Marshall 1974X User Manual

ENGLISH

From the Chairman

Congratulations on your purchase of this handwired
re-issue of the model 1974 18 Watt, all-valve 1x12"
guitar combo. The original versions of this wonderful
sounding amplifier were produced between the years
1966 and 1968 and are now extremely rare and much
sought after. This authentic re-issue of the 1974 is part
of an ongoing series, which will feature revered
handwired products from Marshall’s history. The reason I
have decided to do this is simple – public demand!

One of the things I love doing most is meeting and talking to Marshall users at the many trade
shows, music fairs and shop appearances I do all over the world every year. A subject that almost
always seems to come up in conversation at such events is hand-wiring. In fact, over the past few
years so many people have asked me to please start building handwired re-issue products that I’ve
lost count! One of the most requested vintage Marshall amps to appear in such a guise is the model
1974X combo you’ve just bought – hence its inclusion as one of our first handwired re-issues.

Like a great many vintage Marshall guitar amplifiers, the1974X is relatively simple in terms of
controls, features and circuitry, but sounds and feels fantastic. To recreate the tone and feel of the
original 1974, as well as its eye-catching good looks, my team of designers have gone to enormous
lengths to seek out and/or reproduce all of the original components and materials, plus revisit the
original methods of construction we used back in the mid 1960s. From the handwired, tag-board
circuit housed in an aluminium chassis, to the exclusively re-issued and specially ‘aged’ Celestion 20
Watt speaker, I am extremely proud of the incredible accuracy and authenticity of this re-issue.

I sincerely hope that this handwired piece of Marshall history will provide you with countless hours of
playing pleasure.

Yours Sincerely,

ENGLISH

Introduction

Overview: Tone and Tech Talk

The 1974X is an all-valve, 18 Watt, two-channel,
1x12" combo with valve driven tremolo and no
negative feedback in its cathode-biased output
stage. When building this handwired re-issue our
goal was both obvious and simple: to make it as
close as possible to the original.

As Jim has already pointed out, we went to
incredible lengths to achieve maximum
authenticity in terms of components, circuitry,
constructional methods, materials,
specifications, aesthetics, signal path, performance,
tonal characteristics and feel. We are delighted to report that our suppliers were equally as exacting in their
tasks – none more so than Dagnall Transformers and Celestion Speakers.

As you can see from its top panel layout, the 1974X is an extremely straightforward amplifier. Channel 1 (the
non-tremolo channel) only boasts two, self-explanatory controls: Volume and Tone; while Channel 2, the
Tremolo Channel, boasts four – namely Volume and Tone, plus Speed and Intensity for the valve driven
tremolo circuit.

Like all Marshall valve amplifiers, the 1974X sounds truly majestic when turned up full – and because of its
relatively low wattage this can be done at ear friendly volumes, making it a wonderful recording tool. In
keeping with bigger, non-master-volume, all-valve, Marshall amplifiers such as the 1962 ‘Bluesbreaker’
combo and the legendary 100 Watt ‘Plexi’ head, the 1974X’s sweetly distorted, harmonically rich, thick,
musical tones result from the power valves being overdriven. Our proprietary, re-issued and ‘aged’20 Watt
Celestion speaker contributes to the combo’s unique, punchy yet smooth sound as well. As a result, when
‘cranked’ the 1974X is incredibly touch-sensitive, cleaning up or, if desired, sitting right on the edge of
distortion when the guitar’s volume is turned down. It responds well to picking dynamics too, ‘sagging’ nicely
when you play like you really mean it and, once again, cleaning up as you pull back on your picking attack.

There now follows some information regarding the inner workings and build of the 1974X.

Valve complement: Three ECC83s (12AX7s) in the pre-amp, a EZ81 rectifier and a pair of EL84

power valves working in push-pull. All valves are of the highest quality available and go through a meticulous
grading and testing process.

The way the three ECC83s (V1, V2 & V3) in the pre-amp are utilised is as follows:
V1 is dedicated to Channel 1, the non-tremolo channel. As Channel 1’s pre-amp has a single gain stage,
each half of the valve (the ECC83 being a dual-triode) acts as a dedicated gain stage for the channel’s two
inputs (which are identical). V2 acts as the amplifier’s phase-splitter. V3 is dedicated to Channel 2, the
Tremolo channel. To be precise, one half of the ECC83 acts as the single pre-amp gain stage for the
channel’s two inputs (High and Low) while the other half acts as the oscillator for the amp’s tremolo circuit.

Due to the fact that the EZ81 rectifier valve and also the pair of EL84 output valves attain extremely high
temperatures when the amplifier is in use, their bases are made from the highest grade ceramic available.

Important Note: In order to comply with the strict safety requirements of modern legislation, the 1974X’s
valves have been housed in a removable, vented aluminium cage. This is obviously a deviation from the
original spec. but has no tonal or performance impact on the amplifier what-so-ever.

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