Valve Itch phono

[Salas]

Can this high quality DMM be reliable at nF level without Kelvin wires as dedicated LCR meters have? Also test another nF range capacitor for reference. Film, better never used. Does it read it correctly within tolerance? If the DMM is so true then replace drifter with new C3 of proper capacitance. RIAA curve shaping components if that much drifted can really throw off the music's tone.

 

[vgeorge]

Salas I desoldered the measured when built C3 15,42 nF of one channel, ooops look now how much measured!

What capacitor did you use? What is the voltage rating?

 

[merlin el mago]

Can this high quality DMM be reliable at nF level without Kelvin wires as dedicated LCR meters have? Also test another nF range capacitor for reference. Film, better never used. Does it read it correctly within tolerance? If the DMM is so true then replace drifter with new C3 of proper capacitance. RIAA curve shaping components if that much drifted can really throw off the music's tone.

Trusted DMM

 

[Salas]

At 10uF level the test cables don't interfere. Try 1nF-10nF capacitor. That's the range you are searching accuracy for this application.

 

[merlin el mago]

What capacitor did you use? What is the voltage rating?

FT-1 Russian teflon cap rated 200V & 10% tolerance

 

[merlin el mago]

At 10uF level the test cables don't interfere. Try 1nF-10nF capacitor. That's the range you are searching accuracy for this application.

Auricap it's 1uF

 

[Salas]

Typo, but still uF range

 

[merlin el mago]

Measured 15nF correctly

 

[Salas]

So verified and official your old C3 has drifted too much negative!

 

[Salas]

Maybe random, maybe b-stock unreliable, maybe too close for working voltage. Use higher Voltage spec if you got, avoid oil types.

 

[merlin el mago]

How on earth a film cap has drifted as this one?

FT-1 are teflon film with aluminium foil....

Schematic show 165V I believe 200V is safe...

 

[Salas]

Bad ex-Soviet stock sample maybe. Got humidity in, whatever. That drifter stole your mids warmth! See curve 8.25nF.

 

[merlin el mago]

Listened & suffered long time.

Now I'm afraid of using the same FT-1

 

[merlin el mago]

FT-1 nearest value to 15.75nF are 15.92nF & 15.96nF are excesively high value Salas?

 

[Salas]

Has C3 drifted on the other channel too?

 

[merlin el mago]

Still not measured. I will go to measure.

 

[Salas]

FT-1 nearest value to 15.75nF are 15.92nF & 15.96nF are excesively high value Salas?

Look usable. Bringing only slight warm tilt.

 

[merlin el mago]

It seems in good shape.

 

[merlin el mago]

Now I'm more confident using again FT-1 seeing the other cap is good.

 

[merlin el mago]

Look usable. Bringing only slight warm tilt.

Ok I will use thanks.