home demo blues

10.3pF/ft can't be helping any, the max is 20pF/m so you're getting on for double. And while you're at it try the cables that come with the Naim kit in place of the rest of the Nordost.

Did your dealer set it up and on before he left or did you set it up your self?

gave me instructions but i did the set up myself..but i crossed checked with the connection guide of NAIM that they are the same.  

@ Yeti42: regarding the cables, the same set up is running perfectly nicely at my dealer's ... 

Can you take the whole lot to another room on a different circuit just to see if it's ok there?

Do you have all the original Naim cables to try as an alternative. Could be a defective cable or connector.

What fuse does it blow [@mention:32963504873841469]? House, or amp? 

House...out of 4 times i tried to power the 250 i had twice the house fuse blown and twice no "dramatic" events but simply the 250 front light went out a couple of secs after powering on. Tried a different mains cable on the HiCap and tightened all connections - to no avail.

Is everything connect the same as above? 

Unplug the speaker cables from the amp before trying to turn it on. Does it still shut down?

Sounds like a short circuit.

If the connections are as per Finkfan's diagram and it's still blowing fuse I would contact the dealer for assistance.

Can't be doing the 250 any good if it's taking down fuse.

My thoughts too [@mention:1566878604005007]

DrPo posted:

i had twice the house fuse blown and twice no "dramatic" events but simply the 250 front light went out a couple of secs after powering on.

DrPo,

Are you talking about old-school fuses blowing as opposed to modern breakers tripping? In either case it seems to me you may have fast blow/break protection devices in your mains box that are incapable of handling the initial surge demand of the 250 on power up. You're simply overloading your circuit on start-up of the amp.

Consider plugging the 250 into an alternate circuit apart from the rest of your gear, using a higher-rated amp circuit for your gear, or turning off/eliminating any extraneous power draws on the current circuit when you start the 250. You could also alter your power-up sequence. Your issue seems more about in-house mains limits rather than the connection of boxes, which you seem to have nailed.

All: thanks very much for the response and the tips. I have made progress although I am not sure I have identified the real root cause.

As I cannot move the whole rig I simply tried to power on the 250 alone (no input/speaker output) in a different room served by another circuit - check��. Then powered the 250 (again standalone) on in the "listening room" using a different mains cable - check��. Finally reconnected everything and finally There Was Music:��. Yet I am still not sure whether it was a case of a loose mains cable connection on the 250  or the current required was too much last night (peak demand hour) versus early this morning (low power demand). I have left it powered on till I come back from work, hopefully with a long weekend to listen carefully to the 282 250 set up.

Great news! Enjoy your music filled weekend. 

DrPo posted:

All: thanks very much for the response and the tips. I have made progress although I am not sure I have identified the real root cause.

As I cannot move the whole rig I simply tried to power on the 250 alone (no input/speaker output) in a different room served by another circuit - check��. Then powered the 250 (again standalone) on in the "listening room" using a different mains cable - check��. Finally reconnected everything and finally There Was Music:��. Yet I am still not sure whether it was a case of a loose mains cable connection on the 250  or the current required was too much last night (peak demand hour) versus early this morning (low power demand). I have left it powered on till I come back from work, hopefully with a long weekend to listen carefully to the 282 250 set up.

The only thing I remember from the past that the sudden demand of the power was causing the problem for me before. When they installed fuses which are more forgiven in my house the problem was gone. What might also help for you is switch everything on with a little pause in between, if that's the core problem.

Finkfan posted:

Great news! Enjoy your music filled weekend. 

Thanks Finkfan - and yes, i was looking at the same diagram last night when i was connecting the lot :-)

Bert Schurink posted:

The only thing I remember from the past that the sudden demand of the power was causing the problem for me before. When they installed fuses which are more forgiven in my house the problem was gone. What might also help for you is switch everything on with a little pause in between, if that's the core problem.

i will inadvertently do so. 

I suspect there is a loose wire in the mains lead, or even wall socket... and so if working now don't touch it, but after the break get your dealer to look at.

I don't think it's 'surge' current... in the grand scheme of things these transformers are relatively modest and unless you have lots of them all starting at once the surge will be relatively small.. and you had issues even when the fuses didn't blow.. and old style fuses I seem to remember are slower blowing that many modern circuit trips.

I agree with sis. After a house power cut I have no tripping issues on my rig. And that's 6x135 and 52ps and supercapdr and xpsdr and cdsps and....

If it is any consolation I find that switching on the 300PS, 552PS or the S'Cap will cause my dedicated line circuit breaker to trip about 10%, 5% and 5% of the time respectively. I assume it is when the circuit is made in the cycle that is the main contributory effect, i.e. when the rate of change of voltage is at its peak. I am prepared to be corrected on this.

Adam Meredith posted:

...

 

It is possible that you didn't have the IEC plug sufficiently seated in the socket at the rear of the NAP 250 - allowing intermittent power. Easily fixed.

QUITE likely is that you were a bit tentative in operating the ON/OFF switch on the NAP 250. Slight farting around when doing this can cause problems and these newer switches can fool you into thinking they have engaged/latched - the logo lights up - but disengage once pressure is removed and, sustained by partially charged capacitors, the logo will remain lit for a few seconds after you think you've switched on.

 

...

HI Adam, applying Occam's Razor I think your above point is the most likely explanation at this point. I guess i was hesitant to push too much the IEC plug (most likely fooled by the "elastic" response of the plug under pressure which i am sure is by design). 

To all of you who were kind enough to respond: thank you again and best wishes for 2017!

This demo has turned from "blue" to "really interesting" as in the end I did have the opportunity to listen carefully to a "mid level" NAIM amplification set up at my place. I thought I should post some impressions, all "calibrated" against my current amp which is a very solid and well regarded (primarily in Germany) integrated, albeit at 1/3 the cost of the NAIM amp set up I had on loan:

1.  the good: I think it is the first time I comprehend what people mean when referring to NAIM's PRAT: I had several cases (mostly in symphonic music) where i could distinguish different "fast" bass notes which in my current amp are almost "overlapping". Not sure if this is correct but that feature - whether it should be described as "resolution" or "timing" - was quite evident,  and very much welcome. Also the separation of instruments and lines in an orchestral piece was very good and kept me captivated.

2. the bad: that being said, I felt that at lower listening levels I was missing bass and low mids (I mean much more than compared to my current amp and some others I recently demoed, like a Burmester 035+036 combo) and had to turn up the volume to about 80 db to have a good balance of the music. My speakers are a bit lean on upper bass and mids so that might a factor as well...

3. ...and the ugly: I had twice within the two days (and for about 10' each time) a very noticeable hum noise from the NAP 250 which as I realized seems to be a common issue frequently mentioned on this forum.  

4. I have seen some comments to the effect that NAIM does not do "soundstage"... on the contrary I had marvelous sense of both width and height, much to my (positive) surprise.

Overall I have been very happy with the results and now seriously contemplate going for a NAIM amplification solution, something which i had ruled out 3 years ago when listening to a 202 + 200 combo which I did not find really enticing. I wish I were able to extend my reach towards a 252 as given my music preferences (chamber and symphonic and "classic" jazz)  and from what i hear it is an even more refined and detailed preamp 

ATB,

Greg