Marshall MHZ15 2 Channel 15 Watt Guitar Amp Head Owner’s Manual

AMPLIFICATION MHZ15 & MHZ40C
Owners Manual

MHZ15 2 Channel 15 Watt Guitar Amp Head

From Jim Marshall

I would like to take this opportunity to personally congratulate you on choosing this Haze amplifier from Marshall.
As a musician myself I fully understand the thrill and enjoyment of playing live music – whether that be on a stage to thousands, or in the bedroom to yourself – there’s nothing quite like it. I also appreciate the need for high quality equipment that not only delivers the sound you’re looking for, but that also has the dynamic play-ability and feature set that separates a good amp from a truly fantastic one.
With these ideals firmly in mind, I set the Marshall team the challenge of turning them into a range of all-valve driven amplifiers that would be affordable, portable and look the part too. I must say I was delighted when they presented me with what has now become the Haze Series. Using the latest technology and good old fashioned craftsmanship, these amplifiers have squeezed pure Marshall tone, custom designed digital effects and innovative footswitching technology into both a compact 40W combo and 15W Ministack.
Perfect for either the gigging musician or those seeking their very own valve Marshall stack at home.
As with all Marshall products, the Haze Series undergoes stringent quality control checks throughout its meticulous construction, ensuring that the end result is fit for purpose and continues the high standards expected of a Marshall amplifier.
Whether this is your first ever Marshall or the latest addition to your arsenal of amps, the versatility, response and tone of the Haze Series will only add to the guitar playing pleasure you’re no-doubt accustomed to.
I wish you every success with your new Marshall amplifier. Welcome to the family…
Yours Sincerely,

Overview

Presenting the Haze series – 40 Watt combo and 15 Watt head. Developed and engineered in the UK, these two channel valve amplifiers, inspired by the British tones of the 60s and 70s, provides that classic Marshall roar with a modern edge.
The MHZ40C 40Watt combo offers a dedicated overdrive boost and series effects loop in a classic top loading 1×12″ combo loaded with a Celestion Marquee (G12-66) speaker – custom designed in partnership with Marshall.
The MHZ15 15 Watt head can be paired with the optional cabinets MHZ412A and MHZ412B to form a valve powered mini stack

The vintage voiced effects section stores its settings per channel for instant recall and provides a choice of classic echo, vibe or chorus alongside a reverb providing the warmth and transparency of a spring tank.
The reverb and effects are routed in parallel to the direct signal so that no degradation of the direct signal occurs. By turning the special reverb level and effects depth pots to minimum ‘past the click’ and bypassing the effects loop on the MHZ40C, the effect section is true bypassed, mechanically removing the circuit from the amplifier – leaving the Haze amps with an all-valve signal path.

The Basics

Mains Input & Fuse
Your amp is provided with a detachable mains (power) lead, which is connected on the rear panel. The specific mains input voltage rating that your amplifier has been built for is indicated on the back panel.
WARNING: Before going any further, make sure your amplifier is compatible with your electrical supply. If you have any doubt, please get help from a qualified technician – Your Marshall dealer can help you in this respect.
The correct value of mains fuse is specified on the rear panel of the amplifier. NEVER attempt to bypass the fuse or fit one of the incorrect value.

Getting Started & Powering Up

1. Make sure that the speakers/cabinet(s) are connected to the correct impedance LOUDSPEAKER jack(s) on the rear panel.
   See the Speaker Output guides in this handbook for specifics regarding impedance matching. When using an extension cabinet make sure that you’re using a proper speaker cable.
   Never use a screened (shielded) guitar cable for this purpose.
   WARNING! Failure to do any of the above will damage your amp.

2. Ensure that the two VOLUME controls on the front panel are set to zero.

3. Connect the supplied mains (power) lead into the MAINS INPUT on the rear panel first and then into an electrical outlet.

4. Plug your guitar into the INPUT jack socket on the front panel.

5. Turn the front panel POWER switch on. The switch’s LED will illuminate and then wait a couple of minutes.
   Haze 40 Only

6. After waiting, engage the STANDBY switch.
   STANDBY Switch (17)
   The Standby switch is used in conjunction with the Power Switch (18) to ‘warm up’ the valves in the amplifier before use and to mute the amplifier when required, such as when you are changing guitars. When powering up the amplifier we suggest engaging the Power Switch (18) first, leaving the Standby switch in the ‘OFF’ position for two minutes to allow the valves to heat up.
   When switching the amplifier off, always disengage the Standby Switch a couple of seconds prior to the main Power Switch.

