Kleinn Model 501 Warlock Steel Triple Train Horn Review (2026)

Methodology

This review aggregates publicly available information from manufacturer specifications, retailer listings, and verified user reviews. We do not perform hands-on testing. Last reviewed: September 27, 2026. Primary source: Kleinn’s official Model 501 “Warlock” product page and its spec table. We cross-checked it against Kleinn’s Model 500, Model 502, and Model 730 pages, Kleinn’s open-box and scratch-and-dent 501 listings, Kleinn’s warranty and audio-sample pages, Kleinn’s 6350 and 6450 air system pages, and retailer listings at Pure Diesel Power and Northridge4x4.

Quick verdict

The Kleinn Model 501 “Warlock” is the middle rung of Kleinn’s 500 Series triple train horns, and it earns a 3.9/5 from us. You get three chrome-plated steel trumpets (16”, 14”, and 11”) on the same aluminum right-angle bracket as the rest of the series, a Model 307 Vortex 4 solenoid, and 12 ft of 1/4” airline for $289.95 direct. Kleinn is more open than most brands about specs: it publishes the test pressure (151.8 dB at 150 PSI), the pressure window, the minimum tank size, and the overall dimensions. The catch, in our editorial view, is that Kleinn rates the $239.95 ABS Model 500 at exactly the same 151.8 dB with the same valve and line. That means the extra $50 buys steel trumpets and, per Kleinn, a richer tone, but no extra rated output. It is also horn-only and needs a 140-160 PSI air system.

What it is

The Model 501 is a horn-only triple train horn assembly. It has three individually tuned trumpets formed from steel and finished in mirror chrome plating. They are joined to a single heavy-duty air block on a triangular aluminum right-angle bracket. Kleinn calls it the “mid-tier” and the “bridge” of the 500 Series. It sits above the chrome-ABS Model 500 “Sentinel” and below the Model 502 “Kraken”, which uses the same steel trumpets but upgrades to a brass Vortex 6 VX6003 solenoid and a 1/2” airline.

Kleinn’s own positioning is about tone rather than volume. The product page says the move from composite to steel trumpets produces “a deep harmonic chord” and a “richer, more melodic train sound”. Treat that as the manufacturer’s description; nobody publishes chord frequencies for this horn. Like every 500 Series horn, the trumpets are reversible, so you can aim some bells forward and some rearward. Kleinn says this gives the multi-directional effect of a passing locomotive. The bracket is rated for both under-body and rooftop installs.

The buyer this suits is a truck or SUV owner who already runs, or plans to buy, a 150 PSI or larger onboard air system and wants metal trumpets instead of plastic, without paying for the Kraken’s high-flow valve. Kleinn also lists the 501 as a direct replacement for the horn in its HK6 ProBlaster kit. HK6 owners can move from ABS to steel trumpets without changing anything else. For complete kits with a compressor and tank in the box, see the Kleinn hub.

Specifications

Spec	Value
Model	Kleinn Model 501 “Warlock” (SKU KL 501)
Format	Horn-only triple train horn assembly, individual-mount trumpets
Sound output	151.8 dB at 150 PSI (test distance not disclosed)
Operating pressure	140-160 PSI
Minimum tank	2.5 gallons
Trumpets	3, chrome-plated steel, 16” / 14” / 11” long
Solenoid	Model 307 Vortex 4, 12V, chrome
Airline	12 ft of 1/4” OD (Model 25014-1), included
Mounting	Triangular aluminum right-angle bracket, reversible trumpets
Overall dimensions	15.5” L x 11.5” W x 11.5” H
Weight	Not published on the product page (Kleinn’s store data lists 18 lb, likely a shipping weight)
Chord frequencies	Not disclosed
Power source	Air tank (12V trigger for the solenoid)
Warranty	1-year limited
Price	$289.95 direct from Kleinn; $289.95 at Pure Diesel Power and Northridge4x4

Rated output

151.8 dB at 150 PSI

Pressure window

140-160 PSI

Valve / line

307 Vortex 4, 1/4” OD

Price

$289.95

A note on the dB figure. Kleinn states the pressure behind its rating but not the microphone distance. Without the distance, 151.8 dB can’t be compared directly with ratings from brands that do publish one. Our guide to advertised vs. real dB explains why distance matters as much as pressure.

