What am I doing wrong with hookup of Naim N-Sub

11.2.1 n-SUB InputsThen-SUBprovides one mono and one stereo line level input onRCA Phono sockets along with one stereo set of "speaker-level"4mm input sockets.The mono line level input should be used for AV systems wherean AV processor provides a mono sub-woofer (LFE) output.The stereo line level input should be used when only an auxiliarystereo output is available from, for example, a preamplifier. Thestereo channels are combined to mono within the n-SUB.Noteo not use an amplifier "tape output" to connect to Input2. The volume level from tape outputs does not vary with volumecontrol position

Have you tried powering down the n sub and back on again ?

Have you selected the correct input on the sub's front panel input selection? What have you set as crossover and level parameters?

As Richard said above. Plus, if bought second hand, check that it's inputs are not 'locked' from the previous owner. Also, does the sub make a pop noise when turned on? If not, it may have an amp issue.

.....and make sure you haven’t accidentally hit the mute button!

The stereo line level input should be used when only an auxiliary stereo output is available from, for example, a preamplifier.

Does this mean only one of the N-Sub RCA cables should be plugged in since not using av. Getting sound if i plug in white rca cable into sub in on bottom panel and not plugging in red cable?

You should be connecting both cables into the two RCA stereo inputs. Alternatively, try the high level input from your speakers, which can, subjectively, sound better. 

If you're taking a pre-out signal from the pre-amp (552PS) then a stereo sub lead and stereo connection is what you want. 

LFE .1 AV is a different connection, different input, and different lead - just a single RCA to RCA.

So, are you saying that you it works fine when the left (white) plug is connected but when you plug in the right one (red), signal is lost??  You are definitely connecting into the correct RCAs? - there are quite a few very close together.

Have you read the manual? You need to select the correct input. You need a pair of stereo leads - if you use only one you will only get bass from one channel.

You use the ch 1 and ch2 inputs, and select the input using the ‘input’ button on the front panel.

No sound when plug into channel 1 and channel 2 above as described. White lead into channel 1 and red into channel 2.

Can you also verify bottom left hand din on 552 PS to plug cable into at PS stage if facing 552PS from front? There are 4 of them in total two on top two on bottom along with cord to power 552 from 552PS.

I think you may be using the wrong output on the 552PS, shouldn’t it be the additional signal output DIN on the top row? (If you have a NAP500, that should be using both of the two bottom DIN output sockets, so I’m not sure how you have one of these spare?)

There should be no difference whichever of the three stereo pre-outs you use.  If you've tried or checked all of the suggestions above then it's beginning to look like the n-Sub may need checking over.

It may also be worth checking out how the din plug is wired up. The two channels need to be connected to the ‘out’ connections on the 552PS. I suspect you may be using a phono to din lead, rather than din to phono. The back of the 552PS should show which are the output pins, otherwise it’s in the manual. A few minutes with a soldering iron will then fix it. This presupposes that you have chosen the correct input via the nSub’s front panel. 

Nigel, it's a Naim subwoofer cable (if I read the opening post correctly), so unless it has been modified in some way it should be correct, and should also have the correct 100R loading resistor fitted as well.

You’re right. In that case it’s either the correct input is not selected, the nSub volume is set to nil, muted via the remote, the crossover frequency is too low, or the nSub is broken. 

If I’m reading this corre tly, the N-Sub hasn’t yet uttered a sound. Try disconnecting the input cables, and, with the sub powered up, using a metal object held in the hand (short length of stiff uninsulated wire, screwdriver shaft etc) touch the inner contact of the RCA Ch1 input:  start with sub’s volume (gain) fairly low, but if nothing increase it. You’re listening for a prominent  hum every time you touch it. If nothing try Ch 2, and ‘sub in’, and then each of the red speaker level input sockets (with the latter the hum would be a lot quieter, and may need turning right up to hear).

if nothing on any, then your problem is the sub, whether not working, or muted in some way not obvious to you. If you do get the hum, and it goes faitly loud turning up volume, then that particular input is working, which then points either to your connection with preamp, or if the wrong input, the settings of the N-sub.

..... or get any old cheap speaker cable and see if the high level input works. Some find this to have slightly better sound quality than the low level connection you are currently trying to use.