Two-Rock Jet 50 User manual

Two-Rock
Jet
50/100
OWNERS MANUAL

Dear Customer,
Thank you for your purchase of a Two-Rock amplifier from
Two-Rock Amplifiers, LLC.
As a discerning guitarist, you know the road to great tone begins with
great components.
Our Classic Design, carefully selected parts and hand-built approach
combine to make an extremely versatile instrument.
Please take the time to read this manual. We hope it will answer any
questions that you may have.
We extend a warm welcome to you as a member of a select group of
musicians who have chosen a Two-Rock amplifier.
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. Install in accordance with the manufacturer’s instructions
8. Do not install near any heat sources such as radiators, heat registers, plugs, and the point
where they exit from the apparatus
9. Protect the power cord from being walked on or pinched particularly at plugs and the point
where they exit from the apparatus
10. Only use attachments/accessories specified by the manufacturer
11. Unplug this apparatus during lightning storms or when unused for long periods of time
12. Refer all servicing to qualified 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
13. CAUTION: To disconnect the unit completely from the MAINS, unplug the unit. Turning the power
switch off does not disconnect the unit completely from the MAINS.

Front Panel Functions
INPUT - High impedance input to the amplifier. Plug in your instrument here.
TREBLE + Push/Pull BRIGHT - Adjusts the high frequency response. At lower settings of this
control the tone will be warmer and smoother. As you turn this control up the highs become more
prominent and aggressive adding gain to the signal as well. In the full counter-clockwise position,
high frequencies are bypassed to ground. In the full clockwise position, high frequencies are
allowed to pass to the next gain stage. Pulling the knob to the “out” position: boosts the high
frequency response. This is most effective when the Gain control is set at 12 o’clock or lower. This
is great for adding sparkle to clean tones. The effect is less dramatic as the Gain control is
adjusted past the 12 o’clock position.
MIDDLE + Push/Pull Mid - Adjusts the midrange response. At low settings of this control the tone
will be “scooped” of midrange response, emphasizing the highs and lows. As this control is turned
up, the midrange frequencies are increased. This creates the “body” of your guitar’s tone and is
very critical to both the tonality, feel and overall response of the amplifier. Higher settings of this
control also help your tone to cut through the mix in both a live band situation and when playing
the amp outdoors. In the full clockwise position, mid-range frequencies are allowed to pass to the
next gain stage. Pulling the knob to the “out” position: Midrange is further boosted.
BASS + Push/Pull DEEP - Adjusts the bass response. In the full counter-clockwise position, low
frequencies are cut. In addition, the response of the treble and mid-range controls is greatly
reduced. It’s easiest to start with this control at noon, then adjust to taste. In the full clockwise
position, low frequencies are allowed to pass to the next gain stage.
Pulling the knob to the “out” position: Boosts the lower bass frequencies. This low frequency
contour switch also shifts the emphasis from the upper bass and low mid frequencies to the lower
bass frequencies which helps smooth out and clarify the midrange response.
GAIN - Adjusts the overall gain of the amplifier. Start with this control in the 12 o’clock position
then adjust to taste. This control determines the initial character of your tone, from cleaner/brighter
tones at low settings to fatter/warmer tones at higher settings. As you turn this control up it also
introduces more gain and bass into the signal path, and reduces the amount of available clean
headroom especially when the master volume is set higher.
Pulling the knob to the “out” position: Treble, Middle, and Bass controls are passively
bypassed boosting the natural high and mid frequencies of the guitar. It also increases the amount
of input signal that drives the gain stage. This function is also foot switchable.

MASTER - Adjusts the overall output level of the amplifier. At lower settings on this control the
amp will be much cleaner sounding as well as lower in volume. As this control is turned up the
power section of the amp begins to work harder which increases sustain, fullness, and touch
dynamics as well as increasing the volume of the amplifier. At higher settings on this control the
power section will be pushed into natural overdrive especially if the Gain control is set higher.
Pull this knob “out” to activate the Lead channel. This function is also foot switchable.
LEAD GAIN - Adjusts the input level (gain) of the lead channel.
LEAD MASTER - Adjusts the output level of the lead channel.
REVERB - This is the reverb return control which mixes the reverb effect signal with the dry signal.
At full counterclockwise rotation, the reverb effect is defeated. Using this return control in
conjunction with the reverb drive control on the rear panel, a wide range of natural reverb effects
can be produced.
STANDBY - This switch should be in the down/STANDBY position before you place the Power
switch to the up/ON position. After 20 seconds or more, place the Standby switch in the “up”
position to play the amplifier. When you are taking a break from playing the amp you can leave the
amp “powered up” and simply switch to the “stand-by” position to mute the output of the amplifier
and prolong power tube life.
INDICATOR LAMP - This lamp will illuminate when the rear panel power switch is in the “up”
position, indicating the unit is receiving A/C power.

