User manual NADY GTH-100

[. . . ] This product, in combination with headphones or speakers, may be capable of producing sound levels that could cause permanent hearing loss. Do not operate for a long period of time at a high volume level or at a level that is uncomfortable. If you experience any hearing loss or ringing in the ears, you should consult an audiologist. The product should be positioned so that proper ventilation is maintained. [. . . ] POWER SWITCH This switch turns the main power on and off. Flipping the toggle switch up to the ON+ position will turn on the amp "in phase" with the main AC line voltage. Flipping the switch down to the ON- position will reverse the polarity. In some cases, AC hum (caused by ground loops) can be reduced by reversing the polarity. Select the On position which has the least amount of AC hum. POWER INDICATOR LIGHT Lights when the unit is powered on. HI / STBY / LO SWITCH Flipping this toggle switch to the STBY position will respectively disable the audio to the amplifier and the outputs and put the amp in standby mode. This allows for proper warm-up of the tubes before applying signal to them, and allows the amp to stay warm when not in immediate use. To extend the life of the tubes, always turn the Main Power Switch on first, for 1-2 minutes, before flipping the Standby Switch to LO or HI. Set the switch to LO, which will enable audio with a maximum of 30W RMS output power, if the highest volume is not necessary, or, if you want to achieve more distortion at the output tubes. Flipping the switch to HI will enable audio to the amplifier with a maximum 100W RMS output. HIGH INPUT JACK Input for instrument outputs like passive guitar outputs, keyboard, mics for harmonicas, and other effects devices. LOW INPUT JACK The Low Input Jack has a pad with approx 9dB with lower gain than the High Input Jack. This should be used with higher level electronic devices or to achieve more range from the gain controls before distortion. DISTORTION SELECTOR This three-way switch selects the input sensitivity and amount of overdrive distortion. Position 1 offers the cleanest signal with least amount of distortion. Position 3 has the maximum amount of distortion. 5 Note: The VOLUME and MASTER controls also affect the final signal level and the amount of distortion. · For cleanest operation (least distortion) adjust the VOLUME to a very low setting, the MASTER to maximum, and the DISTORTION to Position 1. · For medium distortion (or crunch) adjust the VOLUME to past the mid position, the MASTER to mid, and the DISTORTION to Position 2. · For maximum distortion adjust the VOLUME to maximum, the MASTER to a very low setting, and the DISTORTION to Position 3. VOLUME CONTROL This adjusts the level of the input signal to the amp. Increasing this level will create distortion dependent on the DISTORTION SELECTOR setting. [. . . ] This may be used for recording by plugging into mixing consoles/recording devices or for stereo effects by using an outboard amp and speaker. 6 S P E C I F I C AT I O N S Power Amp Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Four EL34 Tubes Power Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100W RMS @ 4 -- 8 -- 16 5% THD Preamp Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Three 12AX7A Tubes Input Imp. 45 lbs (20kg) TUBE REPLACEMENT Preamp Tubes 12AX7A -- No adjustment required Output Tubes EL34 -- After replacing output tubes, output tubes bias voltage should be checked with Standby switch set to On, no signal input, and all controls set to minimum. If output tube bias voltage is not correct, amplifier will sound unusually distorted with mushy audio and output tubes may overheat. Normal output tube bias voltage should be -46VDC on Pin 5 of all output tubes. [. . . ]