Audio CFB Opamp

[jackinnj]

Hot off the presses:

it's a wow

http://www.national.com/ds/LM/LME49713.pdf

 

[x-pro]

it's a wow

In what respect "wow"? I can not see anything particularly interesting from the datasheet. Perhaps it may sound good in some appliciations but that only a listening test can tell.

Alex

 

[Ipanema]

This opamp spec sheet looks fantastic. BTW, can it drive a 32ohms headphone or is it good for an opamp based power amp since the current output is +/-100mA.

Thanks.

 

[Tim__x]

Looks pretty nice.
Though the high value feedback resistors will ruin noise performance.

 

[peranders]

The performance is similar other CFB opamps like the TPA6120 but since I like CFB it looks wow.

 

[peranders]

Looks pretty nice.
Though the high value feedback resistors will ruin noise performance.

It's a good point but also quite irrelevant because it's a CFB topology which is useless for high impedance network, it's against it's nature. In this case Tim, you must do you homework about CFB amps.

 

[Tim__x]

I understand how CFB works. Look at page 6, good stability appears to require at least a couple Kohms of feedback resistance.

This CFB opamp is optimized for slightly higher values in the feedback network than many other opamps. It's not a huge concern, but it is a valid and considered complaint.

 

[Tolu]

I don't see the point. 1.2kOhm isn't the issue I think.
The slew rate is extraordinary.

I would test how it sounds in a preamp but National wants 30$ for 4 sample chips!

Anyone just tried it?

 

[banana]

1.2Kohm would be an issue, if u multiple it with 16pA/rtHz current noise density. But that's the case only when gain is low.