Caline CP-81 (v2.1) 10 Band EQ Pedal Review and Voltage Fix

In this video, I do a review of the Caline CP-81. It is an upgraded version to their CP-24 Ten band EQ. Both are clones of the MXR M108S 10 Band EQ, a very solid pedal. The solution for the noise happens at 7:14 if you want to skip to that.
I contacted Caline about this issue and they sent me the schematic to the CP-81, and with that discovered the voltage problem and how to fix it. At the time of recording this video Caline told me their engineers were actively addressing this issue. It helps when you send the manufacturer compelling video proof of the problem. :-) They are not endorsing or compensating me for this video. They have provided me great customer service with sending the schematic. Hopefully they will have a more permanent fix in the near future. For now, this video provides a great inexpensive work around.
The highlights:
- Both the MXR and CP-81 have the SAME Quad Op-amp chips running them! The circuit design is similar in both
- The Caline is advertised to run at 9 Volts only. You CAN run it at 18 volts, but there is no benefit.
- ****The Caline has a special "step-up" converter that takes the incoming 9 volts and makes 18 volts internally to run the PCB. There is no need to feed it 18 volts. the MXR pedal does NOT have this
- There is a design flaw with this voltage circuitry in that it causes a very high noise floor despite the similar circuit designs in both pedals. Running ~9.0-9.1VDC the Caline is very noisy. Running it at 18 volts makes it WORSE!
The MXR claims to have noise suppression circuitry, well this Caline pedal does too. It is normally a few capacitors added to the output stage to bleed off the high frequencies so the noise is less. Output stages of both pedals have similar designs.The step up converter is the cause of the noise floor problem.
HOW TO FIX THE NOISE: I have a power supply that outputs 9.1VDC no load. Using a buck converter, I drop the voltage from the PSU down to exactly 8.5VDC. Notice the drastic reduction in the noise floor. Output 1 of the 10 band eq plugged into the input of a Peavey Basic 112. Pre-Gain set to 4, and volume set to 3.
Input Voltage Resistor: www.amazon.com/dp/B06WP5FJV9
Barrel Tip Adapters:
www.amazon.com/Power-Connecto...
***I used a buck converter in the video, and mentioned I would use a smaller form factor converter, however that converter required a higher voltage than 9 volts to regulate down to 8.5vdc, unlike the one I had used for testing which could be inputed 9 volts and output 8.5V. The less expensive and simpler way to achieve 9V to 8.5V is to use a variable series load resistor. Others have suggested using a rectifier diode which has about a 0.5V voltage drop, however not every pedal PSU is created equally and the tolerances are too small to use a common diode unfortunately. With the multi turn resistor mentioned above, you can dial in the voltage exactly.
www.amazon.com/Caline-CP-81-G...
www.calinemusic.com/products/e...
Op-Amp Datasheet:
www.mouser.com/datasheet/2/30...

[@Bassguitarist1985]

Check out the resolution of this project kzbin.info/www/bejne/d4K3XmuifrN5qsk

[@enwardblackman7730]

Thank you for doing the deep dive and the work. Tinkerers of the world united!

[@Bassguitarist1985]

Its a great hobby! Plus Caline has been super kind to me as a thank you for figuring this out.

[@DrunkDuckXD]

Very technical, I love it, thank you

[@jonniefast]

thnx for the upload ❤ ill use voltage sag on mine

[@deckomorales]

Excelente explicación 😃

[@craigpons7153]

A very informative video , I like the look of the Caline pedal but the only adjustable power adaptors ive been able to find let you set them on either 9 volts, 7.5 volts or lower , would 7.5 volts be to low a voltage to power the Caline pedal without any issues ?

[@Bassguitarist1985]

It will run but it will still have the noise

[@cherrybomb3975]

Hi, sorry for resurrecting a 2 year old post. I appreciate you have spoken about voltage fixes, but have you measured the actual current draw (mA) of the CP-81? The website says 300mA. This seems real high. I know the MXR M-108S is 18 volt, but that is rated at 48mA. The CP-81, 300mA at 9v seems really high, it's up there with some really current hungry digital FX. Could you help on this one?

[@fretBeastForever]

Please correct me if I’m wrong! Besides circuit, building, less noisy... I do believe the frequencies accuracy is the best on MXR 10 Bands ?

[@Bassguitarist1985]

The frequency bands for the Caline and MXR are the same. Not sure what you mean by accuracy

[@michanowak7060]

Hi, I noticed Caline also has CP-24, another EQ but with one output. Did it also had a problem and was it fixed? Or just this model

[@Bassguitarist1985]

Just this particular model. It has a special circuit that takes the incoming 9 volts and steps it up to 18 volts so that you get the extra headroom in the audio signal without having to use a special adapter. Unfortunately there was a design flaw in that circuit and it had to be corrected.

