Problem with phono stage

Dear @ejb 14 and friends: From where comes " stupidity ", normally from ignorance/low knowledge levels and skills.

Between 20+ years from today we made our first intent to design and build a phonolinepreamp due that what been in the market were not satisfied not only my LP reproduction demans in quality overall performance levels. My audio items that were my references in those times were units from FM Acoustics, Gryphon, ML Reference and the like.

So we started with a battery powered design with a single layer boards and using op-amps in two different ways.
We used these ones:

https://datasheetspdf.com/pdf-file/919966/NationalSemiconductor/LM607/1   ( in the plastic not metal package )  and this one:

https://www.ti.com/lit/ds/sbos058a/sbos058a.pdf?ts=1602967034703&ref_url=https%253A%252F%252Fwww... and the opa 2604 too.

https://datasheetspdf.com/pdf/475618/Burr-Brown/OPA2604/1


passive inverse RIAA eq. using teflon caps and Caddock resistors.

I still have this unit and ( believe or not. ) performs really great with no regrets/compliants about and even today can compete with some good " names " units.



After this successfully intent ( because we had to know first if our design could works and it did it ! ! ) we put on paper the targets for a more definitive phonolinepreamp that not only worked but that could outperforms the best of the best phonolinepreamps in the market and that fulufill all the cartridge needs of any cartridge and from here born the Essential 3150 followed by the 3160 and my today unit 3180.

My first phonolinepreamp targets I still have and were writed in plain paper by hand/pen and is dated: 26-11-96 ! !

several of the original targets can't be ( yet ) achieved and some of them are almost " crazy " and for other gentlemans/designers maybe utopic ones.

Anyway here some of the acomplished targets:

The Essential 3160 is an active high gain/low noise fully discrete design that use bipolar transistors in two gain stages for MC phono stage and FETs for MM phono stage.

In reality this phonolinepreamp have three preamps instead of only one: it has a MC phono stage, it has a MM phono stage and a line level stage preamp. All this three stages are totally independent from each other.
 Each phono stage ( MC and MM. ) is designed for its self precise and specific needs.

Our design is a discrete Non-feedback, direct coupled, pure class A , current mode, true balanced ( differential ) input to output, dual mono design and fully regulated input to output.

The dual mono design only share the chasis but both channels are totally independent from each other even in the dual mono external power supply ( that use too a pure silver Kimber Kable power cord. ) that is so important to the performance on this phonolinepreamp, it has separate attenuator volume control ( that been an attenuator design that when is attenuating the SPL at the same time is lowering/attenuating the noise levels. We work with the input signal 100% SPL, no attenuation at all. ) and separate phono/line switch, impedance changes by solder resistors.

Inside parts: teflon Cu capacitors, " naked " Vishay resistors,matched transistors , hand selected parts, no internal wires ( every part, including input/output RCA/XLR connectors, are soldered directly to the four layers circuit boards. ), etc....., only the best neutral non-sound parts ( no step-up transformers, no head amps, etc.. ) and in the critical stages with tolerances at 0.001%. All parts working at no more of its 50% efficiency. A unit impossible to overload it.

A developed proprietary technique guarantee an accurate RIAA de-emphasis accuracy of +/- 0.011 dB from 20 Hz to 20 kHz ( Both channels ), resulting in a neutral phono stage that reproduces exactly what the cartridge generates that are in the recording.  

The result is a preamplifier combining the purity and transparency of a passive preamplifier with the speed, dynamics and drive of an active preamplifier ( Truer to the recording. )

To round off the preamplifier's RIAA capabilities, its has a switchable 3.18 us turnover point Neumann pole. ) to compensate for the cutting head preemphasis HF roll-off during the recording.



The op-amps that mentioned that gentleman were used not to amplify the cartridge signal in no single way, this signal is touched only by passive/active discrete parts. The output buffer is a metal encapsulated fully discrete design that looks as an op-amp but certainly it's not.

Due that my ML 20.6 monoblocks use in the signal input gain stages these metal encapsulated fully discrete devices ( that looks too as an op-amp ):

https://www.analog.com/media/en/technical-documentation/obsolete-data-sheets/MAT02.pdf

https://www.analog.com/media/en/technical-documentation/data-sheets/MAT03.pdf

we were thinking to use it because it has a first rate design but at the end we decided to make our own fully discrete bipolar discrete high gain design that was and still is a fenomenal challenge for any electronics SS designer/manufacturer..

I know that that low knowledge level ( that was the only reason he asked on those op-amps. I think? ) gentleman would like to know more about our design but this is not possible to him or any one else..

You know we in 1996 was thinking/targetting in a current mode design that today is the fashion. Yes welike what we did it and not because we did it but because is well worth our effort: very high rewards.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

   

Btw, I posted this in other forum regarding phono stages:


"""  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. The Lamm ones are not better but only way more expensive.

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     """""



that is the/my unit with " op-amps "  ! ! !  

