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How to get the best Phono Signal?
#21
(19-Jan-2018, 16:51)Confused Wrote:
(19-Jan-2018, 16:35)brit Wrote:
(19-Jan-2018, 16:13)Confused Wrote: It has been speculated in this thread that there may be a difference in the quality / hiss level of the phono stage in various Devialet amps.

OK, with respect to preferences between different external phono stages, this is in part subjective and may be system dependant, all of which is fair enough.

However, the hiss level is easily measurable with a smart phone dB app or similar.  It looks like it might be a dull and wet weekend here in the UK, so something to try if you have some time?  I think it might be interesting if we could establish that there are significant / measurable differences between the phono stages in different amps.

This is a check I performed with an iPhone app tried a while back:

Turn the amp on, select phono, at -40dB, all is quiet.  Up the volume to 0dB and you can hear the hiss very clearly.  Using an iPhone app and the phone roughly in the listening position, it recorded about 36dB as background silence (silence is quite noisy in terms of dB's)  Upping the volume until the app reached 50dB, I checked the Dev and it was on about +2dB

Hi @Confused. Just for clarity, what App are you using to conduct this check?


David

Decibel X - I have no idea how accurate it is, but I guess it would help if we use the same app for consistency.
Hello @Confused. That’s a very smart idea especially if a few of use contribute. It has a great potential to suggest if amp performance is consistent or variable, although speaker sensitivity will surely show variations in results. Maybe contributors could include the sensitivity spec of their speakers which would make working out a result more meaningful. I have a busy weekend ahead, but I have downloaded the Pro version of the app and will give it a go when I have time.

Being in principle a subjectivist, this is (for me) when objective measuring becomes worthwhile. In this particular application, it should eliminate the variance of members preferred listening levels. I am well aware that some like to listen to music with system set to low dB and others like it loud. By implication, my hiss affected unacceptable sound is a level another member would never visit. This test has the potential to identify both that and whether there is inconsistency in our Phono stages.

Many thanks for suggesting this experiment.
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#22
Here are my results using the dB X app:

Background silence = 36dB

-40   38dB
  0   48dB
+1.5 50dB

At my maximum usual listening level of -20dB I can’t hear any hiss from my Speakers and the app registers 36dB.

I guess the results are dependent on which cartridge you are using, and therefore loading values. Does that make sense?
Project Eperience X Pack with Ortofon Rondo Red MC, Oppo BDP 105D, Sonos Connect, QNAP HS251+ NAS with 2*6TB Western Digital Red, Mutec MC-3+USB, Mac 5K 32GB running Lifetime Roon, iPad Pro 12.9" for remote control.  Etalon Ethernet Isolator, Devialet 440 Pro CI, Sonus faber Olympica ll, Auralic Taurus Mkll headphone amp.Denon AH-D5000, Sennheiser HD600 and HD800 with Cardas cable,  Van Den Hul The First Ultimate interconnects, GSP Audio Spatia speaker cable.
South Coast England
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#23
I'd expect the results to depend a lot on the configured gain of the phono stage, which surely will be different for MM and MC, and is likely to be determined by the "max level (mV/µV RMS)" setting.
Roon (Mac Mini), Wilson Benesch Full Circle, Sonos ZP90 (Cullen modified), Devialet 440 Pro, Kaiser Chiara
Warwickshire, UK
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#24
(20-Jan-2018, 10:07)thumb5 Wrote: I'd expect the results to depend a lot on the configured gain of the phono stage, which surely will be different for MM and MC, and is likely to be determined by the "max level (mV/µV RMS)" setting.
@thumb5 . Yes mate, that’s what I was getting at, but you described it better than me.
Project Eperience X Pack with Ortofon Rondo Red MC, Oppo BDP 105D, Sonos Connect, QNAP HS251+ NAS with 2*6TB Western Digital Red, Mutec MC-3+USB, Mac 5K 32GB running Lifetime Roon, iPad Pro 12.9" for remote control.  Etalon Ethernet Isolator, Devialet 440 Pro CI, Sonus faber Olympica ll, Auralic Taurus Mkll headphone amp.Denon AH-D5000, Sennheiser HD600 and HD800 with Cardas cable,  Van Den Hul The First Ultimate interconnects, GSP Audio Spatia speaker cable.
South Coast England
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#25
There are many variables I think, the main one being the phono stage gain as already mentioned, but speaker type / efficiency, the amplifier power and even the room will be factors. From my own experiments with the 1000Pro I needed the amp set 1 or 2 dB lower to get the same hiss level as the D800, but that is compensated by the fact that you would run the 1000Pro at 1 or 2dB less to get the same loudness as a D800. It also occurs to me that results could vary between different models of iPhone, even with the same app.

