Opa549 & Opa541

[kinser]

Hi to all GC DIYer's,
Im busy making my OPA549 and OPA541 PCB's and im using 20k/1.4k
for the feedback network.
i have a 100k resistor then a 4.7uF NP cap and then 20k resistor all at the input (cheak the board to understand better) i would like to have insted of the 100k a 47k resistor, and maby chang the 20k to a 22k resistor (like on the LM38xx chips) is this ok to do? and should i also chang the feedback network resistor to other valuse?

Thanks,
Kinser

[carlmart]

Originally posted by kinser

Im busy making my OPA549 and OPA541 PCB's and im using 20k/1.4k
for the feedback network.
i have a 100k resistor then a 4.7uF NP cap and then 20k resistor all at the input (cheak the board to understand better) i would like to have insted of the 100k a 47k resistor, and maby chang the 20k to a 22k resistor (like on the LM38xx chips) is this ok to do? and should i also chang the feedback network resistor to other valuse?

Except if you are going to use the OPA549 to power a sub, you should be careful with that gain setting.

You can not use the same circuit on the OPAs as you do on the LM38xx, because they have less bandwidth gain.

Try something close to 10x gain, as the examples you can see on the datasheet. Or be ready to change that on the pcb when you are doing your listening tests.


Carlos

[bjengi]

Cuold you give an hint of which values? 1k+10k?

Real noobe

[carlmart]

Originally posted by bjengi
Cuold you give an hint of which values? 1k+10k?

1) Try 20K and 220K. That would allow you use a smaller blocking capacitor, if you are using IGC layout.

2) Try 1K + 10K if you are using NIGC

As I said, try different values, for the small or large resistors, to see how it sounds if you go higher in gain.


Carlos

[sidd_raj2002]

hey could u send me a schematic and a black and white pcb layout in jpg format. i have both opa541 and 549 and i am plannin to use them to power my sub.

i am an amateur so dunno anythin technical abt this. iam just gonna make it like a jigsaw puzzle and hook it up

the sub is of approx. 12ohms and i need atleast 50w