The Dude Posted May 2, 2012 Share Posted May 2, 2012 I know its not comparing apples to apples, and I know its the first good 1 watt that matters. But what exactly will I loose/gain by switch my Kenwood basic m2a power amp rated at 220 watts a channel to a Mcintosh MC250, or MC1205, I was even considering the MC2100 but I thought for a extra couple hundred I could get the MC1205 with the pretty blue lights and gages. But these are the options I was thinking A. One MC250 and see how I like it B. If I like the above option then bridge either a set of those or a set of the MC2100s. C. Or just go with something like the MC2105. Now there are several options of purchaseing these. 1 strait to ebay or cl. for a good starting point. or 2 strait to someone like Terry Dewick were they are all ready good to go. Thats only two but you get the point. I know there are some that think Mcintosh isnt all that and some that think they are but I would like to find out for my selft. I mainly want to know if what seems to me to be great dynamic power I am feeling in my system will go away when dropping from 220watts to 50 watts. For gear I am using a Tubes4hifi kit VTA sp6, and Heresies(various sources). The 220 watts may be way to much to begin with. Thanks Duder Quote Link to comment Share on other sites More sharing options...
USNRET Posted May 2, 2012 Share Posted May 2, 2012 What can I say, for my Belles, Chorus IIs and Quartets I went from NAD, Sony, Pioneer and Onky to Mc and found, found eh, sweetness. A sound that some would describe as 'less harsh' while I would say "smoother". I really liked the Mc 2125 and 2105 but then I got a chance to check out the VRDs and that's where I am staying due to sound, looks, novelty, etc, etc. Do not be afraid to get a really good 2105 / 2125 but pay the bucks to get a good one or at least send it through someone reputable to get checked out and refreshed. Quote Link to comment Share on other sites More sharing options...
djk Posted May 3, 2012 Share Posted May 3, 2012 The Kenwood M2a is very scary, and they can blow sky high, and wipe out the speakers big time. The last one I fixed cost a fortune for the parts, special outputs only available from Kenwood. Any of the old McIntosh will benefit from freshening up the electrolytics. The MC2120/25 is better than the older MC2100/05. I currently have two 2120, a 2100, and a 250. The 2120s are a keeper. ****************************************************************** "Which caps are they DJK? I'll try them in my 2125." Add one 47µF across each ±42V rail at the main filter caps Add a 0.01µF~0.1µF film cap in parallel with C239, 240 (little board on the input jacks, very tight for space) Add a 0.1µF film in parallel with C203, 204 (input coupling cap to impedance buffer) Add a 0.1µF film in parallel with C207, 208 (output coupling cap from impedance buffer) Add a 0.1µF film in parallel with C219, 220 (feedback cap) Add a 0.1µF film in parallel with Q215, 216 (bias transistor) Add a 0.1µF film in parallel with C305, 306 (±15V regulator outputs) Add a 0.1µF film in parallel with D304, 305 (reference diodes for regulators) I cut off all the push on connectors in the power supply and speaker relay and soldered them direct. I soldered a pair of 0.1µF film across the speaker relay contacts and cleaned the relay contacts with a sheet of paper and applied De-oxit. I sprayed De-oxit on the RCA jacks, cleaned the input sensitivity selector switch (very important), and the edge connectors for the L and R amp boards. I removed the 10-32 screws on the main filter caps and used De-oxit before replacing. Do not move the chassis with the bottom off, the glass could crack. Put it on a small piece of carpet to help turn at different angles. The 47µF are under a lot of stress, I used 100V caps even though they only run at 42V. Even though this changes no measurable performance specification, it will change the sound more than you can believe. Jackhammer bass from an amp with a DF of only 14? ************************************************** I own a MC2100 and two MC2120s. Caps wear out. Even when not in use. This list is for the MC2100, electrically it is the same as the MC2105, just without the meters. Even though your old amp is still working, you have no idea how much of the music you are missing. The parts are inexpensive. Digi-Key is good, Mouser has no minimum order. Posted by djk (M) on July 11, 2004 at 04:29:36 In Reply to: Re: MC2105 @ $ 100 even @ 20 yrs old is a