Description
Dynaco Mark VI Vintage Monoblock Tube Amplifier Pair, 120W *NEW Price Dynaco Mark VI Vintage Monoblock Tube Amplifier Pair, 120W *NEW Price General: This listing is for a working set of Mark VI Monoblocks in working condition. Features rare XLR inputs for an amplifier this age. Cool bias meter on the front with rack handles.This pair of amplifiers is labeled Dynaco Wired, however they have underwent a significant modification at some point in the past. The majority of the electrolytic capacitors were replaced, film bypass capacitors were added to the various power supply rails, and slow start relay circuits were added to delay the B+ voltages. Other modifications may have been performed that we are unaware of that sharp Dynaco aficionados may recognize. Both amplifiers were tested to their rated power of 120W. Both meter lamps and meters are working properly.Tubes include RCA 7199, and a mix Sylvania and Philips USA 8417.Please see our pictures for overall condition. More from Dynaco: The Mark VI is a vacuum tube high power basic power amplifier designed for the professional sound installer.Vacuum tubes are most often favored in their ability to withstand enormous physical and electrical abuse - conditions frequently encountered in discotheques, public address and musical instrument applications.Its rugged construction and utilization of superior components, including the patented Dynaco Super Fidelity transformers, permit continuous duty at full power, while maintaining safe operating margins.Protective isolation of the load from the driving circuits, and uniform power output into a variety of load impedances are inherent in all designs which use an impedance matching transformer.The Mark VI employs a basic circuit arrangement which all Dynaco vacuum tube amplifiers have uséd since the inception of the Mark II amplifier in 1955.Refinements of the operating parameters have been incorporated for circuit balance, stability, and for drive capability.The components uséd have been selected to protect against failure, and all parts are operated conservatively to assure superior performance and proper operation for many years. The SkyFi Testing Process for Tube Amplifiers:We start with a visual inspection of all internal components to make sure that there are no signs of heat stress or damage. Capacitors are checked for telltale signs of predictive failure including bulging, shrunken wrappers, or physical leakage. We also inspect resistors and other passive components for signs of overheating. If tube arcing has occurred in the past we can usually spot discoloration on the output tube sockets. On vintage units we often spot check select capacitors for value and ESR.If the amplifier passes visual inspection, we move on to a full test of all of the tubes. We use an Amplitrex AT-1000 Tube Tester which is capable of testing both emission and Gm with a high degree of accuracy. We document the results of each tube and replace any weak or suspect tubes before proceeding. When we power on tube amplifiers for the first time we usually use a variac and current limited AC supply and slowly raise the voltage up to nominal mains level while monitoring plate, screen, filament, and negative bias supply voltages where applicable. If everything is in order we feed a low level test signal into the amplifier’s input and monitor its output on an oscilloscope across an 8 ohm dummy load. At this point we are just looking to verify basic function and confirm that the output transformers are not damaged. Once we have verified that the amplifier is safe to operate, we connected it to full mains power. For fixed bias amps we set the bias to manufacturer spec. For cathode biased amps we monitor the plate to cathode voltage to determine if the output tubes are operating in a safe range. Once the output section is verified we move onto bench evaluation.We start by feeding the input of the amplifier with a low level 1KHz test signal, slowly increase its amplitude while monitoring the amplifier’s output on an oscilloscope for signs of noise, clipping, distortion, or improper channel balance. We continue increasing the signal level until the amplifier reaches clipping. At this point we take an output power measurement and compare it to the spec sheet of the amplifier to verify proper performance. We finish off the bench evaluation with a 1KHz square wave check and a 20Hz to 20KHz sine sweep to assess the amplifier’s frequency response characteristics. This battery of tests will usually reveal if the amplifier has any issues that need further attention.Before the device leaves the bench, we perform a listening test with actual music using a variety of preferred test tracks. Our benches are outfitted with familiar monitor speakers which help us identify inconsistencies that will not always show up on our test gear. The main things that we are listening for are hum or noise with no