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Here's a vintage Dynakit PAS-2 Stereo Preamplifier that I've just recapped and tested. Recapping included not only the electrolytics in the voltage doubler but all the original molded tubulars, many of which were exhibiting low insulation resistance. The quad filter capacitor still shows low ESR and so has not been replaced. Checkout on the bench shows the unit still meeting its original specs. The Special input was not wired by the original kitbuilder, but can be wired by the purchaser as a second low level stereo RIAA phono input or as a pair of microphone inputs. Wiring instructions for these options will be included along with a good photocopy of the manual, but omitting the assembly instructions. These units were famous for very low distortion (I measured .06% THD at a 1.5V output) and the near impossibility of overloading the inputs. If you're looking for a solid, reliable vacuum tube stereo preamp you can't go wrong with this one. Shipping cost is based on Priority Mail insured to Zone 8 (farthest from me). If shipped to a closer address I will refund the difference.
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Dynaco emerged in 1955 from Philadelphia, Pennsylvania, when hi-fi pioneer David Hafler partnered with engineer Ed Laurent to form the Dyna Company. Hafler brought expertise from his earlier Acrosound venture, which produced high-quality output transformers starting in 1950. The duo targeted the burgeoning hi-fi market with affordable, DIY-friendly kits, launching the Mk II 50-watt tube amplifier shortly after incorporation and relocating to a former chocolate factory for expanded operations.
The brand specialized in tube amplifiers that defined its legacy, including the iconic Stereo 70—over 350,000 units sold—alongside models like the Mk III. Dynaco expanded into FM tuners such as the FM-1, bookshelf speakers like the A-25, solid-state amps, and innovative systems like the Dynaquad for simulated four-channel sound. Late-1970s efforts included the Phase III speakers, though the company shifted toward kits and components emphasizing value and performance.
Dynaco holds a revered position as the era's top-selling tube amp maker, beloved by budget-conscious audiophiles for reliable, high-value hi-fi. Liquidated in 1980 after Hafler's sale to a toy firm, its vintage gear remains a collector's staple, with later revivals by Panor Corporation producing replicas for tube enthusiasts seeking that classic warmth and build-it-yourself appeal.
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