Hello peoples of the internet from a new member! 
I have a problem and hopefully this might be the place where I could get some insights from someone smarter and more experienced then myself in these matters.
If yes; thanks in advance, if not; apologies in advance! 🙂
So, my "old trusty"® Rotel RSX-1562 has lately started having some issues. Not sure exactly how old it is, I bought it second-hand a bit over 3 years ago.
Some minutes after turning on (typically 10-20), some crackling noises start coming out of speakers, and it lasts for a good couple of minutes, then they disappear altogether.
However, noises are most audible when HDMI inputs are used (for some reason), and also most audible from center and rear speakers (I have 5.1 setup and typically use 5ch stereo audio mode). My front mains are 4ohm, all other speakers are 8ohm. Also, when audio is switched to stereo mode the crackling noises seem to down a bit, but again it might be to different impedance of the speakers.
To me it sounds like there's some static building up and then being released. It's typically higher frequencies crackling.
From other inputs (analog, coax or optical) noises are much much more quieter and harder to observe (I had to sit on the floor next to the front speakers waiting for crackling to occur) and I only heard them from HF unit (which means they are above 3kHz).
After RSX has been turned off for at least (cca) 30mins, and then turned back on, the weird sounds will reappear.
So far I've tried different computers via bunch of HDMI cables, no difference. Same issue is from my TV box as it also connects via HDMI. Since there's a 7.5m HDMI cable from my PC to RSX which passes by several other power cables and speaker cables, I thought maybe some static can accumulate in it, but wasn't able to prove it so far.
So now I think that something in RSX produces those noises when heated up. I'm in the process of obtaining a different AVR that I can connect instead of Rotel so I can take Rotel apart and check inside.
Any idea as to what might be culprit for these problems? Something inside the RSX or something completely unrelated? My plan is maybe try to replace some of the power caps?
Sorry for the maybe-not-so-coherent-text and rambling, I wrote it as things kept popping in my mind.
Thanks for any suggestions!
https://www.rotel.com/sites/default/files/rsx1562_guts.png
I have a problem and hopefully this might be the place where I could get some insights from someone smarter and more experienced then myself in these matters.
If yes; thanks in advance, if not; apologies in advance! 🙂
So, my "old trusty"® Rotel RSX-1562 has lately started having some issues. Not sure exactly how old it is, I bought it second-hand a bit over 3 years ago.
Some minutes after turning on (typically 10-20), some crackling noises start coming out of speakers, and it lasts for a good couple of minutes, then they disappear altogether.
However, noises are most audible when HDMI inputs are used (for some reason), and also most audible from center and rear speakers (I have 5.1 setup and typically use 5ch stereo audio mode). My front mains are 4ohm, all other speakers are 8ohm. Also, when audio is switched to stereo mode the crackling noises seem to down a bit, but again it might be to different impedance of the speakers.
To me it sounds like there's some static building up and then being released. It's typically higher frequencies crackling.
From other inputs (analog, coax or optical) noises are much much more quieter and harder to observe (I had to sit on the floor next to the front speakers waiting for crackling to occur) and I only heard them from HF unit (which means they are above 3kHz).
After RSX has been turned off for at least (cca) 30mins, and then turned back on, the weird sounds will reappear.
So far I've tried different computers via bunch of HDMI cables, no difference. Same issue is from my TV box as it also connects via HDMI. Since there's a 7.5m HDMI cable from my PC to RSX which passes by several other power cables and speaker cables, I thought maybe some static can accumulate in it, but wasn't able to prove it so far.
So now I think that something in RSX produces those noises when heated up. I'm in the process of obtaining a different AVR that I can connect instead of Rotel so I can take Rotel apart and check inside.
Any idea as to what might be culprit for these problems? Something inside the RSX or something completely unrelated? My plan is maybe try to replace some of the power caps?
Sorry for the maybe-not-so-coherent-text and rambling, I wrote it as things kept popping in my mind.
Thanks for any suggestions!
https://www.rotel.com/sites/default/files/rsx1562_guts.png
UPDATE: Interesting(?) development - I was planning to switch my front and rear speakers for some testing, and for that I had to change my fronts from Large to Small in the settings (for Rotel this means that Large speakers get full freq spectrum and Small only freq above bass cutout) and immediately after I started getting more louder crackling from the front speakers, and it wasn't only from HF unit.
Now, I don't have any idea what this means. I'll try to get some more tests done tomorrow.
??
Now, I don't have any idea what this means. I'll try to get some more tests done tomorrow.
??
My suggestion is, first you have to isolate 'cracking noise source'. According to Rotel SM it has 7 Class D amp modules.
