Soldano SLO-100

The SLO-100 (short for Super Lead Overdrive 100) is a guitar amplifier designed by Mike Soldano and the first production model from his company Soldano Custom Amplification. Released in 1987, the SLO-100 was hand-built and pushed the boundaries of high-gain guitar tone during an era of mass-produced amps that were insufficient for increasingly heavy music without modifications. Hard rock and metal guitarists like Eddie Van Halen, George Lynch, and Mick Mars helped popularize the SLO-100 and its high-gain sound, while the amp's clean and lower-gain tones attracted players like Eric Clapton, Mark Knopfler, and Warren Haynes. The SLO-100 is considered one of the industry's benchmark amps and helped establish the boutique amplifier market.

History

By the mid-1980s, guitarists in hard rock and metal were limited in their pursuit of high-gain sounds to Mesa/Boogie amps like the Mark II or Fender or Marshall amps that had been "hot-rodded" with often expensive modifications by an amp tech—such as Mike Soldano—to produce heavier, more aggressive tones. Between traveling back and forth between his native Seattle and Los Angeles, and taking gigs as a roadie to make ends meet, Soldano developed a prototype of his own high-gain amp design, the SLO-100, and first showed it to Heart guitarist Howard Leese in 1987. Word spread and Soldano quickly received orders from players like Lou Reed, Michael Landau, and Vivian Campbell. Soldano subsequently moved to Los Angeles and debuted his new amp at the 1987 NAMM Show.

The SLO-100 was an immediate success. Its thick, high-gain tones were particularly attractive to lead guitarists like Joe Satriani, Warren DeMartini, George Lynch, and Mick Mars. Eddie Van Halen used an SLO during the early 1990s to record ''For Unlawful Carnal Knowledge'' and later based his own signature model amp, the Peavey 5150, on it. Meanwhile, Campbell, Adrian Vandenberg, and Steve Vai all used SLO-100s during their turns with Whitesnake. The amp's lower-gain tones found prominent fans too, in Eric Clapton, Mark Knopfler, Gary Moore, and Warren Haynes. Haynes even convinced Dickey Betts to briefly play an SLO in The Allman Brothers Band.

From the early 1990s until 2018, Mike Soldano and a small team of employees built the SLO-100 and the brand's other amps by hand in a Seattle workshop. In 2018, he sold his company to Huntington Park, California-based Boutique Amps Distribution—which also builds amps for brands like Friedman Amplification and Tone King—but stayed on as an advisor. The company's product line was "rebooted" in 2020 under B.A.D. with the flagship SLO-100 receiving multiple player-requested features. A version closer to the original's specs, known as the SLO-100 Classic, is also produced.

Design

''Vintage Guitar'' wrote that, sonically, the SLO-100 was difficult to describe through typical references to previous amps—noting it had characteristics of Mesa/Boogie, Marshall, and hot-rodded Fender amps—and concluded that Soldano's amp ultimately stood on its own as "a high-concept modern design rather than a modified vintage circuit". With the SLO, Soldano felt he had achieved a "high-gain sound without losing a lot of the fundamental character of the initial note"; he explained that while it was important to maintain the guitar's clarity and detail, he also "wanted to overdrive the hell out of it."

The SLO-100 features two channels, ''Normal'' and the higher-gain ''Overdrive'', which share a four-band EQ (Bass, Middle, Treble, and Presence) but have independent gain and master volume controls. The Normal channel also has a toggle switch for choosing between ''Clean'' and ''Crunch'' modes. The amp's 100 watts of power are provided by four 6L6GC power tubes, which contribute to its tight low-end, with solid-state rectification and a significant amount of filtering. Having cloned a Mesa/Boogie Mark II from the early 1980s as a formative DIY project, Soldano employed a similar cascading-gain preamp structure in the Overdrive channel of his amp, which added a thickness to its "high-gain sizzle". The preamp structure consists of two stages of 12AX7 preamp tubes for the Normal channel, which are then combined with another two when switching to the Overdrive channel. The signal then passes through a buffered effects loop, a tone stage based on a modified Fender Bassman topology, the master volumes for each channel, and finally a phase inverter. A key part of the SLO-100's success is that its overdriven tones are created entirely in the preamp section and therefore it does not require "ear-splitting" volume levels to sound its best like many other amps.

''Guitar World'' described the SLO-100's Overdrive channel as providing "tight, dynamically expressive and harmonically rich high-gain tones and smooth attack", and wrote that the Normal channel offered "very distinctive clean tones that are crisp and slinky". A common aftermarket modification to the SLO was the addition of a ''Depth'' control to its power section to add low frequency attenuation; this mod later became a standard feature.

SLO base-models come stock with a black tolex covering, but can be ordered in purple and snakeskin variants.

Legacy

The SLO-100 is one of the guitar industry's benchmark amplifiers. ''Premier Guitar'' credited the SLO-100 with having "set the standard for high-gain amplification", noting its "searing harmonics and the perfect balance of gain, sustain, and tight touch response." Soldano's success with the SLO-100 was a pivotal inspiration for the subsequent generation of amp-techs-turned-amp-builders in the late 1980s and 1990s, with ''Guitar World'' crediting Soldano with founding the boutique market.

Since its release, Soldano has offered multiple iterations of the SLO-100 sound and circuit to make it more accessible to everyday guitarists. Boutique Amps Distribution released the solid-state ''SLO Mini'' head in 2022, adding Soldano to its roster of high-gain boutique amp-makers like Bogner and Friedman in creating inexpensive, compact versions of their flagship models. As of 2021, Neural DSP offers an official ''SLO-100 Suite'' audio plug-in. The following year, Soldano joined the "amp-in-a-box" overdrive pedal market with the ''SLO Pedal'', based on the SLO-100's Overdrive channel. The brand later introduced a two-channel version of the pedal, the ''SLO Plus'', to include tones based on the SLO's Normal channel.

See also

*Marshall JCM800
* Mesa/Boogie Rectifier

References

{{reflist

External links

Official site

Instrument amplifiers
Valve amplifiers
Products introduced in 1987