McIntosh MC275 MK IV (2004-2006) Tube Amplifier

Description: McIntosh MC275 MK IV (2004-2006) Tube Amplifier - Complete McIntosh MC275 MK IV (2004-2006) Tube Amplifier - Complete General: Great sounding and collectible amplifier from McIntosh in its MK IV (MK 4) designation which is second next to newest. Not old enough to be considered vintage, but new enough to have all the reliability benefits of the newer generation models including balanced inputs and usable speaker terminal strips. The MK IV sounds as good, if not better than the current MK VI (MK 6), and foregoes what many think to be silly LED lighting on the tubes and the more complicated speaker binding posts. This amplifier was also fitted with a full set of official Russian Genalex Gold Lion KT88 and new McIntosh Branded JJ 12AT7 and 12AX7. The original tube cover "cage" is also included as well as the manual forming a complete kit, in superb condition. Best of all it will ship in an official McIntosh box for safe travels. SkyFi Technical Notes: Tube Notes: This amplifier was fitted with a strong testing set of Russian Genalex Gold Lion KT88 and new McIntosh Branded JJ 12AT7 and 12AX7. Brand Background: McIntosh Laboratory is an American manufacturer of handcrafted high-end audio equipment based in Binghamton, New York. The company was founded in 1949 by Frank McIntosh. The company designs and produces audio amplifiers, stereo tuners and other consumer electronics products. Ownership: Single Owner Connections: RCA and XLR Inputs, Removable Power Cord, Screw Terminal Speaker Connectors. General Sound: Big beautiful musical sound with little fatigue. Cosmetic Condition: 8/10 = Very Good. Excellent front faceplate, one minor flaw on chassis side or top. Working Condition: Working perfectly and tested in our lab and listening room. Included: Unit, manual, and power cord. Packing: Original Manufacturers Packing Specs: CONTROLS and CONNECTORS: • Speaker barrier strips for 4, 8 and 16 OHMS • XLR BALANCED INPUTS (L+R) • RCA UNBALANCED INPUTS (L+R) • UNBALANCED GAIN controls: 2.5V to 1.0V • MODE Switch: MONO or STEREO • INPUT Switch: XLR Balanced or RCA Unbalanced TECHNICAL SPECIFICATIONS: Power Output: 75 Watts Per Channel (Stereo Mode) 150 Watts Total Bridged (Mono Mode) Frequency Response: 20 - 20 kHz (+0 -0.2dB) Distortion: 0.5% Noise & Hum: -100 dB (A weighted) Output Impedance: 4, 8, 16 ohms in Stereo Mode 2, 4, and 8 ohms in Mono Mode (25 V line) Damping Factor: Greater than 10 Input Impedance: 100 k Unbalanced 180 k Balanced Input Sensitivity: 1.0 V Unbalanced 2.0 V Balanced (Unity Coupled) Power Requirements: 120V at 400 Watts Tube Complement: 4 x KT88/6550 output 3 x 12AX7A 4 x 12AZ7 (Solid state rectifier Bridge) Dimensions: 7-1/2" H, 12" W, 16" D Weight: 67 lbs. Approximate Age: 2005 Testing Process: 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 a modern Amplitrex AT-1000 Professional 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 1 KHz test signal, slowly increasing 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 1 KHz square wave check and a 20 Hz to 20 KHz 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 minimum. 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. 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. ---------- 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 v1.8 × × × × × × × × × × × × × × × 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 WyWires Silver Series Phono Interconnects - 5 Pin DIN w/ XLR Connectors - 4ft Music Reference RM-9 Tube Amplifier With EL34's 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

Price: 6480 USD

Location: Glen Rock, New Jersey

End Time: 2024-11-28T19:07:16.000Z

Shipping Cost: 0 USD