Resistance was futile - 552 arriving soon!

kevin J Carden posted:

Thanks HH. I have to say that contrary to Laxton's first 10 seconds, my initial response was more 'OMG that's awful' ! Tinny, flat, colourless, stuck in the speakers. 1 hour later it was starting to bloom and I think just needs to warm, as do the NDS and 500 which have been unplugged for 4days. I'm off to bed soon and hoping to wake up to a different sound!

Hi Kevin, don't worry about it as the run in process can vary from unit to unit. I had a similar bad run in experience of my 300 DR upgrade that didn't mirror others' experience but it all turned out well.

You may want to check that the transit screws are all removed, the unit is sited on a level shelf, the snaic coiled around the burndy cable, powerline fully plugged in, etc.

Guess what?

It sounds a bit, er.. different 24hours on! 

Frequency extremes (both ends) took a while to settle and I think probably have some improvement still to come, but transformed from a day ago. Colourless couldn't be further from the right description now. If anything, if I were criticising it now I'd say it's a tad too sweet and smooth sounding. I'm sure it will be different again tomorrow, next week and next month. 

Question:

I have the head unit sitting on a Hutter Rack and I notice that it won't sit perfectly on all 4 feet and can be rocked very slightly if I press top left and bottom right of upper panel. Tiny amount of travel, I reckon much less than half a mm, but it won't sit on all 4 feet. Checking now the NDS, it's exactly the same - not sitting on all 4 feet, so either the Hutter shelves are both slightly warped or the feet aren't quite exactly level.

=> Does this matter and if so, any suggestions of what to do to remedy?

When I first got my 552..the transit screws had loosened during freight and the brass plate had come off its pin suspension. ..it actually sounded worse than the 52 that way. ..You DID remove the transit screws. ..didn't you? 

Hi Ron. I did Sir!

Ron, How did you find out that the brass plates had come off its pins ? Did you have to send it back, or did you look inside?

kevin J Carden posted:

Guess what?

It sounds a bit, er.. different 24hours on! 

Frequency extremes (both ends) took a while to settle and I think probably have some improvement still to come, but transformed from a day ago. Colourless couldn't be further from the right description now. If anything, if I were criticising it now I'd say it's a tad too sweet and smooth sounding. I'm sure it will be different again tomorrow, next week and next month. 

Question:

I have the head unit sitting on a Hutter Rack and I notice that it won't sit perfectly on all 4 feet and can be rocked very slightly if I press top left and bottom right of upper panel. Tiny amount of travel, I reckon much less than half a mm, but it won't sit on all 4 feet. Checking now the NDS, it's exactly the same - not sitting on all 4 feet, so either the Hutter shelves are both slightly warped or the feet aren't quite exactly level.

=> Does this matter and if so, any suggestions of what to do to remedy?

Yes, it does matter. You can either get some thin metal shims or, and this is what I would do, order a Naim glass shelf and the balls and cups, and place it on the Hutter. 

HH yes I was thinking about that. First, I must try a piece of regular glass just to see if it's the Hutter shelves or whether the feet just aren't level... it's actually very difficult to manufacture ny 4 legged thing to stand on all it's feet equally, which is why many (including Naim with Fraim shelves) resort to 3 feet to make sure. Will check both unite tomorrow on my glass topped coffee table.

What HH said. Shims might be in order but it is more likely that you have an uneven shelf. As you say, best to check the shelve first.

The metal feet in my 552 came with tiny stick on gel dots to stop it sliding around. They will also serve to remove very slight differences in feet height or surface trueness. And then there's shims, but hopefully it won't go that far.

kevin J Carden posted:

Ron, How did you find out that the brass plates had come off its pins ? Did you have to send it back, or did you look inside?

Easy....it rattled like a 10lb brass plate inside of a biscuit tin, which was apparent when I first lifted it out of the box. It was an interesting exercise to hear just how much the brass plate contributes to the performance by having had it both ways. If everything feels (and sounds) like there isn't a loose billet inside of your 552 chassis, then everything probably is as it should. 

The dressing and stress relief of the Burdy is also vital....if there is ANY torsional stress, the sound becomes quite ordinary. You would think these medical grade connectors would not be so fussy....

What else can you check....well, the tape monitor mute needs to be engaged, and you probably need to NOT use the powered input. You may also want to try flipping the chassis grounding switch of the NDS. 

And if you have not already done so, disengage the digital out on the NDS....that makes an immediate and quite noticeable improvement. 

And if you are using the Powerline on the 552PS, make sure it is FIRMLY seated, which is quite easy to get wrong. 

From what you are describing, there is more likely than not something amiss with the setup. While it will not reach its full potential in a few hours, it should sound WAY better than dreadful. 

And finally, if you did have your system broken down before you installed the 552, double check that the speaker wires are not out of phase. Yes, I know....I'm sure that would never happen to you. But is sure has happened to lots of other people!

Reading Ron's post reminded me of a visit I made to a dealer who, I had been told by the local distributor, had been evaluating a NAC552 and demoing it to they best customers for the past few weeks.  The response had been not so positive and the distributor was puzzled, hence why I had been drafted in to go and see what was possibly amiss with this unit.  Well, it took all of 10 seconds to see what the problem was - the transit bolts hadn't been removed!  Red faces all round - especially the distributor, who had couriered the unit to the dealer so not been able to go through installation in person.  Anyway, 30 minutes or so later, with the bolts removed, head unit feet properly shimmed so absolutely no rocking, Burndy checked, relaxed and strain relief very slightly backed off, even from cold (the 552 had been turned off before we arrived) the transformation in performance, according to our host, was nigh on miraculous.  The music seemed to breathe and flow whereas before it sounded pinched and forced and a bit hard.

