Transformer hum (again)

Naim state that a badly distorted mains waveform is responsible. They recommend seperate spurs to help sort this out.

Dedicated spurs also bring sonic gains too...there are plenty of discussions on this topic on this forum...why not do a search?

laurie S

Thanks - I realise the benefits of separate spurs etc, but was wondering if there was anything else I could do in the meantime - I only get the hum occassionally, but when I do it's LOUD! - the 'hi fi' room is on its own ring, would I benefit by temporarily, having a separate CU for the front room ring?

I've found that a separate spur has not helped my Humming.

Sometimes playing with the power cable routing can help

Fisbey

Just turn up the volume.

Regards

Mike

Spending money I don't have on things I don't need.

Fisbey

Some things that have made hum other than mains supply have been:

1. dimmer switch on same circuit
2. Poor contact at amplifier for speaker cable
3. wrong lead plug in from supercap
4. drawomg power first to the amp on a power strip

Hope this is of some use to you

Terry Borth

OK

1, I have dimmer switches in nearly every room in my house...
2, I'll check the speaker connections
3, I don't have a supercap!
4, Er - what?!

Not to be gloomy but
You should add:
1) You running your washing machine.
2) The next door neighbour running her washing machine.

and so on

I get a lovely hum from a fine group of transformers inside my 250mkII, XPS2 & SC when my washing machine is on.

As Mike says when the music is playing you can't hear it. If you can, either you listen to very quiet music, or you have a serious hum problem.

regards
GEOFF

Dear Fisbey

Sorry about number 4!

What I meant to write was
4. Drawing power to the power amplifier (from the power strip) at the begining of the power strip (where the cord goes in).

Terry

Fisbey,

If you release the transformer-mounting bolt (normally the largest allen key on the bottom of the product) a turn and then do it up tight again that sometimes helps.

Graham.

Not a lad any longer and not from London!

quote:

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I've found that a separate spur has not helped my Humming.

---

I can second that, but.........

quote:

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I have dimmer switches in nearly every room in my house...

---

Bad, bad, bad news. Get rid of them.

I have a separate spur and when my PC is connected to the ring main, it still degrades the sound of the system.

If you isolate such things as dimmer switches, electric blankets etc: from your ring main, you are still at the mercy of your local supply.

I used to have 135's that buzzed like buggery, until the local supply was overhauled and serviced. The buzzing was thereafter, virtually inaudible.

The good news is that it doesn't affect the sound quality and paradoxically is most annoying when one is not playing music.

Good luck.

Six separate spurs and mine still hum.

QED

OK - thanks, I've got a feeling it may be the fridge....
But I'll see what I can do about the dim switches etc. etc.

other potential culpprits are:

(1) neons (like those found in 4 way extension blocks)

(2) energy saving (florescent) lamps

(3)switched - mode power supplies (as found in TVs, VCRs and PCs)

laurie S

Blimey the TV and video are on the same ring!

Fisbey,

have you tried the bolt ? See above

Graham.

Not a lad any longer and not from London!

quote:

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Blimey the TV and video are on the same ring!

---

Forgetting the hum problem for a moment, sorting this out is likelyto improve sound quality


Laurie S

Whilst visiting Robert Ritchie on Monday I mentioned that I had been suffering some hum from the 250 and he gave me a little circle of what appears to be a neoprene like material. This is added to the underside of the transformer (there will be one there already - this one will fit on top) and provides extra isolation from the case. Only fitted it last night so it's far to early to say whether it's worked or not, but I didn't hear as much hum last night but then sometimes that varies.

Speak to Naim and maybe they'll send you one of these sticky circles for your transformer...

John

I'd need more than one sticky circle! - all my transformers hum....

I'm fairly certain it happens when the fridge switches on or off and it can be pretty loud, therefore p***ing me off!

I've just had one hi cap serviced and the other one will go soon (I'm only using the recently serviced hi cap at present)along with the 250 and the CDI, so I think I may see how things are when all the bits return - I'll be selling the newer hi cap to fund the rest of the servicing, which basically means I'm pretty broke, but the last three items are well overdue for a service.....

Another question, excuse my ignorance (I do have some knowledge/training in installations) but why do my lights go dim occasionally? - does this point to my supply being dodgy, or a problem with the house wiring - some of which has been renewed (by me).

I think if I can sort this out the sonic benefits may well be apparent, I just don't have very much money!

Thanks very much for all your replies incidentally

Fisbey,

Do you mean your house lights or the Naim logo lights ?

Did you try the bolts ????? Its free

Graham.

Not a lad any longer and not from London!

Fisbey,

Once when I moved my Stageline I got a loud hum which overwhelmed the music signal. Problem solved by unplugging and re-plugging the thing in again. Try that with the affected box - it might help and u get to clean your connectors along the way!

Regards,

JonR (fellow Middx bloke)

It's the house lights and it's all three boxes (hi cap, 250 and CDI) that hum (at the same time) but I will try the bolt thing on the 250 to see if it helps.

I have plugged and unplugged the set up many times and the snaics!

Lights dimming slightly can just be a heavy load item being switched on.

However if it happens when no extra load has been switched on it may indicate a poor connection on the ring or at the consumer unit.

Try the bolts, it often helps.

Graham.

Not a lad any longer and not from London!