7. Your amp is ready to play.

Haze 40 Watt combo front panel

1. Input Jack Socket
   Jack input for your guitar. You must always use a screened (shielded) guitar cable and never use an unscreened (unshielded) speaker cable. Also, this cable should be one of good quality. If you are in any doubt regarding this, your Marshall dealer will be more than happy to help and advise you.

2. Bright
   Pushing this switch ‘in’ enables the Bright function. This control works on both the Normal and Overdrive controls.
   On the Normal channel the Bright works in the traditional way, interacting with the Normal Volume control. At lower settings the Bright has an increased effect which lessens as the Normal Volume is increased.
   On the Overdrive channel it adds a little extra bite to the sound and works at all volumes.
   Normal Channel

3. Boost
   Pushing this switch ‘in’ enables the Boost function in the Normal channel.
   With the Boost off the sound remains cleaner for longer as the Volume control is increased providing a greater range of clean sounds.
   With the Boost selected, the channel turns into a classic Marshall Normal channel, starting clean with a thicker sound, overdriving the power amp sooner and bringing out that vintage Marshall non-master volume tone.

4. Volume Control
   This control adjusts the volume of the Normal Channel. At low levels the sound will be clean. As the volume control is increased, in true Marshall style, the power amplifier will start to overdrive giving a classic, controllable distortion which cleans up beautifully from the guitar’s volume control.

5. Channel Switch
   Selects between Normal (out) and Overdrive (in) channels.
   Note: When using the 2-way footswitch this front panel switch is disabled. When using the optional 4-way footswitch this switch operates in ‘catch up mode’ – This top panel switch must first match the current footswitch setting before it will have an effect.
   Overdrive Channel

6. Boost
   Pushing this switch ‘in’ enables the Boost function.
   With the Boost off the tone is a controlled, easy to play, dynamic sound with plenty of scope available to clean up the sound from the guitar volume control.
   At lower volume settings, the sound is very much the classic Marshall Master Volume sound. At higher volume settings, this channel is brilliant at overdriving the power amp for some truly inspiring tones.
   Enable the Boost for a big step up in gain taking an un-boosted rhythm sound into serious lead territory.
   HINT – At higher volumes you’ll find you will need less preamp gain as the power amp starts to overdrive. Experiment to find your favourite balance.
   Note: When using the optional 4-way footswitch this switch operates in ‘catch up mode’ – This top panel switch must first match the current footswitch setting before it will have an effect.

7. Gain
   Controls the level of signal entering the pre-amp. At lower settings the sound will be cleaner and the amount of distortion is more controllable from your guitar or your playing style. At higher settings, more distortion is available.

8. Volume
   Controls the amount of signal fed to the power amp. At lower settings, this will act as a volume control. At higher settings, it will control the amount of power amp distortion.
   EQ Section
   The treble, middle and bass controls form a traditional Marshall interactive EQ section – adjusting one control will affect how the others work.

9. Treble
   By adjusting the Treble control you can add or take away the higher frequencies in your guitar tone. By increasing the amount of treble you will make your tone brighter, ideal for more percussive playing styles.

10. Middle
    Adjusts the middle frequencies. Turning the control anticlockwise will yield a more hollow sound with the bass and treble frequencies appearing to be more accentuated. Turning it back clockwise increases the middle adding body to the sound.

11. Bass
    Turning the Bass control will affect the amount of low frequencies or bottom end in your guitar tone. Rotating this clockwise will increase the amount of lower tones generally making your bass sound deeper and is especially useful at lower volumes. Turning this control anti-clockwise will reduce the bass frequencies in your tone producing a more cutting tone – especially useful at higher volumes.

12. Presence
    This control emphasises the high frequencies in your tone.
    Turning this control up (clockwise), adds crispness and bite.
    Effects Section
    All effect and reverb settings are automatically stored in Normal, Overdrive and Overdrive Boost allowing you to set different effects and/or reverb levels in each of these three modes. Set a clean Normal sound with a lush chorus and a huge reverb, change to Overdrive and set a sparse reverb and a slap back echo and these sounds will be remembered each time you change channel.
    For this reason, the position of the effects controls will not always show the effects settings in use. If one of the controls is changed, the value will ‘jump’ to the control’s new position.
    The Reverb Level and Effects Depth controls use special controls that include switches that allow a part or all of the section to be globally disabled.
    Turn the Reverb Level to minimum ‘past the click’ and it will globally disable the reverb.
    Turn the Effect Depth to minimum ‘past the click’ and it will globally disable the effects.
    Turn both the Reverb and Effect Depth to minimum and the entire effects section will be globally disabled. If the effects loop is also turned off via the rear panel switch a further click will be heard from within the amplifier as the effect section is true bypassed mechanically removing the circuit from the amplifier – leaving an all-valve amplifier signal path.