signal present, proper center image, clicks, pops, or any other obvious undesirable audio characteristics.If the unit passes all of these tests it is moved to our long term testing rig where we simulate real word operating conditions for 6-8 hours. For tube amps we like to run this test at least twice. This allows us to monitor the unit for signs of thermal runaway or intermittent issues that only crop up when it has fully come up to temperature. We find this step to be essential, especially for vintage units. Specifications:Power output:120 watts into 8 Ω (mono)Frequency response:10 Hz to 40 kHzTotal harmonic distortion:1%Damping factor:14Input sensitivity:1.6 VSignal to noise ratio:95 dBSpeaker load impedance:4 Ω to 16 ΩValve complement:4 x 8417, 1 x 7199Dimensions - Each:19 x 10.5 x 8.75 inchesWeight - Each:55lbs Item Included Original Box Not Included Manual Yes Included Remote Not Applicable Cables Yes - Power Only Physical Condition 6 / 10 Working Condition 10 / 10 *Scroll down to view additional images for this listing and click to enlarge. **Please note we are not a repair shop and only restore what we own. ---------- SkyFi Audio - Curators of Vintage Audio Gear SkyFi Audio is a small startup business specializing in the purchase, reconditioning, and reselling of high end audio equipment. We only buy equipment that we admire and are passionate about. No mid-fi, no gimmicks, no junk. Each piece of equipment is cosmetically restored and fully tested in our well-equipped lab by an engineer with 30+ years of experience in the HiFi world. If it does not meet or exceed the original manufactures specifications, it will not be sold. We are very selective about the equipment we purchase, focusing on mostly analog, high-build quality, American, and European built units. Please note we are not a repair shop and only restore what we own. Through our sister company, which is an authorized dealer for McIntosh, Audio Research, Sonus Faber, ClearAudio, Project, and Sony ES, we have access to OEM parts, service, and support. ---------- PURCHASING GUIDELINES: 1) This item will be professionally packaged and insured for safe transit to your home unless you opt for local pickup from our shop. All local pickup items are only wrapped in industrial strength clear stretch wrap if the original manufacturer packaging is unavailable. Local pickup is available in Glen Rock, NJ, 07452, just a half hour drive from Midtown Manhattan, with convenient parking near our building. If we don’t have the original packaging, we use heavy-duty double-ply corrugated boxes with custom made to your item SealedAir Instapak expanding foam custom inserts. In many cases this has proven to be better than the original packaging! We also use high quality fiber reinforced tape to seal our packages. Lightweight items will be bubble wrapped and shipped in a high-quality box. 2) We will not review or accept any offers that do not go through the official eBay system. We have too many items for sale and it’s nearly impossible to keep track of offers outside of the official system. Please do not message, email, or text any offers. 3) All listings are eligible for the eBay Global Shipping Program unless the item exceeds the maximum weight/price requirements to your country. If this is the case simply message us via eBay. We only accept bank wire transfers for international payments and frequently ship worldwide via UPS. 4) Please ensure your shipping address is correct within eBay as we will ONLY ship to the eBay/PayPal Confirmed Shipping Address. No exceptions. 5) eBay may charge and collect sales tax to your state/jurisdiction which we have no control over. eBay v1.7 × × × × × × × × × × × × × × × Buy now and save! Tell a friend Visit store Watch now Postage info UPS Ground - $0.00 Local Pickup - $0.00 Click the Postage tab above the listing description for more info Additional delivery notes PICK UP OPTION Our items are available for pick-up. Pick up procedure is as follows: Purchase the item through eBay Email us to coordinate pickup PAYING VIA PAYPAL We accept PayPal on our all our items so you can shop with confidence. Simple choose the PayPal option when proceeding through the checkout. Additional Information No additional information at this time Ask seller a question You might also like Dynavector 10x3 High-Output MC Phono Cartridge Music Reference RM-5 MK II Tube Preamplifier with Phono Music Reference RM-9 Tube Amplifier With EL34s Marantz Model 150 Vintage AM/FM Tuner with Scope Contact To contact our Customer Service Team, simply click the button here and our Customer Service team will be happy to assist. Ask seller a question © SkyFi Audio Postage Click the Postage tab above the listing description for more info Payment Accepted Payment Methods PayPal Returns Returns are not accepted Seller will pay for return shipping. eBay integration by
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