Soldano Hot Rod 100 Plus

Mike Soldano is the definitive “hot-rod” guitar amp builder, and still one of the biggest names in the boutique amp game after 30 years. After a few tough years of modifying Fender Bassmans, Marshalls, repairing amps, and painstaking prototyping, he found his original design – the SLO – thrust into the backlines of Eric Clapton, Lou Reed and Steve Lukather; to name just three. His basic principle seemed to be very simple: he wanted to embody the sound of a non-master volume Marshall stack running at full tilt, mic’d up, processed and compressed in a top studio. The key was to produce the sound he heard on the early Van Halen records, but without the need for high volume, modifications or studio enhancement. He simply captured the sound 1980s rock guitarists heard in their head, and make it available to them in one relatively simple box that looked and felt the part. His amplifiers, without exception, blend the extrovert style of a hot-rodded car with the exquisite precision and class of a Rolex. Somehow they capture both of these seemingly mutually exclusive concepts and proceed to tie them together in a package that would make a Messerschmitt look under-engineered. The flagship Super Lead Overdrive head uses military spec components, a powder-coated steel chassis and a custom-wound DeYoung output transformer. Even the cabinets are made from marine-grade Russian birch ply.

Soldano Hot Rod 100 Plus
Soldano Hot Rod 100 Plus

What’s particularly astounding about the Soldano company is not just its meteoric rise to fame (by the end of the 1980s Mike’s amps had also featured on recordings by Eddie Van Halen, Warren DeMartini; and even the late Stevie Ray Vaughan had ordered a custom SLO). Nor is it the incredible number of genres Soldanos have been applied to (Warren Haynes, Mark Knopfler and the late Gary Moore being notorious Soldano players too). Nor is it the ridiculous number of hit records that contain the Soldano overdrive sound; or the ever-growing number of digital simulators and other amp brands who attempt to re-package it.

Soldano Hot Rod 100 Plus rear
Rear panel and FX loop

No; the most impressive thing is that despite being (along with the Marshall JCM 800) probably the most definitive distorted guitar sound of the 80s, the SLO has not been significantly altered, cosmetically or internally, for 30 years. What other 1980s product can claim to have been so supremely relevant, unfalteringly stylish, and supernaturally cool for so long? Sure, BMW’s E30 3 series has been a incredibly enduring car design; but try driving one on a wet road, or carrying adult passengers in the rear seat. Marshall have re-issued the JCM 800 2203 model several times; but there was a substantial period just over a decade ago when the originals routinely fetched a ridiculous £350-£400 on the UK second-hand market. By contrast, Mike’s design was so timeless, so complete, and so utterly unassailable at everything it set out to do that it has remained the industry standard in high-gain guitar amplification since its inception. Other industry standards such as the Mesa/Boogie Dual Rectifier and the various 5150 amps have re-packaged and tweaked the SLO’s Overdrive circuit with huge success; but instead of making the SLO seem obsolete or overpriced, this merely added to its “halo effect”. Remember at this point that the SLO was Mike Soldano’s first amp design. His second complete build went to Howard Leese of Heart!

Soldano Hot Rod 100 Plus - output transformer
Mercury Magnetics output transformer

So, the problem with succeeding relatively early in your career is this: where do you go from there? Soldano wisely decided to leave the SLO’s basic design alone – offering only a few optional factory mods. Instead they set about cleverly expanding the range downwards from the crowning glory of the SLO. Small amps, clean amps, bluesy combos, single-channel amps, multi-channel monsters; Soldano have covered it all. One of the most enduring of the alternative models has been the “poor man’s SLO”: the Hot Rod series. The early Hot Rod 50 was one of Gary Moore’s favourite amps, and it’s achieved almost legendary status in its own right. The Hot Rods, in essence, offer the look and feel of an SLO, with a slightly darker, almost indiscernably gentler version of its famous lead channel (these things are relative: the HRs sound a long way from polite). They manage to retain one hundred percent of its workmanship and tonal quality by downgrading from military spec components to extremely robust off-the-shelf alternatives. The custom DeYoung output transformer is gone; replaced by a highly effective Mercury Magnetics transformer (Mercury Magnetics supply transformers for Bogner, Egnater, and all kinds of “boutique” amp makers). By anybody else’s standards, the non-SLO Soldanos are built almost laughably well, and still come with a lifetime warranty for the original owner. A lifetime warranty – in the modern age of planned obsolescence. Mike Soldano’s idea of a mid-priced amplifier is perhaps a little different than most!

