Cherub WST-600B Tuner and Wrench

Cherub WST-600BTuner.jpg


The Cherub WST-600B is a guzheng multitool that I want to love but falls short. It combines a clip and microphone tuner with a wrench and nail storage compartment, but its clip mode is inconsistent and its wrench damages the tuning pins of my instruments.

The screen, tuning features, and ergonomics are great and it is overall a neat idea, but at $22 USD for a tuner that only sometimes works  in clip mode the value proposition is weak. You probably already have a wrench if you have a guzheng, and a cheaper clip tuner will provide better tuning performance. Is combining those two items into a rather large, single object worth $25? For most people, no, not really. Read on for more details.

Feature Breakdown

Cherub is a brand of products put out by Wei Ke Technology (蔚科科技) a musical instrument accessories company founded in Shenzhen in 1998. Cherub's WST line of tuners is only distributed in Asia, so getting one of these requires waiting several weeks for a boat to bring it over. There are currently two models in production: the 600B reviewed here and the newer 700B. They are quite different, so let's focus on the 600B.

The 600B is a tuning wrench that has been expanded to include a large screen and tuner. It can function in clip and microphone modes. In clip mode it tunes based on vibrations transmitted through the tool's body. In microphone mode it tunes based on the vibrations in the air. Clip mode is intended for use in noisy environments, while microphone mode is better for quiet areas.

The 600B has two tuning modes. There is the automatic tuning mode where it guesses what pitch you are trying to tune to, and a manual mode where you specify the pitch and string you are tuning. There is no loose chromatic mode; a key must be selected for both automatic and manual tunings. The 600B recognizes the keys of A, D, G, C, F, B♭, E♭.

The display shows a pitch meter from 50 cents below to 50 cents above the target pitch, the selected key, the A4 reference pitch, and indicators for mic/clip mode and auto/manual mode. The A4 reference pitch can be changed from between 430Hz to 450hz. 

The 600B has a few hidden features as well. First is its tuning fork mode: If you press the button that switches the tool to Manual mode, then press that button a second time, the tuner will sound whatever note is shown on the screen. Press the manual button again to silence the sound. The pitch that is sounded is affected by the A4 reference pitch you've selected, which is necessary and good.

The second surprise is a nail compartment. Removing the tool's back cover exposes the batteries (2xAAA) as well as a rubber-lined compartment for extra nails. The compartment is small, however, and cannot fit nails and tape. It's a good place to leave an emergency set of nails but cannot store taped nails.

Back to the front of the Cherub: The screen is big and easy to read, the device is physically pleasant to hold with rubber grips added along its plastic body, and the screen is big and easy to read. There are five buttons and three LEDs on the front: The LEDs light up too show when the pitch is too high, too low, or just right. The five buttons are various types of multifunctional: The first row is Power, Manual Mode, and Key Change. The second row are arrow keys.

Long-press Power to turn the 600B on and Off. Short-press to change between microphone and clip mode. The middle Manual-mode button either turns the device to Manual tuning mode when in Automatic mode, activates the tuning fork if in manual mode, and turns off the tuning fork if it is currently making noise. The third button, Key Change, cycles through the available keys when in Automatic mode, or changes the tuner to Automatic mode if it is in manual mode. 

The two arrow keys either change the A4 reference frequency when in Automatic mode or change the string/note combination when in Manual mode.

The wrench head is made of a high-hardness tool steel. It has 8 points cut into its head rather than a standard wrench's 4. This is supposed to give the tool twice as many angles you can position it on a given tuning pin, so as to find a better angle. In reality, this causes some problems. The Cherub comes with a right-angle attachment to the wrench that effectively rotates the screen towards the player when the device is on a tuning pin. I found this to be a worse viewing angle, and so do not use this attachment. 


The issues with the Cherub is in the wrench. Its 8-point interior is novel and does provide more positioning options for better viewing angles, but that comes at a significant cost. 

Cherub wrench, bottom, compared to a ~10 year old (left) and two modern wrenches. Notice square vs. 8-point star interior.

Cherub wrench, bottom, compared to a ~10 year old (left) and two modern wrenches. Notice square vs. 8-point star interior.

The 8-point star on the interior of the wrench provides a snug fit for pins that fill its 6mm span (the distance between parallel walls of two right-angle corners). However, most modern tuning pins are 5mm with rounded corners. Such pins do not fit snugly in the wrench, instead wiggling and remaining loose. This poses three problems:

1, Because the fit is loose, it is difficult to judge how much to move the wrench to make fine adjustments to the string's tension.

2, Because the fit is loose, when applying force, the tool can slip and mar the surface of the tuning pins. Here the super hard tool steel and the sharp internal edges of the 8-point star work against it. The tuning pins are coated in a soft metal, perhaps nickel. Tool steel easily messes that up. I wish this wasn't the case but I have to say - I don't want to use a tool that will physically scratch my instrument. Sure, pins are maybe $0.50 each and if the wood is undamaged taking a pin out and putting a new one in is a minor, if time-consuming bit of maintenance... but it just feels wrong. Why give myself that extra work when I can use the wrench that came with the instrument and avoid all of it?

3, Because the fit is loose, the tool has trouble receiving vibrations in clip mode. It always misses several strings, no matter how I brace it on the tuning pins. It's gotten so frustrating that when using this in a noisy environments, I hold the wrench head against the string in one hand and pluck and move bridges with the other. I'd be better off with a cheaper clip tuner.

I compared how the Cherub felt on 5mm tuning pins to my experience with wrenches with 5, 6, and 7mm spans, pictured. The 6 and 7mm wrenches had as much play as the Cherub, certainly, but thanks to their square interior they did eventually lock into place and did not cause any damage to the pins. 

Finally, for the nail compartment on the back I have one question: why? The compartment is large enough that loose nails will bounce around, but is too small to store nails with tape on them. Unlike guitar picks that just get tossed around, guzheng nails (and their inches of tape) are far harder to lose.  I suppose it is useful to have a backup set of nails with you, but I have yet to need them.


I really like this tuner. There is something about its shape and feel in my hand. The size of the screen is wonderful. The concept is great. And yet, clip mode only works 70% of the time and using it as a wrench damages my instrument. For that reason I can't recommend it. If Wei Ke improves the fit or coats the wrench in a softer material I will update this review, but at the moment, $22 USD for a microphone-only tuner is just not worth it.


Brand: Cherub

Model: WST-600B

Battery: 2xAAA

Price: $22USD

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