Amplifiers for B&W 801 D4s

[ufguy73]

I am toying with the idea of changing up the amplifiers between my c1100 and my 801s. A few questions, in terms of power and spec match:

- Are the MC611s the optimal sweetspot match for these speakers?

- Would the new 3500s be ‘enough’ power and headroom for these speakers?

- Would 1.2KWs be ‘too much’ power for these speakers?

- Are there any risks of clipping or blowing out speakers with ANY of the above?

Thanks!

[miner]

Early on I had N804 with a MC252. Never clipped or under drove them. 611 will be a fine pairing.


Sorry, I initially thought I saw 804D4. Ignore my comment

[audiogear]

801D4s love power. Both the MC611s & 1.2KWs should have no problems powering the 801s though I've often seen more 801s paired with MC1.2/1.25KWs.

Have not heard the MC3500, hopefully AA owners will chime in with feedback.

[Charles]

Originally Posted by ufguy73

I am toying with the idea of changing up the amplifiers between my c1100 and my 801s. A few questions, in terms of power and spec match:

- Are the MC611s the optimal sweetspot match for these speakers?

- Would the new 3500s be ‘enough’ power and headroom for these speakers?

- Would 1.2KWs be ‘too much’ power for these speakers?

- Are there any risks of clipping or blowing out speakers with ANY of the above?

Thanks!

I can help with this. The 1.25KW's would definitely be the McIntosh solid state amplifier of choice. Unless you are willing to upgrade to a 1.25KW I would definitely not do it. Your speakers represent the ultimate in the B&W lineup at 38K/pair. I doubt there is much difference from it and the Signature other than pride of ownership much like the Anniversary Editions of the C-12000/MCD12000 and 2.1KW's. You have a super speaker. B&W takes a back seat to no one. One of the real problems that I see with folks pairing Mac amps to speakers like a Sasha DAW or your speaker is using something like a 611 or 452. While this will work, the new owner begins to experiment around with impedance and finds that the higher impedance sounds better than the 4 ohm nominal impedance, because they do not have a large enough amp and this leads to dissatisfaction. In your case however this is irrelevant because your speakers are rated at 8 ohms nominal, so while they love power, they are easy to drive. But you need the larger Mac amp, the 1.25KW, definitely. The rule is 10% for solid state amps (the D'AGostino rule) so with a 1.25KW you have 125 superb watts and a headroom of 1000 watts for peaks. So the 1.25KW is your amplifier of choice, if you really want to upgrade.

Now as to the 3500's. They are better amps than the 1.25KW's but they are also less reliable. They drive my XVX easily off the 4 ohm taps so for your 801's, they will do a superb job off the 8 ohm tap. In fact I would say that they would be absolutely perfect for your speakers. The 10% rule does not apply to them and you will have 400-500 watts available to you. With a sensitivity of 90 for the D4's this is more than enough power. IMO, they are the best and most powerful tube amps on the market. I would not trade them even for any other tube amp on the market and I am aware of all the tube amps. The bass they produce is incredible. There's nothing romantic about these amps. But their midrange and treble are very liquid detailed and extended. Coupled with the bass they produce, I've never heard anything like them, and the XVX requires massive current although its sensitivity is over 92 dB. Typically listening to jazz or just popular music they require no more than 3.5-35 watts but for live concerts or roller skating music, the sky is the limit with the XVX. I can't think of a better match for your D4's than a 3500. My preference for the 3500 over the 1.25KW is not a knock against the 1.25KW. There's no solid state amp on the market that I would swap for a 3500. The 1.25KW is a superb solid state power amplifier.

BTW, I'm going to be trading in my 1.25KW's. I have two that have just been setting there silent flanking my 3500's for over a year. Let me know if you are interested. They are in mint condition, untouched and unmoved by human hands, except the knobs, of course.

Best

Charles

[FreddieFerric]

Originally Posted by Charles

...The rule is 10% for solid state amps (the D'AGostino rule) so with a 1.25KW you have 125 superb watts and a headroom of 1000 watts for peaks. So the 1.25KW is your amplifier of choice, if you really want to upgrade.