The channel-switchable Hot Rod 50+ and 100+ essentially offer the Normal and Overdrive channels of the SLO in a simpler package with no mini-switches; and in the case of the early models, no custom modifications. The Hot Rod is simply a distilled rock guitar amplifier; offering the discerning rock guitarist everything he needs and nothing he doesn’t. No clean mode, then!

Soldano Hot Rod 100 Plus - chassis

The Normal channel of the Hot Rods betrays the SLO’s Fender Bassman origins. It simply removes the first gain stage from the circuit for a sound that spanks, clanks, growls and grinds with the best of them. It’s hyper-responsive to pickup selection, playing dynamics and any front-end pedals you can throw at it. This is a remarkably simple circuit, not too far removed from a 1959 Marshall and it feels it. The bottom end can shake the walls on big power chords, yet the treble glistens with a good Strat or Tele. For years I searched for the right sound for Van Halen’s Can’t Stop Loving You and Pleasure Dome; this is it.

Soldano Hot Rod 100 Plus - rear view
Rear view

The Overdrive channel is essentially one or two components removed from an SLO. The Gain control is 1 megaohm rather than 500k, which reduces gain and high end a little bit, and the fourth gain stage is massaged very slightly. The net result is a channel that’s perfectly suited to 1980s or early 1990s hard rock. Like the SLO, it’s a distortion sound that’s difficult to put into words. It manages to combine the focused bottom-end punch, sustain and string-to-string definition of a modern circuit with vintage dynamics that very nearly take your head off. Single note lines have a rounded warmth, yet palm mute the low strings and you’re rewarded with a tight chunk reminiscent of Giant or early ’90s Megadeth. With the optional XL mod or Depth control (more on this later), the lows can get big and rumbly enough for modern metal; yet the snarling, aggressive pick dynamics remain. I have a Peavey 5150 here for comparison, and while its gain structure stays tighter for longer and its lows firmer under pressure, the Soldano circuit makes the 5150 seem very one dimensional and rather fizzy. I’ll add here that the 5150 circuit is still my all-time favourite one-box solution for recording modern metal: but boost the HR with the right pedal and all of this is available too.

Soldano Hot Rod 100 Plus - Sovtek 5881 tubes
Sovtek 5881 tubes

The Hot Rod’s Overdrive channel is most at home doing exactly what it was designed for. It offers a slightly (and I stress, slightly) warmer and furrier version of the SLO’s definitive lead tone. The Hot Rod series is extremely closely related to the rare SL60 used on Extreme’s “III Sides to Every Story” and that really is the sound it produces. It’s a rhythm guitar sound designed to turn heads, and a lead guitar sound designed to slice them off. Being a little lower in gain than the SLO, the Overdrive channel also crosses over into more organic Marshally textures a shade more effectively than its hi-def big brother. Again, we are splitting hairs – most players prefer the SLO but as a rock ‘n’ roll tool the Hot Rod series (like the “other” SLO the Avenger) has a smaller band of extremely dedicated supporters. It offers 95% of the flagship’s lead sound along with a hint of raw, organic character all of its own. When I bought it, I expected a cheaper, simpler SLO – but what I got was far more interesting and versatile than that.

