Yamaha TRBX504 4-String Electric Bass Guitar

Active When You Want It. Passive When You Need It.

The Yamaha TRBX504 is where the range becomes a professional tool. The headline is the active/passive switch: a full three-band active preamp when you want to shape the sound, and a genuine passive circuit the instant you flick it — which also means a flat battery never ends your set.

The pickups change too. YGD-designed H5 humbuckers use a “quad-polepiece design and Alnico magnets” for what Yamaha calls “a clean, open tone” — alnico rather than the ceramic magnets of the 300 series, giving a warmer, more musical character with more usable output in passive mode.

Yamaha describes the preamp as “audiophile-grade” with “level-matched output whether in passive or active”, so switching does not jump your volume. A battery alert LED warns you before it dies. Sculpted mahogany body, five-piece maple/mahogany neck, high-mass die-cast bridge, satin finish. Available in Brick Burst, Translucent Black and Translucent Brown.

The Three Things That Make This a Working Bass

The step from the TRBX304 to the 504 is less about being “better” and more about being dependable under pressure. Three details do that work.

Active/passive switching with level-matched output

Full three-band active EQ or a genuine passive circuit, at the flick of a switch, without a volume jump. A battery alert LED warns you before the 9 V runs out.

YGD-designed H5 alnico humbuckers

Quad-polepiece design with alnico magnets for “a clean, open tone”. Powerful enough to drive the active circuit, sensitive enough to sound right in passive mode — the reason the switch is genuinely useful.

Three-band EQ with a dedicated mid control

Master volume, pickup balancer, and bass, middle and treble. The mid control is what lets you push the bass forward in a busy mix or tuck it politely behind a vocal.

Sculpted mahogany body, five-piece neck

Yamaha's “mass-optimized 3D design” body with a five-piece maple/mahogany laminated neck and a “precision-fitted, bolt-on” joint developed through extensive play-testing.

High-mass die-cast bridge and satin finish

A high-mass die-cast bridge for efficient vibration transfer and more sustain. The satin polyurethane finish is understated and does not stick to your forearm in the heat.

Q. What happens if the battery dies mid-gig?

You flick the switch to passive and keep playing. That is the single best reason to own this bass rather than the TRBX304, which stops working entirely without a battery. A battery alert LED also warns you before it gets that far.

Q. Is passive mode a proper sound or just an emergency setting?

A proper sound. The H5 alnico pickups are specified as sensitive enough to work well passively, and Yamaha level-matches the output so the volume does not drop when you switch. Plenty of players run it passive by default and use the active EQ only when a room needs it.

Q. Is it worth stepping up from the TRBX304?

If you gig, yes — the active/passive switch, the alnico pickups and the mid control are all things you notice on stage. If you play mostly at home, the 304's Performance EQ arguably gives you more usable sounds for less effort, and less money. Be honest about which you are.

Q. Does it have the Performance EQ?

No — that is a 300 series feature. The 504 gives you a full three-band EQ instead, which is more flexible but requires you to dial in your own sounds rather than selecting a preset. Different approaches for different players.

Q. What does alnico give me over ceramic?

Generally a warmer, rounder and more open character with a slightly softer attack, where ceramic magnets tend to be brighter and more aggressive. Neither is better in the abstract — but alnico is the traditional choice for players who want the bass to sound musical rather than modern.

Q. How does it differ from the TRBX604FM?

Electronically not at all — same H5 pickups, same three-band EQ, same active/passive switch. The 604FM changes the body to alder with a flame maple top and adds gold-plated internal parts. You are paying for looks and materials, not more function.

Q. Is a case or gig bag included?

No — Yamaha does not supply a case with the TRBX504. Ask us and we will match a suitable bass gig bag or hard case before it ships.

Why Buy Your Bass from YMS?

• ✓ Authorised Yamaha Premium Retailer: Buy a genuine India-market Yamaha instrument with official manufacturer warranty support.
• ✓ Set up before it reaches you: We check action, relief and intonation, and confirm both active and passive modes work, so it is stage-ready on arrival.
• ✓ Bassist-focused guidance: Ask us about active versus passive, four versus five strings, string spacing and matching amplification.
• ✓ Support beyond the bass: Gig bags and cases, spare 9 V batteries, straps, stands, cables, tuners, strings and bass amps.
• ✓ Pan-India delivery: Order from anywhere in India, subject to serviceability for your location.
• ✓ Physical-store support: YMS teams in Bengaluru and Mangaluru are available for product enquiries and after-sales guidance.