Two generations exist. Kleinn’s open-box (NOB) and scratch-and-dent (SOD) 501 listings, and the retailer listings at Pure Diesel Power and Northridge4x4, still describe an earlier 501. That version had chrome-plated spun copper trumpets in the same 16”/14”/11” lengths, 152.2 dB at 150 PSI and 149.1 dB at 100 PSI, a 175 PSI maximum input, a 17.5” x 15” x 11” footprint, and a 14.9 lb shipping weight. The current Warlock page specifies chrome-plated steel, 151.8 dB, and 140-160 PSI. Confirm which version ships before you order from a third party.

What’s in the box

Kleinn’s “What’s in the box” list for the 501:

• Warlock triple trumpet assembly: chrome-plated steel trumpets in 16”, 14”, and 11” lengths
• Triangular aluminum right-angle mounting base
• Hardware kit with bolts and fasteners for the horn and bracket
• One Model 307 Vortex 4 12V solenoid valve
• 12 ft of 1/4” outer-diameter airline (Model 25014-1)

Not included: compressor, air tank, pressure switch, relay, wiring, or horn button. Kleinn sells these separately as onboard air systems and accessories.

Pros

• Chrome-plated steel trumpets for $50 less than the Kraken, the cheapest way into metal bells in Kleinn’s 500 Series
• Better disclosure than most: dB with test pressure, a 140-160 PSI window, a 2.5-gallon minimum tank, and overall and per-trumpet dimensions are all on the product page
• Complete air path in the box: the solenoid and 12 ft of airline are included, not upsold
• Reversible trumpets and a low-profile right-angle bracket for frame, bed, or roof mounts
• Drop-in horn upgrade for HK6 kit owners, per Kleinn’s compatibility note
• Kleinn publishes a 501 audio sample next to the 500 and 502, so you can compare tone before buying

Cons

• Same 151.8 dB rating as the $239.95 ABS Model 500: on paper the $50 premium buys material and tone, not output
• No test distance disclosed for the dB rating
• Horn only: a Kleinn 6350 or 6450 air system adds $529.95 to $579.95
• The 1/4” line and Vortex 4 valve are the smaller air path; Kleinn reserves its high-flow 1/2” setup for the 502
• 1-year limited warranty, versus two years on Kleinn’s own 730 horns
• Older copper-trumpet listings with different specs still circulate at retailers and in Kleinn’s own open-box stock

Alternatives

• Kleinn Model 500 “Sentinel” ($239.95): same trumpet lengths, bracket, 307 solenoid, 1/4” line, and 151.8 dB at 150 PSI rating, but with chrome-plated ABS trumpets. It’s the value pick if you care about published output more than material. See our Kleinn Model 500 review.
• Kleinn Model 502 “Kraken” ($319.95): the same chrome-plated steel trumpets fed through a brass Vortex 6 VX6003 solenoid and 12 ft of 1/2” airline, rated 155.2 dB at 150 PSI. For $30 more it is, in our opinion, the better buy for anyone chasing output. See our Kleinn 502 Kraken review.
• Kleinn Demon Model 730 (from $499.95): a stainless-steel triple rated 157.8 dB at 150 PSI, with a 2-year warranty. It’s the step up if your budget and mounting space allow. See our Kleinn Demon 730 review.

For a cross-brand comparison, our Kleinn vs HornBlasters guide sets the 500 Series against HornBlasters’ horn-only and kit options.

Install / compatibility notes

Air. Kleinn specifies a 2.5-gallon minimum tank and a 140-160 PSI cut-off pressure for all 500 Series horns. It names two of its own systems as designed to run them. The Model 6350 is a 150 PSI, 100%-duty onboard air system at $529.95. The Model 6450 is rated 200 PSI and 100% duty on the 501 page and sold as a 5-gallon system at $579.95. Any quality compressor and tank that reaches 150 PSI with at least 2.5 gallons of storage meets Kleinn’s stated minimum. A light-duty 120-130 PSI setup will run below the rated pressure. Our air tank size guide and PSI explainer cover how much reserve a triple needs. The air tank runtime calculator estimates blast time for a given tank.

