SONICTONE BA-300 (01) PDF Document

1. Always use the correct types of tubes for this amplifier.

2. Always match the impedance to correct value of the speaker load.

3. Do not attempt to bypass the fuses or use different fuse values.

4. Please only use the provided SonicTone footswitch, which is compatible with this amplifier.

5. Please only use a TRS cable to connect the footswitch to the amplifier.

6. Please operate the amplifier in dry and safe conditions.

7. Please store the amplifier in a reasonable, climate-controlled environment.

8. Prolonged exposure to high sound levels may cause permanent hearing loss. Please take the necessary precautions.

9. If you are experiencing issues with the amplifier, please have it worked on by a qualified service technician only. Do not attempt to open the amp and work on it yourself.

Yes. Dangerous and potentially lethal voltages may be present in the amplifier even after it has been turned off and unplugged. Do not open the amp yourself or touch the inside of it. Only have a qualified service technician open up and work on the amplifier.

The SONICTONE BA-300 is a fixed-biased bass tube amplifier that uses three (3) 12AX7 preamp tubes and six (6) power tubes (6550 or KT88). The features include:

• 2 channels with independent gain controls (footswitchable)

• Shared 3-band EQ with presence

• Master volume

• -15dB input pad switch

• Bright switch on channel 1

• Classic/Hotrod switch on channel 2

• High-pass filter switch

• Mid cut/boost switch

• Buffered FX loop

• Unbalanced 1/4″ preamp out

• Unbalanced 1/4″ power amp in

• Balanced XLR preamp out with a ground lift switch

• 3-way output impedance switch

• Birch plywood cabinet with finger-jointed construction

• High-quality, low-noise, high-volume fan

The footswitch requires a 1/4″ TRS cable to be inserted into the footswitch jack on the rear panel as well as the jack on the footswitch. The “CH 1 / CH 2” switch on the front panel is automatically defeated if the footswitch cable is plugged into the footswitch jack on the rear panel.

1. Pilot Light: Illuminates when the amp is turned on.

2. Power Switch: Turns the amp on.

3. Standby Switch: Allows the amp to be played. When the standby is off, the tubes are kept warm, but the amp will not make any sound.

4. Presence: Active tonal control that can be used to brighten up the amp’s overall sound.

5. Bass, Middle and Treble: Passive equalization controls to adjust the tone of the amp.

6. Master: The overall master volume of the amp.

7. Mid Cut/Boost Switch: Switch to engage a mid-range cut or boost.

8. Volume 2: Control to adjust the overall volume on channel 2.

9. Hotrod/Classic: Switch to engage a bolder tone on channel 2. In “Hotrod” mode, channel 2 will have additional gain and a more aggressive, slightly brighter voicing.

10. Gain 2: Control to adjust the amount of gain on channel 2.

11. Bright Switch: Switch to engage a slightly brighter tone for channel 1.

12. Gain 1: Control to adjust the amount of gain on channel 1.

13. CH 1 / CH 2 Switch & LED: Switch to change between channels 1 and 2 when not using the footswitch. The LED illuminates when channel 2 is engaged.

14. -15dB Pad Switch: Switch to engage a pad for hotter input signals, such as a bass with active pickups.

15. High-Pass Filter: Switch to engage a high-pass filter to filter out some bass and boost the treble, giving a punchy, cleaner sound. It also makes the amp more suitable for guitar.

16. Input Jack: Mono input jack to plug your guitar into.

1. Footswitch Jack: Stereo input jack to plug the provided 1/4″ TRS footswitch cable into.

2. FX Loop Send Jack: Mono input jack for the send FX loop instrument level signal.

3. FX Loop Return Jack: Mono input jack for the return FX loop instrument level signal.

4. Preamp Out: Mono unbalanced output jack to send the post-FX loop line level signal to another external unit or power amp.

5. Power Amp In: Mono unbalanced input jack to send a line level preamp signal from another amp into the power amp of this amp. Once a line is plugged into this jack, the internal preamp is disconnected and the power amp will only amplify the incoming external preamp signal.