SL,SR,CB1,CB2 092 ICEPOWER200AC DIGITAL AMP PCB ASSY
FL,FR,C 092 ICEPOWER200ASC DIGITAL AMP PCB ASSY
Please check from the Pre out sockets, refer to above. you can use a head phone but you need RCA male jack wired to a head phone jack since the pre out might be RCA type.
Check all the pre out channels for the cracking noise.
If all the pre out channels are OK and free from noise, identify the noisy speakers and identify the faulty amp modules accordingly.
7x ICEPOWER200AC DIGITAL AMP
If the cracking noise is noticeable in the pre out channels you have to trace back .
Please check the power supply voltages and cracked solder joints, specially dual power supply for analog ICs
Good luck.
SL,SR,CB1,CB2 092 ICEPOWER200AC DIGITAL AMP PCB ASSY
FL,FR,C 092 ICEPOWER200ASC DIGITAL AMP PCB ASSY
Please check from the Pre out sockets, refer to above. you can use a head phone but you need RCA male jack wired to a head phone jack since the pre out might be RCA type.
Check all the pre out channels for the cracking noise.
If all the pre out channels are OK and free from noise, identify the noisy speakers and identify the faulty amp modules accordingly.
7x ICEPOWER200AC DIGITAL AMP
If the cracking noise is noticeable in the pre out channels you have to trace back .
Please check the power supply voltages and cracked solder joints, specially dual power supply for analog ICs
Good luck.
Do the weird sounds show if you use only the build in FM tuner? Try FM in all channel stereo or mono mode and identify the cracking channels. So you keep HDMI and processing out of the way.
Also do the pre out test.
Also do the pre out test.
Thanks guys for great suggestions!
At the moment I'm not using internal tuner, I need to find out the antennas... However, those cracking sounds appear even when I'm listening to other inputs (radio via analog or pc via optical), so I don't think any more they are HDMI related.
I just tried pre-outs, and crackling still persists. Next step is to find/obtain another AVR so I can remove and disassemble this Rotel (I'm unwilling to do so at the moment as all my audio and video devices are connected through it, so removing it would send me back to stone age 😆)
But thanks for suggestions, I really appreciate them!
At the moment I'm not using internal tuner, I need to find out the antennas... However, those cracking sounds appear even when I'm listening to other inputs (radio via analog or pc via optical), so I don't think any more they are HDMI related.
I just tried pre-outs, and crackling still persists. Next step is to find/obtain another AVR so I can remove and disassemble this Rotel (I'm unwilling to do so at the moment as all my audio and video devices are connected through it, so removing it would send me back to stone age 😆)
But thanks for suggestions, I really appreciate them!
Do you know where I can find/download service manual?
I'm just wondering, as the crackling sound changes dramatically when I change speakers from Large to Small, there must be different circuitry involved for those options?
(as I said, when front speakers are set to Large, crackling from them is barely noticeable and comes only from HF unit-tweeter, but when I change them to Small, crackling is far more pronounced and comes mainly from the midtoner. Quite curios why.)
"Large" refers to feeding the speakers the full range of frequencies (no clipping of low frequencies). What speakers do you use? Are they correct?
Are they capable of reproducing frequencies from 63 Hz?
Are they capable of reproducing frequencies from 63 Hz?
Thanks for the comment! I know what it means, and yes, my front speakers are Sonus Faber Sonetto V so they are capable for whole freq range. What is puzzling me, as I said, when front speakers are set to "Large" those crackling noises are quiet and only coming from tweeter unit, however if I change speakers to "Small" then crackling is far more pronounced and coming from midrange unit. That part is confusing me.
I believe you're referencing the "Clicking or popping sounds when switching inputs" from the OM? If so, this is not the problem, as in my case those noises appear when playing from any input, without switching or anything. And it's definitely not the mechanical relay noises.
Thanks!
Thanks!
You can set your AVR in a "direct mode". Feed an analog signal, like to the analog CD or an aux input and check for noise. So you can isolate the problem to a one certain stage of the whole unit.
Same does connecting a separate amp to the pre out's.
Opening up the Rotel will only show you a whole lot of components. Very unusual to see anything "brocken" with such a fault. You may, after leaving it without voltage for an hour or two, blow dust away and then move any connector you see.
A small chance may be using an ice spray for electronics. While having the AVR connected and the noise appearing, spray a little at suspected parts, if it stops or get's louder, you may have found it.
Even if you find a problematic part, are you able to change it? Do you have tools like an SMD work station?
The only thing you may be able to repair is to change the whole ICE amp section, if it is the problem. What you don't know by now.
Any thing else will be a thing of the service, if such a pink unicorn exists in your country. Best to sell it on eBay and get something new. May be time for an upgrade anyhow.
PS if it is the amp section, you may remove it and use it with external amps
Same does connecting a separate amp to the pre out's.
