Blackstar Amplification JJN-20R MkII User manual

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Owner’s Manual
Blackstar Amplification Ltd, Beckett House, 14 Billing Road, Northampton, NN1 5AW, UK
For the latest information go to: www.blackstaramps.com
Whilst the information contained herein is correct at the time of publication, due to our policy of constant improvement
and development, Blackstar Amplification Ltd reserves the right to alter specifications without prior notice.
Designed and Engineered by
Blackstar Amplification UK
126406M-1 11/19
JJN-20R MkII

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USA / Canada
IMPORTANT SAFETY INSTRUCTIONS
1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. Do not use this apparatus near water.
6. Clean only with dry cloth.
7. Do not block any ventilation openings.
8. Install in accordance with the manufacturer’s instructions.
9. Do not install near any heat sources such as radiators, heat registers, stoves, or
other apparatus (including ampliers) that produce heat.
10. Do not defeat the safety purpose of the polarized or grounding-type plug. A
polarized plug has two blades with one wider than the other. A grounding type
plug has two blades and a third grounding prong. The wide blade or the third
prong are provided for your safety. If the provided plug does not t into your outlet,
consult an electrician for replacement of the obsolete outlet.
11. Protect the power cord from being walked on or pinched particularly at plugs,
convenience receptacles, and the point where they exit from the apparatus.
12. Only use attachments/accessories specied by the manufacturer.
13. Unplug this apparatus during lightning storms or when unused for long periods of
time.
14. Refer all servicing to qualied service personnel. Servicing is required when the
apparatus has been damaged in any way, such as power-supply cord or plug is
damaged, 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.
“TO COMPLETELY DISCONNECT THIS APPARATUS FROM THE AC MAINS,
DISCONNECT THE POWER SUPPLY CORD PLUG FROM THE AC RECEPTACLE”.
“WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO NOT
EXPOSE THIS APPARATUS TO RAIN OR MOISTURE AND OBJECTS FILLED WITH
LIQUIDS, SUCH AS VASES, SHOULD NOT BE PLACED ON THIS APPARATUS”.
This symbol is intended to alert the user to the presence of important operation
and maintenance (servicing) instructions in the literature accompanying the
appliance.
This symbol is intended to alert the user to the presence of uninsulated
“dangerous voltage” within the product’s enclosure that may be of sucient
magnitude to constitute a risk of electric shock to persons.

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Warning!
Important safety information!
READ THE FOLLOWING INFORMATION CAREFULLY. SAVE ALL
INSTRUCTIONS FOR FUTURE REFERENCE!
Follow all warnings and instructions marked on the product!
Danger! High internal operating voltages.
Do not open the equipment case. There are no user serviceable parts in this
equipment. Refer all servicing to qualied service personnel.
Clean only with dry cloth.
Condensation can form on the inside of an amplier if it is moved from a cold
environment to a warmer location. Before switching the unit on, it is recommended
that the unit be allowed to reach room temperature.
Unauthorised modication of this equipment is expressly forbidden by Blackstar
Amplication Ltd.
Never push objects of any kind into ventilation slots on the equipment casing.
Do not expose this apparatus to rain, liquids or moisture of any type.
Do not place this product on an unstable trolley, stand or table. The product may
fall, causing serious damage to the product or to persons!
Do not cover or block ventilation slots or openings.
This product should not be placed near a source of heat such as a stove, radiator,
or another heat producing amplier.
Use only the supplied power cord which is compatible with the mains voltage
supply in your area.
Power supply cords should always be handled carefully and should be replaced if
damaged in any way.
Never break o the earth (ground) pin on the power supply cord.
The power supply cord should be unplugged when the unit is to be unused for long
periods of time.
Before the unit is switched on, the loudspeaker should be connected as described
in the handbook using the lead recommended by the manufacturer.
Always replace damaged fuses with the correct rating and type.
Never disconnect the protective mains earth connection.
High loudspeaker levels can cause permanent hearing damage. You should
therefore avoid the direct vicinity of loudspeakers operating at high levels. Wear
hearing protection if continuously exposed to high levels.
If the product does not operate normally when the operating instructions are
followed, then refer the product to a qualied service engineer.
The U.S. Government´s Occupational Safety and Health Administration (OSHA) has
specied the following permissible noise level exposures:
Duration Per Day In Hours Sound Level dBA, Slow Response
8 90
6 92
4 95
3 97
2 100
1½ 102
1 105
½ 110
¼ or less 115
According to OSHA, any exposure in excess of the above permissible limits could
result in some hearing loss.
Ear plug protectors in the ear canals or over the ears must be worn when operating
this amplication system in order to prevent a permanent hearing loss if exposure
is in excess of the limits as set forth above. To ensure against potentially dangerous
exposure to high sound pressure levels, it is recommended that all persons
exposed to equipment capable of producing high sound pressure levels such as
this amplication system be protected by hearing protectors while this unit is in
operation.
All electrical and electronic products should be disposed of separately
from the municipal waste stream via designated collection facilities
appointed by the government or the local authorities.

