Just got me a Crown XLS 602 used at a price I couldn't resist, sounds great but when hooked up to the laptop which is 90% of my music, picks up lots of noise. I know the noise comes from the crappy laptop PS, but I don't get any noise with any other amp or any other combination amp/preamp other than with the Crown. I've used other Crowns in the past with no issues. Grounding everything and using different outlets doesn't help, also tried different DAC's.
Replace the laptop for a good quality audio player. Noise solved and better sound quality at the same time.
I take when devices have 3 pin PE plugs/IEC sockets you put them in a PE wall socket?! That would be the first to check.
I take when devices have 3 pin PE plugs/IEC sockets you put them in a PE wall socket?! That would be the first to check.
Check the earthing, case to cord end in plug....and RCA shield to ground.
Check for corrosion at wire end to body also
Check for corrosion at wire end to body also
Transformer isolation is not the best sound but it will prove the point if it's a ground
loop for little money.
https://www.amazon.com/Conext-Link-...ocphy=9031046&hvtargid=pla-972919473064&psc=1
I use one of these for very low performance computer speakers where the transformer
doesn't matter.
IF this cleans up the noise issue, then you can build an active interface that DOES sound
good. INA134 or SSM2141 balance line receiver are exceptional. You CAN use a good
opamp with matched resistors but you're not likely to exceed the perfomance of these
laser trimmed amps.
Yes you can use a balanced line receiver with unbalanced audio. The '-' inputs are connected
to source signal ground while the '+' inputs get signal. Any differential signals between the
source and destination grounds get subtracted out. I use one of these for the GOOD system.
There are commercial products that use this technique. You can't use 'bigger wire' for ground
because whatever you use, you cannot get to zero ohms so cancellation is the only option.
G²
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if you run the laptop on PS and keep the PS plugged in but turned off at the wall, does the noise go ? yes =PS hash no = ground loop
if you pull the PS out and run off the battery does the noise go? yes = problem solved
can you just run off battery?
do your DACs have TOSLINK SPDIF in?
do you have a USB to TOSLINK
whats your budget for a fix?
https://www.ebay.com/sch/i.html?_fr...ink+xmos+xu208&_osacat=0&_sop=15&LH_PrefLoc=2
Removing the power supply from the laptop running it on it's battery= dead quiet.
If I could find a regulated or "noise free PS" but at 19v, not easy to find, also none of my other amps have this problem.
- that doesnt rule out a ground loop
- so it may not be the PS
- you ask for help and then ignore advice on both problem solving and solutions so the main problem isnt your system
What advice am I ignoring? I've had so far about ten or more advices since I posted this today, I truly appreciate them all but I'm not about to run just yet spend money blindly every time someone suggests something, again the advice is very much appreciated but I think I should start with the basics first and if you read my posting, it is just ONE out of many amps giving me this problem.
So far, connecting everything to the same outlet doesn't fix the noise, different outlets no change, same ground, different ground, no change, unplug the PS, dead quiet. Just a few minutes ago I borrowed a laptop, plugged it in and dead quiet with its own typical switching PS.
Maybe some posts arent worded well or you missed reading some posts above? Everything you need is already here.
Clearly:
Your laptop SMPS has a non existent or broken earthing wire, or the wire to the laptop is not shielded, happens a lot with replacement bricks.
Check that first.
If you can, try with another supply.
And do check the earthing in your wall.
If you can, check with headphones, and then plug into an outlet with a known good earth.
Tell us what happens.
Your laptop SMPS has a non existent or broken earthing wire, or the wire to the laptop is not shielded, happens a lot with replacement bricks.
Check that first.
If you can, try with another supply.
And do check the earthing in your wall.
If you can, check with headphones, and then plug into an outlet with a known good earth.
Tell us what happens.
Good answer. It could be the power supply, but it could also be a number of other things in the laptop that activate when it is plugged to the power supply: the battery charger, perhaps the CPU switching to a more aggressive power profile, etc.
To discriminate, you can:
- Use a bench power supply instead of the official charger, for testing
- Remove the battery (if there is still noise, then it's not the battery charger circuit)
- Set the CPU power management profile to the same whether it's running on mains or battery
Then grab a cheapo 3.5mm jack to RCA cable, the same you use to connect the laptop to your hifi. Hack the cable so:
- both signal wires from the laptop are cut
- both signal wires going into the hifi connected to ground.
If you still got noise with bots input channels and ground on the hifi connected to laptop ground, then the noise is not in the laptop's output signal, rather it is a common mode noise problem with the power supply. If the noise disappears, then it is not common mode, but voltage noise on the laptop's power rail finding its way into the output.
Don't have a bench PS but did try removing battery and the wires trick connected to laptop ground and still noise, actually, any movement on the screen increases the sound, from opening a new window to moving the mouse around, of course with the PS plugged in.
Not sure exactly how to set this one...
- "Set the CPU power management profile to the same whether it's running on mains or battery"
I'm not going to beat myself on this, but the thing that puzzles me is how this one particular amp picks up the noise when the other amps don't.