The Taming of the Climax/L-1500 Bass

Seeing as how we are fortunate to count Paul Gagon as a member here, it seemed like a good time to give him a home to stretch out in and relax a little. Maybe exercise the grey matter and present a little history of the guitar and bass (amps too!) from his perspective as one of the eminent designers of our time.

Got questions? Great! Good questions might be, "What kind of windings are on the S500 pickup and why?" Or, "What was the thought process behind the MJ-4?" Troubleshooting questions should remain in the regular forums (he reads those too). Finally, please be mindful of how I feel about tech questions via PM or email.

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Re: The Taming of the Climax/L-1500 Bass

Postby Ken Baker » Fri Aug 03, 2018 6:48 am

Alan! Thanks for stopping by.

Chef wrote:Hey all;
I just bought maybe the last new 1505. It's a great bass, but as already noted, the treble boost in active mode is a bit much. And, I sure wish I had single coil as a choice on the coil tap toggle.
While maybe it's easy enough for someone with solder iron skills to do the resistor mode, and swap the coil tap switch for three way function; couldn't one buy a new, pre-wired L2XXX preamp from the G&L store, and then ignore the pickup selector mini-toggle, and maybe have an easier project? Or, is it really easier for a good tech to replace the coil tap switch and current preamp resistor?
Clearly, that person isn't me! But I have a friend here locally who builds tube amps and pedals for a living, who has read this thread and feels he could do the R mod. I hadn't talked to him about the coil tap. He's Byron Neighbors of Byron Amplification, if looking at his website would interest anyone.


I don't think I'd try to graft an L-2x00 preamp assembly into the L-150x. You'd have to mod out the pickup selector, which isn't too tough. The coil switch, while it would work, would leave anyone coming along later to wonder what was going on. I was initially going to say that the coil switching in the Kiloton circuit could be directly used, but the Kiloton has a "K" model pickup with the blue lead. You might also look at using one pickup of the coil switching from this passive circuit, with or without OMG.

As to mods to tame the treble: The R7 and treble cap mods are easy. Byron could probably change both in just a few minutes.

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Re: The Taming of the Climax/L-1500 Bass

Postby Chef » Fri Aug 03, 2018 7:28 am

It takes a different pickup for the three coil selections?
I can’t read a schematic at all but I’m sure Byron can.
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Re: The Taming of the Climax/L-1500 Bass

Postby Chef » Fri Aug 03, 2018 8:28 am

Ack
Maybe I get it now
The L2xxx preamp in the G&L store would not have the K mode single coil option pre wired into it.
So
It’s DIY only.
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Re: The Taming of the Climax/L-1500 Bass

Postby Ken Baker » Fri Aug 03, 2018 9:07 am

Chef wrote:Ack
Maybe I get it now
The L2xxx preamp in the G&L store would not have the K mode single coil option pre wired into it.


Correct. Non-K only.

So it’s DIY only.


Yup. A little bit of this circuit, a little bit of that circuit, a touch of pixie dust, BASS!

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Re: The Taming of the Climax/L-1500 Bass

Postby Chef » Fri Aug 03, 2018 9:11 am

Beautiful, thanks
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Re: The Taming of the Climax/L-1500 Bass

Postby Chef » Sun Aug 05, 2018 6:56 am

Hey Ken or Paul (or anyone!)

Can someone point me to a schematic that will show us how to wire the three way coil tap?
I guess for the L1000 as I think the dual pickup wiring is different because dual pickups ;--)
I don't think I want the OMG version for this bass...but as I recall that's adding a capacitor somewhere, and one could ignore that bit.
If I remember/understand that, which I may not as electronics are for sure not my long suit.


edit:
found the schematics page here. excellent.
https://www.bassesbyleo.com/gl_bbe_wiring_diagrams.html
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Re: The Taming of the Climax/L-1500 Bass

Postby jmarcz » Sun Jun 16, 2019 2:00 pm

Hello,

I just bought an L 1500. It may had been produced be circa 97 (black 3 bolt neckplate with #B033xxx number, chrome bridge and cherryburst finish).
I read a lot of things before buying it. So i knew that output level would be fairly hot.
I thought I knew what it could mean cause I already have a L1K but its way more than I could expect. And the treble boost is way too much for me...
The level difference between parallel mode and series mode is huge. When A/Bing between them, the parallel mode seems to be asthmatic (lows are hidden).

Even before having a test during a rehearsal, I decided to mod It, especially after having read the posts of this thread and taken a look at the schematic.
Its a great source of clear and usefull information for instrument tweakers.

Here the liste of mods I made :

0 - it was the occasion to see that it may had been moded before : the neg polarity of the battery is disconnected via the jack socket when the jack's not in which is not appearing on schematics. That's not a bad news, don't know if it an upgrade made on some production run of if it's been made after production...
1 - I added a PU Load capacitor (1nF, tehe value on my schematic is wrong) to tame a little bit the highs (did not really find a big impact on the tone but I kept it).
2 - R7 mod (R7 replace by a 50k trimpot to keep the possibility to tweak it later, initial valure close to 25k to keep a little treble boost for the fisrt try)►much more usable in active mode after that. I Also add a 22nF cap in paralle with C3 to try to have more lows, did not notice a clear change with that but kept it too.
3 - OMG mode in place of serie mode adding a 0.1uF between black wires on the coil toggle switch (at least i Believe it's a OMG mode)► the mod that have the bigger impact on tone : clear single coil sound with bass boost clearly what I expected form this mod. (also tried with a 330nF but prefer with 100nF)
4 - resisitive divider in front of the preamp to get control of the level difference between active and passive mode.

I find it way better now.

There is still a big level difference between the 2 coil mode and I may change Parallel/OMG switch to Single/OMG. I'll loose the option to have the characteristic sizzle of the parallel mode (maybe more MM SR style, knowing that I did not test a real SR in my life) but I'm sure will live without since the OMG mod on L1500 sound better to my ears.

I'm not so confident on the usefullness of the C3 mod and the possible impact of the resisitive divider in front of the preamp on the battery life, comments could be appreciated...

L1500_MODS.JPG
I added the mods in blue over the official L1500 schematic.
L1500_MODS.JPG (108.01 KiB) Viewed 324 times
Long Stroy Short : thanx for the tech infos that made me get the tone I wanted.
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Re: The Taming of the Climax/L-1500 Bass

Postby Ken Baker » Sun Jun 16, 2019 3:39 pm

jmarcz wrote:0 - it was the occasion to see that it may had been moded before : the neg polarity of the battery is disconnected via the jack socket when the jack's not in which is not appearing on schematics. That's not a bad news, don't know if it an upgrade made on some production run of if it's been made after production...


The jack in the Climax bass was 2 conductor; signal and ground with no power switching. This carried into the L-1500/1505 basses until a few years ago when someone decided to add power switching at the factory. It's an easy mod. You'll need to replace the jack with a TRS (Tip-Ring-Sleeve) jack. Then just disconnect battery negative (-) from its current ground point in the cavity and connect it to the ring connection on the new jack. You now have power switching.

Long Stroy Short : thanx for the tech infos that made me get the tone I wanted.


I'm glad you found our tech information helpful. Thank you very much for sharing your experience and drawing. Good work!

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