VINTAGE McINTOSH MC 250 STEREO AMP with MANUALS
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VINTAGE McINTOSH MC 250 STEREO AMP with MANUALS Picture and Description:
SquareTrade © AP6.0 RKelly5327 Store VINTAGE McINTOSH MC 250 STEREO AMP with MANUALS!! Description : ♥ VINTAGE McINTOSH MC 250 STEREO AMP with MANUALS!! ♥ When you say McIntosh in the electronics world its like saying Rolls Royce in the automotive world. One look at prices for used Macs will demonstrate that in a hurry. I do not like the idea of having to part with mine one little bit, but Ive found that the older you get, you think a lot more when it comes to moving heavy stuff around from one place to another, and this baby is heavy, weighing almost 40 pounds. I still have an old Roberts 997 reel-to-reel recorder that weighs about the same that will probably have to go this same route- eBay. I used to cart that Roberts all over the place, but that doesnt seem to appeal to me any more, either. J Even though Im somewhat familiar with the quality and reputation of Macs, I am really pleasantly surprised at the reputation these old 250s still have. Here are some facts and opinions Ive found on the net that may surprise you as they did me, and may well add to what you know or dont know about the MC 250: First from this site- http://6streetbridge.blogspot.com/2008/10/visit-with-mcintosh-mc-250.html The MC 250 used a transformer to couple the output transistors to the speakers. This seems to be one of the traits that make tube amplification great, so when I had a chance to buy a 250 I went for it. My McIntosh MC-250 was bought at a local record store for a bargain price of $325. (my emphasis) This amp is heavily biased into Class B and can produce big peak power when needed. History: The McIntosh MC-250 (metered version is the 2505) was McIntosh's first foray into the field of solid-state amplification. They certainly held off for awhile since the amp did not come into production until 1967. Most of the hi-fi companies about that time had left vacuum tubes forever. It could be argued that this sudden shift of technology led to the downfall of many of these companies. Early solid-state technology was tenuous at best and the first generation amplifiers were not known for their reliability. McIntosh wanted to get it right the first time. Of course McIntosh is a company that continues to follow the beat of their own drum. The MC-250 has proven to be a reliable beast, having survived the tortures of time with its own unique circuitry - notably the Autoformer and the Sentry Monitor which continue to be used in their top-of-line models. The autoformer is controversial, here is how Roger Russell explains it - From- http://www.roger-russell.com/mcintosh1.htm "Transistor power output circuits can match 8-ohm loads directly. This eliminates the need for the output transformer for most manufacturers. However, output stages that are designed to operate into an optimum load of 8 ohms can double or quadruple heat dissipation when operating into 4 or 2 ohm loads. At some frequencies, speakers rated at 8 ohms can dip as low as 4 ohms. Some 4-ohm systems can dip even lower. This mismatch can cause the amplifier to exceed its thermal dissipation limits. On the other hand, if an amplifier is designed for an optimum load of one or two ohms, a low impedance load would be no problem. However, less power would be available for a speaker having 4 or 8 ohms impedance. The unique McIntosh output autoformer was the answer. Since McIntosh output stages were connected in a single ended push-pull circuit, one side of the output was always connected to ground. They were typically designed to work into an optimum load of 2.1 ohms. The matching autoformer was connected directly to the output. In the MC2505 amplifier, the matching output was for 4, 8 and 16 ohms. Other impedances became available in later amplifiers. Full continuous amplifier power could be delivered to each of these loads. There was no danger of exceeding safe limits or overheating. The autoformer also protected the speakers from damage in the event of amplifier failure. Should a direct current component appear at the amplifier output, it was shunted by the low DC resistance of the autoformer, instead of passing through the speaker voice coil, which could damage the speaker or even cause a fire. McIntosh autoformers continued to be used in the "top-of-the-line" amplifiers. They were all designed and manufactured by McIntosh. Although the autoformers added extra cost, weight and took up extra space, they assured a safe, optimum match to a variety of speakers and speaker hook-ups. They were constructed and performed in the McIntosh tradition of excellence. Although the autoformer provided an efficient match between the power transistor output and a variety of load impedances, a short circuit at the amplifier output or a load that was much lower than the selected autoformer tap could cause excessive current to flow in the output transistors. To complement the new transistor amplifiers, the McIntosh Sentry Monitor circuit was developed which prevented destructive current levels from occurring under any conditions. This circuit sensed the dynamic