[Fetimo]

Dear Head-fi,

After buying my Zero for ~£100 it emits a constant humming from the unit. This has been documented before with no-one coming up with a real cure but I was wondering.

If I changed the voltage it was dealing with to 110v or 220v (UK is 240v) with a converter hopefully the excess voltage would stop the noise. Would I be looking at a device like this to do it? Does anyone have any experience dealing with this kind of thing?

Sidenote: The Zero is secondhand from America where the problem didn't exist so I'm pretty sure that the 240v thing is the culprit.

Any advice is appreciated.

 

[op2003]

Hi,

i had the same issue with a used unit from a 110v-net unit. Tried the following steps and the hum was gone, but actually don't know which one was the effector:

* Disconnected HDAM-Groundwire
* Changed power-cord
* Applied ferrit-cores to both ends of power cord

Probably try using a different power-cord first.

Greetings,
Ole

P.S.: Normally the european 240V-net is more like a 220-240V-net (something in between), so i don't think you'll need the mentioned converter.

 

[Fetimo]

It's very good to know that I'm not the only one and that hopefully there is an easy fix for this =)

So I'm looking at something like this power cable and these cores?

My Zero doesn't have a HDAM fitted (yet!) so I don't think that's an issue although are there any other ground wires that could be a problem? It's fitted with the OPA2604 opamp.

Regards/

 

[op2003]

Hi,

i tried a power-cord from a server i found at work with the ferrit-cores already attached to it, so probably don't spend too much money on it, because i'm not quite sure of it's connected to the hum at all. You could also try to let the Zero be switched on for 12-24 hours first, probably it settles down by itself.

I also noticed that the groundwire from the IEC-socket isn't connected to anything at all. To answer your question: Yes, these are the power-cord/ferrit-cores i am using.

 

[Oskari]

Quote:

Originally Posted by op2003 /img/forum/go_quote.gif Normally the european 240V-net is more like a 220-240V-net (something in between)

From Mains electricity - Wikipedia, the free encyclopedia:

Following voltage harmonization all electricity supply within the European Union is now nominally 230 V ± 10% at 50 Hz. -- -- In practice this means that countries such as the UK that previously supplied 240 V continue to do so, and those that previously supplied 220 V continue to do so. However equipment should be designed to accept any voltages within the specified range.

The reality here in Helsinki in a former 220 V country is close to 230 V measured at my abode. Right now it is 230.8 V.

 

[Fetimo]

Ah ok, so that eliminates the probability that it's a voltage issue, thanks to you both

. I've just tried a different power cable (from the desktop PC) and found a clip-on ferrite core but neither of these have helped. Is it essential to have one either end?

As for leaving it on for 24 hours I'm kinda worried to do that as another user reported that "not long after the humming transformer problem something else in the unit went so that the sound was absolutely horrendous". I don't actually know if it is the transformer humming but that's what they thought.

 

[Currawong]

Try searching for "transformer" in the Zero thread. I can't remember offhand what people did to fix it. It could be unscrewing the transformer and re-mounting it with something between it and the case will help.

 

[Fetimo]

Just opened my Zero up, everything looks pristine. Going to put some rubber under the transformer after work.

Is it safe just to touch the transformer once it's all been disconnected or do I need to do something to release any charge on me/ it. Also, what are the signs that everything's grounded the way it should be?

Thanks Currawong =) had been looking through the thread but never occured to me to search it like that! Found a host of good ideas, it's just trying to filter the good from the bad and what worked/ didn't work.

 

[tomb]

Where have you been placing the amp? All you have to do is position it too close/on top of a CD player or other some equipment and it will pick up the 50Hz hum from the transformer in the other piece of equipment.

Usually people notice this right away if they move the amp slightly, but I thought I'd mention it just in case.

 

[Fetimo]

It's been sitting pretty much isolated from any other electrical equipment on my bedside table, it's got its own socket too. I have experimented with putting it in different parts of the house but it's all the same

Really it's just frustrating because the brief moments that I've listened to it (20 minutes over the past 4 months) has been musical nirvana compared to my usual setup, everything feels so fresh, open and energetic but I know if I don't do anything about this it's going to severely cut down its lifespan.

Any particular rubber/ foam that I should be using?

 

[twylight]

Take a cheap power cord and remove the ground - likely will clear up - very common for me to have grounding problem with amps if I use a 3 prong cable.

 

[Fetimo]

Twylight, can you talk me through doing this? I've got virtually no electrical experience outside school. Isn't there a chance that after doing so I wouldn't be able to touch the unit whilst it's on?

I take it there's no reversing it if you're recommending using a cheap one either

 

[twylight]

on the american plug, break off the round one.

Use a $2 cord - it should be really obvious if it works

I dont even know why amps ship with grounded plugs - most of the big amps I bought for home/ht use dont come with grounded plugs because this is SOOO common.

If its a build in cord, but a $5 extension outlet or cord and break its ground off.

All of my AV gear (10k+) has no ground wire and I have massive custom grounding system as well as for terrestrial cable and I still have trouble.

The humming/oscilitaing/ticking with no input should be gone if this is it.

 

[twylight]

The earth wire (also known as ground, safety ground, or safety earth), if present, is intended to carry electric current only when the connected equipment develops an insulation fault. It serves as a secondary safety neutral to provide a direct-shorting path to blow fuses or trip circuit breakers, and is generally connected to metal cases and other parts of the equipment which may come into contact with humans. Electromagnetic interference filters and surge protectors dispose of unwanted electric charges via the earth wire.

pic of Twylight modded electrical cable heh attached

 

[Fetimo]

Unfortunately I live in the UK and don't think our cables can be so easily broken like that. From what I understand you get the same effect by removing the earth cable from inside the plug but because the DAC isn't double insulated surely it would be pretty dangerous?

Really want to try it but scared of my lack of knowledge

Edit: Thanks for the picture and information =) I'll try snipping the earth wire out from the cable in the morning and hope it does something. It's 1.30am here, think it's time for some sleep! Greatly appreciated and I'll let you know if it works or not!