I assume you are talking McIntosh. If the two amps are equal in price, buy the newer amp if the seller can guarantee its reliability. Mac is reliable as a line but you want to know if either amp you decide to purchase has had any significant repairs. Not a switch not working or a lamp that failed but any work on the signal handling components. If so, make your decision based on that information. Replacement of the output transistors would be my primary concern and even that would not be that important if the work was done years ago and has withstood time and useage.
The newer amp will have more time before any parts show age and might need replacement, though this is more a 20-25 year process when you talk about aging of components. If you have any questions about service repairs of the amp, ask for the serial number and contact McIntosh. If they did the repairs, they should have records they would be willing to share.
Otherwise, Mac is, for the most part, Mac and which you choose isn't going to dramatically affect the sound quality. Mac has moved to better connectors and slightly more "audiophile" components over the years. If the newer amp has superior connectors compared to the 6300, then that would also push me in the direction of the newer amp.
Wattage is not a concern as the difference between two equal amps only differing in output power, say, 100 watts and 150 watts is not going to be heard under most circumstances. Consider cosmetics if you think you might be selling the amp in the future.
I agree with what Jan has said. However, to my ears, the 6900 sounds a bit better. Not a night and day difference or a sonic signature difference, but it just does everything a little better. While the power difference isn't night and day, the 6900 may handle more difficult speakers in a larger room better than the 6300 will.
The 6900 costs a good bit more than the 6300 new, so figuring out why they're about the same price may answer some questions. Is one new and one used? Is one a few years older than the other? Or maybe one priced too low and the other priced too high.
Asking for serial numbers and calling McIntosh is a great start.
The 6300 is transistor output, and rated 160wpc at 4 ohms and 100W@4 ohms, with binding posts for both connections. The 6900 is transformer based output, accommodating 2 ohm speaks as well, all @200 watts.
The 6900 has the awesome eq! Each knee point positioner is completely out of the signal path when center defeated.
From what I see on Mac's webpage both amps have the five band eq. The 6300 is direct coupled while the 6900 uses autoformers. Mac's autoformers are the best in the business but that wouldn't necessarily sway my decision. Direct coupled vs autoformers simply gives a you a choice of advantages and disadvantages, just like any other comparison in audio. If you have difficult to drive loudspeakers, you would appreciate the autoformers. However, if you have difficult to drive speakers, maybe you should consider another line. A Mac amp will sound better with almost any speaker than most of the competition but they expect you to not be silly about the speaker load.
There's a substantial difference in the weight of the two amplifiers but most of that is taken into account by all the iron and copper in the autoformers on the 6900. I'm not sure what DM means when he says the 6300 is "entry level" Mac. That's kinda like saying entry level PeterBuilt.
You're looking at this from all the wrong perspectives. First, there are literally thousands of non Mac pre amps you could choose from. To say a 275 will or won't pair with any one of those thousands is impossible. You'll need to be specific in your inquiries before we can provide good answers and you'll need to supply either a link to the specifications for the intended component or a link to where we can easily access them. We are, at this point, still guessing you are discussing McIntosh. We are not mindreaders, we don't know all model numbers and certainly not the specs for all models ever produced. You're going to have to be more specific in your questions and information giving.
Second, if you're asking about a tube amplifier paired with a non-tube or non- Mac pre amp because you feel Mac or tubes (and possibly solid state) have a particular "sound", you are headed down the wrong path IMO.
Next, you've thrown out a sufficient number of just model numbers asking for advice on each one to say to me you have no particular priorities for music reproduction from your components. You seem to have settled on a brand of component for some unknown to us reason and now you're shopping mainly by price rather than by thoughtful construction of a system. Buying a "deal" is not the way to find good sound.
Last, but not all, if you are considering a tube power amplifier, you need to be more concerned about your speaker selection than your pre amp selection. Tube power amplifiers - amd most especially those of the vintage variety which is pertinent here since the 275 is about to be a 50 year old design - have low current delivery and a high output impedance. This means this tube amp, like most tube amps, is not a good choice if your (modern day, meant for solid state) speakers have a low impedance and the situation gets worse should the speaker have a low impedance combined with a high electrical phase angle. The 275 has a four Ohm tap which will drive low impedance loads but the impedance load must remain relatively stable and not demand high current delivery from the amplifier. Tubes amps are not going to be completely successful driving a speaker with a wandering impedance load since they cannot supply the amperage needed to deal with the demands of the load. The amp's high output impedance means the frequency response of the amp will follow the ups and downs of the load impedance which will result in large peaks and troughs in the overall system response. A 275 will present excellent bass response and extended highs (the output transformers on the 275 are capable of passing a 100kHz signal) with the proper speaker buy might sound thin and rolled off on top with the wrong speaker. So your question should first be whether the 275 will mate well with either your existing speakers or speakers you intend to purchase in the near future. It will not like any of the B&W 800 series speakers but will excel when paired with a 16 Ohm Lowther. Once you buy a tube amplifier you have narrowed your speaker selection down to those models meant to be paired with a tube amplifier. There are plenty to choose from and those of us who understand mating amplifier to speaker have no problems with finding a suitable speaker. However, most tube amplifiers are disappointments not because of their actual sound quality but because the owners have no idea which speaker does not mate with a tube amp and they find their poorly thought out combination unsuccessful.