[@guimeloy8160]

Excellent video! Have you the bass auto wah pedal from caline? The bass auto wah have very noise...

[@Bassguitarist1985]

I do have that pedal yes. It sounds good but one major flaw, it lacks the ability to remix in the dry signal. You would need a parallel pedal mixer to get this feature. I'd say the pedal is okay but there are better options out there.

[@soundknight]

Could one technically run the mxr noise free through the fx send off a mixing desk to give a channel further EQ control?

[@Bassguitarist1985]

Absolutely!!!

[@ScottStieg]

Good video. Voltage difference cause any issues? The MXR is 18v I think?

[@Bassguitarist1985]

With the old v2.1 nameplate says 9v as it will upconvert internally to run at 18V. If you input 18V that's okay as it will pass the voltage through to the chips. The flaw in the circuit has since been corrected in v3.0

[@martinhudson5210]

Hi great video,I've just received this unit new with an included 9 volt input to battery converter lead,does this mean that if I connect a 9v battery to power the unit, when the battery starts to run low the output noise will improve? cheers!

[@Bassguitarist1985]

If you have v2.1 it is possible yes. V3.0 shouldnt be an issue

[@TealScarab]

I was wondering how the Caline works with just 9 volts, and if the difference in voltage would result in different noise floors. I guess I don’t need to get the MXR, besides I need to break out the soldering iron again.

[@Bassguitarist1985]

Thank you for watching! Yeah there are a few ways to acheive the 8.5 volts from a 9v adapter. A series resistor, a buck converter, and someone suggested using a recifier diode in series. As memtioned in another comment the inductor and voltage divider combo for the PL2628 chip that sets the output voltage of the step up converter is out of tolerance slightly. It outputs a solid 17.8V to the chips inside, it is simply picky for the exact output voltage. Other than that the pedal works GREAT!

[@or6944]

Hello, so it can be used with an 18v power supply without making any modifications?

[@Bassguitarist1985]

It is not advisable to run at 18 volts regardless of what version you have. It is designed to run on standard 9 volts

[@vanbarrydillonii966]

I have a 10 outlet power supply that has a sagging option on two of the 9 volt outlets. If I sagged this pedal on one of those outlets, would it work the same way you're describing?

[@Bassguitarist1985]

Yes absolutely!

[@vanbarrydillonii966]

@@Bassguitarist1985 Awesome, I have the MXR version, but it's no longer functional, and thought about getting this as a replacement. Thank you, this was informative.

[@gwshark07]

Do you happen to have a link for that voltage regulator, I can't seem to find it on Amazon? I just got the equalizer and it does have horrible hum, very noticeable...arr

[@Bassguitarist1985]

Here is the buck converter. Get yourself an 18VDC PSU barrel positive tip negative too. The converter will take the 18v and bring it down to 8.5v once you set the potentiometer correctly. You will also need some 2.1mm barrel adapters and some shrink tubing to encase the converter so its insulated. Hope this info helps. DZS Elec 2PCS LM2596 DC-DC Step... www.amazon.com/dp/B06XRN7NFQ?ref=ppx_pop_mob_ap_share

[@gwshark07]

Awesome man, thank you very much for the info, you rock!

[@gwshark07]

Was hoping they had some ready to go like in the video LOL, wishful thinking... I do have a soldering gun still somewhere in my boxes from my old house, hopefully I can figure it out

[@gwshark07]

But thank you very much man

[@Bassguitarist1985]

@@gwshark07 the more expensive Pedal Power supplies actually can do 8.5 volts but you are spending quite a bit of money for that feature.

[@captain6198]

Can you confirm what type of taper they used for the calines slider pots?

[@Bassguitarist1985]

Not sure. Maybe linear?

[@TheOriginalBobbyTouche]

I’m sorry if you’ve already answered this, but is it the v2.1? I see the v3.0 on Amazon now and I’m curious if they’ve solved the hiss on that model. My MXR just crapped out and would rather not spend $150 on a new one.

[@Bassguitarist1985]

Yes Caline and I have corrected the hissing issue. What you will need to do is remove R59 to allow the volume fader to boost beyond 0db. Out of the box it is not made to do that.

[@RrVvMusic]

Hello Just an idea... Do you think a simple 1Amp diode in line (with a voltage drop of 0.7V) can fix the V2.1 noise? 🤔 The input power will then be around 8,3Volt .... Thanks for your videos Oopps : I just see below someone had the same idea 🤭

[@Bassguitarist1985]

Unfortunately no that wont work. I still have a v2.1 EQ I was thinking of fixing the issue, or bypassing the step up circuitry all together. You cant have too many EQs lying around!

