rezistors tolerance

[QBAS]

hi

I would like to ask: if I use regular 5% tolerance rezistors in OPL3 module will be differences between 4 ouputs?

I`m wondering that for egzample 22k is in range from 20k9 - 22k5.

Is this important to match resitors, or I need use better one - like metalized or so?

Can anybody tell me more?

thank you

[seppoman]

Resistor values around OpAmps are of course influencing the gain factor - especially when the two values at one OpAmp stage are off in opposite directions, there can be quite some differences in measured peak volume. But as volume perception is logarithmic, e.g. the difference between 7 and 8 volts peak value are not very drastic - such a difference is well below one dB.

If you already have the resistors, it´s no problem using them. If you do notice a difference between channels, you can try to find matching resistors. If you didn´t buy them yet: I reccomend using 1% metal resistors for everything. In the meantime, I switched to buying only metal Rs, the extra cost is negligible and in some situations like OpAmps or equally strong LEDs, there´s some benefit in using them.

Seppoman

[QBAS]

thank you