The 275 is a very good amplifier in its current (2010) design, it can be quite good if the vintage amp has been updated to modern components in certain areas and it can be a disaster if you are chooing based only on "the deal" you have found. When buying a 50 year old amplifier, unless you know audio quite well, I would suggest you minimize your potential problems by buying from a company such as Audio Classics. You'll pay more but you'll get the guarantees required to make such a purchase worth your money.
Otherwise, the 275 has a very low electrical sensitivity and can be problematic with certain pre amps (solid state or tube) should they have the modern convention of excessively high output voltage. If the taper on the volume control is too narrow, you'll have large amounts of wattage appplied to the speakers at a minimal rotation of the vc and, if the speakers you choose are very high in electrical sensitivity, there will simply be no room for small changes in volume as the levels will jump dramatically with the slightest rotation of the control. This can be an issue with some listeners and it can be worked around but in most cases a novice to tubes would probably be more successful pairing the 275 with a vintage pre amp such as the Mac C22. The vintage 275 also has a high 250kOhm input impedance, which can be good and bad depending on your system set up. You would certainly want to know the pre amp you buy can drive sufficient current into such a high input impedance or the dynamic range of the music will be restrained. This would tell me you need to be dealing with a retailer and not making choices off eBay or Audiogon. Buying vintage anything is not a job where you can just close your eyes and point to what you will own.
Mac has worked very hard to keep their house sound. I think their sand amps sound as close to the Mac tube sound as can be reached without compromising the concept of ss amps, but I like the transformer coupled amps better.
Arien, I have lived with, and still own the 6900 (but for sale). I tried the 6900 with an absurd load, and it stopped pretty quickly on heat. The 6900 has 2 ohm taps for this reason.
You have no such options on the 275.
I suggest you use some of the knowledge (and gear) available before going to a power amp, particularly, tubed.
The 6900 has 2 ohm taps for this reason. You have no such options on the 275."
There was no such thing as a "2 Ohm" speaker load when the 275 was designed. This sort of nonsense is the result of madern day designers with the feeling watts are cheap and, if they design a ridiculous speaker, it's up to the amplifier designers to catch up to their stupidity. However, the point remains, you need to know about what you are putting together and how the system will operate as a whole, not piece by piece. Even McIntosh didn't allow for a silly load just because they had two Ohm taps on their amplifier. A two Ohm load made of several nominally high impedance speakers parallel/series connected together would have been the intention of that tap as whole house sound distribution has become far more fashionable in the last few decades. Designing an amplifier that could do double duty as an arc welder has never been Mac's intention.
Michael:: Obey size restriction for photo of what?:: 400x400 or something like that. Save at 72dpi and the file will be OK for monitor and download quickly, even with slower connections.
I dunno...someone is gonna run that bad boy at the limits in front of me, what did they do to it before...not sure about that as a sales pitch Mr Nuck..lol!
Thanks guys. Art, what will your amp do, when driven wide open for 2 hours? Exactly, you will never need to find out, I have done that for you.
Wait till you see the meters on the 402, Mikey, you will have a seizure, I will have a woodie, and the neighbors will have a 411 call. Art will not find it quite loud enough from Oregon.
Can you refresh us on your speakers and setup? Are you running a TT on the Mac? ================================================= This is the thing now Nuck, I'm using the same MA Silver RS6s...Sometimes I'm afraid I might damage the speaker hence I'm adjusting the low freq using the equalizer and setting to moderate volume level..
I would never drive my amp wide open for 2 hrs...thankfully I can still hear and have no need to...just sayin'! My speakers are so easy to drive that I get all the volume I need within the first few watts.
"I would never drive my amp wide open for 2 hrs... "
Your amp doesn't use Power Guard. You wouldn't have an amp or speakers left if you tried that. You cannot clip a McIntosh amplifier if it has been designed since the company incorporated Power Guard.