Plumbing. The 501 runs on 1/4” OD line, which suits most small push-to-connect tank ports. If you later want the Kraken’s output, the upgrade path is the valve and line, not the trumpets. That means a 1/2” solenoid and matching fittings, which our air fittings guide and solenoid sizing guide cover. Keep the tank-to-solenoid run short.

Electrical. The 307 is a 12V solenoid, wired like any horn valve: a fused feed from the battery through a relay, triggered by a horn button or the factory horn circuit. Kleinn links its solenoid wiring instructions from the product page but does not include the relay, wire, or switch. See wiring a train horn relay for a diagram and fuse sizing.

Mounting. At 15.5” x 11.5” x 11.5”, the assembly fits full-size truck frame rails, bed mounts, and roof or headache-rack installs best. The bracket bolts to a flat surface, and the reversible trumpets let you split the bells forward and rearward. Steel trumpets are heavier than the Model 500’s ABS, so bolt into solid structure rather than sheet metal. Point the bells slightly down under the body so water can drain; see where to mount a train horn. Before using it on the road, check your state’s rules in our guide to whether train horns are legal on cars.

Total cost. Horn plus a Kleinn 6350 air system comes to $819.90 at Kleinn’s direct prices, before wiring and fittings. If you’re starting from zero, compare that with a complete HK-series kit on the Kleinn hub or run the numbers in our total cost calculator.

Sources

• Kleinn — Model 501 “Warlock” Chrome-Plated Steel Triple Train Horns product page — all core specs: 151.8 dB at 150 PSI, 140-160 PSI, 2.5-gallon minimum tank, 16”/14”/11” chrome-plated steel trumpets, Model 307 Vortex 4 solenoid, 12 ft of 1/4” OD airline, 15.5” x 11.5” x 11.5” dimensions, 1-year warranty, $289.95 price, included items, reversible trumpets, 500 Series hierarchy, HK6 replacement note, 6350/6450 compatibility, product photo
• Kleinn — Model 501 store data (JSON) — SKU KL 501 and 18 lb listing weight
• Kleinn — Model 501 Triple Train Horn, New Open Box — earlier-generation spec table (spun copper, 152.2 dB at 150 PSI, 149.1 dB at 100 PSI, 175 PSI max input, 17.5” x 15” x 11”, 14.9 lb shipping weight), NOB pricing, and the same 1-year warranty on NOB stock
• Kleinn — Model 501 Triple Train Horn, Scratch & Dent — SOD listing and warranty terms for cosmetic-blemish stock
• Kleinn — Model 500 “Sentinel” Chrome-Plated ABS Triple Train Horns — Model 500 comparison: chrome ABS trumpets, 151.8 dB at 150 PSI, 307 solenoid, 1/4” line, $239.95
• Kleinn — Model 502 “Kraken” Chrome-Plated Steel Triple Train Horns — Model 502 comparison: VX6003 brass solenoid, 1/2” airline, 155.2 dB at 150 PSI, $319.95
• Kleinn — Model 730 “Demon” Stainless Steel Triple Train Horns — 730 pricing (from $499.95) used in alternatives
• Kleinn — Model HK6 Train Horn System — HK6 kit context for the replacement-horn note
• Kleinn — Model 6350 Heavy Duty 150 PSI Onboard Air System — $529.95 price for the named compatible air system
• Kleinn — Model 6450 Ultra Heavy-Duty 5-Gallon Onboard Air System — 5-gallon system, $579.95 price
• Kleinn — Horn audio samples — brand-published sound clips for the Model 500, 501, and 502
• Kleinn — Warranty information — 1-year limited warranty terms for the original purchaser
• Pure Diesel Power — Kleinn Model 501 Train Horns — $289.95 retail cross-check and earlier-generation specs (spun copper, 152.2 dB at 150 PSI, 149.1 dB at 100 PSI, 175 PSI max, Vortex 4 solenoid)
• Northridge4x4 — Kleinn Model 501 Triple Train Horn — $289.95 retail cross-check, 1-year limited warranty, earlier-generation copper specs and 17.5” x 15” x 11” dimensions

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