My wall-wart heaven (contains DV p75 III content)

Update. Having been doing housework and general running around for a few hours just sat down to grab a breather (getting older). Popped on a bit of Micheal Hedges. Bloody hell! What's happened. Sounds quite a bit different to when I first plugged the iPower in. Even more clarity. Better transient handling, fast notes start and stop more distinctly.  More out of the box sound from the IBLs. Very happy with that £40 upgrade. 

Hmm, the OP's experience is weird. In the UK, the distributor chucks the original wall-wart away and throws in a linear supply wall-wart, so I wouldn't expect a £10 wall-wart to be substantially better. Not heard the ifi product but ifi products are generally well regarded and Mike's testing seems to show substantial improvement so I'd expect an improvement there. Just a bit nonplussed by the OP's experience. 

Frank.

I bought my DV p75III ex-dem from my branch of Audio-T. A heavy, chunky wall wart was included. I only mention the latter because the p75III's manual says, "Power supply is not included. Please purchase a suitable supply at your local dealer", so I thought I'd done alright.

Months later I discovered the wall wart had a small crack in the casing which I disregarded. That is until it started to bug me when I was vexxed with the sound of my records, and tried to look at everything.

The new wall wart is like a mobile phone charger.

Chris

There was a time when we charged £5 for the charger but nowadays we just bundle it. The thing that worries me about the ifi iPower is that it's an SMPS which have a tendency to pollute the mains.

Frank.

So Frank, is my experience still weird?

C.

You might take a read at the iFi iPower www Frank, they claimed the iPower to be lower noise on DC than a linear PS,  it doesn't say anything specific re switching mode noise back into the mains,  but with the latest regs & standards that is not so much of an issue as it used to be.  

Yes Mike, I did. It might be lower noise at the output, but does it pollute the mains like so many SMPSs do? That's the question. And sod the regs - all I know is that every time I yank an SMPS out of the mains the Naim system opens up a bit, all SMPSs which have passed the regs...

Frank.

Frank,  SMPS have a bad reputation & justifiably so, but mostly based on cheap & wall wart type units.  These days practically everything in consumer electrics & electronics that needs DC is SMPS;  I don't think any TV, BRP or PVR has anything but a SMPS,  then what about Linn.   I would be interested in your opinion if you could try one of these iPower units

Marksnaim has found the supply makes a difference. So have I but I think my original was faulty, perhaps as if it had been dropped. What I have now is a working ten pound job.

DV say the quality of the supply makes no difference and you can find out why if you look at the p75 III's pdf. This puzzles me because of Mark's experience. But does it matter, not really. Records sound good.

C.

Sounds like the iFi iPower might be the 'new' Russ Andrews DynaPak.  I remember the incredible results some forum member achieved with the PowerPak on P75's some years back. I bought one primarily to get rid of the wall warts, which are a PITA when you have tapon plugs like we do in NZ.  Can't say i noticed much of a difference over the wall wart that came with my P-75 though. 

Marksnaim posted:

Update. Having been doing housework and general running around for a few hours just sat down to grab a breather (getting older). Popped on a bit of Micheal Hedges. Bloody hell! What's happened. Sounds quite a bit different to when I first plugged the iPower in. Even more clarity. Better transient handling, fast notes start and stop more distinctly.  More out of the box sound from the IBLs. Very happy with that £40 upgrade. 

Hi Marksnaim,  

I've not heard the 'improved upgrade ' wall wart , but from my experiences with a iFi iCan I have to say that you seem to have just , to a large extent described the iFi house sound.  Very interesting 

Glad you like it  Martin

Hi Marksnaim,

Delighted that your iFi iPower is working so well for you.  I have a DV P75 Mk 2 with its original wall wart power supply and would like to try one of the iFi ones.  Which version/model did you use?

Thanks in anticipation, FT

Mike-B posted:

Frank,  SMPS have a bad reputation & justifiably so, but mostly based on cheap & wall wart type units.  These days practically everything in consumer electrics & electronics that needs DC is SMPS;  I don't think any TV, BRP or PVR has anything but a SMPS,  then what about Linn.   I would be interested in your opinion if you could try one of these iPower units

SMPS by their nature generate noise - significantly more noise than a linear power supply. However there are some advanced electronic and signal processing techniques to noise shape and spread the noise that depending on the connected application will produce less noticeable or 'annoying' intermodulation distortion in nearby or connected electronics by increasing the spectral density of the switching noise.

This TI paper http://www.ti.com/download/trn...ice_Gehrke_Segal.pdf 

is interesting as they show some TI methods and chipsets that are specifically designed to modulate the switching carrier that increases the spectral density of the noise but lowers the energy of the harmonic peaks of the noise (this is the curse from SMPS that produces intermodulation  distortion/artefacts). If I was to use a SMPS with delicate electronics this is the sort of thing I would be looking at - but it will be larger and more expensive than your standard wall wart type power supply.