That's not an endorsement of running any amp full out, just an explanation of how the McIntosh works.
True, my amp doesn't use Power Guard, no doubt another excellent feature on an outstanding brand of amp. The quality definitely goes in before the name goes on with Mac.
I do love the sound of my Sonneteer and would not trade it for any Mac I've heard. Not because I think it's better but because it suits me relative to sound and how I use an amp.
Hard to fault anything Mac has designed and built. Gear that is built to last and sound great...nice combination.
I have never heard a Sonoteer amp, Art. From all that I have read (and you have posted), that is likely a better 'first watt' amp than what I own, and likely a very good reason for you to own it.
PS, the max power in the video is for demo purposes only, and maybe the occasional 'holy shite' factor for guests, hehe.
HI Nuck, thanks, that's what i have as well...some manuals and literature on MA 6900 have the HR070.....
Do you still intend to sell yours?
I'm really enjoying the sound of this amplifier, the brightness which was evident before when i was using my krell kav150A with MA RS6s was tamed down..now i can listen on extended period of time...
and oh the EQ is still really good thing for me because i don't have the space hence the speakers are a bit near the back wall so with the EQ i can adjust the lower freq to suit...
during the first setup i used the 8 ohms taps but when i read the manual it says that if the impedance is in between, used the nearest lower tap, so i'm now using the 4 ohms tap as the MAs are 6 ohms...
at the moment i'm still enjoying the MA 6900 but i will soon re-setup my Sumo Athena pre+Krell KAV150A and compare the two...
The 8 ohm taps are fine, I bet, with those MA's. The lower taps are there if the amp gets too hot driving the speaker load. This will vary with speaker wiring and so on, but temp is the telling sign.
I still have the 6900 listed, I have one chap looking at it. i am trying to work with him, as he is self-confessed to needing help with the system build. I don't think this Mac will suit his needs exactly, however, so we may look in another direction to get him set up.
"The 8 ohm taps are fine, I bet, with those MA's. The lower taps are there if the amp gets too hot driving the speaker load. This will vary with speaker wiring and so on, but temp is the telling sign."
I'd have to somewhat disagree with that concept. To begin with, judging just how overly hot an amp gets is a rather less than ideal way to set up your system IMO.
The various taps are on the McIntosh amplifier allow for the most efficient transfer function of the power supplied to the speaker's not very stable impedance load. Judging the lowest point in your speaker's overall impedance will typically yield the best results when matching speaker to amplifier tap. As the manual suggests, if the low impedance point for your speaker falls between tap values, try the lower impedance tap first and then change to compare. Quite often the speaker's lowest impedance point is not easily defined (as "the load" is more complicated than just an impedance measurement) and you'll need to try various taps to get to what you believe is the "best" sound quality overall. If nothing else, you can use the various taps to alter the sound of your system to best suit your ears, your room and the rest of your system.
Connecting to a lower impedance tap will provide the full power of the amplifier (its transfer function) when it works into a low impedance load and conversely (slightly) less power into a higher impedance load. So you will often find you are juggling between what sounds best in the low end vs what sounds best in the upper octaves. Such is life with modern speakers having dramatic swings in their impedance load. Total distortion product will be optimized when the correct tap is used. More importantly, the output impedance of the amplifier is lowered with each lower impedance tap. None of this is dramatic, the amp is not going to change from 300 watts@ 0.01% THD to 100 watts@ 5% THD and the output impedance will not change from 0.5 Ohm nominal to 10 Ohms nominal simply by changing tap connections. But matching the taps to the load is going to change how the system - amp and speakers combined - sound and operate. You paid for the best so it works to your advantage to find how the amp best mates to your speakers.
Any transformer - or in this case, autoformer - coupled amplifier will have a higher nominal output impedance than a comparable direct coupled amplifier (one lacking output transformers). If you've chosen your speaker well (remember we discussed matching speaker to amplifier?), this slightly higher output impedance is not a serious issue for discussion. However, should the speaker's impedance load wander around with frequency (as many modern day, multi-way speakers tend to) this constantly changing impedance load of the speaker interacts with the output impedance of the amplifier in ways determined by the familiar Ohm's Law calculation to subsequently alter the frequency response of the system in ways that might lead to disappointment with the system's overall performance. Additionally, (and this is important if you're the typical rocker/headbanger) as the output impedance of the amplifier drops with connection to lower taps so will the damping factor of the amplifier increase. When you compare the sound of the direct coupled Krell to the sound of the autoformer coupled McIntosh you are very likely going to notice the "tighter" bass response of the Krell due to its excedingly low output impedance (a consequence of being "direct coupled"). While you may never match the Krell's tautness in the bottom octave with any tap on the Mac, experimentation with which tap provides the best pairing of speaker to amp will change just what you make of this comparison. On the other hand, if you prefer the fullness and roundness (Mac fans will say "musicality") of the Mac in the lower octaves, raising the tap connection might actually provide more of what you are selecting as a personal preference.
