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View Full Version : Mains induced transformer hum - how do I get rid of it?



jandl100
14-01-2009, 09:37
I live way out in the back-woods and my mains quality is generally poor, I think.

Lots of amps I have had suffer from transformer hum (they sound fine when used in 'civilised' areas - i.e. suburban areas at bake-offs etc).

How can I fix this? (without moving - it's nice 'round here!)

__

(The hum comes from the amps themselves, not thru the speakers)

MartinT
14-01-2009, 09:42
Buy a PS Audio Power Plant Premier. Apart from all the benefits of mains regeneration, it ensures that the output DC level is zero which is where your transformer hum is coming from. Perhaps you can loan one for a home trial? Once heard, I doubt that you'd send it back.

Neil McCauley
14-01-2009, 09:45
http://www.stereonow.co.uk/psaudio.html

28 days sale or return.

Carriage both ways (in the unlikely event of a return) paid by me.

Regards

HP

jandl100
14-01-2009, 09:54
How much these? Getting on for £2k? Not sure I want to spend this much on the problem.

I already use a PS Audio Ultimate Outlet bolun thing - it doesn't seem to make any odds to the transformer buzz, but does improve the sound. I guess full mains regeneration should do the trick, though!

Neil McCauley
14-01-2009, 10:03
I have an ex-display unit in near mint condition at £1,499 (RRP £1,899) scheduled for my February sale. I rotate all my demo stock around 4 to 6 months depending on circumstances. Anyway, this one comes complete with the remote, inner and outer box, manual and 12 month warranty. If you are seriously interest, I am prepared to release this before the February sale. This is the proper UK spec issue, not some grey import. Thank you.

HP

jandl100
14-01-2009, 10:13
Many thanks, HP - very tempting!

Looking at the PS Audio website, I see they make a thing called a Humbuster. http://www.psaudio.com/ps/products/detail/humbuster-iii Might this be a more cost-effective way of addressing the immediate problem? Are they available in the UK?

Neil McCauley
14-01-2009, 10:21
Hi. The PS Audio UPC 200 HB Humbuster is available in the UK at £399 inc vat post free from me with 28 day Sale or Return. Please note that I have no no direct personal experience of this item and therefore cannot offer any credible comment on its effectiveness.

It is not a stock item for me. However as you are an AOS forum member, I'll buy one in for you to try and without obligation for you to keep it. As usual with me, I'll refund your return postage to me if you decide not to keep it.

Hope this helps

Howard

jandl100
14-01-2009, 11:05
Yup, many thanks Howard.

I see a guy on the Roksan forum bought a Humbuster and it helped sort his hum.
Just to report my hum issue is solved. The ps audio humbuster that i got took away about 50% of the hum. But then came the idea of putting the Audioprism foundation 3 power conditioner that i already had before it Trick Done .....hum is gone
Similar report on AudioReview.

Am getting a few responses coming in now, so I'll hold off for just a little while and consider my options.

Anyone else got any views?

MartinT
14-01-2009, 14:58
Those are very fair offers, Howard. Your reputation as a dealer certainly grows in this forum. I'll bet you don't remember selling me that superb Pioneer PD-91 CD player all those years ago in Charing Cross Records?

Neil McCauley
14-01-2009, 15:55
Good afternoon Martin. Thank you for the kind comment. I was initially a bit puzzled because I never sold Pioneer gear. And then I realised (from the mention of Charing Cross Road) you have me confused with the late (apparently) Howard Woo – he of Covent Garden Records fame. No matter though. Kind words are always appreciated and curiously, generally speaking, fairly rare on this forum.

Sincerely

Howard.

MartinT
14-01-2009, 16:32
you have me confused with the late (apparently) Howard Woo – he of Covent Garden Records fame

Damn, I could have sworn it was you - something about your written body language, if you get my drift. Ah well, perhaps I may be a customer in the future.

