noisey pre-amp (tribute l-2500)

mrniceguy715 · #1 01-25-2007, 09:49 PM

now the tone still kills passive or active. problem is therre is what sounds like faint radio freq when I switch the pre on. and the louder I turn the bass or amp the worse the interference or whatever gets. its is whisper quiet passive and when I flick it to the preamp/boost its worse. sorry if the post seems a little out of order but I've got a headache and cant think in a linear fashion lol

mrniceguy715 · #2 01-25-2007, 10:45 PM

forgot to mention I tried changing cables and looking for things that may help cause it (radios tvs etc) alarm clock thats close but even unpluged I get the faint radio and noise coming in

spideyjg · #3 01-25-2007, 11:14 PM

Shield it up.......
Jim

mrniceguy715 · #4 01-26-2007, 12:22 AM

the previous owner already did, thought they came shielded when I changed the batt lol

Infernal Affair · #5 02-01-2007, 02:54 AM

To sorta stay on topic, my L2k preamp started getting really weird and wonky. When I first plug in I'm fine switching to active, but after it warms up the sound gets really distorted and noisy in a bad way. I had my tech take a look at it and he couldn't find anything wrong with it. This really didn't start happening until he used some double sided tape to tape down the pre as it was flopping all about. I was thinking of removing that stuff and seeing if it'll work ok again. I don't mind running in passive, but I also really like the sound I get out of it when switching to active.

In case I had to replace the preamp, is there an easy way to get a stock G&L pre? I tried contacting G&L's support through email but never received a reply about it, and they don't have it on their online site. Have you guys tried putting any other preamps in there instead? I'm not really versed in this sorta thing, so any advice would be a great help.

xbradx · #6 02-01-2007, 09:00 AM

If you can't get ahold of a new pre, you can check ebay(a l-1500 pickup and pre combo just went for about $80). Or to avoid any re-wiring, you can pick up an external pre. I have a Aguilar DB924(two band aka OBP-2) in my pedalboard that i use with all my basses and the Tribby L2k I used to have sounded great in passive mode through it.
The second option may be a bit more pricey than tracking down a replacement pre, but given you can use an outboard model for other basses as well, it's well worth it.

quickervicar · #7 02-01-2007, 09:35 AM

Quote:

Originally Posted by Infernal Affair

In case I had to replace the preamp, is there an easy way to get a stock G&L pre? I tried contacting G&L's support through email but never received a reply about it, and they don't have it on their online site.

Yup, I tried the same thing last week. No reply yet.

lug · #8 02-01-2007, 02:03 PM

The preamp IC is a National Semiconductor LF441 (newer L2000s) and is on a socket for simple change out:

http://eshop.engineering.uiowa.edu/N...2/DS009297.pdf

spideyjg · #9 02-01-2007, 02:24 PM

Quote:

Originally Posted by lug

The preamp IC is a National Semiconductor LF441 (newer L2000s) and is on a socket for simple change out:

http://eshop.engineering.uiowa.edu/N...2/DS009297.pdf

It may be an LM4250. You have to peek and see which one. My most recent one, an '04, has the 4250. The only one with the LF441 is my Climax.

Jim

Infernal Affair · #10 02-02-2007, 02:57 AM

Thanks guys. I also found an old Dudepit thread that talked about this subject. They mentioned using an OPA704PA from Texas Instruments as an opamp replacement. I removed the double sided tape that was holding the pre down, so we'll see if it acts up again during practice. If it does then I'll look into replacing the opamp with the TI model.

On a side note, I checked mine and it says 4250 (CN) on the chip.