Two-Rock Gain Master 22 User manual

Two-Rock
Gain Master
22/35
OWNER’S 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 + 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 + 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.
NOTE for 22watt version: The Pull Mid function is not included!
BASS + 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.
NOTE for 22watt version: The Pull DEEP function is not included!
GAIN + Pull BYPASS - 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 foot switchable.
NOTE for 22watt version: This function is only accessible by the footswitch!

MASTER + Pull LEAD - 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.
NOTE for 22watt version: This function is only accessible by the footswitch!
LEAD GAIN - Adjusts the input level (gain) of the lead channel.
LEAD MASTER - Adjusts the output level of the lead channel.
CONTOUR - The contour control is an active wide band sweep. In the 12 o’clock position, the
amp’s frequency response is flat. Counterclockwise rotation reduces high end response and
increases low frequencies. Clockwise rotation decreases low end and increases the high
frequency response. This control is very useful for maintaining preamp tone control settings, while
allowing a global adjustment to compensate for differences in room acoustics, speaker cabinets,
or bright to dark guitars (single coils to humbuckers, for example). This control also actively
reduces the articulation available, allowing a softer setting, or extremely open and revealing,
depending on your individual style and requirements.
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.
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.
Effects Loop –
The effects loop on this amplifier is a “passive” type of loop, see FAQ on two-rock.com
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.
Foot Switch Jack - The footswitch connects here.
NOTE: The 22 watt 6V6 powered version’s Clean/Lead and Tone Bypass functions can only
be activated via the footswitch.
S/N - Your serial number is located here. We strongly suggest that you record this number and have it
handy in case you need service, or in the event that your amp is lost, stolen, or damaged.
FOOTSWITCH

Fuse Chart
All Fuses are 3AG Type 250 Volt, SLO-BLO
Export 100V: Domestic 120V: Export 220V, 230V, 240V:
2A - 22/35 Watt 2A - 22/35 Watt 1A - 22/35 Watt
Tube Complement
V1 - 12AX7, Clean Preamp
V2 - 12AX7, Lead Preamp
V3 - 12AX7, Phase Inverter
V4 and V5 - 6L6 (35w) or 6V6 (22w) Power Tubes
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.
BIAS ADJUSTMENT PROCEDURE:
-Power up unit and connect proper speaker load
-DO NOT have an instrument connected to the input during the biasing procedure!
-Take unit off standby and allow a few seconds for the circuit to stabilize.
-Set multi-meter to read DC Volts
-With meter grounded to chassis and + probe inserted into test point, measure voltage.
-Using a small flat head screwdriver, insert into Bias pot and turn slowly adjusting Bias
level
Below is a limited list of comparable tube types:
6L6: 6L6GC, 7581, 5881
6V6: 6V6S, 6V6GT
Bias Ranges: Are measured and set in Volts. But can be measured and set in milliamps.
6L6 type tubes: .060V to .070V for 35watt version Factory Setting: .064V
6V6: tube types: .044V to .058V for 22watt version Factory Setting: .050V
Do not set bias higher than recommended as it can lead to tube failure or failure within the
amplifier!

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: _____________________________