One of the leaders of what we might call the second wave of high-end high-gain tube amps, Soldano has been making a big noise since 1987 – the year Michael J. Soldano released his first production model, the Super Lead Overdrive (SLO-100). The SLO’s ability to churn out searing lead tones with a certain sonic depth, clarity, and dynamics that some other high-gain monsters might have lacked at the time made it a quick favorite with several big-name players, and the likes of Eric Clapton, Mark Knopfler, George Lynch, Gary Moore, Vivian Campbell, Lou Reed, and Joe Satriani – to name but a few – have all flown the Soldano banner at one time or another. Our star this issue is from the very early days of the company, a 1990 SLO 100-watt head with no effects loop, and is a really primo example for an amp with 21 years of rock mayhem under its belt.
For sonic references, you might call the SLO kind of Boogie crossed with Marshall crossed with hotrodded Fender crossed with… well, by the time you stir that pot and season liberally, the stew is gonna’ taste like something original enough to not require any specific references in the first place, so we can pretty much leave it at that. Simple tonal descriptions are more apt, and players tend to be drawn to the big, thick, creamy drive, which can also be plenty nasty and aggressive as desired, while retaining musical highs and firm, chunky lows. In short, you could call the SLO a high-concept modern design rather than a modified vintage circuit, and Michael Soldano certainly burned some midnight oil to get this one sounding its best.
Like many amps by Mesa/Boogie, Rivera, Egnator, Bogner, Budda, and a handful of other top-shelf high-gainsters, Soldanos are built on printed circuit boards (PCBs), though assembled by hand even so. These aren’t your grandfather’s PCBs though (or your cheesy uncle’s); Soldano uses thick, high-quality PCBs (though not the double-sided boards here that would appear in later years), and would no doubt tell you that they opt for this topology for the sake of consistency and reliability, rather than for reasons of economy. While we are accustomed to seeing plenty of high-gain 100-watters with EL34 output tubes, and might be expecting them here, this SLO – and its standard brethren – is based around four 6L6GCs (although some are modded to use EL34s). One goal achieved by this choice is the firm, tight low-end the amp is known for, along with its generally more American high-gain tone, which can generate some Brit-rock crunch, certainly, but has an overall flavor that is more Yank than Limey.
The SLO’s Normal channel, which is selectable between Clean and slightly grittier Crunch modes on a mini-toggle switch, runs through two 12AX7 gain stages. Select the footswitchable Overdrive channel, and the signal is re-routed after the first shared triode to another two stages for plenty of thick, controllable preamp-tube distortion. The two share a cathode-follower tone stack with the full three-knob complement of Bass, Middle and Treble, as well as a Presence control, and each channel has its own independent Master Volume control placed just prior to the long-tailed pair phase inverter. When there’s an effects loop on the SLO, it is driven by another tube, but as the blanked-out holes on the back of this one indicate, there is no loop onboard, a configuration plenty of purists swear yields a truer tone thanks to its less-cluttered signal path. To the same end, this one also lacks the optional line out.
As befits an amp with intentions for sizzling front-end overdrive and firm, hefty output-tube girth, the SLO wields enormous iron, with an output transformer that is virtually indistinguishable in size from the power transformer at the other end of the chassis. Further supporting its bovine back-end are design elements such as solidstate rectification, massive amounts of filtering (including three 200uF electrolytic caps and an in-the-chassis choke), and fairly high DC voltages on the 6L6GC output tubes – around 497 volts on the plates. A look under the hood would reveal several signs of Soldano’s quality workmanship; neat and linear wire runs, a board loaded with Mallory electrolytics, “orange drop” signal caps, metal film resistors to keep the noise down (a priority in any high-gain circuit), and tube sockets that are all mounted directly to the chassis rather than to the main circuit board, or even a supplemental board, as is often done in more mass-manufacture-grade PCB-based tube amps.
Patch this SLO through a 4×12 with Celestions, or indeed a 2×12 with EVs, and prepare to move some air, and to feel a mighty thump in the gut when you hit those low-string runs and power chords. Step on the switch to kick it up a gear, and expect searing, creamy overdrive with just a little jaggedness to its edge for bite, and endless sustain when desired. The SLO was never intended as a “metal amp” as such; rather, it was designed more for the contemporary rock soloist. But dial down the Midrange, crank Bass, and tweak Treble to taste, and you can pound out a mighty wallop, no problem, and the amp’s firm bedding and fast response have no trouble nimbly translating all the shred you want to throw at it. In short, it’s a modern classic of a high-octane rocker, and a still a rival for any screaming new pretender.
Soldano Super Lead Overdrive
This article originally appeared in VG July 2011 issue. All copyrights are by the author and Vintage Guitar magazine. Unauthorized replication or use is strictly prohibited.