My TU-870R vs 3 eBay Chinese amps

Posted by 4season on April 9, 2010 at 14:56:42

It's a slow day at the office and I thought some of you might be entertained by my experiences with a trio of inexpensive Chinese amplifiers and the entry-level Elekit TU-870R.

General description and first impressions:

Chinese amp #1 is a 6P14P single-ended amp with USB DAC which costs about $400 shipped from the USA rep based in California. Fast delivery, really nicely packed, in double boxes, with custom-cut foam inserts. Really looks good with thick milled aluminum and stainless steel parts. Internally, it's pretty tidy with glass-epoxy circuit board, ceramic tube sockets, Rubycon electrolytics and Burr Brown PCM2792 DAC. A couple of the milled aluminum plates were a bit irregular, and some of the lettering on the front panel failed to adhere properly and had flaked off. A standard IEC power cord and basic but tidy owner's manual is provided, though there is no schematic, and the importer did not have one available.

Chinese amp #2 (approx $250 shipped) is billed as "World's smallest" tube amplifier, and it literally fits in the palm of my hand. It accomplishes this with surface mount construction and a switch mode power supply. The amp circuit is based on 6P1 tubes in single ended pentode configuration. I ordered mine through a Taiwan seller and received it about a week later. Also nicely packed, but without power cord or manual of any sort. I did eventually find the schematic published in a Chinese electronics magazine, though I don't read Chinese. Out of the box, it looked a little grimy and really benefited from a bit of detailing. Finish was a bit rough but workmanlike,

Chinese amp #3 ($220, shipped from USA-based distributer) was a departure for me as it's a solid state amp based on the Tripath TA2022 chip, good for around 50 watts into 8 ohms. Appearance is very simple but workmanlike, with rather rough milling around the corners of the thick front panel. Perhaps their tools were chipped or dull. Inside, it looked very good, with substantial toroidal transformer and tidy circuit board with large Cornell Dublier electrolytic capacitors in the power supply. On the underside is a large protruding bolt which anchors the power transformer. A power cord is included, but there is no documentation, though the circuit appears to be similar to the one published by Tripath.

The Elekit arrived from VK Music packed in a recycled carton containing a stock Japanese-market TU-870R kit, product brochures, English-language documentation, the optional power supply upgrade + tube protector I had ordered and most importantly, a 120V r-core power transformer to replace the 100V part included in the kit box. I like the vintage-look artwork on that box and wish someone would offer a poster or sign with that look. Obviously it's a kit whereas the others are fully assembled, but right away, it looked like a very different sort of product. No audiophile pretensions: Tube sockets are Bakelite, RCA jacks are nickel plated PC mounted types, power cord is a fixed, 2-conductor sort, and speaker connectors are the spring clip type. No gold platings to be seen. Even the chassis is mostly simple painted steel with an unadorned clear anodized front panel. I decided to build this 100% stock, closely following the instructions. Where I had several identical resistors or capacitors, I'd match left and right channels as closely as possible, otherwise, I used no special tricks.

Bench tests and listening impressions to follow.

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Topic - My TU-870R vs 3 eBay Chinese amps - 4season 14:56:42 04/09/10 (2)

Bench tests and listening impressions - 4season 16:18:26 04/09/10 (1)

RE: Bench tests and listening impressions - vkung 18:50:56 04/09/10 (0)

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