[guest1632]

HELP!!  Nuforce amp wiring problem.

Gentle People, After receiving my REF 8 Amps, I found that the two were wired differently!  On one of the amps, the ground on the RCA input jack was  sandwiched between the chassis and the plastic washer, effectively grounding the input to the chassis.  on the other amp, the ground was floated from the chassis with the plastic washer between it and the chassis.

My question is which way is correct?  

Kerry

Hi Kerry,

"Some pre-amps connect its signal and chassis ground together (not suppose to do that) and also create loud noise for NuForce." Going by that quote from Nuforce, I would think the RCA connectors are floating. Another words, the ground is not touching the Case. Take a listen and see which one is quieter Whichever one is quieter, then set the other one up to be the same as the quieter piece.

Ray

[nuforce]

The plastic washer should be seperating the ground ring from the chassis.

chassis--plastic washer--ground ring--nut

The anodize alumium chassis is not conducting. But, this is a slip in manufacturing QA.  If you can't do the switch yourself, please contact support@nuforce.com and we'll pay for your shipping.

Jason

[nuforce]

Mr High Fy and other groundless people   , the mod kit should be out by mid next week and will reach most countries in 3 days.
Regardless, for serious audiophile, you should go put in a good ground.

[guest1632]

Mr High Fy and other groundless people  :lol: , the mod kit should be out by mid next week and will reach most countries in 3 days.
Regardless, for serious audiophile, you should go put in a good ground.
So what does the "kit" or "mod" consist of?

Ray

[nuforce]

NuForce Reference 8 produces loud noise (hissing, humming) when used with certain preamps (or other source devices) that have one of the following problems: (1) Preamp chassis and signal grounds are connected; (2) AC input on the preamp is not grounded. This modification is ONLY required if you receive units before June 15 AND experience the above problem.
http://www.nuforce.com/support/F15HER3-preamp-grounding.htm

This modification will be incorporated into future shipment.
Note: The above problems only affect a few people so don't try to ask for the mod unless you really have incompatible source device or no AC ground.

For those who have NO AC ground in their system, this mod might help but you should still put in your AC ground! It doesn't cost much to install the ground rod and all your future switching audio devices will be happy. If you have PC at home, the switching power supply also generates a lot of noise and your AC around the whole house will get affected as the noise has nowhere to escape.

Jason

[Mr. High Fy]

NuForce Reference 8 produces loud noise (hissing, humming) when used with certain preamps (or other source devices) that have one of the following problems: (1) Preamp chassis and signal grounds are connected; (2) AC input on the preamp is not grounded. This modification is ONLY required if you receive units before June 15 AND experience the above problem.
http://www.nuforce.com/support/F15HER3-preamp-grounding.htm

This modification will be incorporated into future shipment.
Note: The above problems  ...

MIGHT help   MIGHT is not a word that pleases my ear. Why are you not sure it WILL help?

[nuforce]

I say it might help for people with NO AC GROUND because we are not 100% sure. The noise has to go somewhere! All switching devices are naturally noisy and there are more and more of these devices in the house. Some user have power strip with noise filtering and that helps.
It is also NOT SAFE to have high power electronics without AC ground.

Jason

[Occam]

I say it might help for people with NO AC GROUND because we are not 100% sure.

Don't you think it appropriate to refrain from posting about your POTENTIAL fixes until you are sure?

The noise has to go somewhere! All switching devices are naturally noisy and there are more and more of these devices in the house. Some user have power strip with noise filtering and that helps.

The last place you want to dump noise is the power ground. Its already contaminated with crap, and you're proposing to fob that crap off to contaminate and compromise the performance of other components? Golly, even Jon Risch has rethought his advocacy of using Y caps to divert noise to ground. There is a reason the Universe has given us such things as CMCs and accross the line caps. No matter how many times you blame the other components, it does not hide the fact that your product has excessive leakage which would prevent it from getting UL, VDE, CSA or EU safety certification. The power ground is there for SAFETY in the event of a fault/short. Your 'design' already has a fault under normal operation. And the best you can come up with is use some POS powerstrip?

It is also NOT SAFE to have high power electronics without AC ground.

No, it is not safe to operate YOUR modest power electronics without a safety ground. Any 3 prong electonic equipment that meets safety standards does not shock someone if the ground is lifted (single fault).

Your amps may be the greatest thing since sliced bread for all I know. But until those obvious safety/leakage issures are FIXED, not hidden via the improper use of a mains ground, IMO you simply don't have a viable product. I'm amazed you'd even attempt to sell such a product in the EU which actually does enforce its regulations.