Of course, the lowest octaves are not the only place in a modern speaker's impedance curve where the amplifier will respond to the load. If the MA's have a rising impedance in the higher octaves, you might find a more pleasing combination with one amplifier tap over another for those reasons also. Ohm's Law works at all frequencies though damping factor is really only a concern in the bottom end with most speakers.
Mac does not believe in the arc-welding current delivery of an amp such as the Krell. Admittedly, the Krell exceeds at driving extremely difficult loads and would be a good choice if that's what you've chosen for a speaker. However, once again, matching the amplifier's output tap to the speaker's load is going to provide the best current delivery into any reasonable load. This becomes more of a concern as the speaker becomes ever more dramatic in its impedance swings until finally you have to give way to the welding gear if that's the type of speaker you prefer. If extremely high current delivery is an issue with your speaker (which it shouldn't be with the MA's), then you want the best transfer function possible to supply the needed "power" to your system. The amp will run hotter as it works harder to drive difficult speakers. So, yes, as Nuck suggests, if the amp is really working hard to drive the load, the amp will prefer a better match to tap with speaker. It's a rather strange way to determine which tap is best suited to your speaker though.
Overall the MA's should be rather easy to drive speakers and it will be up to you to decide whether the 8 Ohm or 4 Ohm tap serves your system to the best of the amplifier's ability and also provides the most pleasing sound to your ears.
Now, Nuck likes his music - to my ears - exceedingly loud and for long periods of time. Check out his video to see how he compares to you in this respect. He likes to serenade the weeds in his backyard just before he pulls them. Under these conditions I don't doubt his amplifier runs quite warm most of the time as he uses the Mac's Power Guard lights for general illumination. If you run your system in a similar fashion, provide the highest amount of air flow to the amp. But I wouldn't be judging which tap is best for your speakers by how long you can leave your hand on the heatsinks. Judge by sound quality at reasonable volumes and you should do just fine.
Oh for heavens sakes, I am not a ham fisted neanderthal with a need for police visits. I simply do not wish to own something that can only do 75% of potential. I need to know what is likely to break or need $ thrown at it in the future. If others can gain from my foray , then I do not mind sharing. Now back to the 1.2KW subs...
The 6900, I guarantee, will be happy on the 8 ohm or 4 ohm taps. The MA's are a reasonable load.
He is using the Gallo's 2nd binding posts which engages the 2nd driver in the woofer supporting frequencies down below his functional hearing ranges. For the bass this serves in much the same capacity for the woofer as a super-tweeter does in support of the higher frequencies, in general there is a stronger fuller bass presence up into the ranges where Nuck's hearing can appreciate it. He is just doing it to a greater degree than most would care to.
Thanks JV and Nuck, I prefer the sound when using the 4 ohms tap... Also, I don't listen really loud as i live in a unit, the volume pot is at 9 o'clock position at most and i listen normally at night time so there's really no need to crank up the volume...sometimes i do make use of the "loud" function....
I heard the 1.6Q maggies with some big heavy Rowland amp, and that worked very well, Leo. With Mac power, yes, I think it would match electrically and sonically, depending on your musical tastes, but you might look at spending 3750$ on a power amp instead of an integrated?
If you come across a MC7300 for 2k$ or so....
Mike, thank you for your support and interest. the mono subs have really blown my mind and made me rethink things...like...how good is it going to be with another 402....
Arien, ideal speaker placement is a gooder solution than the loud button. But as loud buttons go, your Mac is less intrusive than some. The boost rolloff comes much earlier, but your volume may never reach that point.
I believe Mac still describes the operation of their "loudness compensation" control thusly, begin by setting the "volume" control to your loudest average listening level. Then adjust the "loudness compensation" control to a comforatble but not excessive level of compensation for your natural loss of hearing at lowered levels (the Fletcher-Munson Effect). After that setting has been established and proven to be useful for a wide variety of music material, do not touch the volume control for normal listening. Make your level adjustments by using the "loudness compensation" control only. Unless Mac has changed how their systems operate this should provide the best balance of compensation to your ability to preceive low and high frequencies. Again, unless Mac has changed their systems, the "loudness compensation" control boosts both low and high frequencies as it should according to the F-M curves.