Short answer: Both are large-flame bench burners built for furnace-size borosilicate work, but they get there in opposite ways. The GTT Cobra is a three-stage Triple Mix surface-mix torch with a very high jet count, built for the broadest, most versatile flame GTT offers, with the power for fast melt-ins in production. The Herbert Arnold Zenit is a concentric surface-mix ring burner that Herbert Arnold markets as noiseless, made in three head sizes so you can match the burner to your tubing. Choose the Cobra if you want maximum layered power and separately controlled fires for mixed production; choose the Zenit if a quieter flame and a hand-built bench burner sized to your work matter more, and you can accept a likely longer wait on an imported torch. The Cobra is the more expensive tool, at about $5,500 against the Zenit’s roughly $3,300.
If you are still mapping out a big-glass setup rather than choosing between these two specific torches, start with the guide to the best bench burner for thick glass sculpture, which frames the whole category before you narrow to a model.
The two designs at a glance
Both torches are bench-mounted surface-mix burners with high oxygen demand. The differences are in how the flame is built, how loud it runs, what it costs, and where it ships from. The figures below come from each maker’s own pages and are labelled as estimates where they are ours.
| GTT Cobra | Herbert Arnold Zenit | |
|---|---|---|
| Design | 3-stage Triple Mix, layered | Single concentric ring burner |
| Mix type | Surface mix | Surface mix |
| Mount | Bench | Bench |
| Jet layout | 130 jets (7 Lynx center, 33 Mirage middle, 90 Cobra outer) | Concentric rings, 40/50/65 mm heads |
| Oxygen (estimate) | ~65 LPM | ~58 LPM |
| Price | $5,500 (reference) | $3,300 (reference) |
| Made in | United States | Germany (Weilburg) |
Editor’s note: Oxygen figures are catalog estimates, not published working-flame specifications. The Cobra figure is derived from GTT’s flow table at the largest usable flame on propane; the Zenit figure is derived from Herbert Arnold’s 114-series data sheet for the standard 40 mm head. The natural-gas version of the Zenit draws more oxygen than the propane figure shown here. Confirm the current numbers with each maker before you size a supply, and treat these as planning estimates.
Triple Mix vs concentric surface mix: how each builds a big flame
The Cobra is a completely surface-mix torch built on GTT’s patented Triple Mix technology. It stacks three separately controlled fires: a 7-jet Lynx center, a 33-jet Mirage middle, and a 90-jet Cobra outer ring, for 130 jets in total. Because each stage has its own controls, you can run anything from the tiny pinpoint flame of the Lynx center up to the wide Cobra flame, and dial the middle and outer fires independently to shape the envelope. GTT describes the result as Mirage-size capability plus enough added heat for fast melt-ins and rapid heating in production, and it notes the Cobra flame can be large enough that multiple flameworkers use one torch. For the mechanics of how the three fires layer, see GTT Triple Mix technology explained.
The Zenit reaches a large flame a different way. It is a concentric surface-mix ring burner, model 114/21 in Herbert Arnold’s line, with gas and oxygen mixing at the face across concentric rings rather than in three separately valved stages. Herbert Arnold builds it in three head sizes, 40, 50, and 65 mm, and the larger heads handle bigger boro tubing; the maker notes the 40 mm head works boro tubing up to roughly 80 mm. A single twist-grip adjusts the flame from a sharp, concentrated pinpoint up to intensive flames, and the burner is mounted on a solid cast-iron foot with a ball joint so you can angle it to the work. The trade-off is fewer independent controls than the Cobra’s three staged fires, in exchange for a simpler burner sized to a specific head. The concentric approach is covered in more depth in Herbert Arnold concentric ring burners.
Both are surface mix, which keeps the gases separate until at or just past the burner face. If the surface-mix versus premix distinction is new to you, the surface mix vs premix torches guide explains why that matters for flame character and safety.
Noise: layered high-jet flame vs a burner marketed as noiseless
Neither maker publishes a decibel figure, so this is a qualitative comparison, not a measured one. What each maker says about its own torch is the clearest signal available.
Herbert Arnold markets the Zenit as a noiseless bench burner and attributes the quiet to a special flame-stabilization system that lets the burner run with a surplus of air, and therefore a cooler, more stable flame. That “noiseless” description is the company’s own framing rather than a number we can verify, but a quiet flame is a real and often-cited comfort factor for people who spend long days at the bench.
GTT does not frame the Cobra around quietness. It is a very high-jet-count torch built for power and a wide flame, and larger, faster surface-mix flames tend to be louder than smaller ones as a rule of the category. GTT’s own emphasis is on the Cobra’s versatility and heat for production melt-ins, not on running quiet. If all-day acoustic comfort is high on your list, that difference in design intent is worth weighing, while remembering that neither claim here is a tested sound measurement.
