Warwick Hellborg Preamp, 2x250 Power Amp, Club Cab, and Lo Cab

I’m already plotting my reply to your letters. And allow me to paraphrase the future you: “Why waste space writing about a rig nobody can afford?” Because it’s cool, that’s why. So there. Discovering what happens when an amp designer makes no concession whatsoever to price, market viability, or production cost, instead focusing exclusively on sound, is both fascinating and important in terms of the evolution of amp design. And it’s even cooler when the designer is Jonas Hellborg, a virtuoso bassist whose brilliant career exhibits the same steadfast integrity as his eponymous amp.

Hellborg has long nurtured a fascination with the intricacies of audio-equipment engineering, especially after he bought a Neve recording console—the Cadillac of analog studio desks—without the benefit of a maintenance technician in 1985. While he has been professionally involved with a variety of amp manufacturers (even culminating in a short-lived signature amp with the Italian company FBT), the Warwick Hellborg line is the truest realization of Hellborg’s esoteric engineering concepts. Chief among these was an uncompromising commitment to ultra-high-quality components, thus the exceptionally high price (the weak dollar sure doesn’t help).

In addition to first-rate construction, there are several other key pillars to Hellborg’s amp and speaker design philosophy. He loves transformers. No, the rig doesn’t turn into a block-busting robot; I’m talking about the electrical device made up of a bunch of wire wrapped around a ferrous core. In audio, transformers perform a lot of necessary tasks, like changing a signal’s voltage and current, as well as determining the input and output impedances of a device. To Jonas (and he’s got a lot of company among audio geeks), transformers impart a special quality to an audio circuit—a sonic quality often touted as superior to that of their alternatives. Particularly inspired by his Neve console, which is renowned for its transformer-equipped preamps, Hellborg knew he wanted to use a transformer to couple the amp’s input to the first gain stage—unusual for a bass amp. The Hellborg amp’s eccentricity continues into its versatile EQ section, which uses coil-based inductive EQ, like a Neve board, and a Baxandall-style circuit for hi-fi symmetry in the bass and treble shelving curves.

The Hellborg power amp is slightly more typical, but for one highly unusual design quirk: It utilizes an output transformer (OT) for interfacing with speakers. OTs are normally used only in tube amps due to tubes’ extreme sensitivity to load impedance—they convert the high-voltage, high-impedance, low-current output of a tube power amp to a low-voltage, low-impedance, high-current signal appropriate for speakers. While these are an output transformer’s essential roles, OTs also have a few side benefits, like protecting speakers from a cone-shredding dc signal (audio is ac) and more important, introducing a small amount of pleasing distortion into a signal when pushed hard. Finally, by lowering the output impedance, OTs have a significant effect on “damping factor,” the degree to which an amp is able to control the movement of a speaker’s voice coil. Due to their inherently ultra-low output impedances, solid-state amps don’t care all that much about speaker load impedance, at least not when compared to tube amps, so they almost never use an OT. But Hellborg believes that a lot of the magical allure of tube amps—fat tone and a musically dynamic responsiveness—is due to their OT-equipped design, so he added one onto his solid-state amp. In the stereo model I reviewed (there are two mono Hellborg power amps) there are three large transformers in the chassis: the power transformer, and one OT per side. This is why the power amp is absurdly heavy and absolutely no fun to schlep around.

While not as radical as the amps, the Hellborg cabs are still a tad left of center. The two I reviewed, a 15 with a coaxial tweeter and a conventional 15 with no tweeter, are augmented in the line by a 2x15 and a 2x12. Hellborg likes coaxial drivers for their good phase linearity: the high- and low-frequency audio emanates from the same physical location, which some argue benefits fidelity and sonic coherency. In practice, the coax-equipped Club Cab was, as expected, brighter with more treble extension. Both are capable on their own. Delightfully, in contrast to the power amp, the cabinets were light and portable. And like the preamp and power amp, the cabinets were beautifully constructed, although I’d prefer more robust corners than the modest metal ones provided.

Sonic Assimilation

Is it worth it? How good should an amp sound if it costs as much as a car? To answer this, we enter the realm of the highly subjective. I’ve previously argued that high fidelity does not necessarily equal good tone; there are numerous other factors, not the least of which is the instrument and the player. But the amp is an integral component, and as such, ought to work with the player musically, presenting no impediment to free expression, and, in the best cases, actually inspiring musical ideas. To this end, the Hellborg rig is successful. It’s an ingenious concept that, despite its look and price, is not centered on an obsession with pristine fidelity, but rather on fostering a musical partnership with the player.

