Best phono stage?

[ack]

Thank you Ralph. I always assumed that my Pass XP27 simply added gain stages after the lowest 53dB setting, so with the 0.75mV higher output of my Colibri, that was fine. However, Ack above states that the highest 76dB gain setting is "native" and the lower ones divide the voltage. I don't really understand that, but have an email into Pass Lab's Wayne Colburn who designed it. I will also do some listening comparisons in the next few days to see if I can hear a difference between the high gain/low volume versus the low gain/high volume settings.

I appreciate your comments.

Let us know what Pass responds with. I clearly get the highest S/N ratio in here with the highest gain, but only after all of my mods; lower gains sound somewhat anemic by comparison.

 

[Atmasphere]

Here's a longer explanation from the July/August 2020 TAS issue - hoping to see it online some day

The first column is correct, the second column is not! It purports a common myth about balanced line, that there must be a ground connection inherent in the source. This is entirely false. The idea behind balanced operation is to satisfy several goals; one is to allow long cable runs, another is to eliminate high frequency rolloff, another is to prevent cable artifact and finally to prevent ground loop noise. For the latter 2 characteristics to be possible, the ground is ignored. If you read up on the balanced standard which is defined by the Audio Engineering Society file 48 (AES48), you will see this is the case. Mr. Harley probably needed to read up on that.

FWIW, I don't propose that I'm some sort of expert on this stuff; every day I feel like a neophyte. But at the same time, Atma-Sphere has been making balanced line products for the home longer than anyone else worldwide and we made the first balanced line phono preamps as well. Because no-one had done it before, we figured we had to support the operation of normal broadcast studio equipment, and so we did. That took figuring out how to do the phono connection as well.

 

[ack]

It purports a common myth about balanced line, that there must be a ground connection inherent in the source. This is entirely false.

I suppose you are saying we only need one common reference point? If so, I bet Harley understands that, but perhaps did not want to get all too technical. Truth be told, I am also lifting the ground on my XP-25, because it manages to pick up some ground-induced hum despite my star-grounding and using the same length interconnects and cords all around - very small in magnitude, but it's there

 

[PeterA]

Let us know what Pass responds with. I clearly get the highest S/N ratio in here with the highest gain, but only after all of my mods; lower gains sound somewhat anemic by comparison.

Pass responded writing that the designs of your XP25 and my XP27 are different. In the XP25, feedback is altered to change gain. This may change the sound. This explains why I heard differences in the sound when using the different gain settings with my old XP25. I settled on the 66dB setting for my 0.5mV cartridge at the time. With my new XP27, I do not hear those differences, nor am I able to hear the losses you describe in your system with the lower gain settings. My vdH output is high enough to allow me to use the lowest gain setting, and Pass said that was fine.

 

[ack]

Yes, this is very much in line with what I thought I saw in the XP-25 circuit board, more or less. I certainly did not see different/additional gain stages. Great, fast response.

 

[Atmasphere]

I suppose you are saying we only need one common reference point? If so, I bet Harley understands that, but perhaps did not want to get all too technical. Truth be told, I am also lifting the ground on my XP-25, because it manages to pick up some ground-induced hum despite my star-grounding and using the same length interconnects and cords all around - very small in magnitude, but it's there

Actually you don't need a common reference point. Its also obvious that Harley didn't understand how the balanced system works. In his explanation, to be a true balanced source the cartridge would need six leads, as two of them would be center taps of the cartridge. But in reality, that does not work as well because any center tap can't be perfectly placed in the winding and as a result degrades the Common Mode Rejection Ratio. Significantly.

So as a result in balanced circuits a center tap isn't used. Instead the winding (which is often a winding on an audio transformer, but it could be a microphone or cartridge too) has no center tap, and is simply connected to pins 2 and 3 of the XLR connector. This is true whether an input or output. Pin 1, the ground, is then tied to chassis. In the case of a turntable, this is the tonearm, plinth and motor.

