Simplistic NJFET RIAA

[spaceistheplace]

Also, can someone point me in the right direction for a pcb kit or test jig for matching Jfets in the parameters most important for these kinds of builds?

Would something like this do?

http://www.stompville.co.uk/shop/en/23-jfet-matcher-kit.html

Seems like many exist for guitar effects pedals... wondering if the voltage and other parameters make for good use for our purposes.


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[AndrewT]

Borbely

 

[Salas]

Seems like many exist for guitar effects pedals... wondering if the voltage and other parameters make for good use for our purposes.

For the FSP avoid any JFET types substitutions. The specific Toshiba types Yfs, noise, and Vgs (off) specs, are relied on and designed in for correct bias and performance.

 

[spaceistheplace]

For the FSP avoid any JFET types substitutions. The specific Toshiba types Yfs, noise, and Vgs (off) specs, are relied on and designed in for correct bias and performance.

I misspoke, I meant an idss matching jig for sk170 etc.

I am only asking in relation to the test jig, not parts substitution.


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[spaceistheplace]

Matched generics, no question.

(where "generic" = Epcos, Wima, TDK, Nichicon, Panasonic, Cornell Dublier, Vishay, Kemet, etc...)

In my opinion, expensive caps are 1) tone controls and 2) good for managing expectation bias.

EDIT: In a phono preamp, particularly in the RIAA, I'd much rather have generics than audiophile caps even if both were matched within .1% . Perhaps a fancy-pants cap on the output if one needed color to taste.

I've been through the expensive cap phase of this journey, mostly it's just expensive. (But they do look cool...)

Which high quality / tolerance generics do you have experience with?

The Kemet 1% F461 look good, as well as some of the WIMAs and TDK.

The kemets are also very reasonably priced at less than $2 ea. Makes cost of obligattos etc look that much crazier.

Any "series" by these manufacturers you like that you could hint to?


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[anatech]

Hi spaceistheplace,
Look also at Nelson Pass' forum and web site. You basically measure Vpinch and Idss to define a match. Nothing more complicated than that. I made a matching jig, but it is focused on BJTs, but will match FETs at the particular tail current you want to use, but only after you have pre-sorted by the first method. That project is detailed in a thread about repairing "yet another GFA-565" thread. Something close that title, but near the end of the thread I think.

-Chris

 

[escucalin]

Hello

I am "new" to this thread; actually is my first post, but i went over all 1600+ pages; but i'd like to provide a contribution to the ones that are seniors here in both contribution and following.

I was wondering if anyone finds that the thread became `unbrowsable` (I lost myself tons of times here and search is *not* helping when you do not know the EXACT phrasing)

I am willing to assemble a spider to extract the entire content of this thread in one cute little page and if anyone needs it i will provide it with live links back here ... and maybe ALL the pictures with back annotation to the post they were posted... i don't know what would make things easier.

So... Anyone interested?

Regards,
Calin.

 

[escucalin]

Hello,

For a more "on topic" question; anyone have experimented with a AT 20 SLA/SS cartrige loading? Is a 47K Vishay SFERNICE Foil resistor 5ppm a proper choice?

-C

 

[escucalin]

Hello ;

Regarding post #16667
I've got all the thread in a single giant file for anybody's pleasure. compressed is 3.3Mb; Is there a way to store it on this forum and link it? (i would like to avoid storing it on external sharing providers since things change and link might become broken)

Thank you!

 

[escucalin]

Anyway, here is the link for the ones that need ALL the thread in a nice tight page easy to surf and quick to search:

Entire thread in one page.

Thank you all before and Great Job done here!

 

[Salas]

Hello ;

Regarding post #16667
I've got all the thread in a single giant file for anybody's pleasure. compressed is 3.3Mb; Is there a way to store it on this forum and link it? (i would like to avoid storing it on external sharing providers since things change and link might become broken)

Thank you!

Anyway, here is the link for the ones that need ALL the thread in a nice tight page easy to surf and quick to search:

Entire thread in one page.

Thank you all before and Great Job done here!

Hello,

For a more "on topic" question; anyone have experimented with a AT 20 SLA/SS cartrige loading? Is a 47K Vishay SFERNICE Foil resistor 5ppm a proper choice?

-C

There is no facility for large uploads in the forum's server. As for a low ppm Sfernice foil resistor or trimmer for input loading choice, they are among the best.

 

[Siberia]

Talk me out or talk me into buying DER EE DE-5000 LCR meter.
Prices got really attractive recently.
I just wonder if you guys use it often one the projects like this.
Selecting RIAA caps?
Tuning C3x?
What else?

 

[Turbon]

Talk me out or talk me into buying DER EE DE-5000 LCR meter.
Prices got really attractive recently.
I just wonder if you guys use it often one the projects like this.
Selecting RIAA caps?
Tuning C3x?
What else?

I use it often to measure inductance too and values of electrolythics.

Totally worth its cost!

Regards

 

[vgeorge]

Measuring all sorts of capacitors, inductors in speaker crossovers, resistors with greater accuracy.
You NEED a decent LCR meter.

 

[Siberia]

Accuracy. The word which can almost lull a 100 euros to sleepwalk out of my pocket.

I also still got my Multimeter UNI-T UT603 (RLC) :: UNI-T, but with less ...ehm... accuracy.

 

[alexkosha]

I use it frequently too. Conceder to get IR with USB cable. In my case, it is showing more digits on PC screen vs on its own LCD screen.


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[Salas]

Does it also show more dissipation factor digits?

 

[alexkosha]

I think so. Please see images taken from device LCD and same cap measure on PC screen via USB.

 

[Siberia]

thanks, Alex and all

 

[rickmcinnis]

Dear Salas,

There are lots of 2SK170Vs finding their way into the market - could these be useful for Qs 4/5/6?

Take care,