Problem with phono stage

A quick look at online pictures shows opamps in use in the Black Cube.  Now there are different black cubes so I may not be looking at the right one.

I used mine with Sound Smith Moving Iron and other MM carts.  I had no issues.

As to feedback it can be employed with opamps as well as transistors.  Opamps are easier to set the gain and have good common mode rejection ratios.  Transistors have to be matched.  So in lower costs products, opamps are more likely to be used.

Looking at pics of the Arcam R phono it is also using opamps.

For those that don't know how to spot a opamp look for a black square with 8 legs near the input jacks.  The part number also tends to start with OP.

A slower opamp will also be less noisier, smoother and a bit less detail.

Gain depends on the number of stages but typically expect a gain of 40 to 60 on the first stage.  That gets the signal out of the mud and allows the common mode rejection to come into play to reject noise.

IV phonos also typically use a opamps.  A resistor in series to the signal sets the current which is then gained up by the opamp. 

You can find lots of literature from Texas Instruments.

As to the debate of whether opamps, transistors, or tubes are better that is a a different subject.  There are good and bad examples of each method.

I still would address the record cleaning issue.

That is it for me.  I will leave the navel gazing to others.

Well this escalated quickly, from the last few posts I think of use for the OP Mijostyn summarized

Phono stage overload, loading and lower capacitance cables have been mentioned. Does anyone have other ideas for emilm to try?

I would add if the cable in addition to low capacitance can have some shielding (always low capacitance listed by the manufacture of the cable with the shielding included) if you go DIY shielding results could be unpredictable.

@mijostyn : ""  ego discussing issues that have very little relevance to 90% of us...."""

not was you in your very first post in the thread who asked for and even shouited by your " friend " from you are a follower?

What are you claiming for?

R.

@lewm  : You can't stop your self in the same " boring " subject:

""  MP110 has inductance of ~800mH, as per VE discussion groups.."""

I told you your sources are wrong, I stated that cartridge inductance and is lower than half your figure. Please stop to post the same or at least don't name me any more in this thread in that capacitance issue.

R.

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.