Soldano Hot Rod 100 Plus - circuit board
Circuit board

A note here about the infamous “depth mod” debate. Mike Soldano incorporated a fixed Depth mod into the Hot Rod series in order to keep pace in the Nu-Metal musical landscape of the late 1990s and early 2000s. This amounted to an extra cap and resistor combo in the negative feedback circuit of the power amp and was labelled the “XL” mod. Like Nu-Metal, it went out of fashion as quickly as it came in. Mike Soldano himself doesn’t like the XL mod and now fits the HR series with a variable Depth control instead. Some users feel the XL mod (which is effectively a Depth control set to 11) robs the amp of some mid-range definition and reduces pick attack. Always the tinkerer, I pulled my Hot Rod to bits and tried it with and without the XL mod (do this at your own risk, kids, this amp contains upwards of 500 volts in parts of the circuit if the caps are undrained!). Now, I’m a 2×12″ guy, and for me, it turns out the XL mod is more or less compulsory. The amp simply didn’t keep pace with the low end offered by my Cornford without it. Perhaps there was a sliver of extra midrange definition or string response, but I wasn’t convinced. It was just as easy, in fact, to re-install the XL mod and roll back the Bass control for a clearer midrange. Perhaps the results would have been different with a 4×12″ cabinet, and perhaps I’m not the typical player, but I’m leaving the “mod” in. In any case; this is now a moot point as the newer HR amps come with the variable Depth control, which as far as I can gather is a bit more straightfoward in use than waving a hot soldering iron at a potentially lethal circuit.

Soldano Hot Rod 100 Plus - XL mod
XL mod

The internet’s perennial criticism of Soldano designs has always been the effects loop. The SLO’s (and by extension, the HR’s) loop is designed to provide the hotter signal levels that a high-end processor likes to see. It’s easily modded and, again, the latest HR amps have a more pedal-friendly design. These days, many pedals are designed to accept higher level signals; and the performance of high-end rack processors has now filtered down to reasonably priced floor equipment like TC Electronic’s Nova System. In any case, I was unable to discern any “tone suck” with the Nova System or my bigger G System board. In terms of tonal consistency, the loop behaved just as well as the excellent loops on my Cornford and my old EVH amps. Where the traditional Soldano loop does fall down is that it’s awkwardly placed before the tone stack and its associated make-up gain stages. This means that the sound of your time-based effects can be affected by the position of your tone controls, and the discerning schmo fanatic might detect that their delay repeats are not as distinct as they are used to hearing. Unfortunately the Soldano effects loop is not perfect; but it’s better than most mid-80s designs and can’t be moved without changing the feel of the amplifier. Most of the huge rack guys, in any case, are using their high-end delay units as part of a complex slaved wet-dry-wet system with a line mixer for effects, so won’t be affected by the vagaries of the Soldano loop. In any case, it has turned out to be more than adequate for my purposes; I don’t use much delay and I’m mostly concerned with tone preservation. In this discipline the charmingly rustic Soldano loop performed surprisingly well for me.

Soldano Hot Rod 100 Plus
Soldano Hot Rod 100 Plus – Revised cosmetics and Depth control

To sum up; what is a hot rod? It’s generally a car that’s been custom modified to offer more performance and personalised style than its stock counterpart. In this case it’s a simple rock ‘n’ roll amplifier with the soul of an old Marshall, the build quality of a bank vault, and the high performance of – well – a Soldano. Once again, Soldano Custom Amplification set, followed and completely fulfilled their own brief; an engineering beacon in our disposable post-modern landscape. Now, to replace my obsolete two-and-a-half year old iPhone.

Published by DON STICK | GUITAR

Online session guitarist; supplying high quality bespoke guitar parts for your mix.

10 thoughts on “REVIEW – SOLDANO HOT ROD 100 PLUS

  1. Hi Don,
    Very interesting review. I have used Koch amps for a very long time but i recently bought a five year old HR50+. In find it hard to get the right sound (using a prs). What are your settings?
    Musical regards, Gerwin (Holland)


    1. Eventually I took the XL mod out. Then I found it easy to get the right sound with everything at 6! I could crank Bass to 10 if I wanted and no flub. Gain at 6 too, it gets flubby if you any higher – I’d use a boost instead for metal. With Gain at 6 I could get the perfect SRV sound when switching back to the Normal channel. Great amp 🙂


  2. Hello there. I would like to move the loop. Of my hot rod 50 after the master volume. My delay just sounds drowned in it. It just sucks, it’s a strymon and its. Not using its full potential.

    I took it to a local tech,he did it and added a second master level as he installed a preamp and a new valve to amplify the fx loop but I do need. To. Find the right mix for master volume of the amp and the second one. Is there a easier way to do this? Where can I find the shcmeaics for this mod? Thanks a lot.


  3. I recently acquired a late 90’s Hot Rod 100+. I have been a JCM800 user for years, and thought I was done searching amps. Mine is a 1982 2204, and it has a tone that is amazing.But I saw the Soldano used for a decent price, and went ahead and gave it a shot, simply because of Soldano’s reputation of excellence. I am NOT disappointed! It is a wonderful amp, with a high gain tone that is crisp, harmonically rich, not fuzzy at all, string definition is great, and it has the immediate attack like my JCM800. Another winning factor is that the amplifier is a completely different animal than my JCM800, so I did not buy a redundant amplifier. It IS kind of like a JCM800 with a Tube Screamer or Klon in front, but still has a different harmonic structure. I feel guilty lately, because my JCM800 has been collecting dust on the tubes, due to my choosing the Hot Rod 100+ over the JCM800. I love this amp.

    Liked by 1 person

  4. Ah you got to also point this.

    The single channel hot rods which were then named avengers are different to the hot rod + which follow the SLO preamp.

    Not wildly different, But different enough to have a less compressed and less smoothed out tone and less gain.

    First of all a tube is missing and with the rest of them only a distortion channel is realized and on the versions with no loop, half a tube was unused. In the versions with a loop the half tube became another gain stage (so different yet again) and fed the loop with a way that it was lower signal (but still not so pedal friendly) and high impedance (so hi end processors needed a buffer, what the missing tube does). No biggie as the loop still plays great with any effect with hi impedance and won’t overdrive it like the normal loop but you lose gain and compression vs the SLO and you have a bit less raw vs the hot rod no loop version.

    Then the power has a bit less filtration but this is not a bad thing I think…

    Another key difference is no vactrols. Meaning no switching system. The SLO clean/crunch channel bleeds into the lead all the time. It is drowned out the higher you play the amp (gain and volume) but it is there somewhat. Plus vactrols suck but mike won’t do relays to not lose mojo and the original design or whatever and this is not a bad thing again.

    Also two other companies made transformers for the non SLO amps. All good by the way.

    A hot rod 100+ can come very very close to the SLO and practically (for me) what is left to be different is the layout, super hum of the SLO and different transformers. Which on their own are reasons enough to hear differences. However not always in favor of the SLO.

    And military pots suck. They are sealed and when they start getting rusty and old you can’t do anything but change them. See what randall aiken says on the matter, I think he is right!!!


  5. Hi! Thank you for the review!
    I got a Cornford MK50mk2 that I love and never let go, but I’ve a thing for Soldano since I played a SLO for the first time. Since you have (had?) both, how do you compare them? I don’t want to end up buying a hot rod and not using it because of the Cornford. Also, how does the hot rod sound with V30s? I heard the SLO doesn’t pair well with them.
    Thank you!


    1. Hey man. SLO sounds great with V30s. Everyone just gets hung up on the Eminence BS. As for the other thing… I preferred the Cornford most days as it’s more sensitive and musical. But for a rock thing the Soldano just takes your head off, and the bluesy breakup on the Normal channel is to die for. The Cornford doesn’t really have an equivalent to that sound. I doubt you’d ever get bored with these two side by side!


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