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mains cable/kettle lead. Make any difference in sound quality?


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42 minutes ago, dave said:

And just for Tuga, a graph (I don't really understand).

742fig14.gif

https://www.maximintegrated.com/en/design/technical-documents/tutorials/7/742.html

That wins "Graph of the Month"......and looks like something I drew with a Spirograph. Remember those? Luckily, you lot are all so old, you almost certainly do!. :ph34r:

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To save another 17 pages, let me cover the basics: - If you can't hear the difference a good Mains Cable can make....either your hearing is impaired, or your system isn't resolving enough. -

So here we are then not talking about mains cables. Well while we're not on the subject. Back home just 15 mins away from Nick's and I am listening to my system. I have Tidal playing CD (not MQA)

You might be right. @TheFlash has just called round and stood in the cold outside the window to my listening room whilst I played my system (including the Chord Dave).   Nigel said that my syst

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24 minutes ago, tuga said:

If it was an issue with a DAC input interface which led to the need for a ferrite-clad S/PDIF cable then the man’s not omniscient or at least not infallible.

His DACs are also reportedly improved with aftermarket properly designed PSUs, which incidentally filter the mains current. I suspect that the reason why Chords don’t come with such a PSU is cost.

All equipment is built to a price point and its performance is limited by the designer’s technical abilities. Some are really good with the analogue side, some with the digital side, fewer with both. For some years now computer processing has become an important part of hi-fi, in sources, amplification and even speakers.

Modifying equipment to improve its design and performance requires knowledge that must of us do not possess. So we resort to accessories and tweaks (instead of actually improving the component’s circuit). Some have a large impact on performance (e.g. PSUs when the bundled wall wart is manure), some little and perhaps many no effect at all other than hype-generated expectations.

I think that the main reason why so many cable topics (and other tweaks) end the way they do is because of the sometimes insulting price of such accessories in relation to their performance and also because most claims are baseless from a scientific perspective and hardly ever supported by evidence.

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When I bought the RME I had in mind replacing the wall wart with a proper LPSU. Not because people are reporting good results, I don’t read reports nor do I give credit to people’s anecdotal experience which is often overhyped and sometimes imaginary. But the manual states that the unit has an internal switching regular which prevents internal hum noise, followed by standard linear regulators and then super low-noise regulators, to achieve its technical specs even with less optimal power supplies. It also claims that the bundled SMPS in high power and filtered.

If this sounds a bit Chinese to you then you’re not alone.

My limited knowledge suggests that with the existing configuration I will not get enough of a benefit from just plugging in a proper LPSU so I will only get one when/if I can bypass part of the input in order to reap the full benefits. It’s not something I can do myself so I intend to have someone look at the circuit.

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I would expect the RA cable filter, if indeed it does what it claims, to improve performance in equipment whose PSU does not perform the filtering adequately or at all. I would expect most well designed equipment not to need any help but the designer claims improvements in a top Meridian. I would rather spend £2k in a better DAC or get better speakers...

Your RME smps has a standard switching regulator which as it switches so fast does not have low frequency noise like hum. The inevitable hf noise is then regulated by a standard reg like the 317 family which removes more noise but not at the highest freq. This is what the final reg does I suspect. The latest regs of this type from TI and LT are designed to do this and can work very well getting residual noise down to microvolt levels. This is what they mean. Seems to be a well designed product but it depends what it spec actually is.

By the way the graph is the standard smith chart for matching loads and impedances in RF and microwave applications.

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3 minutes ago, zeta4 said:

Your RME smps has a standard switching regulator which as it switches so fast does not have low frequency noise like hum. The inevitable hf noise is then regulated by a standard reg like the 317 family which removes more noise but not at the highest freq. This is what the final reg does I suspect. The latest regs of this type from TI and LT are designed to do this and can work very well getting residual noise down to microvolt levels. This is what they mean. Seems to be a well designed product but it depends what it spec actually is.

By the way the graph is the standard smith chart for matching loads and impedances in RF and microwave applications.

Thanks, that was very clear.

Does it make sense to you to bypass the first internal switching regulator when the DAC is powered by a well designed LPSU? I had assumed that it was there to improve performance with SMPSs.

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1 hour ago, dave said:

I am not so sure.... any piece of wire can't help but be subject to this lot. Black hole... wouldn't go there (I don't).

https://en.wikipedia.org/wiki/Transmission_line

https://en.wikipedia.org/wiki/Antenna_(radio)

For hardcore techies.

Definitions means Jack... Given by humans just like you and me. 

