My OPA549 Schematic... Does it look ok?

[bigmike216]

This is all made with parts I have on hand.. 1% metal film resistors and such


Gain is fairly low, as it's an opa549.. I'll add a preamp if my schematic here looks like it'll work.

 

[jaudio]

Here I have not checked all the pin layout

Add a .1uf cap to each supply rail

Pins 5 &7 are V- supply both pin must be connected

Pins 10 & 11 are V+ supply both pin must be connected

Try a snubber

 

[bigmike216]

that's the only change that needs to be made? I'll go pick up some 1k metal films then

 

[jaudio]

I m sorry read second post

 

[carlosfm]

Suggestion

OPA549:
Gain of 7.6x.
1uf film input coupling cap, with 47k to ground.

Preamp:
2xOPA637, with a gain of ~7x, PSU voltage +/-18V.
Biased to class-a with a 2k resistor between V- and output.
No input or output coupling caps on the pre.

 

[carlosfm]

PS: Snubberized PSU.

 

[bigmike216]

whoops, I forgot a ground symbol in there I think i'd like to go with a gain of around 10, will it still be stable around 10?

 

[bigmike216]

schematic:

 

[carlosfm]

That's a gain of 11.
I would go a little lower.
Change R3 for 1.2k.

 

[carlosfm]

whoops, I forgot a ground symbol in there I think i'd like to go with a gain of around 10, will it still be stable around 10?

The OPA541/8/9 chips are stable with gains of 1.
The gain of 7.6x I recommended is fine.

 

[bigmike216]

Thanks carlos

 

[bigmike216]

And the PCB.. This is the first one i've ever done, so please tell me if there's something I've done horridly wrong.