Opening up the Rotel will only show you a whole lot of components. Very unusual to see anything "brocken" with such a fault. You may, after leaving it without voltage for an hour or two, blow dust away and then move any connector you see.
A small chance may be using an ice spray for electronics. While having the AVR connected and the noise appearing, spray a little at suspected parts, if it stops or get's louder, you may have found it.
Even if you find a problematic part, are you able to change it? Do you have tools like an SMD work station?
The only thing you may be able to repair is to change the whole ICE amp section, if it is the problem. What you don't know by now.
Any thing else will be a thing of the service, if such a pink unicorn exists in your country. Best to sell it on eBay and get something new. May be time for an upgrade anyhow.
PS if it is the amp section, you may remove it and use it with external amps
I'll bet that that unit has the anchoring glue that I previously spoke of.
It's visible and easy to spot, being brown or black in color.
Used mainly around the power supply to anchor the large filter capacitors, it's also noticed around other areas, and I've seen it over resistors and transistors due to splashover on the PC boards.
Putting a DVM's probes into the glue, it gives a reading of continuity on the meter, interfering with the actual proper values of said resistors, and the junctions of transistors.
Also, if in contact with resistor leads, I've seen it corrode them, requiring new resistors, and a tedious removal of scraping that nasty glue off the PC boards.
With that stated, those compromised components will effect their associated circuitry, causing corrupt operation of IC chips, and in some cases even shutting down or causing noises to appear in signals.
Look inside with good lighting, and if you see any of that adhesive at all, get rid of that unit.
Technicians like me don't want to deal with that issue.
Thanks for another great suggestion!
I've just tried analog IN in bypass mode, and I can't hear any crackling. But as soon as I change audio mode to any other, crackling just explodes (like a kid hiding around a corner to scare someone). Going back to bypass crackling immediately stops.
Not sure yet what this new pieces of information mean, but it's definitely interesting and beneficial.
EDIT: different behaviour then when I tried using pre-outs, on them I still hear crackling.
EDIT 2: Just as soon as clicked "Send" craclking seemed to be back, very quietly (quietest I've heard so far). Although at this moment maybe it's just my mind playing tricks on me. 😕 I only heard it for a couple of seconds and they were gone.
Regarding repairs, I'm definitely handy enough unless it's SMD, for that I do not have any equipment. There are some smaller repair shops in the area that might be able to help with that, if I'm certain enough to have isolated the issue.
I'm not gonna sell malfunctioning equipment, makes no sense. Definitely not gonna sell it as "fully functioning", and getting a couple of € for a defective item also isn't gonna help. I'll continue playing with it or "fix it till it's broken", whichever comes first. 😆
Buying new one is an easy way out, and the least interesting. 🙂
Last edited:
Thanks, I'll be sure for check for those nasty glueing spots as soon as I open it up! 👍
I just want to reiterate once again, the crackling noises eventually "deflate", meaning whatever the mode or settings used, crackling is heard for up to 15minutes, and then it practically disappears (afterwards only a single crack can be heard every once in a while, maybe 1x hour).
Is this still true? If yes the problem is with the digital and DSP section. This is highly integrated and all SMD.
There is nothing negative about selling defective gear at eBay, if you exactly describe the fault. People buying such articles know what they get. They may have a second unit with another fault. As this one got a working ICE 7-channel amp, it will fetch quite some $ defective. Depends largely on the information you give in the sales text.
From a lot of personal experience I have learned not to have 10 year or older electronics repaired. In most cases you pay about 1/2 the used value of a product and have it fail one year later at another part.
Maybe get an ice spray and try it on the large PCB that you see on top. Picture from Rotel.com
Attachments
I meant the possible oxidation of the relay contacts that switch the inputs 🙂 Try to lightly tap on the relay housings, connectors, along the edges of the boards (not on parts).
We can rule that out, as the noise is heard from the amp and the pre-amp as well. Also, noise seems to disapear when the DSP is taken out of the chain.
The large DSP chips can evolve problems, as there are countless soldering points between them and the PCB that may fail over time.
The large DSP chips can evolve problems, as there are countless soldering points between them and the PCB that may fail over time.
I did another test today, just turned the device on on a unused analog input (nothing connected to it). And 20min on the clock, the crackling started. As soon as I switched to bypass, crackling goes away.
So thanks @Turbowatch2 for identifying the problem, apparently it's DSP fault, and the amp is still OK.
I think I'll continue using it for now as is, and see whether crackling will get louder over time (now I turn it on radio in bypass mode and keep it running for an hour before I actually "need" to use it, by then the crackling is deflated and it's not annoying and won't hurt the speakers), and start looking for a replacement, as I personally cannot repair anything in the SMD size. Maybe I'll run it with a couple of repair shops to see their quotes for repair.
Thank you all who participated with their great insights and suggestions!