best buy for me. posted by julian4@telkomsa.net on July 06, 2004 at 14:58:04: The sound would benefit greatly from replacing a few dried out electrolytics, and adding a few film types here and there. C301, 302 is the main input coupling cap. It is a Mylar type so it is likely to be OK, upgrading it to a Polypropylene type with give a smoother sound to the high end (0.47µF). C307, 308 are emitter bypass caps, 100µF 15V. Replace with same type and add a 0.1µF film bypass. C309, 310 are the output coupling caps for the pre-driver section, 10µF 25V. While a film type would be better, size is a problem. The DC bias across this cap also helps out with its being an electrolytic. Replace with same type and add a 0.1µF film bypass. C303, 304 are the DC power supply caps for the front end, 470µF at 25V. Replace with same type and add a 0.1µF film bypass. C1, 2 are the feedback loop caps, 330µF at 3V. The signal goes through these so replacing these with new ones and adding a 0.1µF film bypass really opens up the sound. Go with as high a voltage as what space permits. C11, 12 are the DC supply caps for the voltage gain stage, 150µF at 50V. Replace with same type and add a 0.1µF film bypass. C201, 202 are the main filter caps, 39,000µF at 40V. These may be quite expensive new, although I have seen them surplus for very low prices. I would use then unless signs of leakage or amplifier hum are there. Add a 47µF at 50V cap in parallel with each. C203 is a multi-section cap that will be very hard to find a fresh date code. New caps are small enough that they may be wired to the terminals of the old one, leaving the old one in place. This cap is important as it provides the current for the diff pairs and the VAS. The sections go 80/80/150/50µF with the voltages being 200/200/150/150V. If you measure the voltages 100/95/90/80V are typical, so 200V caps are not really needed, but 100V is not enough. Quote Link to comment Share on other sites More sharing options...
The Dude Posted May 3, 2012 Author Share Posted May 3, 2012 The Kenwood M2a is very scary, and they can blow sky high, and wipe out the speakers big time. The last one I fixed cost a fortune for the parts, special outputs only available from Kenwood. Any of the old McIntosh will benefit from freshening up the electrolytics. The MC2120/25 is better than the older MC2100/05. I currently have two 2120, a 2100, and a 250. The 2120s are a keeper. You want to loan one of those out so I can try it[]. How about a MC2150 any experiance with those. Thanks for all the input I don't think I will be holding back when I come across the right deal. Quote Link to comment Share on other sites More sharing options...
jacksonbart Posted May 3, 2012 Share Posted May 3, 2012 brown stuff happens Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 3, 2012 Share Posted May 3, 2012 The Kenwood M2a is very scary, and they can blow sky high, and wipe out the speakers big time. The last one I fixed cost a fortune for the parts, special outputs only available from Kenwood. Any of the old McIntosh will benefit from freshening up the electrolytics. The MC2120/25 is better than the older MC2100/05. I currently have two 2120, a 2100, and a 250. The 2120s are a keeper. ****************************************************************** "Which caps are they DJK? I'll try them in my 2125."Add one 47µF across each ±42V rail at the main filter capsAdd a 0.01µF~0.1µF film cap in parallel with C239, 240 (little board on the input jacks, very tight for space)Add a 0.1µF film in parallel with C203, 204 (input coupling cap to impedance buffer)Add a 0.1µF film in parallel with C207, 208 (output coupling cap from impedance buffer)Add a 0.1µF film in parallel with C219, 220 (feedback cap)Add a 0.1µF film in parallel with Q215, 216 (bias transistor)Add a 0.1µF film in parallel with C305, 306 (±15V regulator outputs)Add a 0.1µF film in parallel with D304, 305 (reference diodes for regulators)I cut off all the push on connectors in the power supply and speaker relay and soldered them direct. I soldered a pair of 0.1µF film across the speaker relay contacts and cleaned the relay contacts with a sheet of paper and applied De-oxit.I sprayed De-oxit on the RCA jacks, cleaned the input sensitivity selector switch (very important), and the edge connectors for the L and R amp boards.I removed the 10-32 screws on the main filter caps and used De-oxit before replacing.Do not move the chassis with the bottom off, the glass could crack. Put