Elder tubies delighted with the news that the name 'Beam-Echo' has been revived need wait no longer for proof. The reincarnated constructor has re-issued the Avantic DL7-35 monoblock power amp as its debut product, marking the amplifier's 40th anniversary, and the results have exceeded all expectations. Even if it ain't quite an exact replica...
If you've been following the strange but wonderful series of amplifier resuscitations, then you've observed the reappearances of such diverse treasures as the Radford ST-25, the McIntosh MC-275 and C-22, the rare, Japan-only Marantz Model 7 pre-amp kit and the odd Dynaco. In every case, changes have been made internally to account for the passage of time and its effect on parts availability, or to address other modern requirements. Also in nearly every case, the aesthetics were left alone. One thing's for certain, though: the spiritual predecessors to this latest Lazarus were either limited editions or kits with limited distribution. The 'new' Beam-Echo is to be treated as a valid, modern valve amp, not just a bit of nostalgia, so there's no threat of a pre-planned, finite production run.
Hence Stuart Perry and Richard Hussey's considered alterations away from the original, with the reassurance that 'the basic circuit' has been left unadulterated. A genuine 1956 DL7-35 is a typically cubist, wholly utilitarian lump devoid of any real style. It could be any one of a hundred 1950s amplifiers. The new version, on the other hand, is an aesthetic pastiche of the same decade's styling touches, battleship paintwork and wooden end-cheeks and angular folded steel and diagonal ventilation slots and a period badge, the resultant creation being a 420x260x200mm chunk of anachrophilic fantasy. It's like one of those cars that you drew when you were twelve years old and daydreaming in class, a confection combining bits of Morgan, Triumph, Jag and MG into some eclectic mass which screamed 'vintage sports car'. This time, it's dream hi-fi rather than cars and someone else has done the work for you, throwing in the added bonus of a genuine pedigree.
According to legend, the original was a commercial version of the Mullard 520 20-watter designed based on research by Mullard engineers into the characteristics of the EL34 and EF86 valves. And it was certainly a hit in its day. The great Percy Wilson said, "I have never heard anything I liked better", high praise indeed when you see what else was available through the pages of a 1956 Hi-Fi yearbook. Donald Aldous stated, "I cannot fault it." (I'd quote, too, from a contemporary review in HFN/RR, but the reviewer said nothing you wouldn't have found in the brochure.) So expectations were high then and are just as high now.
Classic in every sense of the word, the Avantic is rated at 30W, with a frequency response of 5Hz-30kHz. The input sensitivity is 280mV for rated output and -- at 20W -- distortion is said to be less than 0.05%, mighty specs for an aged valve design. Hum and noise is -85dB at the same rating, confirmed by the amplifier's unvalve-like silences. Designed to work best with 8 or 16 ohm speakers, the taps on the back provide for both. The valve complement (per channel) includes two of the aforementioned EL34 output tubes and an EF86 for the input, plus an ECC83 acting as a phase splitter and a GZ34 rectifier.
Inside, a PCB carries 1% carbon film high stability resistors in the signal path and 1% metal film devices in the HT circuit. On the underside are the capacitors, including 1kV polypropylene types in the signal path and 105deg C electrolytics for the HT section. For those who don't believe that the aesthetics are the only changes to the Avantic, the circuitry mods include only the selection of modern high-spec components and a modern PCB. OK, so it's not hardwired throughout, but this fledgling firm opted for greater reliability, easier manufacturing, better consistency and higher mechanical stability. The output transformers are still hand-wound, with split sandwiched windings.
Outside, it's 16 gauge mild steel shaped by a laser cutting process, the sheet then bent to shape. The top and end plates are milled from solid aluminium. That gorgeous period finish consists of etch primer followed by four coats of a cellulose-based hard metallic paint, colour-matched to an original DL7-35 using a laser colour-comparator, the paint mixed exclusively for Beam-Echo. That sexy badge? Half-millimetre copper sheet, with the artwork silk-screened onto it. The end pieces are solid oak, the knobs are machined from solid aluminium and the dark blue of the review sample is but one colour on offer. Also anticipated as choices for the discerning customer will be gold and 'Ferrari Red', the latter which should prove quite fetching if possibly over the top.
Read more about the Beam Echo on Page 2.