Neil McCauley
14-01-2009, 17:49
Damn, I could have sworn it was you - something about your written body language, if you get my drift. Ah well, perhaps I may be a customer in the future.
Mr. Woo, so I was told was a recovering anorexic. Given my girth at that time plus the fact he was always keen to overtake me as Meridian #1, it is possible that he went beyond mere recovery and swung, if I can use that word, too far in the other direction in I suppose a misplaced attempt at competition. Unhealthy competition in a most literal sense.

I was at that time about 19 stone. Illness has reduced this to under 16 stone with a couple more to go. Mr. Woo however may well have run out of time on that one.

StanleyB
15-01-2009, 08:11
Hi Jerry, you need a stabilizer as used in many third world countries. They are also popular with audiophiles in places like India. Have a browse on http://www.hifivision.com/forum/ for some good info. Sign up and ask questions even. Heay, you might even run into me:lol:.

jonners
15-01-2009, 09:45
Transformer hum is often caused by the intermittent presence of DC on the AC mains. Before spending enormous amounts of money I would try one of these: http://www.hificollective.co.uk/catalog/hifi-supply-blokker-p-4383.html

BUT: Installing it involves getting inside the equipment and tinkering with mains connections - so if you are not comfortable and competent with that sort of thing you must get it installed by a qualified person.

John

jandl100
15-01-2009, 10:07
not comfortable and competent with that sort of thing

That sums me up perfectly, sadly! :scratch:

___

Thanks for the link, Stan - I'll have a look!

purite audio
15-01-2009, 11:12
These might do the trick .
http://www.pcmups.com.tw/product/vanguard2000.html

jandl100
15-01-2009, 17:12
Yup - I'll wait and see how you get on with the 3000, Keith. I'm a bit worried about fan noise ... the beast will be in the room with me - if it is intrusive, there's no point in swapping one sort of noise for another.

i_should_coco
16-01-2009, 21:21
Wow, people want to sell you several grands worth of power conditioning, when a simple DC blocker will probably do the trick.

purite audio
16-01-2009, 21:47
I don't want to sell power conditioning to Jerry, I was going to try one myself and let him borrow it if he thoughtit might do the trick.

Marco
16-01-2009, 21:51
And if it does the trick, then what? ;)

Marco.

Mike
16-01-2009, 21:52
Wow, people want to sell you several grands worth of power conditioning, when a simple DC blocker will probably do the trick.

Well I didn't like to say anything, but.....

i_should_coco
16-01-2009, 21:54
I don't want to sell power conditioning to Jerry, I was going to try one myself and let him borrow it if he thoughtit might do the trick.

I didn't mean you Keith. There were a couple of post above saying he should get some expensive PS Audio thing.

But, the point remains, it's unlikely he needs a full blown power conditioner to solve this.

Mike
16-01-2009, 21:57
Try.... http://sjostromaudio.com/joomla/index.php?option=com_content&task=view&id=62&Itemid=27

i_should_coco
16-01-2009, 22:01
Try.... http://sjostromaudio.com/joomla/index.php?option=com_content&task=view&id=62&Itemid=27

You're kidding, right! Far too cheap. Can't possibly work. :eyebrows:

Mike
16-01-2009, 22:02
We can be a bit cheaper if you like? :)

http://diyparadise.com/dablok.html

i_should_coco
16-01-2009, 22:06
I don't think Jerry's teh DIY type, unfortunately.

Mike
16-01-2009, 22:15
Well, Jerry could do it the easy way by saying something like:

"Mike, could you make me an IEC lead that filters DC to see if thats my problem?" :)

And I might say:

"Sure Jerry, just PM me with your address".

:eyebrows:

i_should_coco
16-01-2009, 22:16
Now there's an offer that shoudln't be refused! :)

Marco
16-01-2009, 22:20
Ah, but the noise won't go away unless it's got a 'PS Audio' badge on it :eyebrows:

Maybe you could make one and stick it on anyway?

Marco.

