Pre-Amps - Classic 100 Series

Model no:   QA-115-STR-Mk3 / QA-115-STR-Mk3-Super
C$3,580 Untitled Document [US$ 2864] / C$4,680 [US$ 3744]

line stage full balanced pre-amplifier with super rectifier + headphone amp + remote volume control

Using the 6SL7/6SN7 tubes as the amplification, and 6L6G tubes as the output buffer section, this unit is also built with a super tube rectifier (can use 300B, 2A3, 866A, 3B27, 3B28 , 1616, 80...etc) and enhanced power supply . All hand-wired to the highest possible standard. With the flexible capability of over 1000 different tube combinations, you can easily fine-tune the tonal quality of this pre-amp to adapt it to the rest of your system.

This pre-amplifier has a special Normal/fast feature switch, it can give you a very high adaptability to different types of music. The Fast position is good for Rock, Pop and Jazz, while the Normal position is good for Blues, Vocal and Classical music. Even though this switch can change the pace of the music reproduction, the alternation can't be detected by any existing measuring instrument. The specifications will not be altered, the changes are only detectable by the human ear.

Built-in micro-dynamic extraction circuit upgrade.

High output power headphone amp built-in with infra red motorized volume control.

Super version comes with the following upgrade features:

1. added true balanced headphone output via Quad core high grade output transformers, 4pin XLR socket included

2. added EL32/CV1052 connection capability (tubes not included)

3. Enhanced power supply with MDE (micro-dynamic extraction) upgrade

4. Hi / Lo gain control switch for matching different signal source, headphone and power amps

5. Adjustable output level control with bypass features, easily match power amp with different gains

6. Level-1 low output impedance upgrade included

7. All aluminum heavy duty chassis with thick super low resonance polymer side panels


No. of inputs 2 sets of  RCA inputs and 1 set of XLR balanced inputs
No. of outputs 2 sets of RCA and 1 XLR balanced pre-amp outputs
Freq response 1Hz - 150Khz (-3db)
S/N > 85 db
Input impedance 68Kohm (option: from 10Kohm to 1Mohm)
Gain x3- x6 depend on tubes
Phase 180deg inverted (option: non-inverted)
manufacturing hand-wired point to point

2 x 6SL7(Alt: 6SN7/6SU7/ECC32/ECC33/ECC35/6188 or equiv)

+ 2x 6L6G (Alt: 6V6/6K6/6G6/6F6/EL34/5881/6550/KT66/KT88/KT99/KT100 or equiv )

+ 3B28/1616 (alt: 2A3 / 300B / 572B / 866A /80 or equivalent)

(Note: The upgrade price below is a special deal for new orders only, modification of previously built unit will be around $300 higher than the following prices due to more works needed for disassemble of the original circuits)

Level 1 upgrade : (+ C$200)

Special designed "Super-Drive" circuit, output impedance lowered to 200ohm (can drive any power amp inputs from 600ohm up to infinity) with better bass control and punch , better definition and improved in overall tonal quality. By adding this upgrade, it sounds like the output with 10 pieces of power tubes being installed .

Level 2 upgrade : (+ C$500)

Level 1 upgrade + Enhanced input circuit design with increase of max. input levels , further lowering of distortion and increase dynamics, as well as better air and openness . Enhanced components quality for better sonic reproductions with higher resoltuions.


add 0/180 deg phase control switch with additional of C$150

Solid-oak chassis add C$250


1 year parts and labor warranty under normal operation conditions
standard chassis : Gold/ Black/Metallic MDF , Aluminum chassis

(optional chassis : Mirror steel, black piano , solid-oak )

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