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Thread: 1980 Texas Instruments RC4558P vs current TI-RC4558P

  1. #21
    INTENSELY corrosive sweat formula73's Avatar
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    Default Re: 1980 Texas Instruments RC4558P vs current TI-RC4558P

    I can’t argue with that!

  2. #22
    Mojo's Minions devastone's Avatar
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    Default Re: 1980 Texas Instruments RC4558P vs current TI-RC4558P

    Quote Originally Posted by PFDarkside View Post


    Everything makes a difference, but enough for you to hear it and enough for you to care?
    That video illustrates a lot of things, soft clipping vs hard clipping, different diodes, and yes, different opamps, not old vs new 4558, but a wide variety of different opamps in the same circuit.

  3. #23
    of the Forum PFDarkside's Avatar
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    Default Re: 1980 Texas Instruments RC4558P vs current TI-RC4558P

    Quote Originally Posted by devastone View Post
    That video illustrates a lot of things, soft clipping vs hard clipping, different diodes, and yes, different opamps, not old vs new 4558, but a wide variety of different opamps in the same circuit.
    I have a tough time hearing the differences between some of the opamps, so I figure I couldn’t hear a difference between old/new of the same component.

    JMP/HBE, have you made your swaps and comparisons yet?
    Oh no.....


    Oh Yeah!

  4. #24
    Mojo's Minions devastone's Avatar
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    Default Re: 1980 Texas Instruments RC4558P vs current TI-RC4558P

    Quote Originally Posted by PFDarkside View Post
    I have a tough time hearing the differences between some of the opamps, so I figure I couldn’t hear a difference between old/new of the same component.

    JMP/HBE, have you made your swaps and comparisons yet?
    The old ones just call you "sonny" a lot and complain about being cold.

  5. #25
    Toneologist JMP/HBE's Avatar
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    Default Re: 1980 Texas Instruments RC4558P vs current TI-RC4558P

    Quote Originally Posted by PFDarkside View Post
    I have a tough time hearing the differences between some of the opamps, so I figure I couldn’t hear a difference between old/new of the same component.

    JMP/HBE, have you made your swaps and comparisons yet?


    Yes ive mixed & matched. The differences were anywhere from minimal to outstanding. The best ones ive gotten so far are USA Raytheons from early 80's. Ive stocked up on them.

  6. #26
    Ultimate Tone Slacker Jacew's Avatar
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    Default Re: 1980 Texas Instruments RC4558P vs current TI-RC4558P

    Quote Originally Posted by JMP/HBE View Post
    Since yesterday ive spoken with Dave Friedman & Analogman Mike Piera and both said the same thing as above.
    So does Brian Wampler
    "So understand/Don't waste your time always searching for those wasted years/Face up, make your stand/And realize you're living in the golden years"
    Iron Maiden - Wasted Years

  7. #27
    Mojo's Minions devastone's Avatar
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    Default Re: 1980 Texas Instruments RC4558P vs current TI-RC4558P

    You might try some Burr Brown OPA2134s, I know, they aren't 4558s, they are much better spec wise and sound cleaner/more open IME, and their pinouts are the same. Of course, part of the beauty of the 4558 in OD/Dist pedals is the same as the LM308 in Rat circuits, they are actually pretty crappy generic opamps. The 2134s were designed specifically for audio applications so they have less noise and are more transparent, that can be a good thing in most applications, but "cleaner" may or may not be what you are looking for.

    https://www.mouser.com/ProductDetail...aGg8q6KvJG8%3D

    Specs - http://www.ti.com/lit/ds/symlink/opa2134.pdf

  8. #28
    Toneologist JMP/HBE's Avatar
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    Default Re: 1980 Texas Instruments RC4558P vs current TI-RC4558P

    Quote Originally Posted by devastone View Post
    You might try some Burr Brown OPA2134s, I know, they aren't 4558s, they are much better spec wise and sound cleaner/more open IME, and their pinouts are the same. Of course, part of the beauty of the 4558 in OD/Dist pedals is the same as the LM308 in Rat circuits, they are actually pretty crappy generic opamps. The 2134s were designed specifically for audio applications so they have less noise and are more transparent, that can be a good thing in most applications, but "cleaner" may or may not be what you are looking for.

    https://www.mouser.com/ProductDetail...aGg8q6KvJG8%3D

    Specs - http://www.ti.com/lit/ds/symlink/opa2134.pdf
    I have one, haven't tried it yet. Ive heard mixed reviews but don't know what to expect.

  9. #29
    Mojo's Minions devastone's Avatar
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    Default Re: 1980 Texas Instruments RC4558P vs current TI-RC4558P

    Cleaner, clearer, more headroom, and less opamp distortion has been my experience. Again, depends on what you are looking for and what sounds good to you, YMMV, ice cream, all that.

  10. #30
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    Default Re: 1980 Texas Instruments RC4558P vs current TI-RC4558P

    IN my experience, the difference in new and old chips is the same as variation between new chip lots, or between the old chip lots.

    Every chip new and old is just slightly different but not enough to even concern yourself, except an occasional actual bad one.
    “For me, when everything goes wrong – that’s when adventure starts.” Yvonne Chouinard

  11. #31
    Slutbucker Pimpologist ArtieToo's Avatar
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    Default Re: 1980 Texas Instruments RC4558P vs current TI-RC4558P

    I think that it was Jack Orman who had an article about this, but I've been searching his webpage and can't locate it. To paraphrase, he basically said that to worry about the sonic characteristics of an op amp, when used in an OD/Distortion pedal, where the primary purpose is to cause extreme distortion, is a bit of silliness. (He said it better.)

  12. #32
    Toneologist JMP/HBE's Avatar
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    Default Re: 1980 Texas Instruments RC4558P vs current TI-RC4558P

    Quote Originally Posted by ArtieToo View Post
    I think that it was Jack Orman who had an article about this, but I've been searching his webpage and can't locate it. To paraphrase, he basically said that to worry about the sonic characteristics of an op amp, when used in an OD/Distortion pedal, where the primary purpose is to cause extreme distortion, is a bit of silliness. (He said it better.)
    Im not after a change in "distortion". Some of these chips have a sweeter midrange than others.

  13. #33
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    Default Re: 1980 Texas Instruments RC4558P vs current TI-RC4558P

    .....it is a game with no rewards worth the effort....but have fun...

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