R.

Ironically, even though Raul hates me, I will admit I own a 3160, and it is indeed superb in its performance.  As a tube aficionado (one reason Raul likes to attack me), I find myself not thinking about whether the 3160 uses tubes or transistors, when I am listening to it. Raul's business partner, Jose', also should be credited for the success of the design and its build.  I suspect Jose' has an EE background. When Raul says "we", he must refer to Jose' and himself.  Funnily, much like a tube preamp, the 3160 to my ears gets better after it has been in use for at least 30 minutes to an hour. It's excellent from the get-go but gets even better when it warms up.  So, Raul, how far off topic do you want to get?
Have you referenced your value for the inductance of the MP110?  I did so in one of my posts above.  If you have not done so, please enlighten me.  I am always grateful to be corrected with correct information.  800mH does indeed seem very very high for an IM cartridge. The owners manual pdf that you provided does not mention inductance, so far as I recall.

@lewm Nagaoka is Jeweltone in Japan, I hope this link will help a bit with info and tech specs for MP models. Use google translate or google chrome browser for automatic translation. 

Dear @lewm  : I don't hate you in any way, for me you are one of my close Agon true friends. That many times we can be in disagreement means nothing about our friendship/relationship. I love you man.

Yes, the tube subject today is just out of my mindn as you know I was a tube lover too for at least 10 tears: no way to come back no matters what. 

Yes, you are rigth about José and that's why you can read in the circuit boards: J&R.

You own the two MC stages version and just looking the circuit boards so kind cared of each single soldered part you know that " there " is something special. Everything was made it by us but the blank circuit boards that we bougth from Silicon Valley company.

Mijostyn could think about ego but no I'm not that kind of person, of course that as a human been I'm proud to own " something " builded by " my self " and that performs so good and addirtional to that I'm happy that exist other 7 proudly owners of our units.
This fact was really a fortuit one because the Essential was designed for my way demanding needs even Jos'e has not the Essential.

We really take care on the overall design and execution to that design even the logic " card " works excellent and it the circuit that starts to works when you switch-on the unit and for around 12 seconds one led is blinking and stops at the end of the check-upprocess that the Essential does it and if the unit has any single parameter out of our really tigth specs/tolerances the Essential just does not works.

The people that do not seen the Essential could think it's a " garage " item but yyyou know that is far away from there, that unit weigth around 27kg that at the end could means almost nothing.

Btw, do you already used the Neumann pole option in your unit?  I have to say that normally that 3.18us pole develops several problems of phase and other issues in the RIAA eq. when it's not well designed and I want to tell you that we really take care about.

That pole is way important to any LP lover because the inverse RIAA eq curve goes down/fall to infinitum after 20khz but during the recording process the RIAA emphasis that goes around 20db at 20khz and up does not goes at " infinitum " due that the cutter head at around 50khz it will be burn-in so exist a filter to stop process ( DMM can goes to 60khz. ) and it's this way as the LP comes to us and that's why all well recorded LPs does not have the rigth response over 20khz but only if we re-integrated the frequencies that goes losting/lowering leves through the inverse phono stages RIAA eq. curve. Anyway you have the option to test it.


The gentleman that always try to hit me but to increment his frustration never has success one time that I posted somewhere about the necessity that a phonolinepream has a wide frequency response over 1Mhz  like the Essential or Spectral and other units he asked why and been he a tube phono stage designer I thinked why is asking for when he must knew about and my answer was that ask that issue to K.Johnson of Spectral. It's way interesting.

Finally, the op-amps main issue. Which the real problem with: high feedback to lower distortion levels.

Feedback is a phenomenon created by mother's nature, Universe function with feedback, and is part of Newton laws. Our day by day life is full of feedback, even our brain works with.

Today op-amps improved a lot over the last 10-15 years. Analog Devices or Ti and other manufacturers improves about each single day. Even the ones I lnked here that we used many years ago in my first PLP and that cames from National ( out of market. ) and B&B whom was bougth by Ti performed really good.

The today op-amps are using NFB? yes but there are several ways to use NFB and depemnding of the skilled and knowledge levels of the designers that NFB " devil " could be not any more the way terrible " devil " of the past.
No one knows more about and how to use NFB that the expert ( true experts. ) engeneers from AD or Ti and other companies dedicated to.

Here what N.Pass says about and even that we could think that NFB is not what we want it read carefully the conclusion at the last sentence ( and this is only one audio gentleman amp designer. I will try to bring here to talk about to Wyn whom colaborated for years and designed for Analog Devices and now retired and working as a free-lance expert advisor. ):

https://www.passlabs.com/technical_article/audio-distortion-and-feedback/

those information comes from 2008, maybe NP could has news about and certainly he has because his First Watt amps use NFB and many people love it !.  Everything is related to the design the rigth way to use feedback. If we are totally afraid of it and I mean amp designers then could be because those amp designers just do not know yet how to " handle " it.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.