Pre Opamp frequency response

[Rafael L]

I am designing a pre-amp circuit based on opamp (OPA134), but I'm not wearing any compensating... This circuit also does not use:

HeadWize - Project: Designing A Pocket Equalizer For Headphone Listening (A HeadWize Design Series Paper)

Will it have any problem? (Attached)



Thanks

[tomchr]

The OPA134 is unity gain stable. It looks like you are running a gain of about 12 dB. So you should not have stability problems.

However, your sim shows a bandwidth of almost 5 MHz. I suggest limiting that to 200 kHz or so by adding a capacitor across the feedback resistor and by adding an RC filter on the amp input. There's no reason to amplify noise in a bandwidth you aren't using.

~Tom

[AndrewT]

I have found that I like the power amp set to F-3dB~200kHz using a single pole RC input filter.
I have also found that using a wider bandwidth on the preamp maintains that nice sound at the speakers.
I normally aim for ~1Hz to 300kHz in the pre-amp to feed a power amp @ 1.7Hz to 200kHz. The result is ~ F-1dB @ 3Hz to 100kHz.

This seems to suit me, my speakers and the various interferences existing in the house.

[Rafael L]

Originally Posted by tomchr

The OPA134 is unity gain stable. It looks like you are running a gain of about 12 dB. So you should not have stability problems.

Hi Tom,
I am using 3 opamps, two in unity gain and the last with a gain

Originally Posted by tomchr

However, your sim shows a bandwidth of almost 5 MHz. I suggest limiting that to 200 kHz or so by adding a capacitor across the feedback resistor and by adding an RC filter on the amp input. There's no reason to amplify noise in a bandwidth you aren't using.

~Tom

Originally Posted by AndrewT

I have found that I like the power amp set to F-3dB~200kHz using a single pole RC input filter.
I have also found that using a wider bandwidth on the preamp maintains that nice sound at the speakers.
I normally aim for ~1Hz to 300kHz in the pre-amp to feed a power amp @ 1.7Hz to 200kHz. The result is ~ F-1dB @ 3Hz to 100kHz.

This seems to suit me, my speakers and the various interferences existing in the house.

Hi Andrew,
Is that my amp already has an RC filter in input, so I asked if it was absolutely necessary.
This is another preamp without concern RF:
Hi-Fi Preamplifier

but other preamp to book D.Self, has compensating: