Turk 182

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On 03/06/2019 at 13:56, rabski said:

Exactly.

Further to that, a lot of the equipment that many of us enjoy was built and designed prior to some things that are now causing problems.

Another issue that I've recently been made aware of concerns non-OEM replacement power supplies. Want to know why you can buy some really cheap ones? After passing certification, it seems some manufacturers in certain countries have realised that a great way to save on build costs is to 'accidentally' leave out a few components. There are a number of examples circulating around the internet of, for example, common-mode chokes and capacitors being left off. It doesn't take a great deal to realise that even a competently-designed power supply would not have been designed to cope with the result of something like that.

Never buy cheap chargers or PSUs with unknown branding, especially from Ebay. They could well kill you.

On 03/06/2019 at 13:13, Bodgit said:

Or to turn that statement around:

Mains will interfere with the sound quality of hifi gear unless such gear is cleverly designed to deal with RFI and other kinds of interference; such design costs money and not all manufacturers will prioritise this aspect of the design in their gear. DC offset in mains will introduce toroidal buzz.

Bearing in mind that all power supplies even in budget amplifiers have very good mains filtering (they would hum if not)  how do you think RFI gets into them enough to add distortion and cause a drop in actual sound quality? It doesn't ever, although it might raise the background noise.

The only way is direct radiation, and that is something all the mains filtering stuff in the world cannot prevent.

Not that it's ever a problem unless you are using a high gain phono stage. 

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Posted (edited)
12 minutes ago, Turk 182 said:

thanks for confirming this.

my old mf xa1 would hum like hell if the hair dryer was plugged in somewhere !

That's because a modern hair dryer on the low setting has a series diode to drop the power. It then causes the mains waveform distortion.

Edited by Muckplaster

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6 minutes ago, Muckplaster said:

Never buy cheap chargers or PSUs with unknown branding, especially from Ebay. They could well kill you.

Bearing in mind that all power supplies even in budget amplifiers have very good mains filtering (they would hum if not)  how do you think RFI gets into them enough to add distortion and cause a drop in actual sound quality? It doesn't ever, although it might raise the background noise.

The only way is direct radiation, and that is something all the mains filtering stuff in the world cannot prevent.

Not that it's ever a problem unless you are using a high gain phono stage. 

I've seen this and similar arguments made repeatedly.

The simple fact is that most equipment actually does not have particularly good mains filtering. Mainly because it isn't all that necessary. It's 'good enough' for most applications, but the more sensitive the rest of the system is, the more that noise (as you say, background noise) becomes an issue.

Unfortunately, many of us have turntables and many of us use an MC catridge or two. Even moderate-gain phono stages have their issues. I'm happy to admit that most of the associated noise is actually from the circuit itself in many cases, but not all of it.

Also remember that transformer saturation can result in not just mechanical noise, but also harmonics. Yes, a 'competently designed' power supply is relatively immune. However, have you seen how much equipment is floating around that was originally designed for a wide range of markets, often with 60Hz supplies or less than the possible UK mains voltage? Transformers are expensive. The world of designing-in sensibly large margins is in many cases a distant memory unfortunately.

I've owned a fair few bits of equipment over the years. Most has been relatively immune to problems, but not all.

A lot of people don't really worry about a slightly high noise floor. I'm afraid I'm not one of them. I want silence when there's no music. I'll accept a little (very) faint hum and hiss as the penalty for using a low-output MC, a step-up transformer and a high-gain valve phono stage, but any more than that and it's in bits on the workbench, because I hate noise.

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On ‎02‎/‎06‎/‎2019 at 16:12, rabski said:

...As others have pointed out. Things like cables, mains conditioning, etc. are at best just tinkering around the edges. Get everything else right first before you even think about thinking about stuff that can only make the smallest (if any) difference.

Very wise words . 

A less than wonderful mains supply never stopped a good and well set up system from playing music in a rewarding way .

...and all the mains conditioners  and fancy  wires in the wold will not extract enjoyable music from a system that's not basically right.

If you have a system that you're essentially happy with , then by all means  experiment with this  stuff to see if it gives any improvement.[some folks' mains supplies are more blessed than others] ...but if you aren't happy with a system, you won't fix the problem with mains conditioning .

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On 04/06/2019 at 21:10, rabski said:

I've seen this and similar arguments made repeatedly.

The simple fact is that most equipment actually does not have particularly good mains filtering. Mainly because it isn't all that necessary. It's 'good enough' for most applications, but the more sensitive the rest of the system is, the more that noise (as you say, background noise) becomes an issue.

Unfortunately, many of us have turntables and many of us use an MC catridge or two. Even moderate-gain phono stages have their issues. I'm happy to admit that most of the associated noise is actually from the circuit itself in many cases, but not all of it.

Also remember that transformer saturation can result in not just mechanical noise, but also harmonics. Yes, a 'competently designed' power supply is relatively immune. However, have you seen how much equipment is floating around that was originally designed for a wide range of markets, often with 60Hz supplies or less than the possible UK mains voltage? Transformers are expensive. The world of designing-in sensibly large margins is in many cases a distant memory unfortunately.

I've owned a fair few bits of equipment over the years. Most has been relatively immune to problems, but not all.

A lot of people don't really worry about a slightly high noise floor. I'm afraid I'm not one of them. I want silence when there's no music. I'll accept a little (very) faint hum and hiss as the penalty for using a low-output MC, a step-up transformer and a high-gain valve phono stage, but any more than that and it's in bits on the workbench, because I hate noise.

It appears that you have no clue. Ah well.

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