hicap connection to nac 62
Posted by: tube1960 on 18 October 2018
Hi all, I am new in this forum and this is my first post.
I have a nac 62 cb, hicap cb and nap 250 cp all fully serviced.
They sound great but I have a little problem with the connection of the hicap to the 62.
If I connect the preamp direcly to the 250 there is now hum or buzzing, if I connect the usual way using snaic from 62 to hicap and then from hicap to 250 there is a slight buzzing in both speakers.
Both power cords have the usual earth connected as it should be.
Please, any suggestions?
Thank you
Tube
I thought the 250 could not power a preamp. I connect through the PSU from Pre to Power. A little residual noise is present as the noise floor is not absolute zero. However, once the music starts then it is not noticeably detrimental.
You should connect the NAP250 by taking signal from the pre-outs on the Hicap, never by connecting to the Din 4 on the NAC62. However, the fact that you are getting hum through the speakers when connected that way suggests there's a problem somewhere.
Six the hum there regardless of source? What if no source?
Are the mains leads all connected to the same mains circuit?
Check your cable dressing. Ensure the pre-amp is kept clear of the Hicap and NAP250.
Have you checked the SNAIC5? Is it still the original grey one or have you upgraded to Naim's improved black one? Also check the DIN-XLR lead. Again, is this original or the later type?
Hello Richard,
All the mains are connected to the same mains circuit,
the buzz is present regardless of source (linn lp12 and one digital source),
original SNAIC5 grey ,
DIN-XRL lead is perfect.
Is it there is you disconnect all sources from the pre-amp?
Haven't tried yet
But never had problems with other amplifiers
Try it and let us know.
Ok, thank you Richard
The buzz may well be due to the digital source signal earth - the system must have only one signal earth. If you disconnect just this source and the buzz goes away, that will tell you.
I will try this afternoon, thank you Hungryhalibut
Hello Richard, I tried disconnecting the digital source and the buzz went away and strangly it sounds better.
At this point there seems to be a ground loop between the naim amplification and the digital source, maybe the best thing to do is to remove the ground from the power cable of the digital source, any suggestions please?
Thank you.
Tube
Removed ground from power cord of digital source and the buzz is gone, but....
What I have noticed is that connecting the nap 250 directly to the nac 62 is quiter, this puzzels me...
Any suggestions please?
Thank you.
Tube
It's not possible to connect a NAP 250 with Naim cables to a NAC 62 and it work. Has something been messed with ?
Removing earth connections from mains plugs is not advised.
I think what Tube1960 means is that they are powering the NAC62 with the Hicap, but taking signal from the DIN4 output on the NAC62. This means that the Hicap is no longer the absolute earth reference for the system.
Note the following with regard to Naim systems:
The absolute earth reference for the system is the reference for the pre-amp, which is the SUPER-CAP, HI-CAP or FLAT-CAP earth. The signal is routed from the pre-amp to the power supply using the same interconnect that takes the power feed from the power supply to the pre-amp. It also connects the two earths together.
This minimises differential voltages caused by interfering electric or magnetic fields being generated between the power feed, signal and earth, so maintaining the correct relationship between signal and earth inside the power supply. The power amp is connected to the properly referenced signal at the power supply output.
Yes Richard, this was what I meant.
What I have noticed connecting direcly the 62 to the 250 is more extremes and punch, maybe a little less organic....
I will continue to compare....
Remember that you are not using the amplifier as designed, and that its earthing arrangements will not be correct. While many things can be fiddled with, you’ll nearly always find its best to use things as intended if it’s musical satisfaction that is the objective.
hungryhalibut posted:Remember that you are not using the amplifier as designed, and that its earthing arrangements will not be correct. While many things can be fiddled with, you’ll nearly always find its best to use things as intended if it’s musical satisfaction that is the objective.
If tube gets more musical satisfaction from more extremes and punch. Pre to power is the way to go.
Out of interest, when the 62 and 250 where designed/initially used, how many signal earths where used.