Masterpiece

[Stefanoo]

Stefanoo has the desire, i have the experience ......

thanks you are the Master!

 

[RCruz]

The Pardise needs the big elcaps to make an AC path at the low frequencies. The high path is formed by the emitter impedance of the input stage in series with the electrolytics.. The formula is simply R x C.
So when R is low you need a big electrolytic or the gain drops in the bass.

There was no misunderstanding after all...

Stefanoo... how did you solve it without the caps then ? Is it because you are using fets ?

 

[Stefanoo]

it is because I am setting an AC path to ground with the feedback resistor to ground.
This contribute to set the gain.
Now why it is not possible to obtain the same gain using a resistor instead of a capacitor goes beyond my understanding now.

 

[Joachim Gerhard]

Question : To where do you like to reference your cartridge ?
Hint : floating will not work in a balanced stage.

 

[RCruz]

Thank you.. you are being really kind answering my nube questions.

I am learning a lot.

 

[Stefanoo]

Question : To where do you like to reference your cartridge ?
Hint : floating will not work in a balanced stage.

The cartridge IMHO will have to be conencted as shown on the circuit between plus and minus of the two halves and referenced to ground with the burden resistor.
Would this work?

 

[buzzforb]

I am very interested. Brother is big vinyl guy. Just giving you hard time about the tiltle of the thread.

 

[Stefanoo]

Thank you.. you are being really kind answering my nube questions.

I am learning a lot.

no problem. I am a nubie too compared to Joachim and many others here

 

[Stefanoo]

I am very interested. Brother is big vinyl guy. Just giving you hard time about the tiltle of the thread.

Then you are welcome in

 

[Joachim Gerhard]

Maybe the "burden" resistor forms a voltage divider with the cartridge.

 

[Stefanoo]

yes it does but it is IMHO necessary to set input impedance and matches the cartridge internal parameters.
Also should help referring the input signal to GND if I am not wrong.

Is that what you meant?

 

[Kindhornman]

Stefanoo and Joachim,
This is an entire preamp section and the RIAA section for a turntable input or is this just the turntable section that we are looking at here? I am assuming it is the pre and Riaa section. Stefanoo are you going to produce any boards that others could build or is this just for your personal pleasure? It does look very advanced in design and complexity but what are we here for if not to build the best and push the limits.

Steven

 

[Joachim Gerhard]

Yes, Stefanoo, you need a reference to ground on both sides.

 

[Stefanoo]

Yes, Stefanoo, you need a reference to ground on both sides.

Don't I have R20 and R52 on both sides to set input to GND?
Is there something I am missing or is that what you had in mind?

 

[Joachim Gerhard]

In what schematic ? You have posted quite a few.

 

[Stefanoo]

Stefanoo and Joachim,
This is an entire preamp section and the RIAA section for a turntable input or is this just the turntable section that we are looking at here? I am assuming it is the pre and Riaa section. Stefanoo are you going to produce any boards that others could build or is this just for your personal pleasure? It does look very advanced in design and complexity but what are we here for if not to build the best and push the limits.

Steven

It is a complete RIAA section amplification just not included yet as we are still evaluating the topology and possible changes to it.
It is probably not going to be produced for DIY purposes and just as you noticed the complexity is a bit great for the "average" DIYer here.
But if you or anybody follows this thread will have all the elements to build his own.

 

[Stefanoo]

In what schematic ? You have posted quite a few.

sorry, I re-post the offcial starting schematic, that is labeled MasterPiece-R1.

 

[Joachim Gerhard]

OK, where is the ground reference for the input J-Fets ?

 

[Stefanoo]

it is offered by the burden's resistor R20/52 at the gate of the input JFETs.

 

[Stefanoo]

I have the balance stage up and running on my lab, so I can confirm you it is operating.