Rear Panel Functions
A/C Input - Connects the amplifier to A/C power via the power cord supplied. Unless otherwise
specified, your amplifier is designed to operate on 120 volts A/C, 60 cycles.
Fuse - See Fuse Chart
Power Switch - Turns power on.
PRESENCE - Adjusts the contour of the high-frequency response. Turning this control up
gradually increases the intensity of the upper frequencies. This is a subtle control which can be
used to either emphasize sparkle and brightness when needed or smooth out your overall tone by
turning the control down.
Speaker Output Jacks - There are 3 speaker output jacks; 4, 8, and 16 ohms.
NEVER OPERATE YOUR AMPLIFIER WITHOUT A PROPER SPEAKER LOAD CONNECTED.
Be sure to match the impedance of your cabinet with the impedance (output) of the amplifier.
Reverb Drive - The reverb drive control adjusts the signal level applied to the reverb unit. Low
settings will provide a smooth, short decay effect, simulating small to medium rooms. Higher
settings will increase the decay time. At maximum clockwise rotation, an extremely wet reverb
effect can be created. This control is used in conjunction with the front panel (return) control (see
FRONT PANEL FUNCTIONS, previous page). The reverb effect is defeated with this control in
the full counterclockwise position.
Effects Loop –
The effects loop on this amplifier is a “half active” type of loop, see FAQ on two-rock.com
EFFECT LEVEL + Push/Pull BRIGHT –Adjusts the effects loop return level. The loop is active in
the circuit even with no effects connected, so the level control also can be used as a additional
master volume control. This function can be useful but also a bit confusing so as appoint of
reference, set this control at 11:00 for unity gain when not using the effects loop. The pull-bright
feature is useful when playing at a lower volume, or when connecting more than a few pedals into
the loop, which sometimes causes high frequency insertion loss.
SEND - Use this jack to send the amplifier’s signal to the effects that you want to use in the loop.
RETURN - Use this jack to connect the output from the effects in the loop back to the amplifier.
Footswitch Jack - The footswitch connects here.

Fuse Chart
All Fuses are 3AG Type 250 Volt, SLO-BLO
Export 100V: Domestic 120V: Export 220V, 230V, 240V:
2.5 - 50 Watt 2.5 - 50 Watt 1.6 - 50 Watt
3.2 - 100 Watt 3.2 - 100 Watt 2.5 - 100 Watt
FOOTSWITCH

(Tube Complement)
V1- 12AX7, Rhythm channel
V2- 12AX7, Lead Channel
V3- 5751/12AT7, Reverb Driver
V4- 12AX7, Mixing/Effects loop
V5- 12AX7. Phase Inverter
V6, V7, V8, V9- Stock 6L6GC, Output
Each fine production tube is tested and matched to our exacting specifications. External bias
adjustment and test points are located on the chassis near the output tube sockets. A digital
voltmeter and small screwdriver are required for bias adjustment.
When replacing power tubes, it is necessary to only use a similar tube type that your amp’s power
section is designed for. Below is a limited list of comparable tube types:
6L6: 6L6GC, 7581, 5881

BIAS ADJUSTMENT PROCEDURE:
- Power up amplifier and connect proper speaker load
- DO NOT have an instrument connected to the input during the biasing procedure!
- Switch the amp out of standby and allow a few seconds for the circuit to stabilize
- Set the voltmeter to read DC Volts
- With the meter grounded to the chassis and the meter’s positive probe inserted into the test
point, measure the voltage
- Using a small flat head screwdriver, insert into bias adjust pot and turn very slightly one way or
the other to adjust the bias voltage
*Bias ranges are measured and set in volts
*Do not set bias higher than recommended levels as it can lead to tube failure and possible damage to
other components in the amplifier!
6L6 type tubes 50watt: .060V to .070V Factory Setting: .064V
6L6 type tubes 100watt: .120V to .140V Factory Setting: .126V
WARNING! No user serviceable parts inside! Refer to qualified service person only.
LINE CORD- For your safety, connect to grounded A/C receptacle only.

We know your new Two-Rock amplifier will provide many hours of
enjoyment and inspiration in the years to come.
This manual is a resource for some of your questions.
Please contact us with any other questions or comments that you may
have. We look forward to hearing from you!
PHONE: [phone]-TONE (8663) (M-F 9am-5pm PST)
ADDRESS: Two-Rock Amplifiers, LLC
619 Martin Avenue, Suite 5
Rohnert Park, CA 94928
CONTACT: [e-mail]
WEB: www.two-rock.com

Two-Rock Amplifiers, LLC
619 MARTIN AVENUE, SUITE 5
ROHNERT PARK, CA 94928
707-584-8663
www.two-rock.com
SERIAL NUMBER: _____________________________