This article explains how balanced line connections work:
https://www.ranecommercial.com/kb_article.php?article=2107

 

[AMR / iFi audio]

Yes i love the balanced circuit design without actually having balanced connections. And a sub rumble filter is a absolutely must on a high end product

It is possible to have a balanced phono input with RCA's - but we have to check the tonearm cable wiring. Anyway the IFI Zen Phono is not targeted towards the high-end audiophiles - it is an interesting product for vinyl revivalists that want to have minimum quality phono preamplification at low cost. Many cheap (or vintage ... ) turntables will need a rumble filter. I loved the political correct way of avoiding insults to the prospective client turntable - calling the filter "sub-rumble"!

Despite the pinch of sarcasm, I kind of like the new phrasing. Do you think we should then change the sub-sonic filter name to the sub-rumble?

 

[Lagonda]

Despite the pinch of sarcasm, I kind of like the new phrasing. Do you think we should then change the sub-sonic filter name to the sub-rumble?

Marketing writing is always taken with a grain of salt. We are talking about your phono stage on “What Best Audio” on a thread called “ Best phono stage “, you are doing something right

 

[AMR / iFi audio]

Mum, we made it!

 

[microstrip]

Despite the pinch of sarcasm, I kind of like the new phrasing. Do you think we should then change the sub-sonic filter name to the sub-rumble?

No, just "rumble", as everyone did during decades and many still do.

 

[silviajulieta]

My vdH output is high enough to allow me to use the lowest gain setting

Dear friend: that 0.75mv cartridge output means " mediocre/average " quality level performance no matters what. I already posted in other threads that the best LOMC cartridges are the ones with lower output levels because the signal " sees " less coild wire that inside the cartridge is extremely important issue: more wire means losted signal information, signal quality degradation.

The best Colibri cartridges are the ones at 0.22mv and you can ask VDH that make one for you and difference for the better is like nigth and day. You have the phono stage gain to handle it.

Sorry but 0.75mv has no sense for that kind of price I suppose you paid for.

Lyra knows a lot about and that's why from the same models from some years now its builds low output versions and owners and reviewers of those low output versions always prefers these ones. For some gentlemans it's not posible to use the low output versions or cartridges with low output because have not the rigth phono stage to handle it.

In the past two of the best LOMC cartridges came with a really low output at 0.05mv ( I still own one of them. ), these ones are the Audio Note IO Limited and the Ortofon MC2000.

Btw, from some time now and today phono stage SS designs all of them has high headroom and can't be overloaded but additional almost all are very good designs. If we listen clicks then comes in the LP, as a fact the vinyl surface is really " tortuose " for the cartridge and non perfect and its inherent imperfections develops the clicks in all LPs but these clicks comes at different SPL that many times because are very low SPL we can't listen it.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

 

[Lagonda]

Who is taking the bait ? Peter, ddk ?

 

[Atmasphere]

Btw, from some time now and today phono stage SS designs all of them has high headroom and can't be overloaded but additional almost all are very good designs. If we listen clicks then comes in the LP, as a fact the vinyl surface is really " tortuose " for the cartridge and non perfect and its inherent imperfections develops the clicks in all LPs but these clicks comes at different SPL that many times because are very low SPL we can't listen it.

This statement, such that can actually be made out, is false and its easy to prove that. It also doesn't address the attendant issue with solid state phono preamps which is their higher input capacitance, which is in parallel with the phono cartridge. This reduces the resonant frequency seen at the phono section input, making the phono section more likely to be able to make an attempt to amplify it. Raul's comment is clearly not addressing the issue of the resonant peak. As a brief review, here is the bit about the peak, from one of my earlier recent posts:

The RFI (or ultrasonic noise, if you have a high output MM cartridge) is generated by a resonant peak caused by the combination of the inductance of the cartridge and the capacitance of the tonearm interconnect cable and includes the input capacitance of the phono section itself. If you have a low output moving coil (LOMC) cartridge, this peak can be as high as a couple of MHz and as much as 30dB! 30dB is 1000x higher than what is not the peak, IOW the audio signal. If the phono section has poor High Frequency overload margin, this peak, when set into excitation by the energy of the cartridge (a resonant peak can be set into excitation by energy of another frequency), can cause a tick or a pop as the phono section overloads. for more on this see
http://www.hagtech.com/loading.html

