It's Decision Time

[kaarmstrong]

Originally Posted by Charles

Freddie, excellent question. First of all, I think you made the right decision regarding the 462 vs 1502 unless you had your heart set on the 1502. Why? Because of the problems inherent with tubes as chronicled in the previous comments. Tubes are not as reliable as transistors but transistors can also fail. Any tube amp needs reliable protection circuits and if they don't have them, you are taking a risk.

To answer your specific question. I have always considered a tube watt about 10X a SS watt. A well made tube power amp will not change in sound quality when it approaches clipping and when it clips it does soft clipping as opposed to the hard clipping of a SS amp.

In addition, a SS amp sounds its best when it is loafing and in some amps you get some class A at one or two watts. The Relentless is 100 watts class A but 1,500 watts class AB. So with this monster amp 99% of the time it will be operating in class A.

With a tube amp like the 1502 I think of it as operating in "class A" probably up to 175-200 watts/ch, since Mac always conservatively rates their tube amps.

There are many advantages of tube amps over SS. I personally have never liked them because of their unreliability. I have purchased a pair of 3500 MKII's. However, I will never sell my 1.25KW's for this reason.

However, I consider the 3500 the more powerful of the two amps (3500 MKII vs 1.25KW) as far as sound quality by a significant margin, since I will have the equivalent of 500 "class A watts". Again, when you read the description of the amp on the website, Mac says "conservatively rated at 350W/ch". My source at Mac says it will do over 500W/ch. The original did 550/ch even though it was rated at 350.

I would never use a tube amp for a sub. These arguments don't apply to subs.

Best

Charles

Charlies, I do not know of any McIntosh amp which is a class A amp including their tube amps. From everything I have read, seems is they are class AB with some early watts at class A. Please share where MC3500 is class A to 350 or 500 watts, I can't find those details any where and interested.
Thanks

[Fbgbill]

Originally Posted by Bwguy

Fbgbill,
I am curious your thoughts on the 611 as compared to the 462. Are you happy with the switch? What improvement did you find?

Are there big differences between the 462 and 611? Probably not that much but obviously more head room. I am very happy with the switch. I had always wanted mono blocks for some reason and at this point in my life I can afford them.

[McMan]

Life is short. I would recommend getting them both in time. Position the equipment so that you can swap cable efficiently.

I have an MC452 and Mc275vi. I love them both, and it is a beautiful experience to change the sound when I wish.

End game MC1.25kw and new MC3500 positioned.

[McMan]

Originally Posted by McMan

Life is short. I would recommend getting them both in time. Position the equipment so that you can swap cable efficiently.

I have an MC452 and Mc275vi. I love them both, and it is a beautiful experience to change the sound when I wish.

End game MC1.25kw and new MC3500 positioned.

Oh, but if you are going to use your amp for movies make sure you have SS. You’ll love the almost infinite power of the MC462.

[Charles]

Originally Posted by kaarmstrong

Charlies, I do not know of any McIntosh amp which is a class A amp including their tube amps. From everything I have read, seems is they are class AB with some early watts at class A. Please share where MC3500 is class A to 350 or 500 watts, I can't find those details any where and interested.
Thanks

Ka, That's the reason I put quotation marks around class A ("class A"). Since a true class A amp operates 100% at idle as well as full power, its sonic qualities don't change with increasing power demands. The same is true for tubes.

The really good watts reside at the first 10% IMO with SS amps unless they are true class A. For tube amps all the watts up to and even into clipping are equally good.

This is the reason speaker sensitivity is important. With my XVX I never listen past 120 watts peak. It will run you out of my room. Typically, I listen at about 6-12 watts peak. Although rated at 1,200 W/ch, my 1.25KW will do about 1,500 so for critical listening I have about 150 watts about the same as a 1502.

As for the 10% rule, this was Krell's stance when DA was CEO of Krell. I listened to an excellent talk concerning the Relentless where the presenter explainted it was both an extremely large amp and a much smaller one. The first 99 watts are true class A and that's where the sonics of this amp lie. To get this, look at the size of the amp.

If I could have any amp tube or SS regardless of price it would be the one. You have to decide whether you would like it more than a 3500 MKII. But its size and price eliminate it for me.

The 3500 is the ultimate amp for me. Other tube amps of comparable power are in the 65K to 75K for one mono amp. They are much larger, heavier, and have poorer S/N ratio. I believe Mac has the best circuit design of all the tube amps. They came up with it in about 1950. It's called unity coupled. It hasn't changed and never will change. It allows for much lower distortion, better S/N ratio, excellent frequency response, bias insensitive, and excellent reliability when compared to these amps without this circuit. .3% IM and harmonic distortion and S/N ratio of 120 db are in the realm of many extremely expensive SS amps.

Best

Charles

[Bwguy]

Originally Posted by Fbgbill

Are there big differences between the 462 and 611? Probably not that much but obviously more head room. I am very happy with the switch. I had always wanted mono blocks for some reason and at this point in my life I can afford them.

Yeah I just purchased 611’s, moving from a Classe 2300. I thought about the 462, but I always wanted monos as well. A little different sound as compared to the Classe,so adjusting. The Classe gave slightly more detail,but could be a little lean at times. The Mac is great in the mid and bass, with a slightly warmer sound. So far so good.

[miner]

Originally Posted by FreddieFerric

May I ask what speakers you are driving with the Mc's?

I am using Sonus faber Electa Amator III - I believe sensitivity is 89db. I use the with the Sf Gravis II sub in my small room (12 x 18 x 8 - open concept).

[FreddieFerric]

Originally Posted by miner

I am using Sonus faber Electa Amator III - I believe sensitivity is 89db. I use the with the Sf Gravis II sub in my small room (12 x 18 x 8 - open concept).

Just returned from the dealer where I had the option to pay for the MC462 and bring it home since they had one in stock, or... cancel that order and order an MC1502. I opted for the later. Paid for it in full.

So now the wait begins. Delivery is looking like mid February, but they told me there is a very outside chance that mid December is a possibility, but don't hold my breath.

Have to say getting back into tubes is rather exciting!

[McMan]

Congratulations! I hope it arrives for you mid December. It would be wonderful to have it for the holidays! Please post photos when it comes in.

[Msegal]

Originally Posted by kaarmstrong

Charlies, I do not know of any McIntosh amp which is a class A amp including their tube amps. From everything I have read, seems is they are class AB with some early watts at class A. Please share where MC3500 is class A to 350 or 500 watts, I can't find those details any where and interested.
Thanks

Any McIntosh tube amp using a Unity Coupled output transformer runs in pure Class B. The output transformer eliminates the switching distortion and allows the amplifier to run very gently in Class B.

Mike S.