Simplistic NJFET RIAA

diyAudio Chief Moderator
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Sometimes I write fast and my native language is Greek. So please kindly pardon some of my linguistic mistakes. English I have learned in school as a foreign language, and I try to write as good as I can in forums, but not always successfully so.:rolleyes:
 
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nicoch46 said:


HI Salas , Andrew do not know my maccheroni English :D :D

HI Andrew

Come on now! Why you say so?:smash:
 

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diyAudio Chief Moderator
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Statistical question for all

Now that I am about to do the schematic resumes, I wonder. What is the mean average IDSS of the BL parts that you have in your inventory? The latest I got from Spencer are bunching rather high for instance. Shall I adjust values during the schematics standard making process too?
 
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salas said:

Hi Salas

What about using a polystyrene ? I have hundreds of those 4700pF (noob´s initial attempts into ebayhigifi)

salas said:

I like hot JFETS too.:hot:
Do jftes like heat ? (Like valves?)

The obbligato caps are beginning to show their capacities... Inittialy very closed, now quite spacy and with tendency to open.
I was thinking about bypassing them but now I will wait and see... Maybe the teflon in C1 will give me the needed extension in highs and lows, so I will not need to bypass the output.
(But I will loose the mid freq magic of the C1 PIO ?!) (Can I bypass the PIO with the FT-3 ?)

Based on your previous comments I understand my riaa is extremely psu dependent, it is also very transparent and reactive to every mod I do. (I am glad I have a super reg now... the difference is awesome...)

Now I can precisely set VTA and down force by hear. ;)

Ricardo

PS

I am building a shielded cable for the output lines, using inner stranded silver cable with teflon coat and the shield comes from a long run of high flex, double shield, marine grade ofc cable.

Of course i will only connect the shiled on one side so it will not conduce signal.
 

iko

Ex-Moderator
Joined 2008
Don't know if it's helpful, but out of the 100 pieces I got, very few were in the 6-7mA range, and very few above 11mA. Most were spread across 7, 8, 9, and 10mA.

I'm curious, do you use a simulator to come up with different part values for different idss, or do you do it on paper/calculator?
 
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RCruz said:


Hi Salas

What about using a polystyrene ? I have hundreds of those 4700pF (noob´s initial attempts into ebayhigifi)


Do jftes like heat ? (Like valves?)

The obbligato caps are beginning to show their capacities... Inittialy very closed, now quite spacy and with tendency to open.
I was thinking about bypassing them but now I will wait and see... Maybe the teflon in C1 will give me the needed extension in highs and lows, so I will not need to bypass the output.
(But I will loose the mid freq magic of the C1 PIO ?!) (Can I bypass the PIO with the FT-3 ?)

Based on your previous comments I understand my riaa is extremely psu dependent, it is also very transparent and reactive to every mod I do. (I am glad I have a super reg now... the difference is awesome...)

Now I can precisely set VTA and down force by hear. ;)

Ricardo

PS

I am building a shielded cable for the output lines, using inner stranded silver cable with teflon coat and the shield comes from a long run of high flex, double shield, marine grade ofc cable.

Of course i will only connect the shiled on one side so it will not conduce signal.

Any good film cap wil do for RF cap.

Your final interstage and output capacitor mix with or no bypass depends to your taste, system, rest of components and cabling. I see that you are very expert in voicing. Since we helped you to go fast in the ballpark, now play ball libero.;)
 
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Re: Statistical question for all

salas said:
Now that I am about to do the schematic resumes, I wonder. What is the mean average IDSS of the BL parts that you have in your inventory? The latest I got from Spencer are bunching rather high for instance. Shall I adjust values during the schematics standard making process too?


Mean 8,6 (Same median)
Max 10,9
Min 6,4
 
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ikoflexer said:
Don't know if it's helpful, but out of the 100 pieces I got, very few were in the 6-7mA range, and very few above 11mA. Most were spread across 7, 8, 9, and 10mA.

I'm curious, do you use a simulator to come up with different part values for different idss, or do you do it on paper/calculator?

I change the Beta data on the simulator's model. I have checked with practical circuit and it ties well. So given your parts, 8.5mA IDSS seems valid. Waiting to hear from more.