Simplistic NJFET RIAA

[merlin el mago]

The nearest to 9.4V is 9.23-9.29 gives 10.79V

[Salas]

I like that 10.79V. Now, is there one that will bring right channel over 10V? Because it looks that we can not match to the 9.4V right as a reference with those you got in hand. Keep exchanging on the right, we are heading somewhere good. Try No6 on right, as you are.

[merlin el mago]

I left more time connected the LSK389 to do more accurate measurement so 9.23-9.29 gives now 10.97V in Left channel.

Right channel the nearest is Idss 9.32-9.25 that gives 11.14V.

[Salas]

Great! Leave them in. Now Ricardo will have a base. 3.3K sharp R1 load resistor for each channel. Its very important, because it reflects the output impedance of first stage. Now if you give it a listen, I expect it to be more focused. For the time being if you feel it is on the soft side too, take the extra caps out of C3's base value, it will pick up in the high mids and treble, until you will do your precise values and maybe resistor types fix with Ricardo. Let me know if it got better.

[RCruz]

Removing C3 // will lift highs but IMO If you got 3k3 for R1 you can go back to post Simplistic NJFET RIAA

Let us know your final choice.

[Salas]

Ricardo, Merlin, what is the spec precision of those LCR meters? Also was the non matched ''6k8'' 6.k9 or 6k79?

[merlin el mago]

Originally Posted by Salas

Great! Leave them in. Now Ricardo will have a base. 3.3K sharp R1 load resistor for each channel. Its very important, because it reflects the output impedance of first stage. Now if you give it a listen, I expect it to be more focused. For the time being if you feel it is on the soft side too, take the extra caps out of C3's base value, it will pick up in the high mids and treble, until you will do your precise values and maybe resistor types fix with Ricardo. Let me know if it got better.

Ok now Left channel 10.97V Right channel 11.14V. Taked out the extra caps of C3's now only 1 cap 15n6. Changed R1 trimmers in both channels for fixed resistor Xicon carbon film 3K3. Let me tonight to hear, tomorrow I will let you know.

[merlin el mago]

Originally Posted by RCruz

Removing C3 // will lift highs but IMO If you got 3k3 for R1 you can go back to post Simplistic NJFET RIAA

Let us know your final choice.

Ok I will go back to post for matching RIAA both channels with R1 3K3. Let me time see if I have combination of resistors & caps on hand to do the request values.

Thks for your kind help, I will let you when I can do the setup.

[Salas]

OK. Are those 3k3 you put 1W rated? Its important, there is enough dissipation.

[merlin el mago]

Originally Posted by Salas

Ricardo, Merlin, what is the spec precision of those LCR meters? Also was the non matched ''6k8'' 6.k9 or 6k79?

Mine LCR can be adjusted with a pot, so when connect togheter + & - I adjust to get exactly 0.00 ohms, other way is check a very good resistor of a tigh tolerance 0.025% or 0.0025% I remember that I have one Vishay like this but now I don't know where is, is not a S102K was another cheaper sell in England I don't remember the series but was also bulk metal foil.

Non matched is: R4 Left channel 6k80 - Right channel 6k79