13. Reverb Level
    This control sets the amount of signal sent to the reverb.
    Turning the control down ‘past the ‘click’ to off globally disables the reverb. However turning the control down to minimum ‘before the click’ turns the reverb off for the current channel only but does not globally disable the reverb.
    When using the optional 4-Way footcontroller its Reverb LED will turn off when the Reverb control is muted or turned to minimum. The reverb cannot be footswitched when the control is set to minimum or disabled.

14. Effect Depth
    This control sets the depth of the chorus and vibe or the level of the echo.
    Turning the control down ‘past the click’ to off globally disables the effects and the light on the effect switch will turn off.
    The effects cannot be footswitched while disabled.

15. Effects Adjust Control
    This control allows you to adjust the modulation speed of the Chorus and Vibe effects or the delay time of the Echo. As the delay time is decreased so are the number of repeats – creating long trailing echoes that reduce to short slap backs and further down to double tracking.
    When changing from a channel with Echo to one without, the effect will naturally spill between channels. When changing from a channel with Echo to a channel with Echo set to a different delay time, the delay effect will not spill between channels. The maximum delay time is 1 second.

16.   Effects
    Pressing this switch cycles between the 3 effects, Echo (green), Vibe (orange) Chorus (red) and Off (no light). When the effects are muted via the 2-way footswitch or optional 4-way footcontroller the light will slowly flash when the selected effect is muted.
    When using the optional 4-Way footcontroller its FX LED will turn off when the effects are muted or set to off.

17. Standby
    The Standby switch is used in conjunction with the Power Switch (18) to ‘warm up’ the amplifier before use and to mute the amplifier when required, such as when you are changing guitars. When powering up the amplifier we suggest engaging the Power Switch (18) first, leaving the Standby switch in the ‘OFF’ position for two minutes to allow the valves to heat up. When switching the amplifier off, always disengage the Standby Switch a couple of seconds prior to the main Power Switch.

18. Power Switch
    This is the On/Off switch for the mains electric power to the amplifier. The LED will light up when your amplifier is turned on and will not be lit when the amplifier is switched off.
    Note: Please ensure the amplifier is switched off and unplugged from the mains electricity supply whenever it is moved!

Haze 40 Watt combo rear panel

1. Mains Input Socket with Mains Fuse
   Your amp is provided with a detachable mains (power) lead, which is connected here on the rear panel – see ‘The Basics’ section at the start of this handbook for more information.

2. HT Fuse
   The correct value of this H.T. fuse is specified on the rear panel of the amplifier. NEVER attempt to bypass the fuse or fit one of the incorrect value!

3. Emulated Line Out Socket
   The amplifier’s output processed through a speaker cabinet emulator is made available at this connector. Use this socket to connect your amp directly to a PA mixer or recording equipment.

4. Speaker Outputs
   WARNING! Never use the amplifier without a load (speaker cabinet/s) attached!
   There are 2 speaker outputs available on the rear panel. They are labelled according to the intended impedances:
   16 Ohm: connect any 16 Ohms guitar cabinet to this jack.
   Also used for the internal speaker.
   8 Ohm: connect any 8 Ohms guitar cabinet to this jack.
   WARNING: Although there are 2 speaker outputs, never attempt to connect speakers to more than one socket at any time. The safe combinations are 1×16 Ohm or 1×8 Ohm only.
   Any other speaker configuration may stress the power amplifier section and in extreme cases may lead to valve and/or output transformer failure.
   ALWAYS ensure you use good quality speaker (unshielded) cables. NEVER use guitar (shielded) cables. ALWAYS use a non-screened Marshall approved speaker lead when connecting an extension cabinet to these units.

5. Effects Loop Switch
   When ‘out’ this switch completely bypasses the circuitry involved in the effects loop. Push this switch in to enable the loop.
   Note: If this switch is accidentally pushed in and there is nothing plugged in to the loop, the signal will still pass through from send to return by means of an internal link on the switching jacks. This link is disconnected when something is plugged into the return socket. The send socket has no effect on the status of the internal link and could therefore be used as a line out to a tuner for example if no external FX are connected.