[nuforce]

The patch addresses preamp compatiblity issues in parts of the world that has 2-pin AC outlets.   This has nothing to do with AC or DC voltage and safety but to address issues with Preamps that are not made by NuForce.

Ref8 is shipped as a 3-wire AC device, and passed FCC and CE as configured and to be used with 3-wire AC cord only.

[Occam]

FCC certification deals with emi/rfi interference levels. Mains safety issues is what UL/CSA certification deals with.

If Nuforce got CE certification with a grounded mains connection, and actually bears that 'CE' on the back of the chassis as required by the 'CE Mark', I'm surprised. But much in this world surprises me.

[brj]

your product has excessive leakage which would prevent it from getting UL, VDE, CSA or EU safety certification.

Occam, I'm familiar (in a non-technical sense) with the UL and EU specs, but what bodies govern the VDE and CSA specs?  (Google hints that VDE might be the German equivilant to the IEEE.)

Nuforce, are you currently pursuing certification with any of the above certifications?

Thanks!

[Occam]

VDE is the German standards organization.
CE has largley superseded the individual national certification standards and permit a single harmonized standard to used in the fifteen member states of the European Union and Norway, Iceland and Liechtenstein.

CSA is the Canadian Standards Association.

[nuforce]

As I mentioned, we already passed FCC and CE. UL etc are not regulatory requirement.  Oh, the tests cost close to $10K and took several weeks!

By the way, if the ground on NuForce amp is floated, there is 70V (on a 110V AC) on the chassis BUT the current is only 4 mA.

Jason

[WerTicus]

woa I JUST noticed something about the nuforce that I never noticed before that might be interesting to some people on here.

I had just picked up and looked under the XLR nuforce and noticed the FCC and CE symbols there to check for occam, and then I realised that my WASHING MACHINE is on!

And there are no clicks and pops and other crap coming throught the line, which I know the washing machine sends out to the AC, and my old NEW amp used to send straight though.  

This has something to do with the power supply?

[nuforce]

So are you saying that NuForce is able to shield the noise from the AC where your previous amp can't do ?

If I understand you correctly, then this is the benefit of both the switching power supply which regulate the power and the noise filtering that we have at the power input stage. I am not technical enough to explain further but if you can confirm my understanding, then I can check with our CTO.

Jason

[WerTicus]

well when my washing machine is on clicks and pops of a rather loud and horrible nature come through the tweeters.

with my old amp

now they are just gone.  it sounds perfectly normal even though the washing machine is going - and with 4 housemates this just solved one big problem

[Mr. High Fy]

well when my washing machine is on clicks and pops of a rather loud and horrible nature come through the tweeters.

with my old amp

now they are just gone.  it sounds perfectly normal even though the washing machine is going - and with 4 housemates this just solved one big problem

Hi again. Hows it cooking?

What about the statement from you, regarding your NUforce.

As you properly know, im waiting for the "noisekiller" kit, but if i turn the volume up, i cant hear the noise, and then the music just floads out of the speakers, in the most dynamic and beautiful way.

Im gonna weep myself to death, if the noisekiller dont work!!!

[WerTicus]

install a ground?  

its simple - just put a copper steak two metres into the ground and hook that up to your gear.

cooking is good anyhow, im tempted to write my review now - but i know there is more breaking in to do

[Mr. High Fy]

install a ground?  

its simple - just put a copper steak two metres into the ground and hook that up to your gear.

cooking is good anyhow, im tempted to write my review now - but i know there is more breaking in to do

Yeah, its surprising how much the sound is changing in the "burn in time"
I would go as far to say: You can´t really say NUforce does anything wrong, and if all the upgrades really works, this IS the holy hifi-grail.

Im sorry, i can´t hold it back, but when your never dreamed of EVER getting an amp. this good, and the same time beeing upsessed with audio equipment, your bound to loose your head  

[ctviggen]

If you do what you're suggesting, you might get ground loops between your house ground and your gear ground.  This could cause hum.  To prevent this, either hook everything up to the house ground (which, if you have a grounded system already in your house, it should be if you connect the ground to the ground in the panel), or connect the gear ground to the house ground using a small gauge wire.  When I lived in a house with an ungrounded (in terms of no independent ground running to each outlet) system, I ran a separate ground wire from a grounded outlet I installed to the neutral bar in the panel, which was grounded to the ground outside using a copper rod.