[Closed] Hi fi - "clean" mains

Some capacitors.

These are what is normally used for decoupling power rails. Your equipment will already have loads, but you can add more in a box if you like and pay 1. not very much if you do it yourself; 2. loads if you want someone else to do it for you.

Wind up, surely?

Unless your mains comes in on a ley line forget it.
Myself, I use batteries charged by solar panels with cold filtered sunlight.

More to it than that surely...I know what they do. It's about cutting out interference etc from the mains itself and introduced by cheapo PSUs on your other eqpt?

If you disagree, what do you suggest? A mix of types an sizes?

Easiest way is to just be sure the loop it's on isn't the same as anything with a high drain or a motor in it. Easiest way is to look at the fuse board, and make sure nothing like that is pluged into the same loop as the hi-fi, and preferably not even in the same phase if possible(assuming your house has 3 phase electrics).

And yes, a noisy mains will ruin a good hi-fi's sound.

Al what equipment do you have?

Please guys, have you even tried listening to decent power supplies on your equipment?

A sh Valhalla board (£50 to me a decade ago) transformed my TD160.

Amused at the thought of someone soldering caps across the mains.

In my flat there's one light switch that when used makes my PC speakers go 'pop'. Would a mains conditioner stop that or is the flat just really badly wired?

Mike

hot-rodded TD160 - valhalla, rewired RB300, (but knackered cartridge), new subchassis & wall mounted support
DNM Start pre-amp
Crimson monobloks
Rega Kytes, soon to be replace by cynic-al floorstanders.

Can SFb et al dullards please stay away

I hope you're not discriminating against dullards ? Don't we have a right to unspiky voltages too ?

we all of course know that such devices CAN NOT POSSIBLY MAKE ANY DIFFERENCE

this is of course quite wrong as it will enrich the people selling mains cleaners

BTW, plenty of interesting reading here, including some stuff about cables 😆 (not sure if there's anything about mains conditioning though):

http://sound.westhost.com/articles.htm

Can SFb et al dullards please stay away

I hope you're not discriminating against dullards ? Don't we have a right to unspiky voltages too ?

we all of course know that such devices CAN NOT POSSIBLY MAKE ANY DIFFERENCE

this is of course quite wrong as it will enrich the people selling mains cleaners

If you have top notch kit a clean mains supply is worth it IMO, and it's relatively cheap compared to a lot of other hi-fi upgrades.

you'll trust the guys who make your kit to convert digital to analogue, take in low level analogue from phono stages, and amplify them in a manner you find appealing to your ears, but you won't trust them to rectify the mains properly?
okthen....

http://sound.westhost.com/cables-p4.htm#power

EDIT: actually that link has nothing to do with mains filtering, but he does have this to say:

"Typical filters will use Metal Oxide Varistors (MOVs) to cut off any high voltage spikes, and a capacitor and inductor network to filter out anything that is not at the mains frequency.

A true 50Hz (or 60Hz) tuned filter will be a large unit indeed, so most line filters only work at frequencies above a few kHz. This is generally enough to get rid of most interference, since a well designed power supply should be able to filter out the majority of noise from the mains."

Del - Member
you'll trust the guys who make your kit to convert digital to analogue, take in low level analogue from phono stages, and amplify them in a manner you find appealing to your ears, but you won't trust them to rectify the mains properly?
okthen....

I think you need to change your name al, perhaps gullible_al would be appropriate.

perhaps gullible_al would be appropriate

I was just thinking that :o) I think the idea is that he's cynical about anything not directly observable, which is a respectable stance (at least, to a dullard)

OK you can be "rich-does-not-trust-own-ears"

FFS.

Do you guys actually listen to components in systems or just do engineering degrees?

I worked in hi fi manufacturing, design and retail. Sorry, but you are just talking nonce-sense!

Out of interest, how many of those Hi-Fi chappies ever get their hearing tested, y'know, just to make sure they're not throwing money away?

...it's not that difficult to see how religion gets going; compared to the Hi-Fi world, it's all far more plausible.

Do you guys actually listen to components in systems or just do engineering degrees?

I only ever listen to music in this context. Listening to the sound of the sound would be entirely beside the point.

[url] http://en.wikipedia.org/wiki/Presbycusis [/url]

[url] http://en.wikipedia.org/wiki/Snake_oil [/url]

[url] http://en.wikipedia.org/wiki/Smiley [/url]

Have you ever listened to this stuff or do you just sit around being "clever"?

I'm wondering whether a UPS would help, me. Summik like [url= http://www.micomonline.co.uk/products.asp?partno=15601&go ]this?[/url]

[i]Have you ever listened to this stuff or do you just sit around being "clever"? [/i]

It's a pretty valid question though. Take a hi-fi amp company that you respect and ask yourself why would the designer not incorporate suitable mains filtering?
The only two reasons I can think of are cost or incompotence. Now filtering (in the grand scheme of things) isn't that costly, certainly not when compared to big transformers, so that would leave incompotence?

