I'm using my Sonos Port basically as a pre-amp, powered by an Acurus A150 2 channel amplifier, and an Adcom GCD-750 CD player. I'm getting really distorted sound.
I've tried taking the Source Level down to 1. I've played around with the EQ. Nothing is working. When I remove the Port and connect it to my volume controller, it sounds perfect.
Any suggestions?
Best answer by GuitarSuperstar
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Excellent. You can note -- or even mark -- the volume position on the passive control, then tuck it away somewhere safe out of sight.
Ok, I see what you are doing now…
Connect from the Port’s analog audio OUT to the left and right inputs on the amplifier. Then connect the CD player from the left and right audio outputs to the Port’s analog audio IN. If you are still getting distortion, try different audio cables. Also try the different Line Out Levels settings for the Port in the Sonos app.
Is your Port set to Fixed or Variable output? The A150 has quite a low input voltage spec and the Port could potentially overload it.
Are you able to test the Port into any other device to verify its outputs are working correctly?
I was curious as to the nominal output level of the CD player’s RCA outputs, to see whether that could explain the behaviour.
Have you tried inserting your ‘ancient’ passive volume control between the CD player and the Port?
Can someone from Sonos chime in here?
Why? Do you think they can offer better advice for this specific problem?
First time here. Saw it on a few threads done the way. Didn't mean to offend.
First time is a good reason/excuse. You will not get better support than what you are getting on this issue from anyone that I know of in Sonos that posts here. It probably won’t even be as good.
One reason why you see some high post counts among some users here is because Sonos is often not to be seen - or seen in time - on many threads here.
One reason why you see some high post counts among some users here is because Sonos is often not to be seen - or seen in time - on many threads here.
Or such users were moderators in an earlier incarnation of this community.
Well, I’m assuming the control is either RCA-in/RCA-out, or it’s combined with an input selector so it’s multiple RCA-in with a single stereo RCA-out. You could post some more info if relevant.
Either way, you’d just connect the CD player to an input and run the control's output into the Port’s Line-In. Set the volume to full, then lower it until (hopefully) the distortion goes away.
Keeping the Port volume control on Variable?
Yes. If successful you’d simply be using the old passive control as a fixed attenuator between the CD player and the Line-In. Normal volume control would be in the Port.
Well, I’m assuming the control is either RCA-in/RCA-out, or it’s combined with an input selector so it’s multiple RCA-in with a single stereo RCA-out. You could post some more info if relevant.
Either way, you’d just connect the CD player to an input and run the control's output into the Port’s Line-In. Set the volume to full, then lower it until (hopefully) the distortion goes away.
Keeping the Port volume control on Variable?
Yes. If successful you’d simply be using the old passive control as a fixed attenuator between the CD player and the Line-In. Normal volume control would be in the Port.
Well by golly it worked! Perhaps it was that 3V versus 2.2V output on the unbalanced that was causing the issue. Thank you so very much!!!
Full should mean zero attenuation and the control is being bypassed, effectively. It is worth a shot at now trying to remove the control leaving the CDP connected directly to the Port with NO other changes. If the distortion comes back, just wire the controller back in.
If things are working fine via either of these routes, and you are getting enough sound levels with the Source level at 1, there is no need to move that around. If you want to play around you will see that as that level is increased, the volume slider level on the Port will have to be reduced a little to get the same sound levels.
Excellent. You can note -- or even mark -- the volume position on the passive control, then tuck it away somewhere safe out of sight.
Maybe a dumb question-it's still best to keep this in Variable, correct? I've read people say that the sound quality is better in Fixed and I'm not sure if this current set up would enable that (or if you believe it really does improve the sound quality)
Fixed would mean that the only way to change volume levels is via the passive controller. Quite inconvenient.
In general if you get the sound levels you desire without having the volume level on a Port in variable mode to be set at less the 50%, sound quality difference from Fixed mode will not be audible.
PS: and yes, as pointed out, for using sources other than the CDP, the Port needs to be in variable mode.
How exactly is the Port connected to the CD player?
How exactly is the Port connected to the CD player?
I'm running analog cables out of the Port, into the amplifier.
I'm running analog cables out of the CD player, into the Port
I think the Port should only be connected to the CD player, not to the amplifier. Connect from the Port’s Digital Out to the CD player’s digital input using a digital audio coaxial cable.
I think the Port should only be connected to the CD player, not to the amplifier. Connect from the Port’s Digital Out to the CD player’s digital input using a digital audio coaxial cable.
If I don't connect the Port to the Amplifier, how will sound get to my in wall speakers? Also, I tried the digital out to digital in and then the Line Out option disappeared from the Music/Browse options.
Can someone from Sonos chime in here?
Can someone from Sonos chime in here?
Why? Do you think they can offer better advice for this specific problem?
Can someone from Sonos chime in here?
Why? Do you think they can offer better advice for this specific problem?
First time here. Saw it on a few threads done the way. Didn't mean to offend.
Is your Port set to Fixed or Variable output? The A150 has quite a low input voltage spec and the Port could potentially overload it.
Are you able to test the Port into any other device to verify its outputs are working correctly?
Thank you for this perspective. I have it on Variable. There's no volume control on the Acurus so I'm not sure how Fixed would work. Would limit the volume to something low versus 100/full?
Now that you mention it, I do have an Onkyo AV receiver that powers 4 in ceiling speakers that I could test it on.
Is your Port set to Fixed or Variable output? The A150 has quite a low input voltage spec and the Port could potentially overload it.
Are you able to test the Port into any other device to verify its outputs are working correctly?
Additionally, when I stream music from Pandora, SiriusXM, or SoundCloud, there's no distortion. It's still being powered by the Acurus (obviously) which makes me think the issue is with the Line In feature.
Okay, so the Port provides volume control. Fair enough.
If other sources are fine through the power amp then the Line-In does indeed sound like it’s the issue. Source Level 1 is the lowest sensitivity, so ought to be fine with any standard line-level signal. I couldn’t readily find a detailed spec for that ancient CD player. You are using the unbalanced RCA outputs I assume?
You could independently test the Port’s Line-In, e.g. using the headphone output from a phone.
Have you tried simply inserting some attenuation in between the CDP and the Port? Either a passive volume control or in-line fixed attenuators?
Okay, so the Port provides volume control. Fair enough.
If other sources are fine through the power amp then the Line-In does indeed sound like it’s the issue. Source Level 1 is the lowest sensitivity, so ought to be fine with any standard line-level signal. I couldn’t readily find a detailed spec for that ancient CD player. You are using the unbalanced RCA outputs I assume?
You could independently test the Port’s Line-In, e.g. using the headphone output from a phone.
Have you tried simply inserting some attenuation in between the CDP and the Port? Either a passive volume control or in-line fixed attenuators?
It's definitely ancient but I've tried other CD players and nothing sounds as good! Yes, using unbalanced RCA outputs. I have the tech specs if there's something that would be helpful. I'm not smart enough to know how it would impact the Port so many thanks again for your help!
I have another ancient piece of equipment which is a passive volume control that can act as a pre-amp. When I hook up the Amplifier and CD player to it, the sound is incredible. BUT, even on "1" it's really loud and obviously no Sonos capability.
Any chance you think it's just a bad unit with a problem in the Line In circuitry?
You could independently test the Port’s Line-In, e.g. using the headphone output from a phone.
Jumping in because I did not see an answer to the quoted. This is an easy way to test the line in circuitry of the Port. Have you done that?
I have another ancient piece of equipment which is a passive volume control that can act as a pre-amp. When I hook up the Amplifier and CD player to it, the sound is incredible. BUT, even on "1" it's really loud and obviously no Sonos capability.
The tech spec for the RCA out of the CDP has two numbers - 3 volts and 6 volts. I don’t know if this means that the minimum is 3; if so that explains to an extent why it goes so loud, but from the little time I spent looking at reviews I did not see this pointed out as an issue by users as one would expect. And I would expect setting Sonos line level to 1 should fix the problem. Unless something is wrong with the Line In, which a test with any phone should throw up.
It looks like 3V is for unbalanced, 6V for balanced. At 3V it could be in danger of clipping on the Port’s ADC, since the Level 1 Line-In spec is 2.2V.
I invited the OP to insert his existing passive volume control into the line, to attenuate the signal and see if that helped.
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