The pre-amplifier is based on the famous Wada Shigehos Style Electric circuit, which was Introduced by Wada Shigeho in the early 1960s and gave an excellent performance. Regarding the Wada Shigehos Style Electric circuit, it not only keeps the good features of Marantz 7, it has superior features in Dynamic, High/Low Frequency Response, Resolution and Signal to Noise Ratio as compared to Marantz7.Specifications:Size : 430 × 90 × 290mmInput impedance : 100KOutput impedance : 600 ohmsOutput max voltage: 15vSNR : 90dBFrequency Response : 10Hz - 30KHzDistortion : ? 1%Input Power : AC100V 60Hz/50HzOutput Tube : 12AT7×2 +12AU7×2 + 6Z4×2Input Sensitivity : 400mTMD : less than 0.01%Input Jacks : 4 RCAOutput Jack : 2 RCAFront color :Silver Bass / Treble / Balance AdjustNet weight : 6kgPackage size weight : 9kgVery good sounding preamp. Has that classic tube sound but with modern tube engineering. Tight bass and airy highs. Great separation of instruments with a stunning midrange. Lots of reviews online.It uses popular tubes which are easy to find for tube rolling. It comes with the stock Chinese tubes which sound pretty good in their own right, but rolling in NOS tubes makes considerable improvements. Rolling in Mullard 12AU7s from the 60s for example brought about that euphonic listening experience where everything is silky smooth, airy and female voices are incredibly beautiful. Instruments have a weighty yet defined presentation with great separation.Electro-Harmonix 12AU7s give a much more precise modern SS sound. Less airy with hard hitting bass and more refined midrange.I purchased this pre while waiting for repairs on a Conrad Johnson pre. It has only been used for 2 months.Very clean.

I purchased this Xiang Sheng 728A preamp new while waiting a year for my boutique integrated tube amp to be custom built. Allegedly the same circuit design as the famous Marantz 7 preamp, this unit sounded fantastic as a preamp into my NAD power amp into Klipsch Cornwall speakers. Lot of air, separation and wonderful soundstage from this combo and wonderful tone and instrument detail to boot. The Chinese certainly can make some very quality gear! Uses 6 tubes in the preamp circuit (the orange tube glowing in the round window is just for show and is not part of the preamp circuit. Relatively low use original tubes with roughly 50 - 60 hours of use - should be loads and loads of life left on them. Cosmetically beautiful except for one slight rub/scratch on top of case - shown in photos. Functionally 100% - no issues. Has a built-in warm up cycle - power light blinks red until the tubes are up to temp then begins to blink blue and finally stays all blue when you are ready to rock. 4 inputs switched with relay switch. Tone circuit bypass button. I especially loved the dual outputs - one to my amp and one directly a subwoofer or another amp - great flexibility to have two outputs. Comes with original power cable and instruction book. I was quite happy with this unit and am passing it along now that I have my fancy and expensive integrated tube amp. Happy to answer any questions.

Very low hours, non-smoking environment. Non-remote control unit. Audiophile parts. High-end sound, smooth, fatigue-free. Input impedance:100 Kohm Output impedance:600 ohm Total Hamonic Distortion:less than 0.01% Frequency Responses:20Hz-30KHz+-1dB Signal to Noise Ratio :90dB Input Jack: 4 groups Output Jack: 2 groups Supply Votage:AC110/220V 60Hz/50Hz. Size:435mm(width)*90mm(height)*290mm(Depth) Used tubes :12AT7*(2PCS),12AU7*(2PCS),6Z4*(2PCS) Net weight: 5.6kg Made in China

728A XiangSheng Vacuum Stereo Tube HIFI Preamplifier. Tested and working. Came from the Jim Fosgate Museum collection. He was a friend of mine. See my other listings for more items from the collection!

728A XiangSheng Vacuum Stereo Tube HIFI Preamplifier. Works like new

728A XiangSheng Vacuum Stereo Tube HIFI Preamplifier. Works like new

728A XiangSheng Vacuum Stereo Tube HIFI Preamplifier. Works like new