Vintage Bench Test: 1967 Marshall Super Bass

Despite the name, many guitarists still regard the 100-watt Marshall Super Bass as an old-fashioned Plexi sound. We look at this very early example and find out why... 

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Bassman is

The design of the amplifier, but in terms of its sound and circuit structure, quickly developed into its own product. Compared with Fender Bassman, Marshall's bass amplifier can be said to be the most popular in the hands of Class A bass –

,

with

Always a fan-but super bass has always been respected by guitarists.

This super bass-using its full name JMP 1992 Super Bass 100-is a very early example, provided by Vintage Tone Factory, a boutique guitar recording studio specializing in remote accent processing. It can be found in the following ways

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Dating accurately back to the 1960s, Marshalls may have problems because there was no consistent serial number system before July 1969. Instead, we must look at the function of the amplifier for clues. The word "SB" is printed on the back of the case-it means there is no prize for the Super Bass puzzle-and the number after it is very similar to other Super Bass examples of the 1967 model we found.

Marshall's earliest 100-watt woofer was the JTM 45/100 model, with a white rear panel with "Super 100 Amplifier" and the word "bass" next to the speaker impedance selector. By 1967, there was a black JTM logo on the front panel, and the gold Plexi rear panel was decorated with'Super Bass 100'. The model name was quickly changed to JMP, with black letters on the front panel, but Super Bass 100 was retained.

At the end of 1967, Marshall also transitioned from aluminum to steel chassis. The chassis must be made of aluminum. Large rubber cabinet feet replaced the smaller gray feet in 1969. Even though the amplifier feet are modern, gray residues can still be seen when the smaller original feet are removed.

You can gather more clues by looking at the circuit. The earliest JMP Super Bass model inherited the larger power board of the JTM 45 Super 100. The JTM rectifier diode is located in the center between the eight side-mounted 32mF RS filter capacitors. Before changing the model name to JMP, Marshall then moved the diode closer to the power transformer. All evidence indicates that the amplifier was manufactured in 1967 and is almost certainly one of the earliest JMP Super Bass 100 amplifiers manufactured by Marshall.

Although the original handle, black Tolex and gold piping remained in good condition during use, the rear panel was lost. Having one that can provide some physical protection for the valve, but these amplifiers will operate at high temperatures and remain open in a home or recording studio environment may be advantageous.

Over the years, there has been relatively little work on the circuit board, but because Marshall will do its best to determine which components to replace, it is difficult to identify. Almost all carbon film resistors appear to be original, not the legendary "Mustard" signal capacitor. The amplifier has a gray RS type and appears to be installed at the factory. Two of the filter covers, the two signal covers and the cathode bias cover of V1 are replaceable, and one of the speaker output jacks has been changed, but other than that, the amplifier is surprisingly original.

why do you like it

Choose to use super bass instead of super protagonist? Super bass enthusiasts will undoubtedly mention less aggressiveness, a warmer tone and a more pedal-friendly front end.

Therefore, Super Bass has attracted some followers, but the difference between Super Lead and Super Bass is only a few components. It's relatively simple to convert the super protagonist to super bass and vice versa.

Broadly speaking, the difference is as follows: the cathode of the first preamp tube of the super bass shares a cathode bias resistor and capacitor, while the V1 cathode of the super lead has its own. Throughout the circuit, a 500pF bright capacitor is connected to the Super Lead's volume control control, and there are some smaller component value differences in the pitch stack-especially the 500pF capacitor on the tweeter control instead of 250pF. Finally, the signal cap that couples the inverter board of the super bass to its power valve is 0.1uF instead of 0.022uF, which will allow more low frequency components to pass.

These amplifiers were made in an era before there was no volume limitation or the cause of long-term hearing loss was widely understood. Super bass is a dangerous amplifier because it sounds so sweet that you may not notice its real loudness until your ears start to close. In a few minutes of testing, our ears have been telling us it's time to connect the attenuator.

Context is everything. When bands played in stadiums and music festivals in the late 1960s, PA system guitar amplifiers were usually not used to enhance the sound. An amplifier with this capability was a necessity, not a luxury. The good news is that today's players benefit from countless attenuation and speaker simulation solutions that can tame these beasts even in the case of home recording.

Such a high output power means a lot of net headroom, and Super Bass's versatility and powerful tone shaping make it an excellent clear and full pedal platform. Use jumpers between the lower left and upper right inputs to link the channels together, increasing versatility; mixing in some of the two channels can enhance bass and mid-bass, especially useful when combined with single coil guitars .

The volume gradually increased until there was a sudden rush, and the potential growl became a growl. Even in the case of attenuation, the sound of overspeed driving sounds loud, and through a set of PAF buzzing, sustain and harmonic flooding becomes crazy.

But the most impressive feature is the dynamic response. The first amplifier owned by the reporter was the 1972 Super Lead. The transient effects were so sharp that it was painful and daunting to play. The reason why the super bass is so is because despite the solid-state correction, it always has a sense of responsiveness and natural compression in music.

If the aggressiveness of the upper mid-range, the trembling treble and the relentless dynamics spoil the wide-range Marshall experience for you, then the super bass will make you reconsider. Hendrix-y polished, the blues rock crunch of the 1960s, the classic hard rock...super bass can do it.

As long as you are strong enough to lift one, modern technology can make high-power amplifiers a viable option for performances and recordings again. This stunning amp is the best old-fashioned Marshall we have ever played, and it makes our favorite low-power amp like a toy. Sometimes, more is more.

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