[@commuterdigitalmedia141]

So will a generic 8.5v dc charger simply fix this issue? (sorry if thats a dumb question)

[@Bassguitarist1985]

Yes it should but most of the time those types of chargers that have a barrel adapter are tip positive and barrel negative, effects pedals in general at least modern ones are tip negative and barrel positive...opposite polarity.

[@BobBob-dv2qh]

Cant you just add a 3 watt heat resistor with a value that would drop the required 0.6 volts and problem solved? Or how involved is it to remove the step up circuit from the chasis completely is it incorporated in the same PCB are the rest of the components?

[@Bassguitarist1985]

Yes step up is on the same pcb. Requires hot air rework and SMD tools to remove. Drop resistor works but its a non standard value required to hit 8.5vdc. I still have this v2.1 board. I'm thinking I may just do a video on how to fix the circuit design or like you said remove the step-up converter completely. The trick is that hardly anyone will have the skills or the correct tools to execute it properly.

[@purimuadmuang2259]

I got a v.3 with very noticeable hiss... do you have any ideas? Might have to check the voltage..

[@Bassguitarist1985]

Shouldn't be any. It needs 9V not 18V. it steps up to 18V internally

[@purimuadmuang2259]

@@Bassguitarist1985 just to update, it went away with a certain model - cheap MIC adapter... I've even tried it with hi-end power supply and had a loud hissing. All of them give out about 9.1v and have more than enough amp, don't really know why.. 🤷

[@Bassguitarist1985]

@@purimuadmuang2259 I'm guessing there's a lack of proper filtering components in the power supply itself.

[@scottconnors8419]

Is this same as the orange n black face version? I just bought 1 for $36 ...

[@Bassguitarist1985]

No it is not. The CP-24 you speak of has a different set of opamp chips

[@danieldesjardins6615]

Do you have the revision number of the board? Thanks.

[@Bassguitarist1985]

V3.0 has the updated circuit with the noise removed. Short r59 to fix the volume fader though

[@meldeer6253]

i just bought this one on ebay used guy said there was nothing wrong with it !!!! you seem to know a fewthings so here gos .......I turn it on and it sounds like im in a cave with a million bats cheeping ??? im using a 9V Boss power supply...... realy bummed out .... i bought it becouse i saw a demo on utube and realy like it .....Caline CP-24 10 Band EQ Aluminum Alloy Electric Guitar Effect Pedal Guitar Pedal thank you

[@Bassguitarist1985]

The CP-24 is the earlier version of the CP-81 in this video. The earlier model does not have a voltage up converter inside. Its not the same guts as the MXR. Sounds like you got a bum u it. Maybe try a different power supply?

[@pensive_]

Just add a rectifier diode in series with the 9v adapter, (you can add it inside the Caline). The forward voltage drop of a rectifier is about 0.5V and the Caline will then see 8.5V from a 9v adapter.

[@Bassguitarist1985]

Great idea! I will give that a try. The tolerance of the PL2628 step up chip is so small even if the voltage was like 8.6 or 8.4 volts then the noise floor gets worse. The voltage divider circuit i beleive is not set correctly. The tolerance of the components is like 5%. My original idea is to use a multiturn 10 ohm resistor in series with the 9v adapter. It would get the correct voltage too. I like the pedal, it works great, just picky on voltage output.

[@Bassguitarist1985]

Also there is already a schottky diode in series. Lower voltage drop than a standard rectifier diode. Likely there for reverse polarity protection.

[@pensive_]

@@Bassguitarist1985 That should have been the first thing that crosses your mind.. You can look at forward bias voltage for diodes there are multiple values, from 02-0.7 and higher. Easy to match.

[@pensive_]

@@Bassguitarist1985 Senseless to use schottky for that purpose. Schottky has low reverse tollerance and is inferior to a standard Rectifier diode for reverse polarity. Someone that designed that doesnt know what they are doing.

[@pensive_]

@@Bassguitarist1985 Also: have you ever compared the Caline CP-24 with the CP-81. What is the difference ?

[@bluesriff418]

Just as a question did you know if they fixed the problem,

[@Bassguitarist1985]

Gino, yes they have. V3.0 has the noise issue corrected. There may still be some v2.1 NOS units out there but this was fixed back in Oct/Nov of 2021.

[@bluesriff418]

@@Bassguitarist1985 ok thank you for the info! Did that units good for bass to? I’m looking right now for a good bass eq pedal. I already have a Moeer 5 bands guitar eq pedal who works good for my guitar but not that good for bass.

[@Bassguitarist1985]

@@bluesriff418 absolutely. A 10 band EQ will definitely span the entire audio spectrum for every single instrument. That EQ pedal you were talking about has bands made specifically for guitar, not optimized for the lower register for bass.

[@davidneily3532]

You used two different power supplies. Maybe try that generic one on the MXR and see if it makes noise as well.