That said, I am actually very surprised at how similar the results are from myself @brit and @Axel. (Thanks for taking the time to try this!) We are all running MC cartridges with slightly different gain settings, but the results are almost identical.

What would be really interesting would be if someone with MC settings in the range of 0.3 to 0.5mV obtained significantly different results. There have been some claims of hiss free Devialet phono stage performance in the past, with MC settings.
1000 Pro - KEF Blade - microRendu - Mutec MC3+USB - Pro-Ject Signature 12
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#26
(20-Jan-2018, 11:49)Confused Wrote: There are many variables I think, the main one being the phono stage gain as already mentioned, but speaker type / efficiency, the amplifier power and even the room will be factors.    From my own experiments with the 1000Pro I needed the amp set 1 or 2 dB lower to get the same hiss level as the D800, but that is compensated by the fact that you would run the 1000Pro at 1 or 2dB less to get the same loudness as a D800.  It also occurs to me that results could vary between different models of iPhone, even with the same app.

That said, I am actually very surprised at how similar the results are from myself @brit and @Axel.  (Thanks for taking the time to try this!)  We are all running MC cartridges with slightly different gain settings, but the results are almost identical.

What would be really interesting would be if someone with MC settings in the range of 0.3 to 0.5mV obtained significantly different results.  There have been some claims of hiss free Devialet phono stage performance in the past, with MC settings.

Hi Confused

It so happens that I was just doing this on a miserable rainy day in Portishead!

At the listening seat (~9 ft from speaker plane) I hear significant hiss from my Koetsu set to 0.35 mv.
My measurements are:

Dev Volume (dB)                 Sound Meter (dB) 

Off (i.e. room sound)                   17
-40                                            17-20
-20                                            20-22
-15                                            26-28
-10                                            29-32

My normal listening volume is around -15dB on the Dev. -10 would be very loud.

I am surprised at how low the readings are as I perceive the hiss at -15dB setting to be quite loud. However my dB meter indicates that it is 'rustling leaves/quiet library'........

It would seem that the human ear is tremendously sensitive to white noise.

The hiss does not bother me (I've had worse valve amps) and is inaudible when listening even between tracks.

Hope this helps

Kevin
Devialet 1000 Pro; Magico S5 loudspeakers; Metronome T3a Signature CD Transport; Krell Connect Streamer; SME 30/2; Graham Phantom Elite; Koetsu Sky Blue; MacMini/QNAP/Air3/ROON; Audioquest Vodka and Carbon Ethernet; Transparent Reference Digital RCA-RCA; Transparent Reference XL MM2 speaker cable; Transparent Reference mains cable; PS Audio P5 PowerPlant; Artesania and Finite Elemente equipment racks 
North Somerset, UK     
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#27
(20-Jan-2018, 12:34)KIBM Wrote:
(20-Jan-2018, 11:49)Confused Wrote: There are many variables I think, the main one being the phono stage gain as already mentioned, but speaker type / efficiency, the amplifier power and even the room will be factors.    From my own experiments with the 1000Pro I needed the amp set 1 or 2 dB lower to get the same hiss level as the D800, but that is compensated by the fact that you would run the 1000Pro at 1 or 2dB less to get the same loudness as a D800.  It also occurs to me that results could vary between different models of iPhone, even with the same app.