Now as to the 3500's. They are better amps than the 1.25KW's but they are also less reliable. They drive my XVX easily off the 4 ohm taps so for your 801's, they will do a superb job off the 8 ohm tap. In fact I would say that they would be absolutely perfect for your speakers. The 10% rule does not apply to them and you will have 400-500 watts available to you.
Best

Charles

Hello Charles. Care to expound upon this "10% Rule?" I've searched hi and lo through google and come up empty.

[Charles]

Originally Posted by FreddieFerric

Hello Charles. Care to expound upon this "10% Rule?" I've searched hi and lo through google and come up empty.

It's from years ago when I used to own Krell. You're not going to find it written down anywhere. The old Krells that were made by Mr. D'AGostino had huge power supplies. My FPB 700 had a 6K watt power supply. The Krell dogma when Mr. D'Agostino owned Krell was the bigger the power supply and the larger the amp the better it sounded. Solid state amps need to loaf along to sound their best. This is not true of tube amps, which is why you hear that a tube watt is worth about 10 solid state watts. As a solid state amp becomes stressed, it can begin to sound hard. For example, when I was running my 1.25KW's with my XVX I could require 250-300 watts on live performances in my relatively small room. It was loud but you want a live performance to sound loud.

An XVX really needs a Krell Relentless or a MC2.1KW to do it justice. A 1.25KW cannot do it full justice. The XVX is a super speaker, maybe the best in the world which is why I bought it. The I.25KW is a very fine solid state amp but let's be honest, it's not remotely in the same league with my XVX, but neither is a Momentum or anything other than a top line Boulder, Burmester, Constellation, etc. costing hundreds of thousands of dollars. No, ufguy 73 needs a 1.25KW for his B&W's if he really likes to play them loud sometimes. It's an excellent amp; perfect for his speakers. Because you don't have to pay for engineering already expensed out, it is the equivalent of about a 40K solid state amp by other manufacturers. That's why Mac is such a good buy, IMO.

This is precisely the reason that folks with 452's or 611's opine that their speaker rated at 4 ohms sounds better off the 8 ohm tap. The amp will definitely supply more watts with the impedance mismatch but the price you pay is a hotter running overstressed amp.

I really liked the way my XVX sounded with my 1.25's. They sounded great. The XVX is an incredible speaker in that it is absolute reference quality but very forgiving and musical. I think it would sound good (within reason) with almost any amp. But I am under no illusion that they could match something like a Relentless matched to my XVX. On the other hand, my 3500's do a much better job. I wouldn't swap them for anything on the market. It really is a great/unique tube amp. Mac has the best tube circuit and the amp puts out 200-300 tube watts with the Mac tube sound that I remember as a kid. In my room it drives my XVX superbly, but in a larger room, you need the 2.1KW or a Relentless, etc. The new 2.1KW is the amp to match with my XVX in a large room. The XVX has no upper dynamic limit.

Best

Charles

Of course, these are just my opinions

[FreddieFerric]

^^Thanks for the reply Charles. I don't mean to derail the OP's thread, so I'll leave it with this understanding. What you're suggesting is that a solid state amp is at its best when it's only using up to about 10% of its rated power output. After that sound quality begins to degrade, so reasonably speaking the remaining 90% exists to handle the large dynamic swings that certain types of music may contain.

I understand a vacuum tube is a different animal with very different distortion characteristics, which may explain why my 1502 sounds so much better than my MA8000.

[Charles]

Originally Posted by FreddieFerric

^^Thanks for the reply Charles. I don't mean to derail the OP's thread, so I'll leave it with this understanding. What you're suggesting is that a solid state amp is at its best when it's only using up to about 10% of its rated power output. After that sound quality begins to degrade, so reasonably speaking the remaining 90% exists to handle the large dynamic swings that certain types of music may contain.

I understand a vacuum tube is a different animal with very different distortion characteristics, which may explain why my 1502 sounds so much better than my MA8000.

Fred, you haven't derailed the thread. And yes, that's absolutely correct. The March 2024 Stereophile reviews the Krell KMA-i800 mono power amp. Here's a quote (Dave Gordon speaking) from the review taken from p.73: "No one is going to use this much power, but it makes average listening levels, which may go up to 100 watts, sound much better, because as you approach the limit, your distortion goes up dramatically..." He goes to elaborate quite eloquently and it is exactly the D'Agostino 10% rule that I just stated. So here it is in print on p.73 March Stereophile under "Goals and Values" if anyone cares to read. I happen to agree with his view and also Mr. D'Agostino's from years ago.

