The Plus versions have had very big changes: 3 position bright cap switch w/2 different caps which influence the sound immensely, new capacitors in the signal path, NOS pre amp tubes and much more.

The JTM 66 strongly reminds of the Marshall JTM 45 from 1966, its strengths are clearly in blues-rock! Equipped with a classic ECC83 pre-amp and as standard with all Gladius amps the Variac power reduction from 0,01 to 30Watts! Only the world's very best output & power transformers (aged) and state of the art tubes are applied! An indispensable extra feature is the internal Channel-Patch, switching both channels (Treble & Normal). Similar to the JTM 65, the KT 66 is used, albeit with more gain, which of course meets the requirements of blues-rock players. The guitarist who thinks the JTM 65 sounds too nice, or the JTM 67 sounds too rocky, will be very pleased with the ultimate Marshall Sound of the JTM 66!

The Rhythm-Lead function (clearly visible through different colors from the Pilot-Light) together with the two different inputs, creates 4 different sounds in one unit which can easily be switched.

Lead-Channel:

As the name already suggests, in this setting the complete Vintage-Sound up to 1966 is covered. Extreme fat, round and 'smacky' in response with a lot of dynamics in the tone. The perfect Blues or Rock sound! Always defined but inclusive of all Vintage-Elements that are so important to create the right distortion.

Rhythm-Channel:

With this setting you will get a clean and stable tone, without the - partially lively - Vintage-Character. Explosive quick in response, without sounding aggressively or too harsh. Fat and round like the Allman Brothers or Peter Green. 

The Gladius story began with further developments of Plexi Style Marshall amps from the late 60's. It was quickly recognized that a power reduction is absolutely necessary for today's customers. In order to be able to do without the unloved master volume, Gladius specialized in the development of a self-developed VARIAC system, which comes close to the sound of a voltage-reduced amp. The Mark II was born. The Mark III then got a rhythm and lead switch, which simulates the characteristics of a 50 watt and a 100 watt Plexis (Except the JTM 65). However, this was too much of the organic crunch for many customers and they also wanted a lossless master volume. Here Gladius decided on the PPIMV modified by Ken Fisher (Trainwreck), which enables the sound to be played at room volume without the loss of dynamics and without loss of gain. The development continued, however, because many customers wanted a more mid-oriented tone that could assert itself better than the Plexi tone even in the most fragile mixes. By changing many little things, the Mark IV was brought to life, which is also clearly more rocky in the JTM 67 and JTM 68. As the last big challenge, Gladius has dedicated himself to the topic "Bright Cap". The internet is full of comments on this topic, what one loves, another hates. One thing is certain, the topic of bright caps is very sensitive, because the sound characteristics change fundamentally. So Gladius has integrated a 3 Way Bright Switch into their now available MKIV PLUS models. This means that the middle position has the previously low Bright Cap, while position 2 has an extremely high value that sounds very, very rocky. Position 1 has the most treble and has a medium value, which can be described very nicely with the sound of AC/DC. Bone dry, very tight and very cranky in attack. Why the name Plus was chosen is obvious. The amp has received more updates than ever before in the history of Gladius JTM's. In addition to the bright caps, there were completely new capacitors in the signal path. Thanks also to the people at Tube Amp Doctor who developed the new Red Base Pre- and Power-tubes, which come very, very close to the sound of old tubes. So now a JTM's over the wide range from classic Plexi tone late 60's to modern JCM 800. There are no amps on the market that are as flexible as the Gladius JTM's without the well-known signal losses. That's Rock'n'Roll Ladies & Gent's.