That said, I am actually very surprised at how similar the results are from myself @brit and @Axel.  (Thanks for taking the time to try this!)  We are all running MC cartridges with slightly different gain settings, but the results are almost identical.

What would be really interesting would be if someone with MC settings in the range of 0.3 to 0.5mV obtained significantly different results.  There have been some claims of hiss free Devialet phono stage performance in the past, with MC settings.

Hi Confused

It so happens that I was just doing this on a miserable rainy day in Portishead!

At the listening seat (~9 ft from speaker plane) I hear significant hiss from my Koetsu set to 0.35 mv.
My measurements are:

Dev Volume (dB)                 Sound Meter (dB) 

Off (i.e. room sound)                   17
-40                                            17-20
-20                                            20-22
-15                                            26-28
-10                                            29-32

My normal listening volume is around -15dB on the Dev. -10 would be very loud.

I am surprised at how low the readings are as I perceive the hiss at -15dB setting to be quite loud. However my dB meter indicates that it is 'rustling leaves/quiet library'........

It would seem that the human ear is tremendously sensitive to white noise.

The hiss does not bother me (I've had worse valve amps) and is inaudible when listening even between tracks.

Hope this helps

Kevin

Addendum!

Surprised at how low the room and hiss recorded, I downloaded the Decibel x app (on a Sony Xperia) that others have referred to for comparison:
New readings are (on a Sony Xperia): 

Dev Volume (dB)                 Sound Meter (dB) 

Off (i.e. room sound)                   46
-40                                            47.5
-20                                            48.5
-15                                            51
-10                                            55

Moral of the tale - one person would have to test everyone else system with the same sound meter to be constant - specially since dB scale is logarithmic!

K
Devialet 1000 Pro; Magico S5 loudspeakers; Metronome T3a Signature CD Transport; Krell Connect Streamer; SME 30/2; Graham Phantom Elite; Koetsu Sky Blue; MacMini/QNAP/Air3/ROON; Audioquest Vodka and Carbon Ethernet; Transparent Reference Digital RCA-RCA; Transparent Reference XL MM2 speaker cable; Transparent Reference mains cable; PS Audio P5 PowerPlant; Artesania and Finite Elemente equipment racks 
North Somerset, UK     
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#28
I don't have an iPhone, and the spl meter I use on android does not agree with my real spl meter, so I don't trust it, so I used my real meter.

Background noise with the system off in my room reads around 30db, a weighted, if I measure this with a mic I know most of this will be dominated by the low frequencies, the real background noise reading for the midrange will be much lower. When I turn up the volume I started to just be able to detect hiss at around -30, but it was around -15 before the spl meter started going up, so the real background noise in my room is around 15db lower than the spl meter reads it, this is to be expected, and explains why it's so audible.

I had to turn the vol up to +9 to get 50db in room, that sounds different but I think it's in line once loading, speaker efficiency and amp power is accounted for.

Although the hiss to me is clearly audible, and is slightly higher than I have had with external stages into the devialet, the hiss largely gets lost once the stylus is in the groove, and the devialet stage sounds so much more accurate than any other phono stage I've heard I find it's still by far the best stage I've used.
Air 3, Rega P9 with Dynavector XX2Mk2 > 440 Pro > Sonus Faber Guarneri Evolution
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#29
(20-Jan-2018, 13:00)KIBM Wrote: Moral of the tale - one person would have to test everyone else system with the same sound meter to be constant - specially since dB scale is logarithmic!

You might be able to do a worthwhile comparison by subtracting the "quiet room" dB reading from everybody's results, perhaps? Provided everyone's SPL meters use the same weighting of course. That said, I've read that most phone-based SPL meters are often pretty inaccurate.
Roon (Mac Mini), Wilson Benesch Full Circle, Sonos ZP90 (Cullen modified), Devialet 440 Pro, Kaiser Chiara
Warwickshire, UK
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