The Taming of the Climax/L-1500 Bass

We are fortunate to count Paul Gagon as a member here, so it seemed natural 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 are the EQ mappings for the M Series preamps?" 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 » Mon Jan 09, 2023 12:35 pm

deltafred wrote:OMG?


You mean OMG mode?

He doesn't want to cut treble.

osmar oliveira wrote:I wonder if there are any mods to its preamp to give it more bass, without taming the highs, which I enjoy.


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

Postby deltafred » Mon Jan 09, 2023 2:29 pm

Ah, I missed that bit!
I should read the posts better.
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Re: The Taming of the Climax/L-1500 Bass

Postby Imogen » Sat Oct 07, 2023 11:01 am

I want to thank everyone for this thread. It sent me on an adventure that has led me back to square one, but I've learned a lot along the way.

Knowing that there was a lot of info on making these sound "better", I started to experiment on my 2011 L1500 (Preamp version 1.1). Hearing how displeased many people were with the preamp, I started adding all the caps and new resistors that many have suggested. I even set up pcb sockets so I could workshop different values and configurations. Throughout the whole process I was considering selling it, because I just wasn't getting a sound that made me happy. I was even at the point where I was considering changing the onboard preamp entirely. But then I began to wonder why I didn't love this bass as much as I used to. When I first bought it I couldn't keep my hands off it, now it was just hanging out on a stand.

Today I decided to undo all the mods I've done and bring it back to bone stock (Replacing the R7 with it's original value and removing the extra .001uf cap from the bass pot). The first few notes reminded me of why I bought this bass in the first place. The juicy, clangy, demonic highs and high mids came back, and it sounded like itself again. The Series mode, (Which was completely anemic with the .001uf mod on the bass knob and the R7 resistor mod) now was usable and at equal level again. With the mods it was so much louder than the Parallel mode and sounded honky and muddy.

Now there's no accounting for taste, and I'm sure there are those of you who love the mods you've done, but bringing this back to the original specs has made me fall in love with my L1500 again. It's a really unique instrument, and I think allowing it to do what it does best, which is melt faces, is the only way this bass makes sense.

If I need a vintage vibe, I'll use my P with flats, if I need an all-rounder, I'll use my Yammy BB435, but I am going to keep the L1500 for those times when I need something evil >:). I'm covering some Rainbow with some friends and I'm certain it will fit in quite nicely.

If you're getting nowhere with your L1500 after a bunch of mods, bring it back to the way it was. Afterwards, Turn the treble down, mess with the bass. Take a reductive approach to the eq. I think some of you might ask why you started doing mods in the first place.

The pots are scratchy as hell and have lost their dampening and the cavity is shielded poorly, so any money now will go to getting some fresh pots and switches, some hook-up wire that doesn't snap when you look at it funny, and a full copper shield job.
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Re: The Taming of the Climax/L-1500 Bass

Postby bozha » Wed Oct 11, 2023 3:36 am

Paul Gagon wrote:If you look at the first plot from this post, you will see the frequency response of an L-1500 pickup unloaded (7.5 KHz). That same pickup, and yours as well, would drop to around 7 KHz when connected to a 1.1 preamp. This is because of the additional capacitance that the preamp and bass wiring would place across the pickup. So imagine that same frequency plot shifted down from 7.5 KHz to 7 KHz.

The Low Cut (Bass Control) is a simple High Pass type filter that rolls off low frequencies when you turn the Bass control down (Counter Clockwise). What low frequencies you ask? Well.....let's look at the circuit and see. With the .0022uf capacitor across the 1meg pot that feeds into a 250K pot (The Volume Control) you get a frequency corner of around 290 Hz. So what this means is that with your Bass Control all the way down (.0022uf cap into a 250K pot) you have a 3dB drop in signal level at 290 Hz. For every octave below 290 Hz you get an additional 3dB drop. So essentially you have 3dB drop at 290 Hz, a 6dB drop at 145 Hz, a 9dB drop at 72 Hz, and a 12dB drop at 36 Hz. As you turn the Bass Control up (Clockwise) you reduce this effect.


Hello,

I am aware how old this post is, but I am about to tune my 1505 towards 2500 as much as it is possible and something is still bothering me...

Is there's any chance you can explain how larger capacitor values affect the controls in this case? Does it move frequency corner and in what direction? Im interested for both low pass (250K "Treble") and high pass (1M "Bass")?

Also, I can see the difference in wiring between the 1505 and 2500 treble control potentiometer. Is it OK to keep the same contact points on the 1505 and just swap to a larger capacitor as it is in the 2500?

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

Postby Paul Gagon » Thu Oct 12, 2023 6:59 am

Hi Bozha,

Yes, you can keep the treble control wiring as is on your bass. Now, on to your main question.

On the bass control, increasing the value of capacitance will minimize the low frequency cut effect. You could experiment with values such as .0033uf, .0047uf, .0056uf and .0068uf but I wouldn’t go much higher than that. If you do, when you turn the bass control down you won’t hear much of a low cut effect. On a personal note, I generally use a .0047uf cap on my low cut controls. I just personally like the way it sounds when I turn the bass all the way down.
On the treble control, increasing the value of the capacitance will make the bass sound darker when you turn the treble control down. Typical values for treble/tone controls are .022uf, .033uf, .047uf and .1uf. The larger the value, the darker the tone when the treble control is fully down.

Thanks for posting,
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Re: The Taming of the Climax/L-1500 Bass

Postby Bemo9 » Thu Oct 12, 2023 4:11 pm

Good to see you back on the board Paul! I've been thinking lately of the tone controls of the treble/bass cut. In particular while I absolutely love the concept, there are times where a mid-scooped sound is desired. Seems to me that rolling back both treble and bass leaves the mid-range unaffected. Of course it depends on what your definition of midrange is. I was wondering with the standard caps, what frequency ranges in the mids is left unaffected. Of course it could be my bad remaining ear and ignorance of most things electronic that leads to asking a silly question.
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Re: The Taming of the Climax/L-1500 Bass

Postby Ken Baker » Thu Oct 12, 2023 5:38 pm

Just so you know...

Paul is retired. He is traveling right now and expects to return in a few days.

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