Take a hi-fi amp company that you respect and ask yourself why would the designer not incorporate suitable mains filtering?

with respect, thought experiments are even more far fetched than subjectivism...

you only have to handle many common products of design to realise that common sense or the needs and abilities of the intended users have not figrred much in the process 🙁

"Take a hi-fi amp company that you respect and ask yourself why would the designer not incorporate suitable mains filtering?"

Many do including Sony,panasonic and LG on their plasma displays as well

>ask yourself why would the designer not incorporate suitable mains filtering?

Judging by the interconnect thread, some people think it isn't so much designed as pulled out of a virgin's chuff 😉

Seriously - you could add a 'mains conditioner' but all it'll do is suppress typically non-periodic transient/switching noise*, and maybe some high frequency noise (tho' your amp supply ought to do that anyway). If that's what you're after then that ought to be fairly cheaply obtainable - I'd guess significantly more than 30 quid and you're being ripped off or into the realm of rapidly diminishing returns.

*actually, transient noise *is* high frequency by its nature, or more accurately, wide-band, but some of the spikiness may get through the amp psu - depends on how the amp's been designed and how spikey the spikiness is.

A UPS generates 50Hz ac from a dc supply - in doing that it'll generate some low level periodic noise (tho' not necessarily audible) - you'll get less supply glitchiness but you equally may get most of the way with a simple mains filter.

If you've got anything particularly noisy on the mains, it'd make as much sense to find whatever it is and deal with that (at a guess appliance motors, switches, dimmers).

>Amused at the thought of someone soldering caps across the mains
Cue 'what caps for house destruction or general messiness ?' thread 😉

Jond, how do UPS generate the 50Hz AC from the DC? If there's some switching in there you could get some audio frequency noise at the switching point. They would possibly filter this out, but I imagine in a lot of cases these products will be built down to a cost.

Well, no. I'm not going to comment. No no no no no... 🙄

Lo' Ads - offhand I dunno - I reserve the right to talk b*llocks 😉

But if you built it as a class D amp - ie using pwm - then you can choose your sample rate
http://en.wikipedia.org/wiki/Electronic_amplifier#Class_D
and it's probably pretty efficient.

Aha:
http://en.wikipedia.org/wiki/Pulse-width_modulation
In fact
http://en.wikipedia.org/wiki/Inverter_(electrical)#Circuit_description
(including the smelly 'lob a square wave in the general direction of a transformer !).

I guess there's no reason you couldn't just use something like a wien bridge and a couple of transistors +centre-tapped transformer to be realtively linear, but the efficiency wouldn't be very good.

>Well, no. I'm not going to comment. No no no no no...

😉

I'm not sure you care about efficiency, just the noise spectrum from all the switch crap going on. Oh yeah, don't talk to me about PWM. I'm just doing a big project on motor control. PWM is OK though as I'm generallly a 0's and 1's guy 😉

I'm just doing a big project on motor control. PWM is OK though as I'm generallly a 0's and 1's guy

I sympathise. I had to design a DSP motor controller for a 1kw ac servo motor a few years back. That used to shit me up big time each time there was a fault in the code 🙂

I'm just doing a big project on motor control. PWM is OK though as I'm generallly a 0's and 1's guy

and it'll sound like shit 🙁

In no way relevant to this thread, but for the motor control people:-

>I'm not sure you care about efficiency, just the noise spectrum from all the switch crap going on.

Agreed, to the extent that someone wants to run their amp off a UPS.
But a UPS is *normally* going to be designed for something that can't afford to be switched off (quickly, at least) and with a limited battery limit, so it'll be designed to maximise efficiency, rather than it's sinewave fidelity - hairchested's link is a a computer ups.
There's nothing stopping you designed something different if sinewave accuracy's what you're after, but that's not yer typical UPS.

>and it'll sound like shit

I think it's come on a long way - saw some figures on something recently and was surprised it was something less than 0.1% thd.

~0.01%:
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1358802

(No, I'm not gonna get into an argument about 'it's not all thd') - this stuff's primarily aimed at being efficient - high power and compact/low dissipation, or portable)

Also, I wasn't refering to PWM being ok for hifi per se, I was refering to it being OK for me to get my head around. But then it's not uncommon for people to get the wrong end of the stick on an internet forum 🙂

Jon, have you actually listened to PWM with your own ears eh? I would have thought the low freq attenuation of your facial hair and standing waves created round your sandals would cause sufficient cross-coupling combobulation to affect both the highlights and soundstage. 😉

simonfbarnes - Member

Listening to the sound of the sound would be entirely beside the point.

Balls, for the first time ever I have to agree with SFB, ****, **** & **** 🙁

>and it'll sound like shit

I think it's come on a long way - saw some figures on something recently and was surprised it was something less than 0.1% thd.

I meant the motor :o)

I recall Clive Sinclair selling a PWM hifi amp back in about 1970 🙂

A bit OT but a few years ago I had a seperate spur for my hi-fi with round pin plugs installed. Cost ~£300, pretty cheap for a hi-fi upgrade. Happy enough (Linn / Naim set up)