When choosing a digital piano, key action, how the keys feel when played, is just as important as sound quality. Let’s break down the three popular actions: GHS vs PHA vs RH3.
Whether you’re a beginner learning your first scales or a seasoned pianist practicing Chopin, the way your fingers respond to the keyboard can make or break the experience.
In this post, we’ll compare three of the most popular weighted key action mechanisms found in today’s digital pianos:
- Yamaha GHS
- Roland PHA Series (PHA-4 and others)
- Korg RH3
We’ll also explain what scaled weighted keys are and how each brand simulates the touch of an acoustic piano differently.
Table of Contents
What Are Weighted Keys?
Digital pianos typically offer three types of key actions:
- Unweighted – Like a synth, keyboard (light and springy)
- Semi-weighted – A bit of resistance, but not piano-like
- Fully weighted / Hammer action – Mimics the mechanics of an acoustic piano
Most serious digital pianos feature graded hammer action, meaning the keys are heavier in the lower register and lighter in the upper register, just like a real piano.
This is sometimes called scaled weighted action or graded weighted keys.
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Comparing the Big Three: GHS vs PHA vs RH3
Three of the most widely used and recognized key actions in today’s digital pianos are Yamaha’s GHS, Roland’s PHA series, and Korg’s RH3. While they all aim to replicate the feel of an acoustic piano, each has its own design philosophy, level of realism, and ideal use case.
Let’s break down how these key actions compare to help you find the best fit for your playing style and goals.
Yamaha GHS (Graded Hammer Standard)
Yamaha’s GHS is the most common key action in their entry-level and mid-range digital pianos, such as the Yamaha P-125, DGX-670, YDP-145, and YDP-184.
✅ Pros:
- Lighter feel — good for beginners and children
- Graded weighting — heavier bass, lighter treble
- Durable and budget-friendly
❌ Cons:
- Plastic keys, not textured
- Less responsive than more advanced actions
- May feel too light for trained pianists
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Variations
Yamaha has developed several key action mechanisms over the years to suit different playing levels, from beginner to professional.
While GHS (Graded Hammer Standard) is the most common in their entry-level models, Yamaha offers a full spectrum of key actions, each improving on weight, responsiveness, materials, and realism.
- GHC stands for Graded Hammer Compact, and it’s Yamaha’s newest entry-level key action. It is lighter and more compact than GHS, and is designed for slimmer, portable digital pianos, such as the P-225. Check out our detailed review of the Yamaha P-225.
- GH3 (Graded Hammer 3) includes a triple-sensor action for faster note repetition (found in higher-end Yamahas). For instance, the YDP-165 uses the GH3 action.
- NWX (Natural Wood X) is an advanced key action feature of wood and plastic hybrid materials, with escapement. It is suitable for advanced players wanting wooden keys and excellent realism without fully entering the hybrid price range. For example, the P-515 comes with the NWX action. Here is a full review of the Yamaha P-515.
- GrandTouch-S / GrandTouch are premium actions with full-length wooden keys, escapement, counterweights, and linear pivoting found in P-525 and Clavinova models.
Roland PHA Series (Progressive Hammer Action)
Roland is renowned for crafting some of the most realistic and expressive digital piano actions on the market. Their PHA (Progressive Hammer Action) series is designed to closely replicate the feel of an acoustic grand piano, complete with graded weighting, textured key surfaces, and advanced sensing technology.
Whether you’re a beginner aiming to build proper technique or a seasoned pianist demanding nuanced control, the PHA series offers several levels of responsiveness and realism to match your playing style and budget.
Key Variants:
| Name | Key Features | Found In |
|---|---|---|
| PHA-4 Standard | Ivory-feel, triple sensor, escapement | FP-10, FP-30X, RP-107 |
| PHA-50 | Wood/plastic hybrid, escapement, top-tier feel | FP-90X, RD-2000 |
More detail reviews on Roland digital pianos:
✅ Pros:
- Progressive weighting — heavy to light across keyboard
- Textured keys — simulate ivory feel
- Triple sensor — supports rapid note repetition
- Escapement — subtle “notch” like on grand pianos
❌ Cons:
- May feel slightly heavier for beginners
- More expensive than GHS-equipped pianos
Korg RH3 (Real Weighted Hammer Action 3)
While Korg is often celebrated for its synthesizers and stage keyboards, it also offers a highly respected key action for digital pianos: the RH3 (Real Weighted Hammer Action 3).
Designed to provide a more authentic piano-playing experience, RH3 features a graded hammer mechanism with a heavier touch in the lower keys and lighter response in the upper keys—just like a traditional grand piano. It’s commonly found in Korg’s professional and performance-focused models, appealing to gigging musicians and classical players alike who want precision, weight, and expressive control in a compact digital format.
Korg’s RH3 action is a popular choice in their Korg Grandstage, Korg SV-2, and Korg D1 models.
✅ Pros:
- Heavier action — suitable for classical players
- Four-zone weighting — more nuanced than some rivals
- Responsive and solid — good dynamic control
❌ Cons:
- Fewer product lines use RH3
- Lacks the textured key surface found in Roland’s PHA-4
Scaled Weighted Keys: What Does It Mean?
All three systems, GHS vs PHA vs RH3, offer graded or scaled weighted keys, meaning:
- Low notes (left side) feel heavier
- High notes (right side) feel lighter
This mirrors the real mechanics of an acoustic grand piano, where the hammer sizes differ across the keyboard.
It improves expressiveness and helps train finger strength appropriately for acoustic play.
Benefits for Transitioning to Acoustic Piano
Learning on a digital piano with scaled weighted keys helps build proper finger strength and control, especially for the left hand, which naturally requires more pressure on the heavier bass notes.
It also trains your hands to respond dynamically across the full range of the keyboard. This makes it much easier to transition to an acoustic piano later, without needing to adjust your touch or retrain muscle memory.
Whether you’re preparing for conservatory-level study or simply planning to play on a grand piano at a recital, practicing on a digital piano with graded action gives you a strong foundation.
Final Thoughts: GHS vs PHA vs RH3
Here is a quick summary of the GHS vs PHA vs RH3:
| Feature | Yamaha GHS | Roland PHA | Korg RH3 |
|---|---|---|---|
| Feel | Light, beginner-friendly | Realistic, textured, premium | Heavy, expressive |
| Variations | GHS → GHC → GH3 → NWX → GrandTouch | PHA-4 Std → PHA-50 | Only RH3 |
| Who It’s For | Beginners, casual players | Intermediate to advanced | Classical, stage players |
✅ Choose GHS if:
- You’re new to piano or on a budget
- You prefer a lighter, easier key feel
Yamaha’s GHS and its variants are excellent for beginners seeking affordability and ease of play.
✅ Choose Roland PHA if:
- You want authentic grand piano touch and faster response
- You plan to play advanced pieces or record MIDI
Roland’s PHA series shines for players who want nuanced control, fast repetition, and realistic textures.
✅ Choose Korg RH3 if:
- You value a heavier action with expressiveness
- You want a solid piano feel for stage or home
Korg’s RH3 offers a bold, expressive action favored by classical musicians and performers.
Summery
Ultimately, the best key action depends on your playing goals, experience level, and personal preference. Whichever you choose, investing in a digital piano with graded weighted keys will set you up for long-term success—especially if you plan to transition to an acoustic piano down the road.
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