please forgive my ignorance... i have a probably stupid question:
can the dual & quad opamps TLV2472/TLV2474 be replaced with these:
TL072 and TL074 ?


  • I could be wrong but I think the TLV ones are low voltage versions since the WTPA is all 5V (again, could be wrong) internally.
  • Yes and no, someone else swapped out the TLV2474 for a TL074. However, the tlv 2474 is a rail-to-rail opamp (the inputs and outputs can go all the way between the power rails) and is designed to work with a lower supply voltage.

    Another difference I'm interested in, perhaps someone more knowledgable can comment on this, is that the TL07X's have JFET inputs. This means it has a very high input impedance (i.e. very little loading on the signal source) which is often a good characteristic to have for audio input, especially if you're using a high-impedance input (e.g. guitar)

    But I'm not sure. Certainly you'd have less headroom with the TL07X's. And Todd mentioned before about slew rate limiting at 5v. Presumably you'd have worse transient / high-frequency response.

    I'm wondering if/how the relaxation oscillator would work differently with a change in input impedance.

    You can give it a try. The pinout's the same, and you're not going to injure anything by trying.
  • Best way to answer this question is to refer to the datasheets :-)

    Short answer, no.
    @Rodrigo is right about supply voltage being the main reason you can't use the TL07x opamps in WTPA. However, they're fundamentally different animals internally, too.
    The TLV246x is valid too, and is a little different. Lots of op amps would work, many with subtle (or perhaps not so subtle) performance differences.
    You CAN use the LM324 and LM358, but I'll let you figure out why not to :-)

  • thanks, Todd for all the helpful emails.
    @all: i've found someone local who can do a Farnell order for me, they carry those hard to get parts (at least for germans). there will be additional cost of €20 because all parts have to be imported from overseas. Farnell also have the sram. so if someone else from around here have problems sourcing the tlv247x or sram too and would like to join the order, let me know. i'll order them these days.
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