Oxygen demand and gas supply: both are large, plan the supply first
These are both big burners with high oxygen appetite, and the supply is the part to plan first. Our catalog estimates put the Cobra around ~65 LPM and the Zenit around ~58 LPM at their large flames, close enough that neither is a meaningfully lighter draw than the other, and both are firmly in the territory where you are planning bulk oxygen rather than a single small concentrator.
Two cautions on the numbers. First, they are estimates derived from manufacturer data, not published working-flame specs, so use them to size a supply with headroom, not as exact targets. Second, the Zenit’s oxygen draw depends on the head size and the fuel: the natural-gas version draws more than the propane figure shown, and the 50 and 65 mm heads are larger burners than the 40 mm head the catalog figure maps to. For how to feed a torch this size, and why a torch starved for oxygen underperforms a smaller torch fed correctly, see oxygen concentrators vs tanks for lampworking.
On fuel, GTT torches are known to run on low fuel pressure, and the Cobra ships with grade “T” propane hose and adapters with filter screens on the outer-fire studs. The Zenit is available for both natural gas and propane. As always, the manufacturer’s own manual sets the required pressures for your specific torch and fuel; do not carry a pressure figure over from another model.
Price, configuration, and what the money buys
At about $5,500 for the Cobra against roughly $3,300 for the Zenit, the price gap is on the order of two thousand dollars. The Cobra price is GTT’s figure for the Cobra with the Mirage inner fire; GTT lists the compressed-air configuration as a separate product at its own price. The Cobra’s money buys three separately controlled fires and the widest flame envelope GTT builds, along with rack-and-pinion adjustment on a powder-coated base, a purple manifold, and color-coded valve caps.
The Zenit’s lower price buys a hand-built German burner mounted on a cast-iron foot with a ball joint, single twist-grip control, and maintenance-free ball valves. Remember that the Zenit’s price and capacity move with the head size: the 40 mm, 50 mm, and 65 mm heads are different burners, and the catalog price and oxygen figures map to the standard 40 mm head. Herbert Arnold also offers the Zenit optimized for borosilicate, and a hydrogen and oxygen execution for quartz-glass work, so the exact configuration you order affects both price and capability. Confirm the current price and the head size you need directly with each maker before buying.
Lead time and sourcing: US-built vs German-made
The Cobra is built in the United States by GTT. The Zenit is made in Germany, in Weilburg, where Herbert Arnold assembles and adjusts each burner by hand, drawing on more than sixty years of experience building burners and machines for glass and quartz-glass processing.
That hand-built, imported nature is worth planning around. We do not have a verified lead-time figure for the Zenit, and it would be wrong to invent one, but individually hand-adjusted burners shipped from overseas tend to carry longer waits than a domestically stocked torch, and import logistics add their own variability. If your timeline is tight, ask Herbert Arnold for a current lead time before you commit, and factor it against the Cobra’s domestic sourcing.
Which to choose
Pick the Cobra if you want maximum layered power and the flexibility of three separately controlled fires. It suits production work where you move between a fine Lynx pinpoint and a wide melt-in flame on the same torch, and where fast melt-ins and rapid heating on furnace-size pieces are the daily job. You pay more, you feed a large oxygen supply, and you accept a louder flame in exchange for the broadest, most versatile envelope GTT builds.
Pick the Zenit if a quieter flame and a hand-built burner sized to your tubing matter more than staged control. Its noiseless framing and cooler, air-surplus flame make it a comfortable all-day burner for scientific and boro work, the head-size options let you match the burner to your glass, and it costs meaningfully less up front. In return you accept fewer independent flame controls and, most likely, a longer wait on an imported, hand-adjusted torch.
What should not decide it is buying the bigger or more expensive torch as a statement. Size the torch to the largest piece you make regularly and the way you like to work, then size your oxygen supply to the torch. A large burner starved for oxygen performs worse than a right-sized one fed correctly.
Related guides
- GTT Triple Mix technology explained
- Herbert Arnold concentric ring burners
- Best bench burner for thick glass sculpture
- Surface mix vs premix torches
- Oxygen concentrators vs tanks for lampworking
Sources
- GTT, Cobra product page: https://www.glasstorchtech.com/cobra
- GTT, Triple Mix torches: https://www.glasstorchtech.com/triple-mix-torches
- GTT, Cobra with compressed-air option: https://www.glasstorchtech.com/product-page/cobra-with-compressed-air-option
- Herbert Arnold, burners overview: https://www.h-arnold.com/burners
- Herbert Arnold, Zenit data sheet (PDF): https://downloads.arnold-gruppe.de/ARNOLD%20Zenit.pdf