cables, I replaced the power cable and hdmi cables (I assumed that the speaker cables and the optical ones can’t cause such issue)
  • One item I can’t really test but may be a culprit is the human factor, ie myself, as I often hot swap / plug / unplug cables, incl hdmi

I’m pretty much out of ideas, who has an idea about what is going on and how I can fix it? (Other than throwing the amp away ;-)

Big thanks for any advice!



Set-up:
  • Receiver: marantz sr5008
  • Speaker configuration: 5.1
  • Speakers: 2 b&w 603, 1 LRC60, 2 M1
  • Subwoofer: AS1, powered, connected via subwoofer cable
  • Inputs: 2 hdmi (HTPC, PS4), 2 optical (Sonos, PS4), FM antenna, Ethernet
  • Output: hdmi out to a beamer
  • Other: except the subwoofer, all appliances are connected to the same power socket, none of the devices are grounded
 

dobrykamil

Well-known Member
Set amp to Direct mode, use CD analogue input and let me know if your amp still makes crackling noise.
 

Olivier816

Novice Member
I left the amp unplugged during the night, then connected a DVD player via optical cable (no hdmi) and put the amp in pure direct mode.
I took a few minutes, but then the crackling noise progressively came back, ramping up to continuous noise after 20min.
 

dobrykamil

Well-known Member
No mate, I want you to use RCA input like CD. We need to find out, which part of your amp this noise is coming from.Digital or analog?
 

Olivier816

Novice Member
Ok - got it!
I don’t have an analog cable handy, will now look for one and give you an update.

Yesterday I tried the amp with no input whatsoever and the crackling noise was still there. (Only power and 2 speaker cables were connected).

I’m wondering whether there is a ‘rogue’ charging of a capacitor. Could that explain why the noise comes progressively and also stays on for quite some time even after all connections are removed?
 

Olivier816

Novice Member
Update: I connected a DVD player via RCA (audio only, no video) and the noise was still there.
The crackling seems to be input independent at this stage, even when when I connect no input and turn the amp on, the crackling noise appears after a few minutes.

Any ideas on what I can do?
 

ChuckMountain

Distinguished Member
Hypothesis and Troubleshooting attempts:
  • initially I thought about a solder issue, because the noise disappears when a lot of pressure is applied to the back of the casing. But this was debunked by the local store, all screws are tight and no soldering issue found
Did they reflow all the solder joints as often a visual inspection will not be enough to identify the offending joint(s)?

It sounds like the amp is getting up to a given temperature and this is causing something at this point to occur. Usually with heat it is an expansion issue and then a contact issue either solder or loose connection.

  • Then I thought about dirty power (the house is quite old) and tries my setup in a different house. The noise still appeared
  • Then I thought about input cables, I replaced the power cable and hdmi cables (I assumed that the speaker cables and the optical ones can’t cause such issue)
Did you try your speaker cables at the other house. While unlikely it is a common factor and should be ruled out.

  • One item I can’t really test but may be a culprit is the human factor, ie myself, as I often hot swap / plug / unplug cables, incl hdmi

Hot-swapping is known to be bad for HDMI (even though it is supposedly supported and plenty of people do it). If this has caused a board to go bad then usually it is a replacement board and that can be cost-prohibitive.

Why can the shop\Marantz not reproduce?

Are you listening to it at particularly loud volumes?
Is your room hotter than theirs? Have you tried it with the amp in a garage\outside to see if it is a temperature threshold issue?
 

Olivier816

Novice Member
Some more infos:

- I do not how exactly they tested the soldering; my assumption would be that it was a visual inspection

- speaker cables: I kept the same cables in all experiments. They are not running parallel to a power line and do not have loops. The cracklings noise comes on all speakers. What fault where you having in mind ? Is it at all possible that one ‘bad’ speaker cable damages an amp so much that all channels get affected?

- hdmi hot swaps: yes, I could imagine that the hdmi board got damaged. It is however weird that the shop didn’t get the crackling in that case.

- temperature is an interesting one. That would explain the gradual noise build up. Room temperature at home is somewhat higher than normal due to dissipation of nearby devices (Beamer, PlayStation, PC) but should definitely stay in ‘standard operating range’, let’s say 25 degrees Celsius. In the other house, there were maybe 20 Celsius when crackling came back and the amp was free standing with plenty of ventilation. I have never tried in really cold conditions; I’ll try the basement, should be 10-ish.

