G&L 2000 preamp issues - Help!

[gazgoldstar]

Hi everyone and merry Christmas and all that!

My friend has a G&L USA L2000 (as do I) and it has a very peculiar fault and I wondered if anyone here has experienced it or what to do? Bass was bought on here by me for my friend but the seller denied any knowledge of the issue.

Basically what happens is that there is a dirty noise that happens when you play a note, it sounds like almost like a layer of distortion (in a bad way) rather than hum. It makes this noise whether the bass is in passive or active mode.

My instinct is that perhaps it needs a new preamp board but i have no idea where to get one or how much they would cost.

Thanks in advance,

Gaz

[icastle]

First thing to do is change the battery.

[cytania]

Check the jack sockets on both the bass and amp are tight and clean.

[stingrayPete1977]

Jack socket connections dirty or not springing down hard onto the instrument cable plug, bad earth connection, loose connection on the PCB, dodgy pot (we've all had some!) Or a good old fashioned batt flattery!

[Graham]

It's not the amp input overdriving is it? Those MFD pickups are very hot, so you'll want less gain than on other basses.

If not that I'd certainly check the battery first.

[gazgoldstar]

Thanks guys, tried new battery and connections seem good. My feeling is that there is something wrong with the electronics maybe a wire is grounding against another or something along those lines. My L2000 doesn't exhibit this issue at all so it makes me think that there is something amiss with my friends one. I think I was hoping that someone had experienced a similar issue and knew the solution. I really appreciate you all taking the effort to help out though!

[3below]

[quote name='gazgoldstar' timestamp='1419363376' post='2639222']
..... maybe a wire is grounding against another or something along those lines.
[/quote]

Get the magnifying glass out, have a good look for 'wire whiskers', bits of stray metal or wires touching somewhere on the circuit(s).

Good look.

[gareth]

is it the same in all settings - passive/active parallel/series normal/high active?

[gazgoldstar]

Again thanks so much for the replies. As far as I know the problem is on all settings but as it is my friends bass now and not in my hands I can't test it for sure. I think the thorough investigation with a magnifier is something I will urge him to do as that seems most likely. I wonder if anyone knows if there is anywhere in the UK where you can get hold of replacement G&L preamps?

[machinehead]

There is some useful information here.

http://www.bassesbyleo.com/forum/viewtopic.php?f=4&t=1764

Frank.

[3below]

This will be fixable without the need to purchase a new pre-amp. A sound clip of the noise would be useful. Without any test equipment / measurements etc my brute force method would be (i) replace any electrolytic capacitors (ii) check for dry joints and re-solder. A good electronics engineer will sort this quickly, it is a straightforward simple circuit, especially with Frank's link to the circuit.

Edited December 28, 2014 by 3below

[HazBeen]

+1, but do verify it is the preamp by trying it in passive mode first.

[quote name='3below' timestamp='1419778070' post='2642622']
This will be fixable without the need to purchase a new pre-amp. A sound clip of the noise would be useful. Without any test equipment / measurements etc my brute force method would be (i) replace any electrolytic capacitors (ii) check for dry joints and re-solder. A good electronics engineer will sort this quickly, it is a straightforward simple circuit, especially with Frank's link to the circuit.
[/quote]

[JapanAxe]

The tone controls on the L-series basses are simple passive ones. The battery-powered preamp is added in to the circuit when you select active mode. If the noise is occurring in both active and passive modes, and you are sure it's not amp overdrive, then there are very few components and connections to check.