it on a small piece of carpet to help turn at different angles.The 47µF are under a lot of stress, I used 100V caps even though they only run at 42V.Even though this changes no measurable performance specification, it will change the sound more than you can believe. Jackhammer bass from an amp with a DF of only 14? ************************************************** I own a MC2100 and two MC2120s.Caps wear out.Even when not in use.This list is for the MC2100, electrically it is the same as the MC2105, just without the meters.Even though your old amp is still working, you have no idea how much of the music you are missing.The parts are inexpensive.Digi-Key is good, Mouser has no minimum order.Posted by djk (M) on July 11, 2004 at 04:29:36In Reply to: Re: MC2105 @ $ 100 even @ 20 yrs old is a best buy for me. posted by julian4@telkomsa.net on July 06, 2004 at 14:58:04:The sound would benefit greatly from replacing a few dried out electrolytics, and adding a few film types here and there.C301, 302 is the main input coupling cap. It is a Mylar type so it is likely to be OK, upgrading it to a Polypropylene type with give a smoother sound to the high end (0.47µF).C307, 308 are emitter bypass caps, 100µF 15V. Replace with same type and add a 0.1µF film bypass.C309, 310 are the output coupling caps for the pre-driver section, 10µF 25V. While a film type would be better, size is a problem. The DC bias across this cap also helps out with its being an electrolytic. Replace with same type and add a 0.1µF film bypass.C303, 304 are the DC power supply caps for the front end, 470µF at 25V. Replace with same type and add a 0.1µF film bypass.C1, 2 are the feedback loop caps, 330µF at 3V. The signal goes through these so replacing these with new ones and adding a 0.1µF film bypass really opens up the sound. Go with as high a voltage as what space permits.C11, 12 are the DC supply caps for the voltage gain stage, 150µF at 50V. Replace with same type and add a 0.1µF film bypass.C201, 202 are the main filter caps, 39,000µF at 40V. These may be quite expensive new, although I have seen them surplus for very low prices. I would use then unless signs of leakage or amplifier hum are there. Add a 47µF at 50V cap in parallel with each.C203 is a multi-section cap that will be very hard to find a fresh date code. New caps are small enough that they may be wired to the terminals of the old one, leaving the old one in place. This cap is important as it provides the current for the diff pairs and the VAS. The sections go 80/80/150/50µF with the voltages being 200/200/150/150V. If you measure the voltages 100/95/90/80V are typical, so 200V caps are not really needed, but 100V is not enough. Good advice! Quote Link to comment Share on other sites More sharing options...
The Dude Posted May 3, 2012 Author Share Posted May 3, 2012 Do I understand this right, but 2120 is 120 watts without glass and 2125 is 120 watts with glass same with the 2150 and 2155 150 watts with or with out. Quote Link to comment Share on other sites More sharing options...
artarama Posted May 4, 2012 Share Posted May 4, 2012 The Kenwood M2a is very scary, and they can blow sky high, and wipe out the speakers big time. The last one I fixed cost a fortune for the parts, special outputs only available from Kenwood. djk, Soo.....how did the Kenwood sound when you finished, compared to the Mac's? 220W is scary period! I have an original (unserviced) M2 that sounded pretty good to my ears at one time, then I moved to a Scott 299. I currently don't use either and it's been a while ince I listened to either. I don't have any experiance with Mac gear except for a C-28 pre, and am interested in your comparison of the Mac's to the Kenwood. Quote Link to comment Share on other sites More sharing options...
djk Posted May 5, 2012 Share Posted May 5, 2012 I didn't really listen to it, I ended up having to sell it for the cost of the repair, the owner didn't want it back. They actually clip at about 350W/8Ω one channel driven. I sold it to a DJ with a pair of LaScala, and in short order both woofers and tweeters were ruined. I ended up getting the pair of LaScala back a few years later and re-furbished them. Quote Link to comment Share on other sites More sharing options...
billybob Posted May 5, 2012 Share Posted May 5, 2012 With Heresies, should OP expect headroom aplenty with the 50-105 Mc's? I would expect so but...do not know... Quote Link to comment Share on other sites More sharing options...
