This is a fully balanced input and balanced output state-of-the-art pre-amplifier. The QA-808 boasts an ultra heavy current tube rectifier and a regulated power supply with NOS filter capacitors. A separate filament transformer and high-voltage power transformer enhances the dynamic range and clarity. This pre-amplifier is built with no compromise in component quality, and it's superlative sound can readily be heard in the delivery characteristics: very sweet and realistic rendition, with excellent dynamic range, musicality, high definition, and a very detailed, deep sound stage. The tube regulator stage acts to tighten up the bass punch without compromise. This pre-amp is suitable for any type of music reproduction, we feel it's performance is unsurpassed by competitor products in any price range.
An AC/DC filament selector switch has been recently added to this wonderful model to give even more flexibility to match your musical requirements, An AC filament sound is more musical and sweet, but might have little bit higher filament noise which may be detected by measurement, but is rarely audible. On the other hand, a DC filament sounds dead quiet with tighter bass punch, but you will lose some of the pure tube sound and is more suitable for pop/rock/new age. So the choice is yours and control is in your hands.
The output buffer stage’s characteristics can change with over 10 different types of tubes: (6G6/6L6/6V6/6Y6/6K6/EL34/6550/KT66/KT88/KT90/KT100) for exact tuning to match the rest of your system.
The lowest photo set shows a version with our most advanced 99 steps convertible volume control.
Now available is a super rectifier tube up-grade for 5U4G, which can greatly enhance the dynamics, high and low frequency extension, and bass punch. Also featured is stand-by switch for pre-heating of the rectifier tubes to ensure the longest lifetime operation. Rectifier tubes are replacable with high quality ceramic sockets installed.
The 5U4G tube rectifier can further upgrade by our super rectifier STR-104 or higher models , direct plug and play without any mod required.
With this super rectifier adaptor, you can use 300B, 2A3 , 45 , 50 , 80, 83, 1616 , 3B28 or 866A as rectifier tubes option.