Now Raul mentions that ALL solid state phono sections don't have a problem with this peak (see emphasis added above in his quote). The problem here is something called Gain Bandwidth Product. This is a value of bandwidth needed such that when you add feedback to the circuit, the gain of the circuit is reduced and the feedback is able to control distortion to a certain degree (I'm really simplifying this so the layman can follow along...). What happens is that it gets progressively harder to have enough GBP to control distortion as the frequency is increased because you just don't have enough gain anymore. In addition, you have another pesky thing called Phase Margin, where as the frequency is increased, the phase of the output signal starts to shift, such that at some frequency the feedback becomes positive rather than negative. This results in oscillation. When you put these two factors together, they describe an upper limit to how much feedback can be applied, and also how much gain you might be able to get, which is of particular interest especially in opamps.

Now keep in mind that the electrical resonance caused by the LOMC cartridge is quite high and well outside of the audio band! Its actually so high that no opamp made has enough GBP to properly deal with it. Also keep in mind that the signal is at the input of the phono circuit (of course ) and quite often the feedback isn't able to correct what's happening in the input stage (because its outside of the feedback loop) so it easily overloads.

One way to deal with this is to simply install an input filter that kills high frequency /radio signals like this; that filter needs to have an F3 (IOW a -3dB rolloff frequency); where are you going to set that? The problem here is that as a designer you can't predict what cartridge or tonearm cable combo is to be used, so you'd have to set that filter to a pretty low frequency- 50KHz perhaps? Even 50KHz is too high for the GBP of most opamps. Is that going to be part of the RIAA EQ in the circuit then?? Just as a bit of a tip- if you have a series/parallel network at the input of the phono section, the components will have an insertion loss and contribute to noise. You're not going to get a -100dB noise floor doing something like this!

So a simpler technique is used- cartridge loading- put out the match instead of a forest fire, right? The only problem is now the stylus has to about 100x more work to do (the typical cartridge load being 100 ohms as opposed to the industry standard of 47,000 ohms) - the forces needed to make it move back and forth in the groove are now much higher. I explained this earlier also- its basic physics with magnetic generators. This makes for possibly greater record wear and possibly less HF bandwidth, and probably greater distortion at high frequencies; since the groove wall and the stylus have to have very intimate contact to work properly.

Obviously these issues are entirely unaddressed in Raul's post; we can see that actually its just simply false. I'm of the opinion that Raul is experiencing the phenomena I've described; his post seems to support that. I've yet to run into an LP groove so

" tortuose " for the cartridge and non perfect

that my cartridge couldn't track it perfectly. If I'm interpreting his words correctly, he seems to think that ticks and pops originate with mistracking or some such!

 

[silviajulieta]

Dear friends: in my post #483 in this thread is/was totally proved two years ago what this gentleman over and over post as a fact and that because it was proved he was totally wrong that information is not only false as Wyn said it but a lie.

I don't go inside any lie it does not matters from whom it comes/came.

Btw, opamps? maybe " 50 " years ago. Today designs are fully discrete and non-feedback. No single cartridge mistrack at any frequency because what that person says, that was proved and he has no facts but only " talk , talk ".

I can't give a direct answer to a lie.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

 

[silviajulieta]

Who is taking the bait ?

Dear friend: it's not a bait but a fact and I'm trying to help nothing more than that. I don't know what other gentleman can explain about to support a high price cartridge with 0.75mv at output level. For me there is no justificable explanation if we are talking to achieve ( for that price. ) really top high quality level permonca in any room/system and ceratinly not mounted in a 3012 tonearm. Impossible or compared to?

Regards and enjoy the MUSIC NOT DISTORTIONS.

 

[PeterA]

Dear friend: it's not a bait but a fact and I'm trying to help nothing more than that. I don't know what other gentleman can explain about to support a high price cartridge with 0.75mv at output level. For me there is no justificable explanation if we are talking to achieve ( for that price. ) really top high quality level permonca in any room/system and ceratinly not mounted in a 3012 tonearm. Impossible or compared to?

