Simplistic NJFET RIAA

Member
Joined 2009
Paid Member
Mounted & adjusted ready to play
 

Attachments

  • DSC00056.jpg
    DSC00056.jpg
    499.2 KB · Views: 246
  • DSC00057.jpg
    DSC00057.jpg
    470.7 KB · Views: 250
Member
Joined 2009
Paid Member
All our fun is thanks to your Simplistic NJFET RIAA:D, I recommend you to increase your effective tonearm mass with isokinetik 8gr brass (If I remember well your tonearm is like my Linn Ekos with mid effective mass) or 3gr don't need to be glued or to adjust VTA tonearm if you do like my pic & you will arrive to Olympos:D
 
Last edited:
diyAudio Chief Moderator
Joined 2002
Paid Member
I have a Mission 774 actually (John Bicht of Versa Dynamics fame sold that design to Mission back then, could be made by Jelco, many British arms of that era were OEMed in Japan). Problem is if I will increase the mass that far away from the pivot point, the counterweight will not suffice. Its already unwound a lot. If it takes some lathe work for reinforcing it with a brass bit, then a front end flat thingy will be easy to diy also. What is your total mass now including cart?
 
Member
Joined 2006
Paid Member
You two are doing some ''esoteric'' stuff for a while now, I am not sure what exactly, but I like it you are having fun.:D Greetings.

Hi Salas

Based on your input, I updated my simplistic simulator that seems to be able to pinpoint the 500.5 pole.

It does not work very well for the higher frequencies so I am basing myself on your latest pdf. (According to my calc there seems to be a "missing 800~850pF" that I am taking for granted and calling it "special miller of the second stage".)

I would like to test this simulator on merlin´s tube schematic but I am not sure how to determine the first stage output impedance.

If Merlin decides to open a new thread I hope you join to help.
 
Member
Joined 2009
Paid Member
I have a Mission 774 actually (John Bicht of Versa Dynamics fame sold that design to Mission back then, could be made by Jelco, many British arms of that era were OEMed in Japan). Problem is if I will increase the mass that far away from the pivot point, the counterweight will not suffice. Its already unwound a lot. If it takes some lathe work for reinforcing it with a brass bit, then a front end flat thingy will be easy to diy also. What is your total mass now including cart?

Fortunately my Ekos counterweight is suffice, another idea it's work without counterweight;)

Tonearm 11.5gr
Cart 8.5gr
Isokinetick brass 8gr
Screws & fasteners 0.5gr

Total 28.5gr

The Denon DL103R compliance rating: 5x10-6 cm/dyne (at 100 hz) at 10 - 11 hz has been calculated to be approximately 11x10-6cm/dyne so now I have a tonearm resonant frecuency of aprox. 9Hz:)

Isokinetick do another to added only 3gr
 
Member
Joined 2009
Paid Member
Hi Salas

Based on your input, I updated my simplistic simulator that seems to be able to pinpoint the 500.5 pole.

It does not work very well for the higher frequencies so I am basing myself on your latest pdf. (According to my calc there seems to be a "missing 800~850pF" that I am taking for granted and calling it "special miller of the second stage".)

I would like to test this simulator on merlin´s tube schematic but I am not sure how to determine the first stage output impedance.

If Merlin decides to open a new thread I hope you join to help.

New thread open, also asked designer/manufacturer the output impedance of first stage

http://www.diyaudio.com/forums/analogue-source/190613-puresound-p10-riaa.html#post2600869

Thanks in advance for kind help
 
Member
Joined 2009
Paid Member
Did you determine true DL103r compliance using a test record ?

I believe it was proven to be much higher than that.

Tested the real cartridge/arm vertical resonance with Hi-Fi New Analogue Test LP result: in the middle between 7-9Hz so I assume 8Hz aprox. (not to far my calculations), doing again calculations I calculated for 8 Hz a real compliance cart of 13.5 (not 11 as The Analog Depot & not 17.5 my previous calculations you linked)

See here: http://www.theanalogdept.com/denon_dl-103r.htm
 
Last edited:
Helppppp please ;)
after extremely good results with the MC Version i´d like to try another
one just for MM-systems. As this thread is so long....could someone please
link me to one circuit...
As for the 170bl...i´ve got plenty of them between 6,6 and 10, so there will be
lots of close pairs and there are also some gr´s from 3 to 4,9

Greetings Ulf
 
Member
Joined 2009
Paid Member
Helppppp please ;)
after extremely good results with the MC Version i´d like to try another
one just for MM-systems. As this thread is so long....could someone please
link me to one circuit...
As for the 170bl...i´ve got plenty of them between 6,6 and 10, so there will be
lots of close pairs and there are also some gr´s from 3 to 4,9

Greetings Ulf

Ulf, Salas PDF here http://www.diyaudio.com/forums/analogue-source/129126-simplistic-njfet-riaa-495.html#post2308275

Cheers, Felipe
 
I have a Mission 774 actually (John Bicht of Versa Dynamics fame sold that design to Mission back then, could be made by Jelco, many British arms of that era were OEMed in Japan).
Not the original 774 AFAIK. Jelco made the various 774LC, LCII, Cyrus, etc.
Do you have the first solid counterweight or the silicon rubber decoupled one?
Did you ever try the fluid damper?
 
Member
Joined 2009
Paid Member
Helppppp please ;)
after extremely good results with the MC Version i´d like to try another
one just for MM-systems. As this thread is so long....could someone please
link me to one circuit...
As for the 170bl...i´ve got plenty of them between 6,6 and 10, so there will be
lots of close pairs and there are also some gr´s from 3 to 4,9

Greetings Ulf

Let us know your NJFET stash so Salas will give you advice about wich will be used & positions