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The digital volume control has 65 steps (0-64, 1 dB/step). Position 64 is the mute level (<-90 dB) and position 0 is the loudest (0 dB). For earlier versions, every time you turn on the power switch, the volume is reset to step 63 and is barely audible. Newer versions can hold its volume position even when the power switch is turned off until battery is removed. Every push changes the volume one step (i.e. 1 dB). To change the volume continuously, press the button repeatedly or simply hold down the button. If the button has not been touched in 1 second or greater, or the volume has reached the maximum or minimum level, the volume will change in the opposite direction next time you push it.
If above logic is too difficult to understand, forget about it. Simply push the button three times or hold it down whenever you want to change the volume. If the volume changes in the wanted direction, don't stop and keep pressing until it reaches the level that you like. If the volume changes in the opposite direction, stop pressing and wait for 1 second or longer, then keep pressing it until the volume reaches your favorite level.
Right after power up or if you hear nothing, try press and hold down the (up) button for up to 8 seconds (it takes 7.3 s to transcend the entire potentiometer). If you still hear nothing, check your source and connection cable. We test every amp before shipping. Note that this amp has no audible noise even at the maximum volume.
The 1-button control is cool, but not so easy to operate. The 2-button version has separate buttons for up and down control - very straight forward and easy to use (the up button is at the right).
Unlike an analogue volume control, a digital one cannot take more than its power supply voltage, i.e. 4.5V (-2.25 to +2.25) in this case. The output level of most portable audio is within -1 to +1 V (0.7 V RMS), and thus there is no problem. Home audio equipment usually outputs at -2.8 V to +2.8 V (2 V RMS) and may cause the amp to clip.
The lately amps (shipped after 12/01/02) has an protection input circuit dealing with this issue and can be safely used for both portable and home audio. Since V5.18, the protection circuit is moved out from the amp and an external home cable/adapter is available. If you hear clippings with you home audio, you need this special interconnect cable/adapter.
Above applies to amps with digital volume controls only.
In order to ensure a very steady power supply, very large electrolytic caps are used in this amp. New electrolytic caps need lots of power cycles to reach their optimum performance. The amp will sound significantly better after at least one week of normal listening. Don't turn the volume too high for burn-in and high volume does not help burn-in but put your amp in unnecessary risk. Sometimes the sound still gets better after three weeks.
You can use any AAA battery, rechargeable or not. When the battery is about to run out, usually the background noise level becomes higher and audible and one audio channel stops working earlier than the other channel. When the battery goes low enough, both channel will stop working and you hear nothing but hiss.
If your amp has a booster connector, make sure the total voltage, internal + external, never exceed 12V (7.2V if it comes with digital volume controls). You can plug to the connector a 9V battery, a booster or any battery case, or an AC adapter. The amp will automatically use the external power (if no internal batteries) or use both (if there are internal batteries). The added voltage provides more headroom for hi-impedance headphones (300 ohm or higher). If you use internal batteries only, make sure to put on the terminator. Again, never let the total voltage be higher than 12V (or 7.2V for digital versions) otherwise the amp may become very hot and be fried. Also, plug an external power source with correct polarity or the amp won't work (no damage though). The following pictures show some examples of using the booster connector.
Since V6.0, crossfeed can be included as an option. The crossfeed is built in and can be bypassed with a sliding switch. Moving the slider to right enables crossfeed, which moves the sound image slightly away from your head and reduces fatigue caused by long-time listening
Visit our website www.fixup.net or send an email to support@fixup.net if you still have questions.
Thank you for using a Xin Super Mini Amp. Enjoy audiophile-level audio anywhere, anytime!