So...  do check that the transit bolts have been removed, that the burndy cable is nicely relaxed and strain relief not over-tight, and also make sure that all four metal feet make even contact with whatever surface they are on - remember that these are metal feet and there is zero tolerance as such.  Most surfaces aren't absolutely flat - not even glass - so the aluminium wafer shims sometimes need to be used.

Richard Dane posted:

....Burndy checked, relaxed and strain relief very slightly backed off....

What's this please?

C.

Err..  I have to be careful here Chris because I don't want everyone to start taking their Burndy cable apart - note that doing so may well cause damage and invalidate warranty.  However, the tightness of the strain relief is pretty critical.  Grasping the connector head in one hand and the cable just below the strain relief in the other, you should be able to twist it and there should be a small amount of movement (hard to describe - you know when it's right and when it's wrong - i.e. too little or too much).  If no movement then backing off the strain relief very slightly can improve things.  However, you do need to be very careful - too much can be just as bad, or even worse.  Most are fine, but i have come across one or two where the strain relief was done up too tightly.

Ok, thanks. Will look at mine on my CDS3.

Cheers, C.

OMG, another world of tweakery. And because Richard mentioned it, it must be important. My take on this is that if the Burndy was put together properly in the first place it wouldn't even be an issue. I'm sure there will be a technical reason why this might not be possible, but do we really want another case of Audiophilia nervosa?

You're right HH.  In 98% of cases there should be no need and indeed, it was probably only really an issue from the early days when we were all finding these things out.  As you say, those that build the Burndys at Naim know how important this is so these days I'd imagine they get it absolutely spot on most of the time.  And to anyone thinking of playing with the strain relief I say here now - don't do it - you have a very high risk of bishing things up which then means an expensive return to HQ for remedial work.  If you don't know what you're doing then leave well alone.

Hi, I'm running in my 552 and I'm seeing something peculiar about the unit. I noticed that the lights on the buttons and knobs do not light up sometimes when I control the volume in display off mode. This happens when I'm using the remote and when I'm controlling via the nds using the RC5 interface cable. 

I've never encountered this on a 252 before so I would like to know if anyone else has experienced this with the 552.

Please let me know.

Quick update on the wobbly feet issue for anyone with an interest. Turns out that if I put the 552 on my glass-topped coffee table it's fine - standing on all 4 feet with no rocking. 

So, afraid glass, balls and cups it shall be...

in the meantime, Richard, what are these metal shims of which you speak please? Are they an official item I can buy, or are we just talking about improvising something?

If you are going for the glass, a bit of paper will be fine for now. No point getting shims only to throw them away. 

Burndy dressing is a bigger issue for me since my power supplies reside in a different room to the 'brains' stack and all connections are passing through a brush-lined letter-box arrangement. This is neccesssary because my power supplies all buzz like hornets and it's not possible to listen to music pleasuarably with them in the listening room. Radical but necessary, not to mention effective. It's the lesser evil for me, however, it does make cable dressing somewhat sub optimal to say the least.. 

As I have it now the Burndy for 552 seems OK at the 552 in that, if I undo the sleeve completely it pretty much stays in the same position, so there is little or no tension at this connection, but of course it's constrained in the ' letter box around mid-way along its length.

So, not much more i can do for now. I have an electrician booked to come and install me a separate dedicated supply that bypasses the main fuse box as discussed on the forum many times. If that cures the buzzing then the brawn stack can come back into ithe listening room..

Kevin, they're official and very necessary mainly because metal feet = zero tolerance.  All 552 head units are carefully levelled up on a perfectly flat metal plate before they are packed.  The nature of the aluminium extrusion used on Naim kit means that the wafter thin aluminium shims are often required to get the feet perfectly level.  552 dealers often have a stock of these shims for when they install the 552 head unit (as well as CDS3, 555 etc..).  Naim can supply to your dealer if they are required. Removing the feet on your 552 you may well find some already used in which case it may be that they can be redistributed to level the feet for whatever surface you want to use.

Excellent, thanks Richard. I'll speak to my dealer in the morning. I'll need some for the NDS too as that's wobbling similarly.

Having said that, I've just spent a couple of absolutely incredible hours in front of the system. Now I get what you've all been talking about. It's not about the sonic differences between 552 and 252 although it is obviously better, but the fundamental difference is about the experience it brings. This thing is insane. Less a component, more a musical instrument. One made by Guarneri.. 

Richard Dane posted:

Kevin, they're official and very necessary mainly because metal feet = zero tolerance.  All 552 head units are carefully levelled up on a perfectly flat metal plate before they are packed.  The nature of the aluminium extrusion used on Naim kit means that the wafter thin aluminium shims are often required to get the feet perfectly level.  552 dealers often have a stock of these shims for when they install the 552 head unit (as well as CDS3, 555 etc..).  Naim can supply to your dealer if they are required. Removing the feet on your 552 you may well find some already used in which case it may be that they can be redistributed to level the feet for whatever surface you want to use.

Yes. When my dealer installed my 552 earlier this year there was some barely detectable rocking when placed on my Quadraspire bamboo SVT. He brought back a shim kit, which I didn't know existed, and got the unit perfectly level.  BTW I seem to recall that the shims don't go between the feet and shelf but between the feet and the unit.  Very neat and discrete.   

Yes, you unscrew the feet and the aluminium shims fit between them and the extruded case.  All units with metal feet are shimmed up where need be to be perfectly level on packing up in the box from new.

I've decided to go down the route of glass shelf, balls and cups. Quick question to anyone who can help though.

i can get get the support Items from the web, but will get the glass made locally.

Q1. Presumably this is just regular toughened safety glass?

Q2. I can see dimensions for Fraim glass in Naim spec sheet, but it doesn't say what thickness the glass is - anyone?

I believe it's 10mm.