6. FX Loop – Send & Return
   The FX Return socket (6) on the rear panel is used to connect the OUTPUT of the effects processor or pedal you are using in the effects loop. The FX loop is series and set at instrument level so both guitar FX or professional units can be connected. The FX Send socket (7) on the rear panel is used to connect to the INPUT of the unit you are using in the effects loop.

7. Footswitch
   Connect the supplied 2-way footswitch here. The footswitch enables you to change the channels, Normal or Overdrive, and globally turn the effects on and off.
   Note: When the 2-way footswitch is connected the front panel channel switch will not function.
   The optional extra 4-way footcontroller (not supplied) PEDL-10049 expands the functionality of the Haze amplifier.
   Four footswitches enables you to select between normal and overdrive channels, switch between overdrive and overdrive boost, enable / mute the internal reverb and enable / mute the internal effects.
   Four status LEDs reflect the current status of the amplifier – channel, boost, reverb and effect.
   Mute settings are stored per channel rather than globally applied.

MHZ40C Combo Technical Specification

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Bright Switch|
Reverb|
Effects|
Footswitch| 2 way supplied
Main Guitar – Input Impedance| 1MΩ
Dimensions (mm) W, H, D| 590 x 486 x 254
Weight (kg)| 20.3

Haze 15 Watt head front panel

1. Power Switch
   This is the On/Off switch for the mains electric power to the amplifier. The LED will light up when your amplifier is turned on and will not be lit when the amplifier is switched off.
   Note: Please ensure the amplifier is switched off and unplugged from the mains electricity supply whenever it is moved!
   Effects Section
   All effect and reverb settings are automatically stored in Normal and Overdrive allowing you to set different effects and/or reverb levels in each of these channels. Set a clean Normal sound with a lush chorus and a huge reverb, change to Overdrive and set a sparse reverb and a slap back echo and these sounds will be remembered each time you change channel.
   For this reason, the position of the effects controls will not always show the effects settings in use. If one of the controls is changed, the value will ‘jump’ to the control’s new position.
   The Reverb Level and Effects Depth controls use special controls that include relays allowing the effect section to be globally disabled.
   Turn both the Reverb and Effect Depth to minimum, past the click, and a click will be heard from within the amplifier as the effect section is true bypassed mechanically removing the circuit from the amplifier – leaving an all-valve amplifier signal path.

2. Effects
   Pressing this switch cycles between the 3 effects, Echo (green), Vibe (orange) Chorus (red) and Off (no light). When the effects are muted via the 2-way footswitch the light will slowly flash when the selected effect is muted.

3. Effects Adjust Control
   This control allows you to adjust the modulation speed of the Chorus and Vibe effects or the delay time of the Echo. As the delay time is decreased so are the number of repeats – creating long trailing echoes that reduce to short slap backs and further down to double tracking.
   When changing from a channel with Echo to one without, the effect will naturally spill between channels. When changing from a channel with Echo to a channel with Echo set to a different delay time, the delay effect will not spill between channels. The maximum delay time is 1 second.

4. Effect Depth
   This control sets the depth of the chorus and vibe or the level of the echo.

5. Reverb Level
   This control sets the amount of signal sent to the reverb allowing it to naturally spill between channels.
   Turning the control down to minimum ‘before the click’ turns the reverb off for the current channel only.
   EQ Section
   The bass, middle and treble controls form a traditional Marshall interactive EQ section – adjusting one control will affect how the others work.

6. Bass
   Turning the Bass control will affect the amount of low frequencies or bottom end in your guitar tone. Rotating this clockwise will increase the amount of lower tones, generally making your bass sound deeper and is especially useful at lower volumes. Turning this control anti-clockwise will reduce the bass frequencies in your tone producing a more cutting tone – especially useful at higher volumes.

7. Middle
   Adjusts the middle frequencies. Turning the control anticlockwise will yield a more hollow sound with the bass and treble frequencies appearing to be more accentuated. Turning it back clockwise increases the middle adding body to the sound.

8. Treble
   By adjusting the Treble control you can add or take away the higher frequencies in your guitar tone. By increasing the amount of treble you will make your tone brighter, ideal for more percussive playing styles.
   Overdrive Channel

9. Volume Control
   This control adjusts the volume of the Overdrive Channel. From minimum to about half way, this control increases the volume of the overdriven sound. From halfway onwards, the power amp will start to overdrive adding extra power and complexity to the tone.