MartinT
16-01-2009, 22:22
There were a couple of post above saying he should get some expensive PS Audio thing

Talk about misrepresentation! I stated clearly that the PS Audio would cure the DC-on-mains problem but would also bring many other benefits too. I have also said elsewhere that it is one of the best upgrades for a good hi-fi system I know, and I stand by that.

purite audio
16-01-2009, 22:22
Mike Hi, could you make me an IEC lead that filters DC to see if that is my problem, or perhaps I could borrow the one you make for Jerry? Jerry?
I don't sell power conditioners by the way Marco!

Marco
16-01-2009, 22:24
Who's "Jerry? Jerry?" Do I know him?

Marco.

Mike
16-01-2009, 22:24
Sure, etc..... :)

i_should_coco
16-01-2009, 22:25
Talk about misrepresentation! I stated clearly that the PS Audio would cure the DC-on-mains problem but would also bring many other benefits too. I have also said elsewhere that it is one of the best upgrades for a good hi-fi system I know, and I stand by that.

Yes, let's use that £2000 sledgehammer to crack a nut. I don't recall Jerry asking for the 'other', unspecified benefits.

purite audio
16-01-2009, 22:26
Mike that would be cool, Keith.

Mike
16-01-2009, 22:30
Talk about misrepresentation! I stated clearly that the PS Audio would cure the DC-on-mains problem but would also bring many other benefits too. I have also said elsewhere that it is one of the best upgrades for a good hi-fi system I know, and I stand by that.

OK, calm down :)

We're just trying out a cheap method of looking into whether or not DC offset is causing the buzzing transformer problem....

It won't be 'high end' but at least it'll be free. :smoking:

purite audio
16-01-2009, 22:49
Mike Hi I don't expect it to be free, it will be cheaper than 'Odin' though won't it? Keith.

Mike
16-01-2009, 22:54
Mike Hi I don't expect it to be free, it will be cheaper than 'Odin' though won't it? Keith.

Blimey... just about anything would be! :)

MartinT
17-01-2009, 02:09
Yes, let's use that £2000 sledgehammer to crack a nut. I don't recall Jerry asking for the 'other', unspecified benefits.

You're still not getting it. I proposed a solution which I'm pretty sure will work. Not only does the Premier have pretty sophisticated DC blocking, it also incorporates Multiwave which modifies the waveform supplied to components. If you look for another thread elsewhere you will see that it cured my (not mechanical but system induced) hum through the phono input. And there was no price limit set at the start of the thread.

Finally, Howard made a very generous offer of sale or return so that it can be trialled for real.

Now, what solution exactly did you propose?

jandl100
17-01-2009, 06:47
Well, Jerry could do it the easy way by saying something like:

"Mike, could you make me an IEC lead that filters DC to see if thats my problem?" :)

And I might say:

"Sure Jerry, just PM me with your address".

:eyebrows:

Mike, could you make me an IEC lead that filters DC to see if thats my problem?

:)

jandl100
17-01-2009, 06:53
Buy a PS Audio Power Plant Premier. Apart from all the benefits of mains regeneration, it ensures that the output DC level is zero which is where your transformer hum is coming from. Perhaps you can loan one for a home trial? Once heard, I doubt that you'd send it back.

Notwithstanding Mike's kind and generous offer, the Power Plant Premier is on my Want List - although a cheaper option of the pro-sector Vanguard 3000 is also interesting - but that is well over 50Kg and is fan-cooled .... not sure I like either of those aspects. We'll see how Keith gets on with his, if he gets one.

I used to own a Powerplant P300 (PS Audio's 1st mains regenerator) and it was indeed a sonically worthwhile unit - but it couldn't really supply the juice I needed - the Premier can though.

StanleyB
17-01-2009, 07:47
but it couldn't really supply the juice I needed

Switch off that 10K bar heater of yours and there should be enough juice left to power up the rest of your house;).

i_should_coco
17-01-2009, 08:16
You're still not getting it. I proposed a solution which I'm pretty sure will work. Not only does the Premier have pretty sophisticated DC blocking, it also incorporates Multiwave which modifies the waveform supplied to components. If you look for another thread elsewhere you will see that it cured my (not mechanical but system induced) hum through the phono input. And there was no price limit set at the start of the thread.

