Simplistic NJFET RIAA - Page 713

Salas · 4th January 2012, 11:32 PM

Quote:

Originally Posted by Bksabath

OFF topic.(I been Acused that I listen to cheap records which is actualy true)

Bksabath · 12:10 AM

Not realy the dogi track on the Island print (the Chatering Magpie)

But a treath newer the less Caledonia - YouTube

Glorious Simplistic and F5 on a pair of Polks
Bodhran to ticle your tummy and the fidles that realy make you discover parts of my ear I did not remember to have.

Bksabath · 5th January 2012, 12:08 AM

Quote:

Originally Posted by Salas

AndrewT · 5th January 2012, 09:04 AM

I seem to recall, but it was many years ago, reading that tapes used for storage had to be re-wound, periodically, to reduce the effect of the magnetic "print through".
Pre-echo and post echo were just a few of the common problems for the careless technician in analogue recordings

RCruz · 09:58 PM

Pre echo.... a good description for my findings

Anyway I had never noticed it on vinyl before I built the simplistic. With the other riaas I used to listen to, there was not enugh SNR and definition to notice this effect

Jebem · 5th January 2012, 11:35 PM

Hi, Salas,

Great Post here... I like the SE design apparent simplicity, and plan to build this preamp for may Lyra Lydian MC cartridge.

It happens that I have a bunch of 2SK146 matched NJFET's, and I wonder if I can use them instead of the 2SK170's without to much circuit modification.
What do You think?

Salas · 5th January 2012, 11:37 PM

Not compatible. Too much transconductance and input capacitance for this circuit.

Jebem · 6th January 2012, 09:04 AM

Thank You for Your information, Salas.
That is what I was thinking about... but these 2SK146 old beasts matched pairs in a single thermal capsule shows a very low noise for a JFET, maybe one of the quieter semiconductor devices ever made...
I am not a spice modeling user, however I believe that a simulator is in order to validate a SE design using these 2SK146 devices... I will report back.

Salas · 6th January 2012, 12:35 PM

Not good for the bandwidth and gain of the second stage which is the ''engine'' of this design. It can be tackled differently but it will be another design. Wishing success in researching implementation for that particular component.

Bksabath · 12th January 2012, 03:40 PM

Hopefully the public library is closed so

Litle update from me

I got the Simplistic working wit the reflektor and LM317
Tanks Joao litle caps work and on my list of things to do is have a play with type and values (got 100n MKS at the momement)

IT does sound realy good as I even managed to ge rid of the hum (one to many ground vires)

On the Reflektor I had a dogy plastic washer on one of the Mosfets and could not spot that with case open and ground floating so that sorted after a few hours and about 5p worth of new washer.

Sound wise I am realy happy I can still ear the pre Echo on the over mudulated late (nothing to do with tapes) copy of Bonaparte Retreat.

And I have been pushing the F5 with the volume pot as far as it could go.

Have a treat.
Pavlov's Dog - Julia (HQ) - YouTube

I am going to keep it as it is for a couple off weecks
Then rig up the bateries again and have a listen to the 2 versions back to back.

PS I got the 24 V version at the moment with prepre for MC (litle transistor and 4 2SK170) as I still intend to give bateries a fair chance.

After that I most definetley will go for the proper spec version that I am shure will sound even better.

5th January 2012, 12:07 AM	#7122
Bksabath diyAudio Member Join Date: Dec 2007	Not realy the dogi track on the Island print (the Chatering Magpie) But a treath newer the less Caledonia - YouTube Glorious Simplistic and F5 on a pair of Polks Bodhran to ticle your tummy and the fidles that realy make you discover parts of my ear I did not remember to have. Last edited by Bksabath; 5th January 2012 at 12:10 AM.

5th January 2012, 09:54 PM	#7125
RCruz diyAudio Member Join Date: Sep 2006 Location: Saxon Blog Entries: 1	Pre echo.... a good description for my findings Anyway I had never noticed it on vinyl before I built the simplistic. With the other riaas I used to listen to, there was not enugh SNR and definition to notice this effect __________________ RC Last edited by RCruz; 5th January 2012 at 09:58 PM.

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5th January 2012, 09:04 AM	#7124
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	I seem to recall, but it was many years ago, reading that tapes used for storage had to be re-wound, periodically, to reduce the effect of the magnetic "print through". Pre-echo and post echo were just a few of the common problems for the careless technician in analogue recordings

5th January 2012, 11:35 PM	#7126
Jebem diyAudio Member Join Date: Dec 2011 Location: Lisbon	Hi, Salas, Great Post here... I like the SE design apparent simplicity, and plan to build this preamp for may Lyra Lydian MC cartridge. It happens that I have a bunch of 2SK146 matched NJFET's, and I wonder if I can use them instead of the 2SK170's without to much circuit modification. What do You think?

5th January 2012, 11:37 PM	#7127
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	Not compatible. Too much transconductance and input capacitance for this circuit.

6th January 2012, 09:04 AM	#7128
Jebem diyAudio Member Join Date: Dec 2011 Location: Lisbon	Thank You for Your information, Salas. That is what I was thinking about... but these 2SK146 old beasts matched pairs in a single thermal capsule shows a very low noise for a JFET, maybe one of the quieter semiconductor devices ever made... I am not a spice modeling user, however I believe that a simulator is in order to validate a SE design using these 2SK146 devices... I will report back.

6th January 2012, 12:35 PM	#7129
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	Not good for the bandwidth and gain of the second stage which is the ''engine'' of this design. It can be tackled differently but it will be another design. Wishing success in researching implementation for that particular component.

12th January 2012, 03:40 PM	#7130
Bksabath diyAudio Member Join Date: Dec 2007	Hopefully the public library is closed so Litle update from me I got the Simplistic working wit the reflektor and LM317 Tanks Joao litle caps work and on my list of things to do is have a play with type and values (got 100n MKS at the momement) IT does sound realy good as I even managed to ge rid of the hum (one to many ground vires) On the Reflektor I had a dogy plastic washer on one of the Mosfets and could not spot that with case open and ground floating so that sorted after a few hours and about 5p worth of new washer. Sound wise I am realy happy I can still ear the pre Echo on the over mudulated late (nothing to do with tapes) copy of Bonaparte Retreat. And I have been pushing the F5 with the volume pot as far as it could go. Have a treat. Pavlov's Dog - Julia (HQ) - YouTube I am going to keep it as it is for a couple off weecks Then rig up the bateries again and have a listen to the 2 versions back to back. PS I got the 24 V version at the moment with prepre for MC (litle transistor and 4 2SK170) as I still intend to give bateries a fair chance. After that I most definetley will go for the proper spec version that I am shure will sound even better.