Extremely large solid state amps are ideal for folks like me and ufguy who have large speakers that can play loud and soak up a lot of watts. These amps are excellent but a pair will set you back 73K. I think the 1.25KW is totally competitive with them at a cost of 27K. The KMA-i800 if you read the review has a lot of new engineering developed exclusively for it. And you pay for it. I have no problem with that. Most manufacturers when they introduce a new flagship or a new model, always include significant new circuitry. However, the 1.25KW simply improves the design with better parts like the Thermal Trak output transistors, larger capacitors, shorter circuit paths, Solid Cinch binding posts, etc. But the basic technologies do not change. I personally think that a 1.25KW is 100% competitive with the new Krell flagship at 36% of the price. I personally would prefer the 1.25KW. It will be in production long after the KMA-i800 has been discontinued and will outsell it probably 20 to 1. It weighs more than the Krell and produces as many watts. You must decide whether you like the Mac or Krell sound better. For me it's a no brainer. I have never said that Mac sounds the best but that the Mac sound is competitive with anyone's. I have just purchased a MC2.1KW. I received an excellent trade in for my three 1.25KW's. Why? because they are still in production and will be for many years to come. This will not be the same for the KMA-i800. It was not over a mere four years before the Dag Relentless was "improved" to the Epic for a cool 349K for a pair. If you have an unlimited budget just send your Relentless back for the upgrade costing thousands of dollars on top of the hundreds of thousands you have spent on the original purchase. I prefer the 2.1KW for 50K that will remain unchanged in production for the next 15 years. The wattage and weight and all specs for the two amps are comparable. I waited patiently for many years to buy this Mac amp

Best

Charles

p.s. I am using the Relentless as an example because I think Mr. D'Agostino is possibly the greatest of all the audio engineers. The same could be said for a Boulder, Burmester, Constellation, etc. flagship. They cost hundreds of thousands of dollars for a pair and will not remain in production unchanged over 5-7 years.

[ufguy73]

Appreciate the thoughts!

and Charles - I will let you know if end up going down the 1.25KW route....there is a great allure/appeal to the 3500, however, and I feel like that may be what I REALLY want!

On a separate topic, I am also hugely tempted by the MCD12000 as a spinner and DAC...the c1200 is quite nice, also, but I am not feeling the upgrade pull on that as much over my current c1100 preamp!

What I also need to decide is whether to try and pull the trigger on anything in the 75th anniversary form. I know the products are no different than the non-anniversary but there is irrational temptation on that front too lol

[Charles]

Originally Posted by ufguy73

Appreciate the thoughts!

and Charles - I will let you know if end up going down the 1.25KW route....there is a great allure/appeal to the 3500, however, and I feel like that may be what I REALLY want!

On a separate topic, I am also hugely tempted by the MCD12000 as a spinner and DAC...the c1200 is quite nice, also, but I am not feeling the upgrade pull on that as much over my current c1100 preamp!

What I also need to decide is whether to try and pull the trigger on anything in the 75th anniversary form. I know the products are no different than the non-anniversary but there is irrational temptation on that front too lol

I would actually prefer your C-1100 over the C-12000 for myself. Are you into vinyl? The phono Stage for the C-12000 is significantly improved over the C-1100. I'm not into vinyl and never will be. I think that the main difference between the C-1100 and C-12000 is the phono stage and the greatly improved flexibility being able to choose between solid state and tube. The C-12000 is a true bargain if you have the money. Look up the review of the C-12000 in the recent Stereophile. The measured performance is amazing. JA calls it among the best that he has ever measured. It received an A+ in every category and I suspect the MCD12000 would, if reviewed receive the same measured performance. I want gear that measures well and sounds good too. I want gear that meets its published specifications. The more expensive the gear, the more lousy it measures, usually. Typical examples of this are expensive tube amplifiers that don't come close to meeting their wattage specs. I won't name names.

The MC3500 is guaranteed to meet all its published specs and I understand that it will do 500 watts. It has a S/N ration of 120 dB and distortion of less than .3%. And the Mac tube sound is beyond compare. All this for 30K. I love mine. I think that you are on the absolute right track. I would go with the 3500/MCD12000/C-12000. Your B&W's are keepers. I almost never buy used gear but if you do decide to pull the trigger I might be interested in your C-1100.

Best

Charles