Finally, Howard made a very generous offer of sale or return so that it can be trialled for real.

Now, what solution exactly did you propose?

I'm not getting it? You're kidding, right? I think a reality check is in order.

Jerry has a simple problem, i.e. transformer buzz, which can in all likelihood be fixed with a simple (and cheap) solution. I did propose such a solution - a simple DC blocker. Mike has offered to make him one. The sensible thing is to try the simple solution first, rather than going for the full blown (expensive and most likely unecessary) power conditioning. If the simple solution doesn't work, then would be the time to consider other options. Jumping for the full blown power conditioning strauight away is quite frankly daft. It's ridiculaously expensive and overkill for the problem at hand.

Quite frankly, your recommendation reads more like marketing spiel.

jonners
17-01-2009, 09:22
Jerry has a simple problem, i.e. transformer buzz, which can in all likelihood be fixed with a simple (and cheap) solution. I did propose such a solution - a simple DC blocker.

I said exactly the same thing back in post no.14. Is this thread going anywhere? Answers on a postcard.....

John

Beechwoods
17-01-2009, 09:45
:nocomment:

StanleyB
17-01-2009, 10:20
I remember as a kid using dynamite to catch fish in the West Indies. The older guys working at the local bauxite mines would nick and shove some of the glycerine soaked stuff in their cooling flask to keep it cool and from exploding...
Somehow this discussion reminds me of those days.

Mike
17-01-2009, 12:53
I remember as a kid using dynamite to catch fish in the West Indies.

I like that... 'Thinking in images' is fun! :)



Anyway... I'll make up a pair of leads for Keith and Jerry and we'll see how it goes, perhaps you guys can report here on what you find?

Like I said, these won't be high end in any way, quite the opposite, just bog standard IEC 'kettle' leads (I assume that's the type needed?) with a box of gubbins in the middle of them. Probably 'butt ugly' in fact! ;)

They won't do anything fancy to your mains supply like a PPP or other products can do, though it would be possible to add some basic filtering in there too, but lets keep things simple for now.

I'll do some 'Wombling' later to see what I've got hanging around but I may have to order a few bits (boxes & caps) so bare with me. I should be able to get them out to you by the end of the week but I've a couple of other jobs I'm behind on that I need to get out of the way first. Hope you don't mind?... Not least of which is my own amp, which is sat right beside me upside down with it's giblets exposed still!

Cheers...

Neil McCauley
17-01-2009, 15:17
Quite frankly, your recommendation reads more like marketing spiel.

So Mr Coco (if that really is who you are) my own suggestion as stated earlier re the PS Audio PPP "Finally, Howard made a very generous offer of sale or return so that it can be trialled for real." should be seen in a similar light should it? Well ... thank you.

Second and final time I'll do that on this forum I assure you.

Nothing personal - of course! You won't take it like that will you?

Anyway – The commercial writing is very large on the wall and it's time I clamped my firmly-business 'hat' to my head. Everyone else seems to. With cynicsm such as yours, why don't I just go with the commercial tide instead of against it – by which I mean that if I understand you correctly AOS members are in the final analysis merely a group of potential punters waiting for cunning foxes like me (and presumably every other member who is tainted with even tiniest odour of business about them) should behave accordingly ?

It's situations like this that make me wonder if Antony Michaelson of Musical Fidelity wasn't right all along.

Incidentally, what do you have to fear that needs the cloak of a pseudonym?

I ask simply because I take the view that I'd say nothing on a forum that I wouldn't be prepared to say face to face. That's why I use my own name and my physical location is easily located. Presumably you don't enjoy a similar level of confidence - or have I (and presumably some of the other forum members) misjudged you? If so, I apologise in advance.

Marco
17-01-2009, 15:48
Howard, I suggest that you edit the threatening tone from that post or I may have to 'edit' your posting rights for a week.

Thanks in advance.