Regards and enjoy the MUSIC NOT DISTORTIONS.

Raul, You seem to be addressing my tonearm/cartridge combination, so I posted my response to your claim in the vdH Grand Cru thread so as to keep this discussion about Best phono stage(s):

https://www.whatsbestforum.com/threads/van-den-hul-colibri-grand-cru.30507/page-13

 

[silviajulieta]

Dear friend: the title of your thread is " vital " for the LPs lovers. I don't know what could be changed in the gentlemans opinions that posted by 2014 to today 2020. I tryed to read almost all posts and I can't find out any post that could answer the thread title. Almost all the posts do not explained why that gentleman thinks that the model he posted can be in the top list of " best phono ".

As almost always in audio each one of us have our preferences for different reasons and I would like to write first the " ideal " design characteristics for the title " best phono " out there. Btw, I don't think exist " the best " because that can't exist, no thing in audio is perfect always are some and different trade-offs. So maybe could be better to say contenders for that title but design ideal targets is critical to make any phono stage evaluation. Objective targets because when we go inside each one subjectivity nothing is valid but each one opinion.

For me the functions of a phonolinepreamp first than all are that can achieve an accurated inverse RIAA eq with zero frequency deviation at each phono stage channels ( both channels should have evenly frequency about. ) the other main target is to have active high gain to handle any output level cartridge. As a fact phono stages exist because these two main targets/functions.

We need high gain but we need it along very low noise. These 3 targets are the hart of any phonolinepreamp and the true challengs to any manufacturer because it's really a hard task to achieve all those targets.

I like many phonolinepreamp in the market some of them already mentioned here: FM Acoustics, Gryphon, Spectral, CH, D'angostino, etc, etc. Yes only SS because tubes in this specific function can't do it and I owmned from humble to top design tubes electronics by around 10 years so I'm not speaking of my preferences but audio devices that its technology can in true be nearest to those targets.. This is only an opinion and I think is valid as any of your opinions.

I don't like very much to talk about tubes in phono stages but I will put an example through Aesthetix IO ( I listened the first time at A.Porter house and latter on 3 more times in other systems. ) where they say the unit has active high gain with low noise and yes it has 80db of gain that's a tribute for an all tube design but unfortunatelly failed on noise level that was measured a poor A-weigthed 57db and where the RIAA eq. deviation has ( by manufacturer spec. ) a high 0.5db swing deviation. That frequency response goes even worst because it depends of the control volumen that at different volume position different frequency response.
Now, that was the manufacturer spec but if any one of us makes measures ( example: trhough an Audio Precision system 2. ) things will goes even worst and you can confirm it even with SS top Phonolinepreamps like the ones I linked here.

Now, very important for tube phono stages owners: normally both channels ( tube or SS designs. ) overall measures show that each channel measures different against the other one and not only in the RIAA eq but in overall frequency response, input impedance, output impedance, gain, distortion levels, etc, etc.
All tube owners like to make rolling/rotating tubes for " better " ones and when you make that tube change with different tube specific characteristics to what the manufacturer took in count to his item measure/even its specs you are making " things " really worst it does not matters that those tube changes like it more the unit performance because in true is not that way.

RIAA eq. frequency deviation levels is critical because in theory must be to mimic in inverse way the recording RIAA eq. to we can have a flat frequency response.
Not an easy task even for SS designs because that eq. is not a " delicated " one but goes from around -20db to +20db, this is a huge equalization with several problems not only about frequency response but phase and other issues.

Here I give you measured SS inverse RIAA eq. deviation frequency charts on very well know top SS active high gain phono stages and then we can understand my words about:

https://lh3.googleusercontent.com/K...7w4Jt7YB76_gYRhrCrdGU=w819-h524-no?authuser=0


https://lh3.googleusercontent.com/9...5F42QP3t4NJz6y276pbmI=w819-h582-no?authuser=0


https://www.stereophile.com/images/archivesart/910Vitfig1.jpg


this last one of the 3 links came from the Vitus top of the line ( 60K+ ). You can look that starting at 500hz and below it the Vitus has a really high 20hz RIAA deviaTION OF -1.5db !! Even that J.Atkinson posted there:


"" This massive, beautifully built, two-box phono preamplifier offers almost unrivaled versatility, excellent channel matching, and almost zero RIAA error, but is not as quiet as I would have wished so expensive a product to be. ""

and more critical than that is what MF reviewed with that unit:


"" Its bass extension, control, and weight were granitic. "" how is that when in the bass range the Vitus is really poor performer ! ? ? ? !

