Two-Rock Studio Pro User manual

Two-Rock
OWNER’S MANUAL
Studio Pro

Dear Customer:
Thank you for your purchase of a Two-Rock amplier from Premier
Builders Guild.
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 amplier.
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 specied by the manufacturer
11. Unplug this apparatus during lightning storms or when unused for long periods of time
12. Refer all servicing to qualied service personnel. Servicing is requred when the apparatus has been dam-
aged 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.

Input Jack- High impedance input to the amplier. Plug in your instrument here.
Push/Pull Treble Control- Adjusts the high frequency response. 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. When the knob is in the “out” position, the high frequency response is
boosted. This is most effective when the input gain is set at 12 o’clock or lower. The effect is less dra-
matic as the input gain control is adjusted past the 12 o’clock position.
Push/Pull Mid Control- Adjusts the mid-range response. In the full counter-clockwise position, the
tone will be somewhat “scooped” of mid-range response, emphasizing the highs and lows. In the full
clockwise position, mid-range frequencies are allowed to pass to the next gain stage. When the knob is
in the “out” position, the mid range frequency response is boosted.
Push/Pull Bass Control- Adjusts the bass response. In the full counter-clockwise position, low fre-
quencies are cut. In addition, the response of the treble and mid-range controls is greatly reduced. In
the full clockwise position, low frequencies are allowed to pass to the next gain stage. When the knob
is in the “out” position, the low and low-mid frequencies are boosted. This is a low frequency contour
switch, changing the low and low-mid response.
Gain- Adjusts the overall gain of the amplier. Start with this control in the 12 o’clock position.
Master Volume- Adjusts the output level of the amplier.
Reverb Send- The reverb drive control determines the amount of signal applied to the reverb tank. Low set-
tings will create a very open, small room reverb effect with a short decay time. Advancing the control clockwise
increases the signal applied to the driver, and a very saturated effect with a sharp attack and a long decay can be
obtained.
Reverb Return- The reverb return control mixes the reverb effect signal with the dry signal. At full counterclock-
wise rotation, the reverb effect is defeated. Using the return control in conjunction with the reverb drive control, a
wide range of natural reverb effects can be produced.
Contour- The contour control is an active wide band sweep. In the 12 o’clock position, the amps’ frequency
response is at. Counterclockwise rotation reduces high end response and increases low frequencies. Counter-
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 (PRS Humbucker to Strat, for example). This control
also actively reduces the articulation available, allowing a softer setting, or extremely open and revealing, de-
pending on your individual style and requirements.
Stand-by Switch- Should be in the “down” or “stand-by” position when you apply power to the unit. After a few
seconds, place the switch in the “up” position to use the amplier. You may leave the unit “powered up” and place
this switch in the “stand-by” position to mute the output.
Indicator Lamp- This lamp will illuminate when the power switch is in the “up” position, indicating the unit is
receiving A/C power.
Front Panel Functions

Rear Panel Functions
A/C Input- Connects the amplier to A/C power via the power cord supplied. Unless otherwise specied, your
amplier 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 amplier.
Return Level- This control has a pull-bright function. The loop is active in the circuit even with no effects
connected, so the level control acts as a master volume. The pull-bright feature is useful when playing at low
volume (a low fx control setting) or when a large number of outboard efects are used in the loop, which some-
times causes high frequency insertion loss.
Effects Send- Use this jack to send the ampliers signal to outboard effects.
Effects Return- Use this jack to connect the output of your effects to the amplier.
Pickup Loading- This control has 5 settings. In the rst position(fully counterclockwise), there is no additional
pickup loading, with 4 additional settings available. Fully clockwise(last position) is full loading. Loading the
guitar pickup(s) to varying degrees changes the impedance relationship between the pickup and the amplier’s
rst gain stage. Loading reduces inductive “ringing” in the pickup coils. The effect is a more controlled high fre-
quency response and a reduction in high frequency artifacts produced when a pickup’s magnets and coils feed
back with each other, usually at or near the pickup’s saturation point. The damping effect will also reduce the
gain, which is normal.Tonally speaking, reducing these artifacts results in a cleaner waveform and an apparent
lack of harshness in the upper frequencies.
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.
All Fuses are 3AG Type 250 Volt, SLO-BLO
Fuse Chart
Domestic Fuses:
2.5 - 40 Watt
Export 220, 230, 240 Fuses:
1.25 - 40 Watt
Export 100 Volt
2.8 - 40 Watt

Each ne production tube is tested and matched to our exacting specications. External bias adjust-
ment 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 ADJUSTMENTS:
Power up unit and connect proper speaker load.
Set master volumes and effects return controls to zero.
DO NOT apply any signal to the input during the biasing procedure!
Take unit off standby and allow a few seconds for the circuit to stabilize.
Set voltmeter to Millivolt scale (or lowest volt scale 60 millivolts=.060 volts.)
With meter grounded to chassis and + probe at test point, measure voltage.
For other tube types (5881, 6550, EL34) check with the manufacturer or contact us for recommenda-
tions.
Settings higher than 65 mV (.065 Volts) with 6L6 tubes may cause premature tube wear and possibly
damage the amplier.
Keep in mind that tubes vary in quality, and some tubes can handle upwards of 40 mV each (a read-
ing at the test point of 80 mV (0.80 Volts.) However, to be on the safe side, use the above as a guide.
WARNING! No user serviceable parts inside! Refer to qualied service person only.
LINE CORD- For your safety, connect to grounded A/C receptacle only.
Tube Complement
V1- 12AX7, 1st Stage Reverb
V2- 12AX7, Pre Amp
V3- 12AT7, Reverb Drive
V4- 12AX7- FX/Reverb RTN
V5- 12AX7, Phase Inverter
V6-V7 - 6L6 or 6V6 Power
All Fuses are 3AG Type 250 Volt, SLO-BLO
Fuse Chart

Two-Rock ampliers are brought to you by Premier Builders Guild.
We know your new Two-Rock amplier will provide many hours of enjoyment and in-
spiration 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)
FAX: [phone]
ADDRESS: Two-Rock
619 Martin Avenue, Suite 6
Rohnert Park, CA 94928
E-MAIL: Mac Skinner, General Manager
[e-mail]
INTERNET: www.two-rock.com
PRECAUTIONS:
DO NOT expose to rain or any other moisture.
DO NOT use cleaning solvents. Wipe exterior with a clean, dry cloth
only.
Refer servicing to a qualied service technician.

This is a product of
Two-Rock
619 MARTIN AVENUE, SUITE 6
ROHNERT PARK, CA 94928
707-584-8663
www.two-rock.com
SERIAL NUMBER:_____________________________