Marco.

i_should_coco
17-01-2009, 15:54
So Mr Coco (if that really is who you are) my own suggestion as stated earlier re the PS Audio PPP "Finally, Howard made a very generous offer of sale or return so that it can be trialled for real." should be seen in a similar light should it? Well ... thank you.

Second and final time I'll do that on this forum I assure you.

Nothing personal - of course! You won't take it like that will you?

Anyway – The commercial writing is very large on the wall and it's time I clamped my firmly-business 'hat' to my head. Everyone else seems to. With cynicsm such as yours, why don't I just go with the commercial tide instead of against it – by which I mean that if I understand you correctly AOS members are in the final analysis merely a group of potential punters waiting for cunning foxes like me (and presumably every other member who is tainted with even tiniest odour of business about them) should behave accordingly ?

It's situations like this that make me wonder if Antony Michaelson of Musical Fidelity wasn't right all along.

Incidentally, what do you have to fear that needs the cloak of a pseudonym?

I ask simply because I take the view that I'd say nothing on a forum that I wouldn't be prepared to say face to face. That's why I use my own name and my physical location is easily located. Presumably you don't enjoy a similar level of confidence - or have I (and presumably some of the other forum members) misjudged you? If so, I apologise in advance.

Yes, I am extremely cynical about salesmen masquerading as do gooders trying to do someone a favour. I don't care if you offered it for free, it's clear you *are* trying to get a sale out of it. But, the real point is that at the end of the day it's a daft solution (way overkill) to a simple problem.

Your reaction speaks volumes.

The fact that I choose not to reveal my name is neither hear nor there.

Neil McCauley
17-01-2009, 16:01
Yes, I am extremely cynical about salesmen masquerading as do gooders trying to do someone a favour. I don't care if you offered it for free, it's clear you *are* trying to get a sale out of it. But, the real point is that at the end of the day it's a daft solution (way overkill) to a simple problem.

Your reaction speaks volumes.

The fact that I choose not to reveal my name is neither hear nor there.

Err some mistake surely? Other than substituting 'hear' for 'here' I mean. A juxtaposition issue I think. How about?

"The fact that I choose not to reveal my name is neither hear nor there.

My reaction speaks volumes."

And of course, it does.

Meanwhile, this has been my final appearance on AOS. Thank you to those of you I've had many intelligent dialogues with. These were far more frequent that I'd could ever have reasonably hoped for. Gentlemen - it's been a pleasure. It really has. Maybe the truth is that forums and vested interests just don't mix so well. And I think we should all leave it at that.

i_should_coco
17-01-2009, 16:03
Err some mistake surely? Other than substituting 'hear' for 'here' I mean. A juxtaposition issue I think. How about?

"The fact that I choose not to reveal my name is neither hear nor there.

My reaction speaks volumes."

And of course, it does.

Meanwhile, this has been my final appearance on AOS. Thank you to those of you I've had many intelligent dialogues with. Gentlemen - it's been a pleasure. And I think we should all leave it at that.

Wow, way to overreact! :mental:

But, perhaps forums and vested interests don't mix so well.

Marco
17-01-2009, 16:07
Ok guys, enough is enough.

Howard, I think that the word 'disengenuous' sums up many of your activities on here and we've known this for some time. Quite simply, you've realised now that the game is up, but not before we've decided that your asset-to-liability ratio has now gone into a position of deficit. Thank you for your contributions and your occasional flashes of insight, but as you say the time has now come to say goodbye, so I wish you all the best for the future.

I will re-open the thread later once things have calmed down, as I feel there is much more useful information pertinent to the thread topic that can be still be contributed.

Marco.

Steve Toy
17-01-2009, 17:43
There are plenty of other trade members here who manage just fine not to polarise their potential customers and the trade itself.

Marco
17-01-2009, 18:39
Thread now reopened. Everyone play nice and let's return to the thread's original topic only. It's an interesting subject so I'm sure there's plenty more to discuss :)

Marco.

StanleyB
17-01-2009, 19:09
Out of interest Jerry, did your problems just started to happen, or is this something that has been around for a while? If the answer is the latter, then some/all of your test reviews might well have been incorrect:scratch:.

