MPP

[Algar_emi]

Finally had time to start to assemble my Paradise preamp boards. Both shunt supplies section are working fine. I tested them using a simulated preamp load, and was able to check my pre-reg and rc-filer small pcb as a complete circuit. That confirmed that the pre-reg pcb is ok, and with the specified parts, the RC filter drop resistor gives me 26.5V at the input of the preamp insuring that the shunt heatsink is not too hot. I'll continue the assembly of the preamp.

 

[Joachim Gerhard]

That looks great !

 

[mkoerner]

And would even look better in the Builder Thread ?!

 

[Algar_emi]

What is the recommended IDSS value for the 2SK170 used in the circuit?

 

[Joachim Gerhard]

Around 8mA. It can be higher. That value gives the range where the JFet works in class A
( aprox. ), so 8mA give you 80V dynamic range into 10kOhm, that is ample.
Into 1kOhm that transfers into 8V, still enough.

 

[FdW]

Finally had time to start to assemble my Paradise preamp boards. Both shunt supplies section are working fine. I tested them using a simulated preamp load, and was able to check my pre-reg and rc-filer small pcb as a complete circuit. That confirmed that the pre-reg pcb is ok, and with the specified parts, the RC filter drop resistor gives me 26.5V at the input of the preamp insuring that the shunt heatsink is not too hot. I'll continue the assembly of the preamp.

Very nice very nice, high five - YouTube

 

[Algar_emi]

Installed all the preamp parts, all matched per sections. Here my readings, I'll check the RIAA curve accuracy this evening. Since everything is well balanced, I guest it is working fine.

Supplies +/-18V, 150ma ea

TP3= +14.5V TP5, 6= +16.36V
TP4= -14.5V TP9,10= -16.36V

Each Gain Cell transistor, each emitter resistor V=115mv (3.5ma each)

Vin = 0mv (adjusted with R1)

Vout: DC offset keeps changing around +/-25mv

Gain: 61.4dB at 1Khz
Vout max: 30Vpk-pk

 

[Joachim Gerhard]

That looks good. DC offset will go down after a while i think.

 

[Joachim Gerhard]

I added a line input to my smallest preamp called " Das unbeschriebene Blatt" ( The Blank Page ). It has DIN A4 proportions. The cables go in from the top.

 

[Joachim Gerhard]

In the backround you see a phono stage
called " Stille " ( Silence ) i prepare for the Vienna Klangbilder show.

 

[Benedetto]

You are a very bad teaser...

 

[Joachim Gerhard]

Ricky Lee Jones " Tell me everything ! "

 

[Joachim Gerhard]

Rickie Lee Jones :: Up From The Skies Lyrics - Absolute Lyrics

 

[Benedetto]

You first...
Fast Edith

 

[Joachim Gerhard]

I wanted to play "Das unbeschriebene Blatt" in Krefeld.
Thomas Fast only said " Unverkäuflich" ( unsellable ) so i kept it in the mens room.
It is in a class of it´s own, unverkäuflich !

 

[Joachim Gerhard]

It does not bear much secrets. The line stgae is very similar to the " Rose" i posted here.
Our friend from Poland Marcin and i work on a DIY version of the Rose, also on the power buffer i published. We called that " Progress". Any time soon we wil have a preamp and power buffer you can build. Then we have a complete chain, phono-pre-power.
Another guy on DIY ( Sergio Santos ) is working on a DA converter and i already made a filter-buffer for EUVLs ESS board.

 

[Benedetto]

Im mind chewing on comparing the Paradise to Salass Mesmerize
because of some similaritys in structure and parts...

 

[Joachim Gerhard]

Sure, Frans Shunt is not that different from Salas. Constant current source, then shunt.
Frans uses feed forward though. That is really hard to explain. How do you know before hand what will happen in the future ?

 

[Joachim Gerhard]

On the other hand the Salas simplistic phono stage is very different from the Paradise.
Same parts choices show up, sure. We have "our" DIYAUDIO toolbox. We just work on different buildings.

 

[Joachim Gerhard]

Frans also worked hard that his shunt does not oscillate under a lot of conditions. I would say in retrospect that his contribution was the least painful and very professional.