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Introduction
Thank you for purchasing this Blackstar JJN-20R MkII amplier. Like all our products,
this amp is the result of countless hours of painstaking Research and Development
by our world-class design team. Based in Northampton (UK), the Blackstar team
are all experienced musicians themselves and the sole aim of the development
process is to provide guitarists with products which are the ultimate tools for self-
expression.
All Blackstar products are subjected to extensive laboratory and road testing to
ensure that they are truly uncompromising in terms of reliability, quality and above
all TONE.
The JJN-20R MkII’s exible two channel design features the unique patented ISF
(Innite Shape Feature) control and although it has a comprehensive control set, it
is still simple and intuitive to use. Please read through this handbook carefully to
ensure you get the maximum benet from your new Blackstar product.
If you like what you hear and want to nd out more about the Blackstar range of
products please visit our website at www.blackstaramps.com.
Thanks!
The Blackstar Team
Features
The JJN-20R MkII is a highly versatile ampliers suited to a wide range of playing
styles and situations, by including the great tone and innovative features of the
award-winning HT Venue MkII range.
The Clean Channel has two voices; one based on a classic American circuit and
the other based on a classic British tone. The Voice switch recongures the preamp
voicing, EQ and valve gain structure, as well as the power amplier damping. This
produces a clean, bright and tight but solid bass response for the American tone
and a highly responsive ‘chime’ with looser bottom for the British tone that can be
pushed into a midrange overdrive when driven hard. The Voice setting can also be
selected via footswitch.
This amplier also has two voices on the Overdrive Channel, providing a broad
palette of overdriven tones.
As with the Clean Channel, each of these voices can also be selected by footswitch.
The Overdrive voices are characterised by a tone which is high in gain, but avoids
any of the detached top-end ‘zz’ often found in other designs. This is a result of
unique preamplier and power amplier shaping techniques, which also benet the
player in the way the overdrives clean up beautifully as the guitar volume is reduced.
Even at the most extreme settings, the Overdrive voices remain natural sounding.
The patented ISF (Innite Shape Feature) control is unique to Blackstar Amplication
and represents a major step forward in tone shaping exibility. The ISF control
shifts the response of the three control tone stack between, a US type response
at one end, and at the other, a UK type response. Importantly, in between the two
extremes lie an innite number of alternative tone choices that would be otherwise
unavailable.
The amplier features naturally sounding digital reverb that can be adjusted via the
Reverb control on the front panel.
A Power switch is provided on the front panel to switch the amplier between full
power and 10% power. This means that the full tonal depth of the power valve
stage can be enjoyed at any volume, retaining the distinctive sound of power valves
working hard.
A USB connector allows for sending a speaker emulated output into a computer for
recording purposes.
Two further outputs on the rear, a stereo jack socket and balanced XLR, also allow
the speaker emulated signal(s) to be connected to external devices for practicing,
recording or live use.

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Front Panel
1. Input
Plug your guitar in here. Always use a good quality screened guitar lead.
Clean Channel
2. Clean Volume
This controls the volume of the Clean Channel. Turning it clockwise increases
the volume. At extreme clockwise settings the preamplifer will start to overdrive,
particularly in the ‘British’ mode.
3. Clean Voice Switch
This switch selects between the two clean voices. With the switch out, the ‘American’
setting is very clean and bright but with a solid and tight low end. When this Voice is
selected, the Voice LED is unlit. With the switch in, the ‘British’ setting has a looser
bass response with warmer mid-range and is very sensitive to the output level of the
guitar and the player’s dynamics. When this Voice is selected, the green Voice LED is
lit. The EQ voicing and valve gain structure is completely recongured between each
voice.
4. Tone
This is a dual control that eectively adjusts the treble and bass for the Clean
Channel at the same time. Fully counter clockwise (CCW) will be darker and bassy
in character. Rotating the control clockwise (CW) will progressively brighten the
sound and thin the bass.
OD (Overdrive) Channel
5. OD Select Switch
Press this switch to select the OD Channel. When the yellow LED is on, the OD
Channel is selected. When the yellow LED is o, the Clean Channel is selected.
6. OD Gain
The OD Gain control adjusts the amount of this Channel’s overdrive or distortion.
Low settings (anti-clockwise) will deliver a clean sound on the edge of break-up.
As the Gain control is increased clockwise the sound will become more overdriven,
moving through crunch tones until, at its maximum position, a full distorted tone is
reached.
7. OD Voice Switch
This is a momentary switch that selects between the two voices of the OD Channel.
When the small red LED is unlit, this channel has a ‘classic’ but ‘hot-rodded’ overdrive,
with medium power amp damping. With the red LED lit the overdrive sound has a
more ‘modern’ voicing that includes a strong mid-emphasised pre-overdrive boost,
as well as a looser, more aggressive sound due to reduced power amp damping.
8. OD Volume
This control adjusts the overall volume of the OD Channel. Turning it clockwise
increases the volume.
9. Bass
The Bass control adjusts the amount of low-end frequencies in your tone. This amp
has an advanced tone shaping circuit which allows the tone to be varied from tight
and cutting when counter clockwise, to warm and thumping when fully clockwise.
10. Middle
The Middle control adjusts the amount of middle frequencies in your tone. The middle
frequencies are particularly important in setting the amount of ‘body’ your tone has.
With the Middle control set to its minimum position (fully counter clockwise) the sound
will be aggressive and scooped, a tone ideal for aggressive rhythm playing. As the
Middle control is increased (clockwise) the amount of ‘body’ is increased, which is
more suitable for sustained lead guitar tones.
11. Treble
The Treble control allows exact adjustment of the treble frequencies within the
sound. At low settings (counter clockwise) the sound will be warm and darker in
character. As the Treble control is increased (clockwise) the sound will become
brighter. At the maximum settings the sound will be aggressive and cutting.
12. ISF (Infinite Shape Feature)
The patented ISF control works in conjunction with
the Bass, Middle and Treble controls. It allows you to
choose the exact tonal signature you prefer. Fully counter
clockwise has a more American characteristic with a
tight bottom-end and more aggressive middle, and fully
clockwise has a British characteristic which is more
‘woody’ and less aggressive.
Unlike conventional ‘contour’ controls and parametric equalisation systems, the Bass,
Middle and Treble controls remain interactive with each other just like in a traditional
guitar amplier tone stack. This leads to a very familiar, musical response.