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13 minutes ago, tuga said:

Thanks, that was very clear.

Does it make sense to you to bypass the first internal switching regulator when the DAC is powered by a well designed LPSU? I had assumed that it was there to improve performance with SMPSs.

Sorry I wasnt clear enough. The first switching regulator is the fundamental part of the smps not additional ( have a look at something like an LM3481). An LPSU might benefit from the using the two analogue regulators but you might run into LF noise problems. If you going to change the psus better to use a properly designed LPSU in the first place I would have thought. Incidentally you can get as good if not better results using passive filter then a cap multiplier (much cheaper).

Re mains leads. In my experience main borne noise can effect upstream equipment but its relatively easy to design the equipment to reject it. I just use ordinary mains cable with good solid connectors.

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1 minute ago, Nativebon said:

Definitions means Jack... Given by humans just like you and me. 

Sounds a bit like Cue @ n o n...

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6 minutes ago, zeta4 said:

Sorry I wasnt clear enough. The first switching regulator is the fundamental part of the smps not additional ( have a look at something like an LM3481). An LPSU might benefit from the using the two analogue regulators but you might run into LF noise problems. If you going to change the amps better to use a properly designed LPSU in the first place I would have thought. Incidentally you can get as good if not better results using passive filter then a cap multiplier (much cheaper).

Re mains leads. In my experience main borne noise can effect upstream equipment but its relatively easy to design the equipment to reject it. I just use ordinary mains cable with good solid connectors.

I guess I was even less clear, or I could be totally confused as well.

My question is whether I need the first switching regulator which is inside the box (the first component after the AC input socket) with a properly designed LPSU.

To go from this:

SMPS > DAC ( switching regulator > standard linear regulators > super low-noise regulators )

to this:

LPSU > DAC ( standard linear regulators > super low-noise regulators )

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1 hour ago, dave said:

And just for Tuga, a graph (I don't really understand).

742fig14.gif

https://www.maximintegrated.com/en/design/technical-documents/tutorials/7/742.html

In the grand scheme of audio playback power cables is one matter that is not worth my effort. It’s pretty though.

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3 minutes ago, tuga said:

I guess I was even less clear, or I could be totally confused as well.

My question is whether I need the first switching regulator which is inside the box (the first component after the AC input socket) with a properly designed LPSU.

To go from this:

SMPS > DAC ( switching regulator > standard linear regulators > super low-noise regulators )

to this:

LPSU > DAC ( standard linear regulators > super low-noise regulators )

So if I understand that right the first smps is an AC/DC converter supply. This feeds DC (with hf noise) to a DC/DC converter in the DAC (which is also a smps). If so it would be important to know what the voltage conversion is ie 12V to 5V and probably other voltages that the DAC needs like 3.3V. These noisy DC voltages are fed to the linear regulators.

So if you wanted to replace all the smps you need an LPSU with all the right voltages.

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1 minute ago, tuga said:

power cables is one matter that is not worth my effort

Yet here you are. xD

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7 minutes ago, zeta4 said:

So if I understand that right the first smps is an AC/DC converter supply. This feeds DC (with hf noise) to a DC/DC converter in the DAC (which is also a smps). If so it would be important to know what the voltage conversion is ie 12V to 5V and probably other voltages that the DAC needs like 3.3V. These noisy DC voltages are fed to the linear regulators.

So if you wanted to replace all the smps you need an LPSU with all the right voltages.

I won't be doing this myself anyway, but thanks for questioning my logic. It's good to know it makes sense (though whether or not such a modification will improve audible performance is yet to be proven).

KQfn7sZ.gif

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21 minutes ago, Griff500 said:

Yet here you are. xD

Indeed. Just to p1ss you off... :P

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12 minutes ago, tuga said:

I won't be doing this myself anyway, but thanks for questioning my logic. It's good to know it makes sense (though whether or not such a modification will improve audible performance is yet to be proven).

KQfn7sZ.gif

No problem. What Ive done in the past to check out whether there was any improvement when changing power supplies like this is to rig up some batteries to supply the linear regulators. Not usually practical in the long run but you can be sure your not getting mains or switching noise so can tell you what it utlimately can sound like. Sometimes its tempting to leave them in ! 

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16 hours ago, tuga said:

Are there any other filtering power cables?

I don’t know if this counts as filtering, but apparently it changes the waveform rather than reducing RFI.  Our own @hifinutt is a fan. 
https://isoteksystems.com/products/evo3-syncro/

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probably something like this:

xfmr-dc-f8.gif

https://sound-au.com/articles/xfmr-dc.htm

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