Phono stage hiss - Measurements

[Confused]

Yet another update.  I have exchanged a couple of emails with Mathieu Pernot.  He has asked me to produce two more recordings, using a "silent" track on the test record, and another track that has the 1 kHz tone at -20dB.  These I have produced today and emailed to Mathieu.

Analysing these tacks myself, one thing is clear, silence is quite noisy on vinyl.  The test record has a degree of surface noise, and is it is also very fractionally warped.  I mentioned in an earlier post that there was a slight "thlump" noise in the 1 kHz recording, I can now see this visually matches a fractional "hump" in the pressing.  Thanks to all this, silence clocks in at a whacking -49dB peak at 25Hz, and -44dB at 8Hz.  (and yes, this is with RIAA 1976)  Although above about 200Hz, silence measures between -92 and -115dB.  Consider that the infamous "hiss" comes in with a peak of about -81dB (again peaking at lower frequencies), this perhaps gives a degree of perspective to this matter.  Indeed, in the past I have stated that the hiss is annoying because I know it is there, but I do not notice it when actually playing records.  This rather subjective view appears to be in line with the measurements.  What the measurements do show is how the noise follows the RIAA curve, so with hiss, surface noise or whatever, the RIAA curve is boosting this at low frequencies.  Back on the RIAA 1976 issue.  Mathieu has advised me that the RIAA curve includes a 20Hz 1st order high pass filter. "This filter is of the lowest possible order and only provides a limited rumble attenuation."

Attached below is Mathieu's FFT plot of my 1 kHz test recording.  This shows the harmonic effects quite clearly, and how the RIAA curve adds stacks of noise at the lower frequncies.  Mathieu uses Adobe Audition for this analysis.  (which clearly produces vastly better plots than Audacity)  According to Mathieu "The distortion is of course mainly a cartridge/mechanical thing. I wonder if @f1eng could help on the amount of distortion commonly found on vinyl playback. The phono preamp does have some unwanted harmonics but the levels are simply not comparable at all. That's part of the "LP way of life".  (Mathieu used @f1eng 's actual name, but I edited it here as it would be a little impolite to post on-line)

   

[Waiski]

Any idea, what next? Basically we know that the problem is there. How to fix this?

[thumb5]

Well, we know some hiss is there but that is inevitable and was never in doubt.

What we still don't know is (a) whether this is within the design parameters of the phono stage, i.e. considered acceptable by Devialet, or (b) whether there is significant sample-to-sample variation between supposedly-identical amplifiers.  The latter might explain why some people find it more objectionable than others, but it could equally be due to differences in settings and/or personal taste/sensitivity.

Based on Mathieu's responses to @Confused's recording it seems he is not perturbed by what he's seen in that example, at least, but apart from that we haven't much to go on.

To make further progress, Mathieu has been clear that anyone who find the hiss a nuisance should get in touch and send him recordings; this would help establish whether (a), (b), both, or none of the above applies.

[Finn]

Agree With Ian .we still wait for some progress , and a Way too stop Hiss . What Can Mathieu find out?.

[Finn]

Any hear from devialet about the Hiss ploblem?

[Confused]

Any hear from devialet about the Hiss ploblem?

Yes and no.  As I mentioned in post #31, Mathieu Pernot asked me to make some additional recordings.  Mathieu sent me an email last week to say that he had been very busy recently, but that he hoped to analyse my recordings next week.  When I here something further from Mathieu I will advise.

With that said, I do not think this will progress the issue much.  Mathieu has already advised that he thinks the performance of MY phono stage is excellent.  Add to that, I am someone who thinks that the level of hiss is "not too bad".  Not ideal, I would prefer silent, but for me it is acceptable.

So this leads us back to @thumb5 's comments in post #33, in particular his point b).  So what is essential to this issue is for those that feel that the level of hiss is unacceptable (yourself, @Greg, others ) make a similar recording for analysis.

As an open offer, if anyone who feels that the level of hiss is unacceptable makes a recording, I would be more than happy to make a recording using my phono stage using identical settings for gain and loading etc.  This would start to build data to establish if there is any significant variance between individual phono stages.

Furthermore, Thumb5 has found some excellent free software for analysing the recordings:

https://www.sonicvisualiser.org/

This can produce analysis graphs / plots that are pretty much as good as Mathieu's Adobe Audition.  So, if those experiencing unacceptable hiss can provide a recording, I can make an equivalent recording, and we have the means to do a meaningful analysis.  At the very least, this will provide some hard data and provide a good indication of the nature of this problem.

Frankly, in the absence of the above, this issue is going absolutely nowhere.

So over to you guys! 

[Finn]

We Can sent 10000 eksempel about hiss too Mathieu and he look about it, but What Can he do about it ? Sometimes i Think do devialet listen too all the Pu settings , and they lisen hiss ? If they do ,Why they put a phonostage inside the devialet who make hiss , ( many low cartrigde ) do so. I like the Sound of devialet , it is a great amp , but it make hiss , i Read a lot about streaming ,ploblems With Roon, and other things , but we Are someone who play winyl and What about US? , is it ok ,that i bye a seperart , phonostage , or transformer , too kill the hiss ? Is devialet Looking about the streaming, or ther phonostage , i Don,t know , but i Think it is crazy that i need to bye other things too kill the hiss. To do that With devialet who is not cheap ,is stupid ,but if i want play winyl i need to do something, ( who i have ) but it should. Not be nessary.

[f1eng]

Sorry, don't check in this often!
The distortion levels are very dependant on setup and cartridge choice but the levels in Mathieu's graph are fairly typical of a good quality cartridge. The Devialet distortion level is so much less than this all the distortion is coming from the record player.
The noise levels too don't look unexpectedly high to me either. Perhaps it is the frequency content of the noise which people are noticing???
It would be interesting for those concerned about it to compare recordings of the Devialet phono stage direct with another of a different stage connected to an analogue input to compare the noise plots.
I use a low output Ortofon A90 with its matching T3000 transformer with mine an have no hiss problem. I found the Devialet D-Premier phono stage better than the Goldmund PH2 but haven't compared them using the O d'A since I am completely happy with the phono input when I play LPs.
Sorry not to be more help, but that plot shows vinyl noise and distortion at the expected level for me.

Edit:
I should add that whether I use my conventional speakers or my 109dB/watt horns if I set the Devialet volume control at a normal to loud listening level I can only hear noise with my ear near the speaker, none from my listening chair, and the vinyl noise which starts when the stylus drops into the groove is much louder than this so in my system I don't have the complaints others do.
I don't play LPs that often though either.

[Hugh]

I would like to put my two cents in.

With all my due respect, I really don’t understand the “added value” of this discussion.

Vinyl and 0101 sources of music are two different things, coming from two different eras, having two different tastes.

If somebody says that: “Devialet is doing very well with streaming sources but its phono stage doesn’t sound the same as my tube-based preamplifier”, it sounds more reasonable and interesting to me.

If it sounds like: “Devialet lets me down, because what I am looking for is the best analogue phono stage available on earth under the same chassis with the best high tech digital single platform”, the discussion will be misleading and much less interesting to me.

Imagine the following situation: One has got in his garage the best EV car available on the market that many other people want to have. That car performs very well almost on every aspects. When he bought it, his main focus was on the environment. Someday he heard somebody saying: “The EV car’s weakness is that it cannot make a roaring sound like a premium sport car”. He thinks: “It makes sense”. After this day, his main focus is placed on how to make his EV car roar like a sport car. And he forgets that he has one of the best EV car on earth.