Even JA made a comment about on that review:

"" Unfortunately, while the Vitus MP-P201 Masterpiece is well engineered, there is nothing in its measured performance that would indicate why Michael Fremer was so taken by its sound quality. ""




This next one comes from my room/system active high gain low noise phonolinepreamp:



https://lh3.googleusercontent.com/g...Rcb8d3mjRmnhWYmR9zeio=w819-h557-no?authuser=0



This phonolinepreamp in my system measures a low RIAA eq. frequency deviation: 0.011db. I remember that one time we achieved 0.0097db but we could not sustained for more than 48 hours because unit inside developed temperature ( pure class A total dual mono with two independent phono stages one MC one MM and one line stage. Fully balanced/differential and fully discrete design with 4 layers boards and no inside wires/cables. Everything is connected directly to the input(outputs connectors. ), parasitic and some kind of " vibrations " that affected the passive parts as the Teflon Cu caps and the Visay naked Z foil resistors. ASnyway, the issue is that that inverse RIAA eq. is ahuge challenge.



Look, graphic equalizers in the audio market as Accuphase, Soundcraftsmen, Crown, Klark-Teknic, etc, etc. ( I owned all and other ones been parametrics. ) in the best case its control levels by octave or 1/3 octaves can give you a range between: -15db to +15db and the RIAA demands -,+ 20dbs ! !


I have no dog on this battle ( well I have and is SS technology. ) and only saying that does not exist that " best " but only contenders. Btw, what we like ( including me ) is not important if the phonolinepreamp can't achieve those 3 targets or at least stays really near it.
As nearer those main targets as higher each one of us enjoyment of MUSIC. There is no different road to fulfill cartridge signal needs, there is in this specific thread subject only one road to arrives Rome.

Through my first hand experiences in my room/system and several other room/systems is that even than money always helps the MUSIC/sound level quality reproduction depends mainly of our each one knowledge levels not money. Kowledge levels about MUSIC and about whole audio subjects.

One really important personal issue that helps a lot to achieve the highest quality levels is the how high demanding we are of that top quality levels. We have to be our each one challenge by our self targets and very good common sense levels.


Regards and enjoy the MUSIC NOT DISTORTIONS.

Dear friends: only for you can read a little precaution with the addiction that have the tube unit owners: rotating/rolling tubes. Please read inside the post about before the SS links.


Regards and enjoy the MUSIC NOT DISTORTIONS.

 

[Atmasphere]

Here is a helpful Wiki page on opamps. It can be seen from this page that an opamp used in a phono circuit or line stage will in fact need loop feedback. I don't dispute that I talk a lot, but I did actually go to school to learn this stuff.

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

The aspects of opamps outlined at the link above have changed little in the last 50 years, although the bandwidths they achieve has changed quite a lot!

I'm not commenting further at this point as Raul's comments directed at me were an obvious violation of the site rules, and if the offending post gets pulled down it can be a mess for the moderators to clean up succeeding posts if any contain the forum violation (when such a violation occurs, if it gets quoted it is then 'owned' by the member quoting it). Since I don't know exactly how they will handle that, I'm not commenting further for now.

 

[AMR / iFi audio]

No, just "rumble", as everyone did during decades and many still do.

See, it is always an interesting game aiming to strike the right balance between an original name for a new product or technology and not pushing it too far at the same time.

 

[groovemaster]

A -fine combination- , that was the aim of a community member with his -Ruis Borges- special Edition Record Player.
The AS Phonolab Phonostage is connected to the Horch Preamp. Tremendous sound.