MartinT
17-01-2009, 20:52
Everyone play nice and let's return to the thread's original topic [U]only[/U

Frankly, that's a big pill to swallow.

As far as the original problem is concerned, there may be cheaper solutions but I'm positive the PS Audio Premier would meet the challenge and I have direct experience of it reducing hum in my system. I am not a 'salesman with an agenda', just a satisfied customer.

It seems a shame that we have lost an interesting contributor to this forum.

Marco
17-01-2009, 21:02
Martin,

Please, I did ask, now...

I happen to rate the PS Audio Premier, but feel that in this particular application a less expensive solution to the problem is more appropriate; others apparently agree.

In other applications the mains regenerating function of the PSAP would guarantee its value as a superb product.

Marco.

sastusbulbas
17-01-2009, 21:09
I have some hum from my Classe amps, my old Ca-100 caused slight hum which I could hear at the speakers, which ended up with me buying a CA-101 as a replacement, which did exactly the same thing. I guess it is just the design and my ears being sensitive to such. I am actually after another CA-101 for bridging now, having given up caring about the bloody hum I hear when a foot or so from the speaker.

As I can hear it at the amp case with my ear pressed close, and at the drivers of the speakers with my ears up close I guess I am being fussy, problem is, with sensitive speakers it gets more noticeable, no use with my 103db CV's and irritating when walking by my bigger Kef's.

My Krell amp is silent, even with an ear up to the tweeter, as is my Technics and Yamaha. Though at certain times of the day you can sometimes hear a small buzz come and go from the Krell transformer.

One of the reasons I moved away from valve amps was amp noise, I got rid of some decent amps due to becoming more and more irritated by small buzzing noises and hiss, these days I am under the impression that most audio is just plain noisy.

Edit, I also found my Audio Research pre's and the Classe amps benefited from careful placement, only recently have I made a birds nest of my careful cabling and noticed a slight increase in noise (I think).

jandl100
17-01-2009, 23:31
Out of interest Jerry, did your problems just started to happen, or is this something that has been around for a while? If the answer is the latter, then some/all of your test reviews might well have been incorrect:scratch:.

What?! You been drinkin' this evenin', Stan? :cool: :doh: What are you on about?

Anyway, to answer your question - yes, I've had some mild transformer buzz from some amps in my last two houses for the last 5 years or so.

Does that invalidate my views on gear I've used in those systems? I don't think so. But maybe a certain bargain priced DAC that I thought was a genuine giant killer may in fact be a piece of junk. :lolsign:

Slight transformer buzzes come and go and are inaudible anyway for the most part, when music is playing.

But my new StudioCraft Tantra TS12 subwoofer - with a 500W amp and presumably appropriately sized transformer - does buzz a little more. Still tolerable, but I'd prefer if the buzz wasn't there.
___

And by the way, a 'thank you' to the now-departed HPopeck for offering me a $300 PS Audio Humbuster for £399. Quite a bargain that - I wonder why I didn't take the kind and generous offer up? :scratch: :lol:

___

And many thanks again MikeH - of course, I am happy to wait for your DC-blocking mains cord (impatient animal, though I am!) :)

StanleyB
18-01-2009, 00:07
Does that invalidate my views on gear I've used in those systems? I don't think so. But maybe a certain bargain priced DAC that I thought was a genuine giant killer may in fact be a piece of junk. :lolsign:
I was wondering about that. I couldn't help noticing that everyone mentions which version of my DAC they got, except for you;).

jandl100
18-01-2009, 00:33
I was wondering about that. I couldn't help noticing that everyone mentions which version of my DAC they got, except for you;).

But you told me not to say! ... on pain of pain, iirc!

... OK - I've got a prototype of Stan's next DAC - the 7510+. (Is that right, Stan?). And bloody good it is too -except of course it must actually be crap 'cos of the occasional transformer buzz from my amps. :lol:

leo
18-01-2009, 00:50
Just had a read through this thread

Anyway DC on the mains was a problem at my old house which caused havoc with any of my transformers , implementing the simple DC filter already mentioned on here cured it nicely, it cost a few quid in parts, I tried it in a lead, it worked so implemented in the actual kit

My advice is take the guys offer up to implement you one in a mains lead, if it cures your problem you can splash out on one of those expensive things later if you feel the need.

