Guess the photo? blue resistor

[kuly]

Why is this resistor of a different color and size?
Is he special? why is he different?
What's this? for the detail? written 220 ohms
1-resistor of another power
2 thermistor
3-resistor high precision?

blue resistor

 

[Mooly]

Well it looks like it had to be a different type to fit the space available. Non of the others would physically fit. Its very small if you consider the the T092 package next to it.

 

[Osvaldo de Banfield]

I don't see any particularity in such resistor. Only different manufacturer. What's your doubt on it?

 

[kuly]

ok---resistor (0.5-0.25W)

 

[PH104]

It's an old Corning NA55 metal film which is the commercial version of RN55, I think. As Mooly said, probably chosen for size.

 

[kuly]

thanks I got it. one more question )))

What is the number of resistor !!????? see attach

6040 ,,,??? 6к+ 40 ohm ???

 

[PH104]

6040 ohms is a legitimate E96 value.

 

[kuly]

ok--super

 

[cliffforrest]

It looks as though the schematic has been printed out before the parts designation has been assigned. this has nothing to do with the value, but the manufacture's ID on the BOM, hence c?, R? etc..

Some CAD systems apply this "on the fly" as parts are added. Some need a button push to generate or update it.

 

[analog_sa]

The 220R resistor is trimmed to the particular jfet, so it's value is not fixed. Perhaps this is the reason it is different to the rest. You should ask JC.

 

[johnego]

Why is this resistor of a different color and size?
Is he special? why is he different?

The small resistor is indeed better sounding than the Roederstein (the bigger ones). The 0.5W version will be very expensive, hence the smaller size. I don't know whether it is a critical position for a good resistor (it is less than 1k anyway), but who knows?

 

[analog_sa]

Not likely to be very critical in the ccs.

 

[johnego]

Not likely to be very critical in the ccs.

I know ccs or current setting resistor can be critical. It's the resistance that is probably too small to be critical. But i have never proved it by ears. For very small resistance where noise or temperature is not an issue (usually in series with signal: base stoppers or output resistors) I simply use Allen-Bradley for its 'organic' sound when used as FB resistor (due to less inductance may be?) where it is not really suitable in this FB position due to high resistance, high current, critical duty.

 

[kuly]

I want to tell everyone a big thank you for your help! You are professionals. I am an amateur!
Tell me more advice! - I hope you are not funny !!
Is there a contact at these points? 1-2-3 I do not understand

Color drawing is that right? or mistake

 

[Mooly]

Mistake

The three FET's should be in parallel and so to the resistors.

 

[analog_sa]

I know ccs or current setting resistor can be critical.

Cannot argue with this as a general statement, just not in this particular context: there are many more critical resistors in this circuit.

 

[johnego]

Cannot argue with this as a general statement, just not in this particular context: there are many more critical resistors in this circuit.

Yup. I think you're right. And I don't listen to resistors. I just know it by accident when I design amplifiers (by ears) when looking for the right values.

 

[kuly]

Mistake

The three FET's should be in parallel and so to the resistors.

I will fix the fee --- thanks I hope everything is right

 

[analog_sa]

kuly, curious to know what fets you intend to use in your project. And how will you select them by Idss. If i were to do it i would start with a simulation but perhaps you have better ideas.

 

[kuly]

I want to run a layout !!!
instead of transistors (2sk147-2sj72---2sk240-2sj75) I use 2SJ74/2SK170
the rest of the transistors, I will put the same name.

If the layout starts working --- I will buy original transistors in a Japanese auction
PCB-there is a mistake, I will correct