6. Balanced Out: A transformer-driven balanced XLR output jack to send the post-FX loop signal to a PA or mixer.

7. Ground Lift: Switch to engage a ground lift to attempt to mitigate any ground buzz or hum that may occur in the balanced out signal.

8. Parallel 1/4″ TS Speaker Jacks: Mono input jacks to plug the speaker(s) into.

9. SpeakON NL4 Jack: Four-pole SpeakON jack to provide a sturdier connection against vibrations for louder, high-powered applications.

10. Impedance Selector Switch: Switch to select the correct impedance of the speaker load hooked up to the amp.

11. Bias Probes: Test jacks to check the approximate bias point of each power tube in millivolts (mV).

12. Fuse Holders: Receptacle for the amp’s main fuse. There’s an additional high voltage fuse located inside the amp.

13. AC Jack: Jack to plug the provided AC cord into.

It is important to make a distinction between the FX loop and the “preamp out/power amp in” jacks. The FX loop is a lower instrument level signal designed for FX units and requires the “make-up” gain of the return stage. The “preamp out/power amp in” insert point is post-FX loop and is a higher line level signal that needs no recovery stage. The two insert points have different purposes and behave differently because of this.

In summary, the FX loop is designed to feed external FX units via the send jack and receive the processed instrument level signal to the return jack. The “preamp out/power amp in” insert point is designed to feed other power amps, or receive a line level signal from another preamp.

You can connect speakers using the parallel 1/4″ TS Speaker Jacks or the SpeakON NL4 Jack. All of the speaker jacks are in parallel. If you plug two equal impedance speaker loads into them, you must set the impedance switch to half their impedance. For example, with two 8 ohm speaker loads plugged in, the impedance switch should be set to 4 ohms.

The Bias Probes are test jacks used to check the approximate bias point of each power tube in millivolts (mV). Each positive bias probe is connected to one half of the power tubes (three tubes for the BA-300).

To estimate the value per tube, divide the measured value by 3 (for the BA-300). For example, a measurement of 150mV on the BA-300 would imply each tube in that trio is at approximately 50mV.

Important Note About Biasing: The value given at the bias probes represents the voltage drop across an internal 1 ohm resistor. Using Ohm’s law (V = IR), the value in millivolts (mV) can be converted to milliamps (mA) to get the approximate cathode current. This is only an approximation. The bias pot is located on the top of the amp chassis near the power tubes. Always have a qualified technician service the amp and set the bias. When biasing, all measurements should be performed with the amplifier warmed, set to play mode, and with all controls set to zero.

Proceed with caution with the following settings! The following settings will set the amplifier in a way that it will produce extremely loud output. Please take care and use hearing protection at all times.

To “open up” the BA-300 and really get the most out of the preamp and the 300-watt power amp, you can set it to the following:

• Lower the master volume and gain 2 to zero.

• Take volume 2 out of the circuit by turning it up to 10.

• Switch on channel 2.

• Using gain 2 as a preamp volume, turn gain 2 up to the desired preamp level and use the master volume control the overall volume.

Depending on how hard you drive the preamp, the result will be an incredibly bold and loud bass tone, all on the edge of breakup with amazing compression, touch and feel.

Product Series: BA Series

Product Model: BA-300 Bass Head

AC Input & Fuses:

• Standard IEC jack for U.S. 120VAC (International 240VAC)

• Slo-blo mains fuse: US 120VAC 300W – 10A (240VAC – 5A)

• Slo-blo high voltage (B+) fuse: 300W – 3A

Tubes & Power Output (300-watt Model):

• Three (3) 12AX7 preamp tubes

• Six (6) power tubes (6550 or KT88)

• 300W @ 8, 4 or 2 ohms

Footswitch:

• Single button SonicTone footswitch

• TRS cable required for proper operation

Dimensions (300W Head):

• Width: 24 in

• Height: 10.75 in

• Depth: 11 in

• Weight: 66.5 lbs