BTW DC on the mains usually causes actual mechanical hum/buz from the transformer

StanleyB
18-01-2009, 01:05
But you told me not to say! ... on pain of pain, iirc!

... OK - I've got a prototype of Stan's next DAC - the 7510+. (Is that right, Stan?). And bloody good it is too -except of course it must actually be crap 'cos of the occasional transformer buzz from my amps. :lol:
That is not what I meant, but now that you mention it I was wondering if it is because the DAC is so detailed you can now hear the transformer hum from your system:scratch:.

jandl100
18-01-2009, 07:52
The hum/buzz that afflicts my kit comes from the amp itself - not thru the speakers. Disconnect the speaker leads, and the amps still buzz. I had said that at the start, I think!

Here is my original post .....


I live way out in the back-woods and my mains quality is generally poor, I think.

Lots of amps I have had suffer from transformer hum (they sound fine when used in 'civilised' areas - i.e. suburban areas at bake-offs etc).

How can I fix this? (without moving - it's nice 'round here!)

__

(The hum comes from the amps themselves, not thru the speakers)

leo
18-01-2009, 08:53
The hum/buzz that afflicts my kit comes from the amp itself - not thru the speakers. Disconnect the speaker leads, and the amps still buzz. I had said that at the start, I think!

Here is my original post .....


Yes, but thought it was worth adding the reminder, reading some posts gave me the impression some folks may have missed that;) again this points the finger towards DC on the AC which can usually be eliminated or at least greatly reduced cheaply

jandl100
18-01-2009, 09:10
Yup, thanks Leo.

A guy is coming around today with a mains filter (Anthony has seen some techie details about it and gives it a tentative thumbs up as the sort of thing he has done in the past). It includes a DC blocker.

If that works I'll wait on spending the £££ involved for the filter pending MikeH's DC-blocked mains cord. But will be interesting to see what the filter does for my system in general.

StanleyB
18-01-2009, 09:21
What you need is a mains isolating transformer. It is the only sure fire solution.

Stan

jandl100
18-01-2009, 09:23
What you need is a mains isolating transformer. It is the only sure fire solution.

Stan

I'm not sure what that is, Stan, I'm not a technical whizz like you! Can you provide more info or links?

StanleyB
18-01-2009, 09:43
Mains isolating transformers are often used in laboratories and industrial applications. Most of the repair departments I worked in had them, and I had one installed in the lab I built at my old work place.
What is it? Well, it is a transformer:). The raw mains comes in at one end(primary), and the mains at the secondary is used to power up whatever is connected to it. As you know, DC can't pass through a transformer, so the DC is left behind at the primary side of the isolating transformer.

The 2nd advantage of it is that as a noise filter. The 3rd advantage is that it can solve ground loop problems in most cases as well.For audio application you need a grounded version.

Just found this wikipedia write up:
http://en.wikipedia.org/wiki/Isolation_transformer

Stan

jandl100
18-01-2009, 09:52
Ah - OK.

Big & expensive?
Where can I buy one? (Offers of a £1900 box will be declined with thanks!) :)

StanleyB
18-01-2009, 10:14
You can start at
http://www.steinmusic.de/netzeng.htm
Or do a google. Coming to think of it, I might get one myself after having used them for decades. I love the improved quality, safety and security of the sound it gives, especially with valve stuff. You can hear the bumblebee sneeze in 'Flight of the Bumblebee', since there is no mains noise to worry about any more. And it covers your rear in case of electrical shock.

Try these guys as well:
http://www.transformer-equipment.co.uk/

Stan

jonners
18-01-2009, 10:19
What you need is a mains isolating transformer. It is the only sure fire solution.