So if you can use a linear power supply then do so - if not then ideally use a SMPS with a modulated switching frequency...

I have no idea whether the iFi or Linn power supply uses noise spreading/shaping signal processing  techniques... if they do these are far from your standard SMPS power supply used in consumer electronics... but they INCREASE the noise density - but REDUCE the noitcable intermodulation distortion from the harmonics. Perhaps someone with one of the iFi PSUs can open the lid and see if its using a noise spreader signal processing chipset as described in the above paper.

Simon-in-Suffolk posted:

.......................    Perhaps someone with one of the iFi PSUs can open the lid and see if its using a noise spreader signal processing chipset as described in the above paper

Maybe when the warranty runs out - maybe, Also it looks like a no screw click together box so it might prove to be a bit harder to reassemble than disassemble.   

I will keep trying to find a circuit diagram of some sort,  but iFi don't seem too keen to make these available,  like that cmpy in Salisbury. 

It might be more interesting to give an iFi iPower to someone with the equipment to test for mains switching mode noise & also see how the DC 1uV claim matches up 

Frank Abela posted:

... In the UK, the distributor chucks the original wall-wart away and throws in a linear supply wall-wart, so I wouldn't expect a £10 wall-wart to be substantially better...

Frank.

Hi Frank,

Are you sure that the P75 as sold in the UK uses a linear power supply wall wart?  I have a P75 mk II and its wall wart is certainly a lot chunkier than the small SMPS wall warts that you normally see with phone chargers etc.

I ask because last year, when I was trying different phono stages etc.,  you recommended that I put the P75 on a different ring main than the dedicated radial that supplies all the Naim boxes. The logic being that the SMPS with the P75 would make the Naim system sound a bit "sat on" if fed off the same supply.

After a bit of swapping over, I find music to sound slightly calmer and smoother when the P75 is on the same mains radial as the Naim boxes. This would suggest to me that my P75 does indeed have a linear power supply and yes, it's the one that came with the P75 when I bought it new.

Separately, I have ordered a pair of iFi iPower wall warts for the  Netgear Ethernet switches, but am wary of spoiling the party when my vinyl front end is sounding so utterly gorgeous and involving!

best regards, FT

Doesn't either the Statement pre or mono blocks have some sort of SMPS within it ? I thought I read about one being used to power the logic control for something.

Foot tapper posted:

Hi Marksnaim,

Delighted that your iFi iPower is working so well for you.  I have a DV P75 Mk 2 with its original wall wart power supply and would like to try one of the iFi ones.  Which version/model did you use?

Thanks in anticipation, FT

Hi FT, I just got the 12V iPower. Maybe the improvement in sound comes not from what it does for the DV75 but what it doesn't do to the mains? I'm no expert of course. Anyway for £40 I'm happy, even if it's all in my head (although I'm reasonably sure that's not the case) Neater than the old supply that was supplied with the DV in the first place too.

Thanks Mark.

I have just checked with Pear Audio (the UK distributor for Dynavector) and they have confirmed that the wall wart that they supply to UK customers with the P75 mk II and mk III is a linear power supply, not an SMPS, so I am going to stay with mine as it is.

I've raided my Panama City fund and pulled the trigger on a 12V DC iPower. A nation waits......

C.

Foot tapper posted:

I have just checked with Pear Audio (the UK distributor for Dynavector) and they have confirmed that the wall wart that they supply to UK customers with the P75 mk II and mk III is a linear power supply, not an SMPS, so I am going to stay with mine as it is.

Also worth reading the blurb that DV have on the P75 re the 12vDC supply,  they mention that the wall wart PSU has no effect on the P75's SQ because they have their own internal power supply system that converts 12vDC to 250kHz to supply the amp stages.

Now it might prove interesting considering Marksnaim post on his positive SQ changes,  & now Chris has raided his Panama Piggy Bank,  the plot thickens   .............   

It's still possible that the improvement I have heard is not due to any direct effect on the DV75 but on the effect (or lessening of effect) that the iPower has on the mains. Difficult to prove either way without access to adjacent dedicated and non dedicated mains supply.

I suspect that might well be so to some degree at least,  I'm also not convinced about the DV internal switching device & that it will completely block whatever switching mode noise the wall art brings.  Simple basic (cheap) SMPS can have noise that goes up to MHz's & that is not so easily blocked.          

Christopher_M posted:

I've raided my Panama City fund and pulled the trigger on a 12V DC iPower. A nation waits......

C.

 

Continents await!

A report posted this morning re iFi iPower on a DV P75  .................   I did a very quick A-B comparison, literary just a couple of bars of "When the Levee Breaks" and I'd say that straight out of the box there was notable improvement over the stock wall wart.       ..............................    

And final point to double check before connecting ...... P-75 Mk-1 & Mk-2 have a negative central pin.  Mk-3 has a positive central pin ......... the iPower kit has a negative pin adaptor included