The Dude Posted May 6, 2012 Author Share Posted May 6, 2012 Ok maybe someone can clear something up for me. I was down talking to a local tech, who also sells audio gear out of his shop, to see if he had any older mc2105, or something of the sort. Long story short, he claimed a issue with some of the older MCs as they use a auto former. Now I know absolutely nothing about this sort of stuff, thats why I am asking but what would the issue be with them using a auto former. If there is a issue with them using them, then is there certain models to look out for. Quote Link to comment Share on other sites More sharing options...
bobdog Posted May 6, 2012 Share Posted May 6, 2012 Ok maybe someone can clear something up for me. I was down talking to a local tech, who also sells audio gear out of his shop, to see if he had any older mc2105, or something of the sort. Long story short, he claimed a issue with some of the older MCs as they use a auto former. Now I know absolutely nothing about this sort of stuff, thats why I am asking but what would the issue be with them using a auto former. If there is a issue with them using them, then is there certain models to look out for. The ones with the autoformers are the ones you do want. Personally I would not look at the ones without them. Quote Link to comment Share on other sites More sharing options...
kevinmi Posted May 6, 2012 Share Posted May 6, 2012 I'm not trying to start a war or anything but.... I went from a McIntosh 2125 to a tube amp rated at 60 wpc and I think the tube amp is every bit as powerful plus having the warmth of tubes. Of course the 2125 was old and not refurbished, and the tube amp was a new build. The 2125 did have a warm sound for a SS amp, though. Quote Link to comment Share on other sites More sharing options...
djk Posted May 6, 2012 Share Posted May 6, 2012 The difference between an MC2125 and a 60W tube amp is only 3dB, not all that much. You can drive the tube amp into clipping and raise the average power level into the speaker so it will play louder. Most well behaved amplifiers can be driven 6dB into clipping and most people can't hear it. Turn off the PowerGuard on the McIntosh and it will play louder than the tube amp will. Quote Link to comment Share on other sites More sharing options...
The Dude Posted May 10, 2012 Author Share Posted May 10, 2012 is it comin for the right channel on a mc2505 to go out if so what was the problem, what are the chances it can be a autoformer. I have found two of these units with the right channel not working. Quote Link to comment Share on other sites More sharing options...
djk Posted May 10, 2012 Share Posted May 10, 2012 Autoformer? Slim to none chance it's bad. Find a good shop, could be almost anything. Quote Link to comment Share on other sites More sharing options...
The Dude Posted May 10, 2012 Author Share Posted May 10, 2012 From the pics it looks pretty clean, I guess I will find out when it arrives hopefully safely[]. djk, You had some good advice on the 2125 for updates do you know of any for the 2505. thanks Quote Link to comment Share on other sites More sharing options...
djk Posted May 11, 2012 Share Posted May 11, 2012 Just compare the schematic with the schematic of the 2100 and use the mod same list. The only real difference is the extra outputs on the larger amplifier, they're basically the same design. Quote Link to comment Share on other sites More sharing options...
The Dude Posted May 19, 2012 Author Share Posted May 19, 2012 Recieved thursday, other then some real slight bubbling on the bottom left corner the face is in great shape. There is some rustting on the chrome but I read a thread somewhere that talks about cleaning it up. Now for the bad news yes I knew the right channel didnt work but when I plugged her in and turned her on some smoke came out from under the heatsink cover and I get nothing now from the left side. I opened it up but cant see amything so time to get out the volt meter amd do some checking. Quote Link to comment Share on other sites More sharing options...
Taz Posted May 23, 2012 Share Posted May 23, 2012 brown stuff happensIn my profession we call it the Hershy SquirtsTaz Quote Link to comment Share on other sites More sharing options...
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