Stan

Then the transformers in your gear will be quiet. But what happens when DC on the mains is passing through the primary of the isolating transformer - maybe that will buzz instead! :scratch:

John

Ali Tait
18-01-2009, 10:53
Jerry,a scan on ebay may net you an isolation transformer at a cheap price.It's basically a transformer that doesn't step up or step down the voltage i.e. you put 240v in,and get 240v out.As Stan says,it will prevent any dc from getting to your components.One problem I've read though is that they can affect the sound of a system in various detrimental ways.Just what I've read though as I haven't tried one myself.

StanleyB
18-01-2009, 10:59
Then the transformers in your gear will be quiet. But what happens when DC on the mains is passing through the primary of the isolating transformer - maybe that will buzz instead! :scratch:

John
Nope. Isolating transformers are designed to get rid of that problem.

sastusbulbas
18-01-2009, 11:16
Well I believe I have similar problems regarding mains, so any more links to UK sites which are selling non Foo mains transformer thingies or DC blocking mains leads which do not cost a fortune would be nice.

My own experience with mains filters and such like the Isotek mains filter, Tacima and such have had no benefit to this problem, hence my preference has been unfiltered RA 8 socket blocks.

purite audio
18-01-2009, 11:26
I spoke to Sowters regarding isloation transformers they recommended the 3575, there is a thread over on the Wam might be worth a quick look, the Sowters are approx £35.00.

StanleyB
18-01-2009, 13:20
Well I believe I have similar problems regarding mains, so any more links to UK sites which are selling non Foo mains transformer thingies or DC blocking mains leads which do not cost a fortune would be nice.

My own experience with mains filters and such like the Isotek mains filter, Tacima and such have had no benefit to this problem, hence my preference has been unfiltered RA 8 socket blocks.
Aah, but that's before I decided to get serious about taking part in this thread;).
I believe in using a pen knife to open a nut. Others prefer a sledgehammer:mental:.

sastusbulbas
18-01-2009, 15:36
Aah, but that's before I decided to get serious about taking part in this thread;).
I believe in using a pen knife to open a nut. Others prefer a sledgehammer:mental:.


:scratch: What am I missing?

jonners
18-01-2009, 16:08
:scratch: What am I missing?

Whatever it is, I'm missing it too! :scratch: :scratch:

leo
18-01-2009, 23:38
Aah, but that's before I decided to get serious about taking part in this thread;).
I believe in using a pen knife to open a nut. Others prefer a sledgehammer:mental:.

Nice :lolsign:

Mike
25-01-2009, 13:25
Jerry & Keith,

Your DC blocking leads are built and tested... Will post tomorrow.

Cheers...

purite audio
25-01-2009, 15:08
Mike you are a good man, I shall put a good word in for you with the Pope, very best Keith.

Mike
26-01-2009, 18:25
Posted! :)

Apologies for the delay... Been a bit preoccupied.

stobear
30-01-2009, 21:01
I would be very interested to hear if this makes a difference, apart from the occasional tantrum on this thread, its helped address a problem for me also. If Jerry reports a positive on the cable I am willing to put my hand in my pocket for a wad (of coins!:-)) for another cable. The French amp currently keeping me warm suffers....

Mike
30-01-2009, 21:06
It's early days at the moment, 'modifications' are afoot! ;)

To be continued...

eisenach
25-07-2015, 15:35
What happened ? Did this go to another thread ? Were Jerry's problems solved. Did the inline DC blocker work ? I have similar problems with ATC power packs and am curious to see whether nirvana was achieved !

Box13
25-07-2015, 17:50
I live way out in the back-woods and my mains quality is generally poor, I think.

Lots of amps I have had suffer from transformer hum (they sound fine when used in 'civilised' areas - i.e. suburban areas at bake-offs etc).

How can I fix this? (without moving - it's nice 'round here!)

__

(The hum comes from the amps themselves, not thru the speakers)

Get an electrician to put a spur on your electricity box just for your audio socket.
Try to find a none switching socket there are still some to be found.
Then run an earth from the spur and clasp it to your cold water mains pipe with a good solid clip.