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Originally Posted by t c  Thanks for the reply and the advice, Jimtoonz!
Yes, I tried it in various locations/positions and the buzz was consistent. Is there a parts# or nomenclature for the preamp chip at Digikey? I used their search function and had no matches. |
There is a thread on here that discusses the chip and its common replacements at length. Look at the one that is currently in the circuit and enter the number on the Digikey web site. It will list any similar parts they have in stock. The part is typically an LF441 or LM4250. Texas Instruments also offers a replacement that is favored by some G&L owners. That part is OPA704. IIRC, it(the TI chip) has a bit better performance as far as slew rate and headroom than the other chips mentioned.
I have also used an LM741(available at most Radio Shack stores for around 99 cents) in a pinch. Although the 741 likely has inferior specs, my L-2500 sounded fine with it installed until I could order the correct part. All of these should be relatively inexpensive, depending upon your source. If a vendor gets much above $3.00/ea for any of them, look elsewhere.
Although there is difference between the specifications on the parts mentioned above, I am not sure that most people would know the difference by the sound of the bass when pressed to tell them apart. Your actual mileage may vary.
One thing I neglected to ask you.... you describe this as a "buzz" - is it a sort of brittle, "midrange-ish" buzz, or is there a lot of low end "roar" present(as in a grounding problem)?