- I have no idea why neither the shop nor marantz could replicate the issue. I went twice to each and stayed there for nearly 6 months. The only idea that could give me was to check the subwoofer, that something is electrically wrong with it and the subcable would mess the amp up.

Now that I think about it, when it came back from the shop, the amp has worked properly for about 2 weeks non stops, time during which it only was connected to 2 speakers and an optical source. Then I connected hdmi and sub and a few days laters the crackling was back. Could be a coincidence or not
 

ChuckMountain

Distinguished Member
So temperature related, I am not saying it is outside a normal range just there is a fault that occurs when a particular part of the hits a certain temperature.

Let's for argument's sake say this is when a faulty board\solder joint gets to 35C, this might only occur in your house when you are running all 5 speakers. That joint might get to say 38C in your house because your ambient temperature is 25C, yet in the workshop, as they are running different speakers and maybe only a pair it only gets to 34C, then the fault is not going to occur. This is just a hypothesis but might explain the issue.

As you say try the basement where it is cooler, start off with two speakers, before connecting the others, leave the sub out for a bit to eliminate that.
 

Al83

Member
Hello there, I may be a bit late to the party, but hopefully, this will help some people.
English isn't my mother tongue, so please excuse my insufficient English skills.

I had the same problem like you, but get managed to repair my sr5008. I had crackling noises, high frequent tones and sometimes no signal at all. So I brought it to a repair shop, but I'm sure all they did, was spray some contact spray on the connectors. Everything was ok for 2 month, that costed me 25 euros.

You can remove the speaker connectors at the back with a bit more force. Then you'll see that the contacts are tiny, it's note even a square millimeter. I guess corrosion is the problem, not much to fix here, you can try to clean it, but that won't last long.

I opened the receiver and disassembled the "3d" build pcb. Almost 50 screws later (you have to remove almost every screw on the back side, I printed a schematic and placed the screws on it to remember.. ), I realized that there's no chance for me to replace a relay or clean the contacts inside because that would require a complete desolder of those pcbs. So I cutted 16(or 12? For every speaker connection) wires, each about 10cm long and soldered them on the bottom of the pcb where the relays are soldered on. It's just a bypass, let the wires go outside and put them in the speaker connectors with the speaker cable.

This fixed it for me, don't be scared of disassembling it.

Stay safe, kind regards
Al83

Edit 1: 1 typo, but there may be more.
Edit 2: added information about shop
 
Last edited:

KCML

Novice Member
Hello there, I may be a bit late to the party, but hopefully, this will help some people.
English isn't my mother tongue, so please excuse my insufficient English skills.

I had the same problem like you, but get managed to repair my sr5008. I had crackling noises, high frequent tones and sometimes no signal at all. So I brought it to a repair shop, but I'm sure all they did, was spray some contact spray on the connectors. Everything was ok for 2 month, that costed me 25 euros.

You can remove the speaker connectors at the back with a bit more force. Then you'll see that the contacts are tiny, it's note even a square millimeter. I guess corrosion is the problem, not much to fix here, you can try to clean it, but that won't last long.

I opened the receiver and disassembled the "3d" build pcb. Almost 50 screws later (you have to remove almost every screw on the back side, I printed a schematic and placed the screws on it to remember.. ), I realized that there's no chance for me to replace a relay or clean the contacts inside because that would require a complete desolder of those pcbs. So I cutted 16(or 12? For every speaker connection) wires, each about 10cm long and soldered them on the bottom of the pcb where the relays are soldered on. It's just a bypass, let the wires go outside and put them in the speaker connectors with the speaker cable.

This fixed it for me, don't be scared of disassembling it.

Stay safe, kind regards
Al83

Edit 1: 1 typo, but there may be more.
Edit 2: added information about shop
Hello Al83,

Thank you for sharing your story.

I have the same issue. First I thought it was the input and changed it and the issue was gone but after a while it came back. When it begins and you pull at the speaker cable it stops.

Can you explain in a bit more in detail how to make the bypass. See the attached photo.

Kind regards

Jurgen Termeer

p.s. Not 16 nor 12 wires.. It's 14 ;-)
 

Attachments

  • IMG_2450.jpeg
    IMG_2450.jpeg
    600 KB · Views: 29

The latest video from AVForums

AVForums Movies Podcast: Which is the best decade for horror movies?
Subscribe to our YouTube channel

Full fat HDMI teeshirts

Support AVForums with Patreon

Top Bottom