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G&L L2k preamp...

So at a gig it started to make cracking noises. I thought okay batteries dead I'll replace it when I get home. Well I stuck a new one in and blurp. At first I got a weird phase like sound that was a bit delayed then nothing, dead. I'm wondering if there's anything I could check, I'm opening the wiring diagram right now. I'm also going to email customer service. I don't know while I've always really liked what the G&L preamp did I am a bit interested in a different preamp as well. Any recommendations?
 
3ZB ... Audere & MFD's are yummy!
l25_3.jpg

Switches are 3 -way zmode and Series/Single/Parallel coil switching for each pickup.
Controls are Vol, Stacked Mid on Blend, Treble on Bass.

Here is an early clip. Both pickups, various z-mode & coil settings. I've since dialed the low z and hi z modes down so while there is a change in tone, it's a more sublte change. Normally I just leave the EQ flat, neutral zmode, single or parallel coils and I rock the blend for emphasis.

Notably Dave Meadows (aka Mr Audere) has an L2K that I modeled my switches after. His controls are Master Volume, neck vol, bridge Vol - no EQ - and it sounds great - that's pretty much the bass that convinced me to try Audere...
 
umm... see above ?

What I gave up was the active mode and treble boost. What I call 'boost on a stick or 'boost 'n clank on a stick'... and a pickup selector in favor of blend and the z-mode.

I also gave up the passive Bass & Treble cut only tone controls in favor of a 3 band active, cut and boost.

No new holes. Well none except I drilled a 1/8th inch hole on the lower edge and mounted the battery indicator LED there down by the jack.

The MFD humbuckers are way better than just OK. IMO - for an L series G&L they are the main event!
 
So at a gig it started to make cracking noises. I thought okay batteries dead I'll replace it when I get home. Well I stuck a new one in and blurp. At first I got a weird phase like sound that was a bit delayed then nothing, dead. I'm wondering if there's anything I could check,...

I had this same problem on mine after about eight years. There was a metal tang that had been soldered to the bottom of one of the pots, and it had broken off. Think it was either the lo cut or hi cut pot.

Anyway, soldered it back nice and solid - no more problems.
 
It could be the opamp. If it is a USA model, the opamp chip is socketed and can be easily replaced by gently removing it with a small flat blade screw drive (push up getting between the 8-pin chip and the socket). G&L will probably send you a replacement for free (they are cheap). If the chip is an LF411 that is in there you can replace with LF411AFN, LF411CN, or OPA704. If the chip is an LM4250 you can replace with an LM4250CN, LF411AFN, LF411CN, or OPA704. Do not put a LM4250 in a preamp board that has a LF441 coming out of it. The slew rate will be compromised becasue the preamp board will be missing a critical biasing resistor.

Unfortunately the opamp in the L2Ks are not well protected. They are a week point. They can fail in a manner so that passive does not work as well. That is because the opamp is always in line with the pickups even when in passive.