TL071/4 substitutes

[richwalters]

Hi there.....I'm on the hunt for a sim low noise Jfet input opamp, BUT with rail to rail input capability with sim low thd as TL0 family i.e 0.002%.....other noise and Vcc parameters sim.
The National Semi website isn't really helpful on thd selection.

Any hints ?

rich

[Evan Shultz]

LF411 and LF412 are very similar spec wise.

The OP275 is also a very high quality part I suggest. PMI and Analog Devices make it.

Most BB op amps are FET input. The OPA604 is highly regarded.

[richwalters]

Yup...taa for reply......I suspected the BB...and OP275 infact the OP604 could fit my circuit very nicely..........I also came across loads of LF357's (which I discovered in a ledger after posting the mail).....another high flyer with a nice output stage...although somewhat hairy ic to use....although.......the biggest drawback with the TLO family is lousy output loading capability v.s distortion and this is the application I'm after.

I'll try all. thanks

richj

[purplepeople]

TI OPA-x134 series is okay for 600R output load. It has also been used in some headphone amps.

:)ensen.

[richwalters]

It has also been used in some headphone amps.

[/B]

Hi there.....yes that's my end application but as a high performance driver.
I'm using 4x 5532's in parallel (each channel) with sep resistors to sort out the unequal o/p currents.....of all the power op amps I've tried, the parallel combination of the 5532 seems to offer the best performance i.e lowest noise -105dB (audio band weighting) with lowest thd. Many ic's don't have the output swing to take headphone impedances of around 30 ohms at the 1watt level with the lowest thd.... It may not be cost effective but multiple parallel operation is a good way to do this. When I've done hte cct diag I shall post it...

good morning

richj