For your consideration, and from my own personal collection,is this pair of 1958 vintage Marantz Model 5 vacuum tube power amplifiers with sequentialserial numbers (1729 & 1749). These rare monoblocks were originallysold as a matched pair making them even more rare.The amplifiers were part of a custom console cabinet and wereordered without the optional tube cages. They are in very good condition as youcan see in the many pictures below. All original signal caps including the famed... Good-All epoxy dipped mylars and Sprague bumblebees. Beautiful point to pointwiring with military laced wiring harness and silver plated turret boards. It doesn’t get much better than this!The Model 5 was designed by Sid Smith and was the firstMarantz amplifier designed to be used in pairs for stereo. It also features a veryadvanced output transformer using a tertiary secondary winding for negativefeedback. This greatly extends frequency bandwidth while reducing parasitic oscillations. Unlike the stereo Model 8 and 8B, the Model 5 uses vacuum tuberectification courtesy of the legendary GZ34/5AR4. This provides a warmer, less harsh sound than solid state rectifiers. Also, the monoblock designyields superior stereo imaging and sound staging. No crosstalk or separationissues. Individual power supplies means the demands of one channel will not affect power delivery of the remaining channel.The Model 5 was also Sid Smith’s favorite amplifier. After retiring in Sea Cliff NY, he sold all of his amplifiers but kept a pair ofModel 5 prototypes. Do a Google search for “marantz model 5 sea cliff” to read an article with pictures of Sid Smith's personal Model 5.Tube complement include 1960’s NOS RCA black plate 6BH6’s,1960s RCA Clear Top 6CG7’s, 1960’s Mullard GZ34/5AR4’s and a Maximatcher matchedquad of NOS Svetlana (Winged C), EL34s from 1999. The Svetlanas were manufacturedat the SED St. Petersburg factory and are no longer being made. These 1990’svintage tubes are considered the very best, rivaling Mullards in sound qualityand reliability.The amplifiers have been tested with a Marantz 7 preamp, ChartwellLS3/5A and a Lampizator Atlantic tube DAC playing high resolution PCM, DSD andDXD filesThe sound quality is absolutely gorgeous. The famed Marantzmidrange is there with great top to bottom extension. Pure magic!Like all Marantz tube amps, these have more power reservesthan the official wattage rating may suggest. They also cannot be made toaudibly clip even with the inefficient BBC LS3/5A monitors.There is no noise, no audible hum. Bias meters workperfectly. The bias is rock solid. The amplifiers are factory wired for 30 wattultra linear operation but can be wired internally for 18 watt triode operation, ifdesired. If you are looking for superb pair of rare Marantz vacuum tubemonoblocks, look no further!I will pack these amplifiers with double boxing and plentyof inner padding. My packing is legendary.I ship worldwide.Thanks for looking and good luck bidding!