operating time, voltage and current of each amplifier output stage and controlled the current flow, confining it to non-destructive limits. The arrangement assured complete circuit reliability for all load conditions. The Sentry Monitor did not limit the rated power output available from the amplifier in any way. McIntosh power amplifiers continue to use the Sentry Monitor circuitry." McIntosh is an American icon and they continue to make their amplifiers at their Binghamton, New York plant. The new ones are bloody expensive, but you can own one of their older amplifiers for a decent price. Do your ears a favor and check 'em out. http://www.audioscope.net/mcintosh-250-power-amp-230-volts-p-797.html The McIntosh 250 Power Amplifier. When it first hit the market, consumers were amazed by this Transistor Power Amp of the first generations. Enormous power resources and soft & tender sound... Just like the old tubes. The huge output transformers - representing the beginning of the McIntosh´s particular nature - perfectly controlled the 32 cm /12 inch woofer of our JBL 166 Horizon test speaker. Definitely not a neutral sound. With brilliant harmonic distortion in the entire frequency range, it made its way to one of the most significant and stylish amps ever built. others- The 250 is the immediate successor to the 240 and is as close to tubes as you are going to get without the heat. My first Mc was a 250 and it was good enough to get me hooked. from ebay- "I've been a tube amplifier listener for a long time and I bought this amp as a summer backup unit to drive my old Altec speaker setup. I was shocked how good this amplifier sounded. Very warm and with great dynamics, sounding much more powerful than its rated 50WPC. This amp is for the music lover and makes you forget about amplifier upgrades." **************************************************************************************************************************** A pretty scruffy looking chassis was listed here on eBay for almost $50. Another one with no topside parts at all except 2 capacitors was listed for almost $170. That says something about these Macs. CONDITION: Its really difficult to get good pics because of the reflections from the chrome. I think you can see there is some scuffing on the top of the transformers, but they still do not look bad. There is also some pitting on the chrome, but overall the unit does not look bad at all. One thing youll notice if you are familiar with these 250s is that three jacks have been added to the front. A shop did this and did a nice job. These jacks are a great added bonus. All you have to do is plug the speakers in instead of having to wire them to the strip or rig up a special plug to the socket. Wires were also fed out of the chassis directly to the terminal strips to facilitate changing the ohms factor. As the label on the transformer shows, the outside jacks are for speakers and the center one is for headphones. I have not used this for a few years now, mainly for the reason stated above; weight. I dont have speakers for it either, for the same reason. Its called downsizing, regrettably. The amp was performing just fine the last time I used it. For the same reason, weight, I am not taking returns on it, but as I said, it performed fine the last I ran it. Besides, even though Ill pack the best I can, its still possible for something to happen during shipping. Im not a store, just someone 75 years old trying to lighten my load. I hope you understand. One great PLUS for you is that I have the original manuals for this amp! I have the Owners Manual and the Service Information manual. I also have a pdf Owners Manual which is set up a little differently than the paper one. I will email that to you after the auction. If I forget, remind me! Between the two youll have good info on the unit. The specs on these things are incredible. The frequency range rated at both outputs is +0, - 0.25dB = 20Hz 20KHz; +0, -3dB = 10Hz 100KHz. The output tabs are provided for 4, 8, and 16 ohms for stereo and half those values for mono. Its rated at 50 watts set up on stereo or 100 watts mono. If you missed out on the last MC 250 listed here on eBay, you have another chance at one now. Dont miss out again. I wish you success in your desire to nab one of these before there simply arent any more to be found. I will be insuring this unit for whatever the final bid is. Im also shipping UPS so it can be tracked as it finds its way across the country to you. Shipping cost will be pretty high. Even so, I am not trying to make money on shipping. If you end up paying way over what the shipping costs me, I will refund that amount to you. If this eBay calculator comes up short, please expect to pay the difference. Deal? Id like to thank you for stopping by my page and checking this out. If you have any questions, please ask. I Shipping : Shipping via UPS. Insurance is required. Shipping to Continental U. S. only, unless prior arrangements are made. Payment : Please pay ASAP after the auction ends. PayPal only. click to Enlarge click to Enlarge click to Enlarge click to Enlarge click to Enlarge click to Enlarge click to Enlarge click to Enlarge click to Enlarge inkfrog terapeak i000000