Simplistic NJFET RIAA

[kerux]

Newbie question about Power transformer? I have been reading the pdf file that PSGR produced about the transformer required for a MM Cartridge. I have a shure m 97x, so I need the 24V 50VA transformer. Can I use the Hammond 166L24 which is a 24v 48VA transformer? It is cheaper from digikey than a 24v 50va toroidal transformer. Any input is appreciated. Thanks

I was planning to build the Salas Riaa using the PSGR pdf for the MM Cartridge. I got some matched 2sk170's that are matched at 7.6 idss. Can I use them in the pdf schematic requiring 8-9ma? Or I see some of the older schematics require 7-8ma. Should I build one of these?

Any input is appreciated.

 

[merlin el mago]

No. It will output 30dB gain before Riaa, and grossly overload your MM input.

Make this one I attach instead, you can check it out using just a 9V battery.
Has 10x gain with a 2SK170BL. The input resistor can be your MC cartridge manufacturer's recommended load value instead of the indicative 150R.

How many Idss for NJFETs?

 

[cjcc67]

Yes. What is your now MM phono stage you want the MC pre pre for?

Salas attached my current phono stage. It is best opened using windows picture viewer so you can zoom

 

[vgeorge]

Used to have this preamp years ago.
Try to built Salas one ASAP! Not only an MC satge.
There is no comparison.

Salas attached my current phono stage. It is best opened using windows picture viewer so you can zoom

 

[cjcc67]

I built this in 1990. Iam getting some extra fets for a Salas RIAA. I also like to try the Allen wright design all tube

 

[Salas]

I was planning to build the Salas Riaa using the PSGR pdf for the MM Cartridge. I got some matched 2sk170's that are matched at 7.6 idss. Can I use them in the pdf schematic requiring 8-9ma? Or I see some of the older schematics require 7-8ma. Should I build one of these?

Any input is appreciated.

Will simulate your Idss in that MM circuit and let you know.

 

[Salas]

I built this in 1990. Iam getting some extra fets for a Salas RIAA. I also like to try the Allen wright design all tube

Tubes we have checked out many through the years. Including Allen's and Steve Bench's. For those I developed the SSHV originally. 🙂

P.S. I did one too http://www.diyaudio.com/forums/analogue-source/140635-valve-itch-phono.html

 

[cjcc67]

which is your favourite?

 

[Salas]

The Itch and the Bench. The Itch was made by listening to the Bench and the Simplistic. The Bench managed after I measured its Riaa transfer function and changed a key value. Without the SSHV PSU was less than the Itch. Kofi Annan made it with SSHV and the Riaa mod. Had a thread here. I have given the Itch to a friend who had the Thorsten grid leak and did not get to apply an SSHV to it so to know how it goes with it. He does not give it back for experiment, he listens to vinyl every day! But I will grab it one time!

 

[merlin el mago]

How many Idss for NJFETs?

@Salas

 

[Salas]

I was planning to build the Salas Riaa using the PSGR pdf for the MM Cartridge. I got some matched 2sk170's that are matched at 7.6 idss. Can I use them in the pdf schematic requiring 8-9ma? Or I see some of the older schematics require 7-8ma. Should I build one of these?

Any input is appreciated.

You will need to change R2 to 43R and R7 to 1.5K in the PSGR PDF'S MM, and you are good to go.

 

[merlin el mago]

No. It will output 30dB gain before Riaa, and grossly overload your MM input.

Make this one I attach instead, you can check it out using just a 9V battery.
Has 10x gain with a 2SK170BL. The input resistor can be your MC cartridge manufacturer's recommended load value instead of the indicative 150R.

Wich Idss value for 2SK170BL?

 

[kerux]

You will need to change R2 to 43R and R7 to 1.5K in the PSGR PDF'S MM, and you are good to go.

Thank you for the help. I will get these resistors.

 

[Salas]

Wich Idss value for 2SK170BL?

I used 8.5mA which is common in BL. 7.5-9mA will do nicely for that basic pre pre.

 

[merlin el mago]

Thank you Salas.

 

[smpkje]

Yes, you just use 33R for R1, 1k6 for R2, and 12V for V1 battery or whatever. That will give 26dB=x20 times.

hi Salas. Is the 8.09 and 8.12 good matched for 2sk170?

 

[Salas]

 

[smpkje]

Thank you Salas. I will try it in my opa604 diy MM phono stage

 

[Franz Gysi]

Hello

Some time ago, I built the "original" Le Pacifique circuit and I am very pleased with it.

I plan to build now the cascoded and output buffered version (thanks ikoflexer for the resuming document posted here http://www.diyaudio.com/forums/analogue-source/129126-simplistic-njfet-riaa-271.html#post2007362 )

But I have only 2SK170 V's, mostly about 14mA IDSS.

Could I use it for this circuit?

What are the drawbacks / changes?

Maybe it is already described in this hughe thread?

Any pointer is appreciated.

Franz

 

[Salas]

Just let me know your cartridge and I will see values for proper bias with 14mA IDSS of the respective circuit. Half of it is the supply, you gotta make it too, been voiced together.