pic of the innards from the internet (here). pic at the bottom of the article is from audioreview (here)
Review: Rotel RB-870BX amp (official literature here)
The RB-870BX is a 100 wpc stereo amp that doubles the power into 4 ohms (2 ohm not rated). It can be bridged via a small switch at the back (though you have to be careful about the speaker cable connection), and rated at 300 wpc into 8 ohm. Look at the impressive power transformer and bank of lytic caps, of good quality. My friend 300B123 once commented on the excellent components inside, deeming it a great candidate for DIY mods to take it to another level. While it may not be an absolute paradigm of high-current amplifier, it is no slouch and phenomenal value for money. I am sure its many cousins are similarly worthwhile.
One thing, the manuals used to be all available on Rotel's website, but doesn't seem so now (model is listed, but clicking it draws a blank), so download asap from other sources or cached copies if you are interested.
A diversion. Despite the internet, the true history of Rotel the company has been buried almost beyond excavation. The current official website, inferior to the old one, says nothing about the company's history, and reflects the superficiality of our age.
Here's something from the internet (2002): "...According to the Rotel site, the company was formed in 1961 by the "elder" Tachikowa and currently run by the son, Bob Tachikowa (one slight variation that I did come across was an audio site that listed the company as being founded in 1961 "by a Japanese audiophile" and then adopted by the Tachikowa family in 1979)...Tachikowa's address is listed as the Rotel offices in Japan but all research and design are driven out of the UK (and mfg out of Hong Kong)....So while Rotel could ceremonially be called a Japanese company, operationally its a UK company..."
A note from Taiwan's Audio Art magazine: "...談 起Rotel的歷史，它原本 是六○年時期的英國製造廠商，成立初期就建立了良好的名聲，不過在七○年代末期一度瀕臨倒閉，幸好有了日本資金以及繼任總裁兼工程師Tony Mills加入，Rotel這個品牌才得以起死回生。1982年對Rotel來說非常重要，因為他們藉由一系列不同於以往的產品設計，開始受到市場的注 意，並且慢慢的穩住經營腳步。雖然Rotel已非昔日的純英資公司，但是其設計理念並不因為日資進入而有所改變，反而在品質控管上更加嚴謹，造就了 Rotel在保持傳統英國味道之外，還使得品質更加提昇；再加上合宜的價格，使得Rotel在中低價位市場上佔有一定的地位。..." Basically, the author implies the company was originally UK, but received infusion of Japanese capital in the 70's.
From another Chinese site: "...Rotel成立於1961年7月1日，但剛開始並非以Rotel為品牌，直到1969年才開始正式以Rotel為商標推出音響製品。由於早期 Rotel的英國經銷商推廣產品十分成功，許多人以為Rotel是英國品牌，但實際上Rotel總部位於日本東京。Rotel早期產品以擴大機與CD唱盤 等兩聲道音響為主，外觀平實但性能出眾，是公認「物超所值」的音響首選之一。目前Rotel的產品線已拓展到家庭劇院的領域。.."
It took a search of "Rotel + Tony Mills" to uncover what I think is the Definitive Rotel History as related in the website of Lyric HiFi USA, and I quote: "...The only Japanese electronics firm anywhere near its age still owned by its founding family and run by a family member, Rotel has operated continuously since the late 1950s, when it was Sylvania’s TV distributor in Japan.
By the 1960s, founder Tomiko Tachikawa was focusing on audio and building products for blue-chip U.S. hi-fi companies, including Harman-Kardon, H.H. Scott and Marantz, all of which had found Japan a cost-efficient source for reliable products.
The first Rotel-branded units appeared in 1969, but for various business considerations the firm continued manufacturing for other companies. As a result, when Consumer Reports magazine awarded an early Rotel-badged receiver a Best Buy rating back in 1973, it also gave high marks to two American-branded units that few people knew had been built in the same factory.
!!!Rotel maintained an especially long and fruitful relationship with Adcom and manufactured that firm’s GFP-400 tuner/preamp, its GFP-555/565 preamps and its GFA-535/545/555 power amp series. High end aficionados today consider those units classics.!!! I didn't know that!When the first Rotel-branded hi-fi products came to market, Western consumers were reluctant to buy any gear identifiable as Japanese, but Mike Bartlett, now the firm’s vice president and general manager, had a solution for that problem. Mike, a fervent hi-fi fan since boyhood, joined Rotel in his native England in 1979. He was soon collaborating with a fellow British audiophile on an amplifier design project that would make Rotel a recognized high end brand.
That effort made perfect sense to Bob Tachikawa, the company founder’s son and Rotel’s current president, who is also a high fidelity enthusiast. Though born and bred in Japan, Bob had an in-depth understanding of the American audiophile market, gained during his student days at the University of Virginia, where he earned an engineering degree, and afterward during a four year stint at Rotel’s New York office. The muscle car he owned back then underscores his love of high-performance products: a Dodge Charger R/T, the vehicle used by the assassins who pursue Steve McQueen’s Mustang during the movie Bullitt’s classic chase scene.
As for Mike Bartlett’s design collaborator, Tony Mills, he had modified a mainstream Japanese receiver, the performance of which stunned Mike. If Tony could make a mass market unit sound so good, what could he do with a Rotel amp?
The audiophile pair decided to find out and, with Bob Tachikawa’s blessing, worked many a late night before completing a prototype for what would become the Rotel 820B amplifier, a unit that raised eyebrows when it was introduced three decades ago.
Tony Mills spent the next 15 years developing highly successful CD players for Rotel before retiring. At that point, another UK designer, Robert Burn, took up the torch and has since been refining the company’s audiophile units from his base in England.."
I highly commend Lyric HiFi for this article, showing, despite their hi-end image, they care about even the details of the smaller guys. In comparison, the official website has completely cleansed itself of anything that smacks of the Japanese, in the interest of prestige and sales perhaps? Shame!
For a pittance, I got my first RB-870BX bundled together with its matching preamp, the RC-870BX (official literature here). While the preamp is quite nice, it really is not the match of a decent tube preamp (what is!). It does have a decent MM/MC phono section that should be the equal of many of today's cheaper outboard phonoamps.
It is the RB-870BX amp that is the star. It is rather modern sounding: fast and detailed. I noticed the mono bridging feature and decided to get a second one to try it out, and am I glad I did!
In the coming article on the JBL 4312A there would be some description of the amp used in both stereo and bridged modes.