Used NAC 552

[PhilP]

@Richard.Dane

To get the evenness and flatness required, I’m told that you start with a very large “perfectly flat” sheet

What if we didn’t need it 100% super flat… It’s just to place our equipment on with slight imperfections hidden…? [ok I’ll stick to Naim glass… more cost effective for once… ] lol

@Suedkiez

The Naim glass is from Pilkington

Thank you… Yes I’d read this earlier somewhere here but didn’t note the name.

Naim Pilkington glass seems to sound about the fastest so far…
but I guess we don’t mind looking for alternatives to try for some fun
in our hobby to see where it takes things.

[Suedkiez]

@PhilP

What if we didn’t need it 100% super flat…

The feet on the 500s (and SuperLine) are hard metal, and the internal suspension only works as designed if there is no rocking

[PhilP]

Yes… it’s a wonderful work of engineering and some serious thinking to address microphony.

Interesting idea of aluminium meanwhile.

[Filipe]

@PhilP

Curious if the glass used on Fraim is “tuned”
in any manner. Not all glass is the same.

A number of people on this forum believe that the positioning of the Naim cups for the ball bearings provides a means to tune each box. From a physics perspective this makes complete sense. However, the theoretical modelling might be complex as the speakers and room probably affect the model quite a bit. Essential it is the sound vibrations including the those coming up through the racking that are the issue.

In another thread a while ago an alternative brass cup and non metal ball bearing was described and found to be a good alternative.

Phil

[PhilP]

Thanks Phil.

[JimDog]

@Geko

Experimented with rubber, spikes, ball bearings, nutters, rubber bladders, air bags, carbon fibre. Not found the right combination yet but I think it’s out there somewhere!

Hi Geko

Have you seen this system for making glass vibration isolation platforms?

Basically, on silicone nitride balls, in dents in brass cups.

Vibration Isolation / Support for Glass

I can’t accommodate a Brain / Brawn stack arrangement so the system has to cope with the vibrational harmonics of the transformers transmitted from lower on the rack. So, how to mechanically isolate the ‘Brain’ components. First: rule out solutions based on damping, such as sorbathane. Second: rule out spring systems as; 1, they’re more difficult to design and build; 2 some of the boxed have vary asymmetric weight distributions. So, think about using the properties of systems based on dissim…

It works well for me on a Quadraspire rack.

Jim

[JimDog]

Any luck with re-racking?

[Geko]

Hi JimDog,

Yes, I followed this with interest and fully understand what was trying to be achieved. I’d already done something similar but with a set of die taps. The round ones have a small four point contact on a ball bearing and are hardened steel. However, going back to the standard shelf I always thought it had a slightly more rounded and organic sound. I just couldn’t get rid of that pitchy glass character whenever I tried glass on it.

If I’ve taken anything away from my experimentation it’s that mass seems to play an important part in the equation. I think the Mana tables gives us this clue. Lots of stacked similar, double or triple mass tables. It’s like there is either a constructive or destructive energy sink. When it’s right it sucks away energy very quickly and very efficiently. When it’s wrong it seems to reflect it. Just my personal opinion.

[ASenna04]

Hi,

A slightly unrelated question.

I can’t help to notice that these naim boxes are kept in a cupboard with doors and no ventilation. Now we know the boxes generate heat (for sure the power supplies). Is there not a danger of higher temperature inside the cupboards affecting :-

1. Their performance when playing music
2. Reduce the equipment life with the parts inside getting damaged or requiring more frequent service than normal.

Richard, is there a ‘normal operating temperature range’ the units should be kept at? Or an optimum temperature maybe?

I don’t want to divert the thread of the OP, but want to use this example to understand the experience of other members and Naim’s recommendations.

Thanks,

[PhilP]

Not just for some heat… but sound which frees up so much more when there is adequate space around Naim equipment. EM hum and microphony is a continual challenge.

[ASenna04]

Thanks Philp. That too.

@Richard.Dane any comments on the recommended operating temperature for Naim boxed?

Thanks,

[Richard.Dane]

Under normal conditions Naim pre-amps power supplies and power amps shouldn’t get hot. However, when power amps are asked to work hard then they will need too dissipate some heat. Free air flow helps here. The power amps have a thermal trip that protects them should the temp exceed 70 degrees C.

Network players can get quite warm thanks to all the ICs. As with the power amps, the casework acts as a heatsink.

[HiFiman]

Two weeks in I’m loving my used 552DR it really is a remarkable pre amp, big thanks to Vicki (my understanding wife) who allowed the purchase she’s now in bed but I’m enjoying a bit of Paul Simon - Graceland and even at low volume it’s never sounded so good!

[davidf]

My wife also Vickie allowed me both a 552 and 500……DR both

David

[roda]

I need to go on a dating app and find anyone called Vicki.

Seems like you can’t go wrong with that idea.

[ASenna04]

Thank you Richard. So no issue storing the units in a cupboard.

What is the experience of other people what have done this?

Thanks.

[Richard.Dane]

I wouldn’t say no issues. There can be issues depending upon a number for factors; the units themselves and how much air is there to circulate around them, overall ambient temperature, and how hard the amps are made to work.

[By-Tor]

Thanks for the prompt to revisit Graceland. Currently on headphones and sounding great!

[HouseholdNaim]

@HouseholdNaim

[my 552] is now back at HQ having the low volume balance issue resolved. The well-used Grade A refurb that the dealer kindly supplied to keep me going was head & shoulders better as soon as it went on the rack, which suggests that my new one has a lot more to give but is also going to be a bit of a disappointment when it returns and replaces the current stand-in.

It’s been back for a couple of weeks, fixed with all imbalance gone and a rock solid centre image all the way down to zero. More usefully it sounded great as soon as it went back in as a straight swap for the temp refurb loan stand-in, which could suggest that the pot replacement also improved sq to where it should have been.

The first 3 months of ownership were a disappointment. It’s been superb ever since it came back. Make of that what you will.