[@Bassguitarist1985]

Unable. The generic one is 9vdc. MXR needs 18vdc.

[@Mystninja]

I have the V1 the yellow and black one. Never noticed the sound

[@Bassguitarist1985]

different internals for the CP-24 compared to the CP-81

[@patrickmcmanus5373]

Did they fix it. I bought one recently.

[@Bassguitarist1985]

Yes all new ones should be v3.0

[@patrickmcmanus5373]

@@Bassguitarist1985 thank you. I enjoyed your videos.

[@aldifrh8825]

can this worked on v1 caline 10 band?

[@Bassguitarist1985]

You mean the CP-24 or version 1.0 of the CP-81?

[@aldifrh8825]

@@Bassguitarist1985 sorry, i mean cp-24 bro

[@Bassguitarist1985]

@@aldifrh8825 i havent worked on that pedal, but it does not have the up converter inside. Its a different chipset inside.

[@esmeulonsouzadeoliveira3636]

⚡🔱⚡👏👏👏 .

[@attybong]

i think the problem is not with the cadine eq .. it is with your power supply .. that power supply may have a lower mA than what mA the cadine requires .. you just have to replace that power supply with one having a higher mA

[@Bassguitarist1985]

No there was definitely an issue with the circuitry inside. It has since been corrected in later revisions greater than v3.0

[@prettyricky3765]

I need some green and blue LED lights for that anyone have a name or place I can look for some at

[@Bassguitarist1985]

Amazon, they are 2x3x4mm sized LEDs for the Caline. If you change colors the drop resistor values may need to change. But you can try it. :-)

[@prettyricky3765]

@@Bassguitarist1985 thanks you are awesome

[@boimesa8190]

They made it 9 v because most people have 9 volt adaptor is already especially guitarist who are just starting out will buy a cheap power supply with isolated outputs. En sinds there target demographic will be mostly made up of starting guitarists it's actually a smart move ;) By the way do you have calines contact info for us? Been trying through AliExpress without Suc6.. :S

[@Bassguitarist1985]

I 100% agree they are catering to the beginner's market. It's actually a very creative circuit to take 9 volts and step it up to the 18 volts which provides the headroom advantage. Unfortunately the previous versions had a configuration issue but it has been solved. I reached out to Caline on FB messenger initially, but then I have continued conversation through their main customer service email. That's the best way to get a hold of them. I usually communicate at night since I am in the eastern United States and they are over in China due to the time difference.

[@boimesa8190]

@@Bassguitarist1985 could u share the email with me? Or their Facebook page?

[@Bassguitarist1985]

@@boimesa8190 TEL：[phone] MAIL：[e-mail] B203, Weatern Industrial Building, 22nd Area of Baoan District,Shenzhen 518101, China

[@lemosstephen]

#caline #calinecp81

[@johnpauldeguzman823]

there might be crickets inside

[@Koake1002]

Love how deep you got into the pedal and how to make it work correctly. But honestly that wasn’t worth the money saved especially when Mxr is a better known brand and most likely has a warranty you can just pop into your local store you got your pedal from and swap it for a new one. Might be worth the money saved but to have this set up on a pedal board would just be to much trouble. Unless your just using it for home use. Great video though

[@Bassguitarist1985]

It was worth it because not only did i bring it to the attention of Caline, fhey fixed it and it saved others the work I went through, and they also gave me a bunch of their pedals to try/review at no charge. So win win!

[@vascoferreira891]

​@@Bassguitarist1985❤

[@PintaoLoko]

What about their guts?

[@Bassguitarist1985]

What did you want to see specifically? There are other videos in this series that actually show the inside of the CP81

[@PintaoLoko]

@@Bassguitarist1985 actually I'm trying to compare the CP81 with my CP24 in order to make some improvements. But it's just an attempt due to the difficulty to find both schematics.

[@Bassguitarist1985]

@@PintaoLoko cp24 for sure uses different opamp chips and lacks the 9 to 18V step up circuitry. I have access to schematics for both but not sure what improvements you can make. SMD boards are hard to mod

[@PintaoLoko]

@@Bassguitarist1985 yes, I'm pretty sure of that. They use 074 opamps. But I'm not really sure about the gyrators components quality and values. Maybe they could reach a different Q factor. Do you think I could have both schematics from the manufacturer?

[@Bassguitarist1985]

@@PintaoLoko email their customer service. It takes him a few days to get back but my contact always reaches back out. They are also available via Facebook Messenger.

[@aegisraven1284]

Caline requires no voltage fix it's a 9v pedal.

[@Bassguitarist1985]

On the v3.0 board no, but the v2.1 yes

[@aegisraven1284]

@@Bassguitarist1985 works fine on 9v.

[@Bassguitarist1985]

@@aegisraven1284 the v2.1?