Guitar Center recently ran a 10% off used gear coupon for Memorial Day so I perused the listings and spotted this very nicely priced Hot Rod. Even from GC’s notoriously poor pictures, I could tell this was going to be a unique piece, with two additional knobs on the front panel and a clearly visible 6V6 tube in the rear. Sometimes mods like this can be risky, and I never want to end up with someone else’s “rat’s nest” problem, but I figured this was worth a shot.
Well, there’s some good news and some bad. I’ll start with the background: This is an early Hot Rod 50+, probably from somewhere around 1997. The first HR50+’s came out in 1995 and ran until 2006. Post 2006 HR50+’s are easy to identify as they have a factory Depth knob and lack the Slave Out 1/4 jack on the rear panel. There is also the non-plus Hot Rod, which came out as early as 1992 and lasted until the Plus changes around 2006, but finding earlier models is much more common than later ones, likely because the non-plus Hot Rod’s didn’t sell that well once the Plus came out. Very early Hot Rods such as this one came with Schumacher transformers (just like Mesa Rectos!), but later ones like my example from 2004 switched to Mercury Magnetics.
This beauty comes wrapped in a snakeskin headshell which is definitely a cool look, although I sold my snakeskin Kramer Baretta already - too bad, that would’ve been a nice pairing. All of the knobs go up to 11, except for the controls added by the mod. It’s a 2-channel amp, the first channel is called “Normal” and the second is “Overdrive,” and the only way to use both channels is via footswitch.
The Normal channel is not really a clean channel, although you can kind of dial it that way. It lacks headroom and gets pretty crunchy even with the gain around half, and is roughly equivalent in gain to a single channel JCM800 with the gain maxed out, but voiced differently of course. It uses different values, but the basic structure is very similar - 3 gain stages, cathode follower driving the tone stack, but with a tube-buffered effects loop crammed in before the EQ controls. This is somewhat similar to a Marshall 2555 Silver Jubilee, which also has the effects loop before the EQ - and odd choice that some people don’t like, as it can cause level issues. It also means your effects get a louder, raw non-EQ’d guitar tone, and then your amp’s tone controls have an impact on the sound coming from your effects. In contrast, the more standard effects loop design is located after the EQ but before the master volume (or phase inverter), so your effects pedals would see a signal that has already been through the amp’s EQ.
The Overdrive channel shares some of its signal path with Normal, but with the addition of another gain stage which is the famous “cold clipper.” For perspective, the JCM800 2203 also uses a cold gain stage in the 2nd stage (out of 3), but Soldano’s design uses a much more aggressive cold clipper as the 3rd stage out of 4, excluding buffers and cathode followers (note: Bogner Ecstasy Red also does this). This Overdrive channel’s bones are extremely similar to the flagship SLO100 model, but with a handful of different voicing values.
Now on to the mods. So far there are two notable ones, the most obvious being the addition of an Accutronics long-spring reverb tank. This mod adds reverb to the amp, obviously, but the implementation is the most unique I’ve seen in any amp, and it’s the kind of mod I dreamed of doing at various times to other amps as a lover of great reverbs. Basically, this is done in the style of a Fender outboard reverb tank, like the Fender ‘63 Reverb RI. That includes the addition of a single 6V6 power tube and another 12AX7 to drive the reverb signal. The original Fender outboard units used a 12AT7 and a second 12AX7 buffer, but this design isn’t an exact duplicate of the Fender circuit, and the amp already has a tube buffer for the effects loop (which this reverb uses half of). The addition of these two tubes did require the power tube sockets to be moved over to the side and additional holes drilled in the chassis, which you can see in the picture below:
There’s also a transformer mounted to the top of the chassis as well as the standard RCA send/return jacks for the spring tank. Internally, the Schumacher choke was also moved to the side to make room. All of the reverb circuitry is mounted to terminal strips, no PCB’s, and it’s even footswitchable with a 1/4 jack on the rear panel. Also on the rear panel is a “drive” control, this is essentially the “dwell” control on a Fender outboard unit and controls the length of the reverb decay. On the front panel, there are two additional controls added, labeled “level” and “tone.” Level is essentially the mix control, how much reverb signal you hear compared to the unaffected signal, and tone is a very useful control that can be used to dial in just how bright the reverb sounds. The tone turned up high results in a very present reverb sound, extremely clear but maybe a little distracting at higher dwell/mix levels. Many digital reverb pedals allow you to set a Hz or KHz taper where the treble is rolled off, same thing here with the analog circuit, and you can roll that off as much as you need to. It’s very flexible and sounds absolutely fantastic.
I’d also like to give a special thanks to my friend Micha, who traced this reverb circuit out for me. It sends just after the effects loop send buffer tube stage, and returns after the EQ just before the phase inverter. Our best guess is that this mod was done in 2001. Now the bad news, as he pointed out to me, it looks like there is a little troubleshooting to be done here as there is a bad cap and clearly burnt resistor as part of this circuit (pictured below). The work never ends!
There is another mod on this amp, which you can barely see in the above picture at the top left, a yellow capacitor and piggy backed resistor. This is a “depth” mod, but instead of a pot to allow adjustments, it is a fixed value. I suppose I’d prefer a knob to turn but I really can’t complain with this value as it sounds great. I did quite a bit of A/B testing between this amp, my 2004 Hot Rod Plus, and my 2004 Avenger. This Hot Rod is much thicker and fuller sounding than my 2004 model, maybe a hair less cutting in the high mids, but overall a bit more pleasing sound to my ear. The Avenger is very similar sounding to this, as that amp has a depth control already, so it can be dialed to be very close. I think the two channels and the very flexible reverb give this amp the edge though, so I suppose this is now my favorite Soldano amp of the three.
