The Catalinbread Dirty Little Secret Deluxe represents the next logical step in Marshall Plexi emulation, reaching beyond the preamp circuit and adding the rest of the amp for an extremely authentic take on everything inside that chassis.

Upgraded Version

Catalinbread’s original DLS circuit has been tweaked and upgraded throughout. It now features a phase inverter, power amp sim, and output transformer, as well as some new features and the most requested modifications for the original. One such addition is a toggle switch on the outside to select between Super Lead and Super Bass modes, and Catalinbread also externalized the Presence knob to easily dial in your preferred Marshall flavor. Also added is a piece of the Dirty Little Secret—a single preamp tube simulator—as a built-in boost circuit that can be used independently of the main circuit. You can run the boost and DLS in any order you like; put the boost before the DLS for a high-powered, saturated tone or after to pummel the front end of your amp. A new tightness knob lets you shave off the sub-bass for a little extra clarity or completely attenuate the low end for some cool thrash metal tones. A line-out jack gives you a dedicated +10dB output that you can use with a mixer or DAW, and you can use both outputs simultaneously. Between the Boost, order selector, and the external Super Lead/Super Bass modes, the Dirty Little Secret Deluxe is engineered to be a total performance tool that does the line justice.

Master

A descriptor that’s normally a formality, this knob occurs before the phase inverter and output transformer rather than at the end of the circuit, just like a real amp. Catalinbread designed the output stage to be more impervious to input saturation than most power sections, so really cranking it doesn’t alter the tone in an extremely noticeable way. However, those that plan to use the DLS DLX as an always-on can find some subtle sag and gentle compression living within the whole of the volume knob.

Preamp

Catalinbread has taken the original preamp control and tweaked it to deliver a wider gain range with more cleans on the lower end and more cranked Marshall tones on the higher end.

Presence

Formerly an internal trimmer on the original, the Presence control is a powerful low-pass filter that attenuates frequencies by 3dB above 1.59KHz when turned all the way down, and the cutoff point climbs to an indistinguishable frequency by the end of the turn.

Boost

The boost circuit is actually one of the tube emulation building blocks that make up the DLS itself. When you run the boost before the Dirty Little Secret, it acts as another ‘preamp tube’ added to the front end of the device for some saturated JCM900 tones. When run after, it makes everything louder without sacrificing clarity.

Boost Vol

The boost circuit is actually one of the tube emulation building blocks that make up the DLS itself. When you run the boost before the Dirty Little Secret, it acts as another ‘preamp tube’ added to the front end of the device for some saturated JCM900 tones. When run after, it makes everything louder without sacrificing clarity. This knob is a volume control for the Boost side, so at lower points in the knob’s turn, the boost signal can get below unity gain. This helps you dial in maximum tone shaping for combining the two effects.

Tightness

Depending on the kind of music you’re playing, you may expect a certain ‘tightness’ from your amp. In real terms, what is called ‘tightness’ is in reality bass attenuation via a subtle high pass filter. This particular high-pass filter is designed to cut nothing audible when turned down and cuts up to ~230Hz at maximum for a full bass cut extending into low mids.