10. Gain Control
    Controls the level of signal entering the pre-amp. At lower settings the sound will be cleaner and the amount of distortion is more controllable from your guitar or your playing style. At higher settings, more distortion is available.

11. Bright Switch
    Pushing this switch ‘in’ enables the Bright function. This control works on both the Normal and Overdrive controls. On the Normal channel the Bright works in the traditional way, interacting with the Normal Volume control. At lower settings the Bright  has an increased effect which lessens as the Normal Volume is increased.
    On the Overdrive channel it adds extra bite to the sound and works at all volumes.

12. Channel Switch
    Selects between Normal (out) and Overdrive (in) channels.
    Note: When using the 2-way footswitch this front panel switch is disabled.
    Normal Channel

13. Volume Control
    This control adjusts the volume of the Normal Channel. At low levels the sound will be clean. As the volume control is increased, in true Marshall style, the power amplifier will start to overdrive giving a classic, controllable distortion which cleans up beautifully from the guitar’s volume control.

14. Input Jack Socket
    Jack input for your guitar. You must always use a screened (shielded) guitar cable and never use an unscreened (unshielded) speaker cable. Also, this cable should be one of good quality. If you are in any doubt regarding this, your Marshall dealer will be more than happy to help and advise you.

Haze 15 Watt head rear panel

1. Footswitch Socket
   Connecting the 2-Way footswitch here enables you to perform two functions; you can change the channels, Normal or
   Overdrive, and turn the effects on and off.
   Note: When the 2-way footswitch is connected the front panel channel switch will not function.

2. Speaker Outputs
   WARNING! Never use the amplifier without a load (speaker cabinet/s) attached!
   There are 3 speaker outputs available on the rear panel. They are labelled according to the intended impedances:
   1×16 Ohm: connect any 16 Ohms guitar cabinet to this jack.
   1×8 Ohm or 2×16 Ohm: connect any 8 Ohms guitar cabinet, or two 16 Ohm guitar cabinets, to these jacks.
   WARNING: The safe combinations for speaker cabinet connection are 1×16 Ohm, 1×8 Ohm or 2×16 Ohm. Any other speaker configuration may stress the power amplifier section and in extreme cases may lead to valve and/or output transformer failure.
   ALWAYS ensure you use good quality speaker (unshielded) cables. NEVER use guitar (shielded) cables. ALWAYS use a non-screened Marshall approved speaker lead when connecting an extension cabinet to these units.

3. HT Fuse
   The correct value of this H.T. fuse is specified on the rear panel of the amplifier. NEVER attempt to bypass the fuse or fit one of the incorrect value!

4. Mains Input Socket with Mains Fuse
   Your amp is provided with a detachable mains (power) lead, which is connected here on the rear panel – see ‘The Basics’ section at the start of this handbook for more information.

MHZ15 Head Technical Specification

Symbol 5](https://manuals.plus/wp-content/uploads/2023/07/SEALEY-VS0220-Brake- and-Clutch-Bleeder-Pneumatic-Vacuum-Symbol-5.jpg)
Reverb|
Effects|
Footswitch| 2 way included
Main Guitar – Input Impedance| 1MΩ
Dimensions (mm) W, H, D| 498 x 223 x 224
Weight (kg)| 9.3

* EUROPE ONLY **– Note: This equipment has been tested and found to comply with the requirements of the EMC Directive (Environments E1, E2 and E3 EN 55103-1/2) and the Low Voltage Directive in the E.U.
* EUROPE ONLY – Note:** The Peak Inrush current for the MHZ15 is 18 amps.
The Peak Inrush current for the MHZ40 is 18 amps.

Note: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC rules.
These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and the receiver.
• Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
• Consult the dealer or an experienced radio/TV technician for help.

Follow all instructions and heed all warnings
KEEP THESE INSTRUCTIONS!

Suggested Settings

AMPLIFICATION
Marshall Amplification plc
Denbigh Road, Bletchley, Milton Keynes, MK1 1DQ, England.
Tel : +44 (0)1908 375411 Fax : +44 (0)1908 376118
www.marshallamps.com
Whilst the information contained herein is correct at the time of publication, due to our policy of constant improvement
and development, Marshall Amplification plc reserve the right to alter specifications without prior notice.
BOOK-90026-01 / 2 / 09

References

• Marshallamps.com
• Manual-Hub.com – Free PDF manuals!

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