Marshall JH-1 Jackhammer Manual

Jackhammer Suggested Settings

IMPORTANT Precautions

Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been damaged in any way, such as liquid has been spilled or objects have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does not operate normally, or has been dropped.

Do not expose the apparatus to rain or moisture. Do not expose the apparatus to dripping or splashing. No objects filled with liquids should be placed on or near the apparatus. Do not use this apparatus near water.

Clean only with dry cloth.

Changes or modifications not expressly approved by Marshall Amplification plc could void the user's authority to operate the equipment.

Heed all warnings.
Follow all instructions.
Keep these instructions.

Introduction

The Jackhammer is the next step on from previous Marshall distortion pedals. It contains our most extreme distortion levels to date, combined with a Contour section that allows you to not only scoop out the mids, but also choose the frequencies at which the scoop occurs. This means that you can tailor your sound to your own individual requirements.

Although the Jackhammer has more aggresion and gain than any other Marshall pedal, we never forget our heritage. The sounds contained are always natural and realistic, like a super high-gain valve head pushed to the max.

The Jackhammer features two modes; Overdrive and Distortion. Overdrive delivers an open crunch for that classic Marshall roar, whereas Distortion gives you a smooth and singing compressed high gain tone.

The Jackhammer features a passive bypass for the main signal path, to ensure complete tonal integrity and has a quality of tone matched only by its versatility.

Here follows a complete run down of the Jackhammer's features for your information. We have also enclosed a number of suggested settings to help guide you. It should be remembered that these are only suggested settings and you should experiment as much as possible.

Setting Up

Always use good quality shielded leads.
Always use 9V regulated DC supply with centre negative.

Although it may seem obvious the first action in achieving a good effected sound (be it duration / compression etc.) is to find the perfect bypassed sound. This will then allow the correct level to be set with the effect unit to allow a cut or boost in volume and a realistic tone.

On clean channels it is advisable to set the gain (or volume) to a setting of no less than one quarter maximum so as not to get unrealistic results due to any volume dependent tonal shaping on the amplifier preamp.

Features

1. Jack Socket
   This is the output of the Jackhammer and is for connection to the amplifier or to another effects pedal.
2. Mode
   Allows for selection of the Jackhammer's two modes; Overdrive and Distortion. Overdrive gives you traditional Marshall open roar, similar to JCM 800 style Master Volume models with more bite and dynamics. Distortion Mode delivers a more saturated high gain compressed tone, similar to the high gain channels on JCM 2000 models.
3. Gain
   This increases the amount of distortion, taking you from vintage breakup, ideal for big crunchy chords, sweet singing blues and classic rock on Crunch mode; and from powerful overdrive to full on high gain distortion and compressed super saturation on the Lead mode.
4. Volume
   Adjusts the volume of the Jackhammer, allowing you to set the pedal for a boost or cut in volume when in operation, should you so wish.
5. DC Input
   For input of a 9V DC adaptor (as detailed previously) should you not wish to use batteries
6. LED
   Indicates when the Jackhammer is in operation.
7. Treble
   Adjusts the Treble frequencies in your tone.
8. Bass
   Adjusts the bass frequencies of your tone.
9. Contour Freq.
   By adjusting the Contour Freq. you can govern exactly which frequencies the Contour control (item 9) will scoop. With the Contour Freq. set at 12 o'clock the Contour acts like a traditional Marshall Contour control. Turning the Contour Freq. anti-clockwise cuts lower mids and bass from your tone, while turning the Contour Freq. clockwise will cut upper mids and treble.
10. Contour
    The Jackhammer features a stunning Contour control, modelled on the acclaimed Contour circuitry found on our Valvestate models. This allows you to 'scoop' certain frequencies from your tone. This item controls the amount of scoop in your tone. Turning clockwise will scoop out more mid. When full counter-clockwise the Contour section, including the Contour Frequency control, is bypassed.
11. Jack Socket
    This is the input jack, for connection from your guitar or from another effects pedal if you are linking pedals together.
12. Foot Switch
    For switching the Jackhammer on and off.

Trouble Shooting

	CHECK BATTERY	CHECK LEADS	CHECK PEDAL CONTROLS	DC INLET	CHECK AMP CONTROLS	CHECK GUITAR
WHAT IF NO OUTPUT
NOISE IN BYPASS
INDICATOR LED NOT ON		INPUT LEAD
SOUND TOO TREBLY OR FIZZY
SOUND TOO MUSHY OR BASSY
UNUSUAL FEEDBACK			REDUCE TREBLE		REDUCE TREBLE
UNUSUAL HUM					MOVE AWAY FROM AMP
BASS FEEDBACK						PICKUPS MAY BE VIBRATING

Battery Replacement

1. To replace the battery, open the easily accessed coin screw battery cover plate by loosening screw as shown, then disconnect the battery connector lead.
2. Use PP3 or equivalent battery(for improved battery life use alkaline type)
3. Always ensure that the battery is removed when the pedal is not in use for long periods.
4. Dispose of old battery in a safe place.

Technical Specification

Power: 9V DC Centre Negative Regulated
Current Draw: 13mA
Controls: Overdrive & Distortion Mode, Gain, Volume, Bass, Treble, Contour & Contour Frequency controls
Switches: On/Off Switch
Indicators: On/Off LED
Jacks: Input/Output 'Jacksockets'
Input Impedance: 1MΩ
Output Load Impedance: < 20kΩ
Dimensions: 120mm x 65mm x 55mm
Weight: 510 grammes