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MC33078: Where is opamps upgrade page

user5784015
Prodigy 30 points
Part Number: MC33078
Other Parts Discussed in Thread: OPA1678, OPA1642, OPA1662, OPA2209, TL072, TL074, OPA1652

Hello,

Just few weeks ago here was nice page with opamps upgrade table
http://e2e.ti.com/support/amplifiers/precision_amplifiers/w/design_notes/upgrading-op-amps-in-audio-equipment

Now its disappear. Where to find something similar on TI site?

  • 0
    TI__Expert 6250 points
    Hi user5784015,

    At present, we don't have a replacement for the old audio op amp upgrade table. If you have a particular device you are looking to replace, we can help select an alternative part, however.
  • 0 in reply to Alexander Davis
    Prodigy 30 points

    Hi,

    I have Adam A5X active monitors, there is fifteen mc33078 in preamp active filters. Which opamp with better specs you recommend for drop in replace?

  • 0 in reply to user5784015
    TI__Expert 6250 points
    Hi user5784015,
    We typically recommend OPA1678 as a drop-in replacement for the MC33078, since it offers better distortion, significantly lower current noise, and slightly higher unity-gain bandwidth than the MC33078.

    You could also consider OPA1642 or a bipolar-input op amp such as the OPA1662 for that application. Keep in mind that while bipolar-input op amps tend to have lower voltage noise specifications than FET or CMOS input types, their higher input current noise may actually contribute considerably to the circuit's overall noise in many common audio circuits.
  • 0 in reply to Alexander Davis
    Prodigy 30 points

    It is OPA2209 also suitable to replace 33078? What difference of sounding 1642/1662?

    In this preamps also two TL074 and one TL072, can you recommend any alternative with more "audiophile" sounding?

  • 0 in reply to user5784015
    TI__Expert 6250 points

    Hi user5784015,

    OPA2209 could be used as a replacement for the 33078.

    As far as the sound of different op amps, that's not something we can really comment on. Much of the performance and sound of any op amp is going to depend on the exact circuitry around it, particularly when talking about noise or distortion. For this reason, I'd recommend consulting forums (diyAudio, for example) for reports of other similar swaps, and the sound quality they've achieved. 

    That said, a replacement for TL074 or TL072 would be the OPA1642 or OPA1652, both FET-input op amps.