cambridge audio 540 optical prob

Parthian Shot

Active Member
hi all
i can t get the amp to play sound when using the dvd button(optical) on the amp i have set the input to opt/coax in the osd i have set dvd to digital my dvd is a panasonic dr es-10 the only way i can play sound from my dvd is by using 2 phono leads out of dvd into the amp and using the video 1 button
any ideas
ps when i press the dvd button on the amp it says unlock?


Well-known Member
What have you set the DVD player itself to output to? I don't know that particular DVD player - but if it has the option to output via PCM or bitstream, try setting it to bitstream


Adam Shaw

Active Member
UNLOCK will appear in the display of the AV receivers if they are not receiving a signal over the selected digital inputs. This can be for a number of reasons;
1) There is no digital connection into that input.
2) The digital input has not been assigned to the source. The optical and coaxial inputs have default locations that may differ from the source you are trying to use. They can be reassigned to the input you want via the onscreen menu's.
3) There is a connection but the amp is not looking at the correct input type- ie the amp is looking for a coaxial connection when the actual connection is optical. This can be changed using the INPUT MODE function.
4) The bitrate is too high for the amps. This applies with particular regard to DVD/A and SACD where even if the signal is not physically blocked from the digital outputs, it will be too high a bitrate to decode. Signals should be 96K or less. If the source machine is outputting a signal higher than 96k, you will need to adjust this in the setup of the machine you are connecting to your AV reciever. Ideally, digital signals should be transmitted to the reciever as RAW format (rather than PCM).


Standard Member
I've just bought a 540 V2 and I'm having exactly the same problem as the OP.
I have a Samsung V330 (dvd recorder/VCR combo) and I've set the audio output to bitstream, the output is 48k, and I've tried a coaxial and optical connection to the DVD input on the amp. I can a phono signal through on the dvd phono input when the input is on analogue but nothing when I switch the input to digital.

Can anyone help?

(I know the speaker output is set up correctly as I'm getting 5.1 from tmy sky+ box)


Standard Member
Hi Adam

I'm getting unlock in the display.

(I can get sound the the analogue connection but when I try the coaxial or optical I get unlock)

Adam Shaw

Active Member
Ok, If you were getting UNLOCK on optical, but not coaxial, then this would imply a faulty optical cable, but to get this on both means that the unit is not recieving a digital signal at all.

Does it make any difference if you use a different inout on the amp, and can you test this with any other digital sources, such as a DVD player, PS2, etc..

Finally, does it make any difference if you (take a note of your settings and then) reset the amp via the reste hope on the rear panel?


Standard Member
I've got an old dvd player that I was going to try and hook up later when the kids aren't around although as you suggest, my suspicion is that the dvd isn't sending the digital signal even though I've altered the setting to bitsream. What is strange (to me, but as I'm a realtive newby to all this it may not be) is that even when I changed the dvd audio output to bitstream from PCM, it's still sending an analogue signal as the amp still recognises the phono inputs.

As I said before, the sky+ 5.1 is working fine so I'll try that through the dvd input to make sure that's ok and I'll try the other dvd and or my xbox 360 to see what's happening.

Thanks for your help so far.

(I'll try the reset option depending on what happens.)


Standard Member

I tried another DVD player and it worked fine. The good news is I bought the other DVD on 3/1/07 so it's still under warranty (which will make things easier) so I can take it in tomorrow.

Thanks again.


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