I’ve never heard an amp that sounds anything like the Hellborg. It’s exceptionally difficult to attribute its unique sonic signature to one design aspect, although it’s easy to corroborate the intended results of his ideas. The amp has a remarkable feel; its fast attack is leavened with a plush note envelope, giving it a buttery, tube-like character but without any sludge on the uptake. The EQ is seamlessly integrated, although with the preamp’s beguiling disposition when flat, I generally favored the EQ-off option. The transformer-equipped di out tracked beautifully: The Hellborg preamp would make an excellent alternative to one of the many instrument-input-equipped high-end preamps often favored for recording bass (Avalon U5, Millennia TD-1, Universal Audio LA-610, etc.). In fact, the Hellborg preamp incorporates several features more typical of serious recording gear, like a unity gain position on the gain and master knobs and a –10dBV/+4dBu switch for the effect loop to ensure optimum gain staging for both professional and consumer effects.

Despite the Hellborg power amp’s relatively low power rating, I was never wanting for headroom or volume on several big gigs. Its stereo design promotes bi-amping, but the mono preamp eliminates that option without a third-party crossover. Since it incorporates an output transformer, there’s an impedance selector switch on the rear panel, like with tube amps. Perhaps it’s the use of an output transformer (actually, it probably is, considering the amp is otherwise a pretty straightforward Class AB design), but the Hellborg power amp has a uniquely full-throated and pliant attack. Partnered with the balanced- and poised-sounding cabinets, the rig projected broad-spectrum warmth into a room but was able to dart out quickly and brightly for the stray pop, retaining coherence as my bass line fell back into a consistent dynamic range. The rig was all-over sweet and beautiful sounding, not at all sterile or twinkly.

The Jonas Hellborg rig is one of the hippest-sounding amps I’ve heard. Its precision and swift attack is couched in an overall coziness that’s immediately seductive. Bonus: It looks seriously cool, especially if, like a hungry squid, you love bright lights. Yeah, most of us will never indulge in such a luxury, but aren’t you glad it exists? The Hellborg rig is packed with clever ideas that work—maybe some will trickle into gear we could actually buy.


Hellborg Preamp
Input level range –6dBu to +60dBu
Input impedance 1/4", 500kO; xlr, 600O
Tone controls:bass: ±18dB @ 40Hz (shelving); lo-mid: ±15dB @ 110Hz, 300Hz, 800Hz; hi-mid: ±15dB @1.5kHz treble: ±18dB @ 15kHz (shelving)
Weight 8 lbs

Hellborg Power Amp
Power rating 2x250 watts rms @ 2, 4, or 8O; 500 watts rms @ 4, 8, or 16O
Topology Stereo Class AB with output transformer
Weight 49 lbs

Hellborg Club Cab
Type 1x15, coaxial
Frequency response 50Hz–20kHz
Power handling 250 watts (600 watts peak)
Impedance 8O
Sensitivity 99dB SPL @ 1w/1m
Speakers Custom-designed Celestion 15" coaxial
Weight 48.5 lbs

Hellborg Lo Cab
Type 1x15
Frequency response 40Hz–3kHz
Power handling 300 watts (600 watts peak)
Impedance 8O
Sensitivity 99dB SPL @ 1w/1m
Speakers Custom-designed Celestion 15" woofer
Weight 48.5 lbs

Made in Germany
Warranty Two years limited

Hellborg Preamp

List $3,799
Street $3,040
Pros Beautiful, clean-sounding preamp with excellent EQ
Cons Expensive, considering the features
Bottom Line A faultless design with killer tone.

Hellborg 2x250 Power Amp

List $3,999
Street $3,200
Pros Lush-yet-swift power delivery with excellent dynamic response
Cons Freakin’ heavy and boy, is it pricey
Bottom Line An innovative design yields wonderfully musical results.

Club & Lo Cabs

List $1,099 (Club Cab); $979 (Lo Cab)
Street $880 (Club Cab); $780 (Lo Cab)
Pros Balanced and coherent tone; excellent portability
Cons None
Bottom Line Sweet-sounding cabs with a personality all their own.

Soundroom Policy

We test products in real-world environments, evaluating them with regard to price and the manufacturer’s design intent. Advertising does not influence our product coverage. We invite manufacturers to fact-check product reviews prior to publication, and we print dissenting opinions when applicable. Street prices are approximate.


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Warwick WA 600s, WCA 115 & WCA 410

WHEN WARWICK TEAMED UP WITH Jonas Hellborg a while back to produce a line of amps and cabinets, the resulting Hellborg Preamp, Power Amp, and cabinets made a big impression here at BASS PLAYER.