1981 L2000 preamp chip - TI upgrade OK?

Discussion in 'G&L Bass Forum' started by jtlee, Jul 23, 2007.


  1. jtlee

    jtlee Supporting Member

    Mar 2, 2005
    Portland, Oregon
    I've got a few of the TI chips that I used to upgrade the preamp on my late model L2000s, but the 81 L2000 I have (soon to be for sale) has a ECG944M chip in it. The pre is not working, so I assume the chip is blown. Whould the Texas Instrumentes OPA704PA work in place of the ECG944M? Specs :

    Part Number = ECG944M
    Manufacturer Name = Philips Semiconductors
    Average Price = 3.693525
    Description = Single Current-Programmable Gain Op Amp - +/-1 to +/-18V Supply Voltage
    Input Bias Current Max. (A) = 75n¾
    V(io) Max. (V) = 6m¾
    I(io) Max. (A) = 20n
    Com Mode Inp Range (VICR) = 13.5
    P(D) Max.(W) Power Dissipation = 500m
    Nom. Supp (V) = 15
    Package = DIP
    Pins = 8
    Military = N
     
  2. jtlee

    jtlee Supporting Member

    Mar 2, 2005
    Portland, Oregon
    Decided what the heck...I went ahead and popped it in, put in a fresh Duracell and voila...working L2000. :D
     
  3. I believe the TI chip should work with old or new L2000s regardless of the opamp chip despite the two models' original chips having compatibility issues. I stuck one in mine and it worked great!
     
  4. jtlee

    jtlee Supporting Member

    Mar 2, 2005
    Portland, Oregon
    Thanks...nice to have corroborating evidence. :)

     
  5. DavePlaysBass

    DavePlaysBass

    Mar 31, 2004
    CO
    The TI chip is a drop in replacement for the LM4250 as you found out. However it does not work the other way around.

    EDIT: I am not aware of the Philips chip. I cannot find a proper datasheet for it, but I suspect it was their version of the LM4250.
     
  6. darmstat4545

    darmstat4545

    Sep 25, 2007
    HELLO....Does anyone have a schematic or wiring diagram for the G&L 1505?
     
  7. Jimtoonz

    Jimtoonz

    Aug 26, 2007
    Nashville, TN
    At the G&L site, click the link that reads "support", then follow the bouncing ball...
     
  8. Jimtoonz

    Jimtoonz

    Aug 26, 2007
    Nashville, TN
    ECG was a line of replacement semiconductors that was marketed as a subset of the Sylvania line. Best I remember, the designation "ECG" stands for Electronic Components Group and was first used in the late 1960s. The ECG line was quite extensive, offering off-the-shelf replacements for literally hundreds of thousands of transistors and ICs.

    The assets of ECG, held by Philips Electronics, were acquired by NTE in 2001 and the numbering conventions used by ECG were retained. In most cases, ECGXXX will be the same part as NTEXXX. In this case the ECG944 (which is, in fact, a generic replacement for LM4250) would now appear on a parts counter as NTE944.

    As a tip, should you ever be in an emergency situation, LM741(which can be found at most Radio Shack locations for 99 cents) can work in place of a blown LM4250. The more modern op-amps have lower noise and better gain characteristics than older parts like the 741, but a spare in the case can help get you through the gig if you can't find 4250s in your town.
     
  9. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
    Sep 19, 2021

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.