Mark Levinson No. 23.5 vs new Class D power amps?

[pantera_rapida]

I saw a Mark Levinson No. 23.5 power amp for sale and read up on it, reviews of that time (decades ago) are super positive about the power, performance and capability of this power amp.

I got to wondering how the newest (2023/2024) Class D amps that are smaller, less costly (some of them) and consume less power, yet put out prodigious power (400 watts at 8 ohms, etc.) would fare against this amp (and others of that era) from brand names? Are they as musical? Will they be around in 30 years?

Has anyone done a direct comparison of their Mark Levinson No. 23.5 and a Class D? Or done data specs/measurements on the Mark Levinson No. 23.5?

 

[Doodski]

Will they be around in 30 years?

I don't think anybody really knows the answer. We'll wait and see I guess.

I got to wondering how the newest (2023/2024) Class D amps that are smaller, less costly (some of them) and consume less power, yet put out prodigious power (400 watts at 8 ohms, etc.) would fare against this amp (and others of that era) from brand names? Are they as musical?

I looked at the specs for the ML No. 23.5 and while they are good from 8 Ohms to 4 Ohms they do not exceed the better class D amps of today. Some of the better class D amps today have excellent 2 Ohms drive linearity. I suspect other than the bullet proof long life expectancy of the No. 23.5 that the class D would be better than the No 23.5

I am all about the power output linearity of the unity gain stage (Current amp section of the amplifier.) and the signal path linearity from input to output because in my opinion that is where the magic happens per say. The control over the varying loudspeaker impedance (Z) comes from the power output linearity and I believe that the subtle small differences in imaging and impact detail come from the power output linearity of the unity gain stage. I am very interested in reading what the experts here at ASR that have super strong skills in this topic have to say and please dissect my ideas if you will and set the record straight for me and all here.

 

[Doodski]

as anyone done a direct comparison of their Mark Levinson No. 23.5 and a Class D? Or done data specs/measurements on the Mark Levinson No. 23.5?

Stereophile did a test review and measurements.

Mark Levinson No.23.5 power amplifier

"A high-quality amplifier must be capable of passing rigid laboratory measurements, meet all listening requirements, and be simple and straightforward in design in the interest of minimizing performance degradation..."—Cdr. Charles W. Harrison Jr., Audio, January 1956 (footnote 1) "It don't mean...

www.stereophile.com

 

[Mikig]

beautiful ML 23.5. but if you want to buy it, check:

- that it is healthy, not manipulated

- remember, ML spare parts are now a rare commodity, take this into account.

- ask them to tell you if the capacitors are new or the original ones; the originals after all these years may be less and less efficient.

- check that, if repaired, it has been repaired by official centers or competent repairers.

If it is in good maintenance and box conditions, it is always a beautiful amplifier, with a great sound, and, subjectively, nice to look at and to have in the system.

 

[pantera_rapida]

With some prices for 23.5 models still in the $2-3000 price zone it makes sense to see where Class D amps are in that price range for similar power and performance. If anyone has actually listened to a 23.5 vs a new Class D I'd be curious to know the outcome.

 

[Theta]

I don't think anybody really knows the answer. We'll wait and see I guess.

I looked at the specs for the ML No. 23.5 and while they are good from 8 Ohms to 4 Ohms they do not exceed the better class D amps of today. Some of the better class D amps today have excellent 2 Ohms drive linearity. I suspect other than the bullet proof long life expectancy of the No. 23.5 that the class D would be better than the No 23.5

I am all about the power output linearity of the unity gain stage (Current amp section of the amplifier.) and the signal path linearity from input to output because in my opinion that is where the magic happens per say. The control over the varying loudspeaker impedance (Z) comes from the power output linearity and I believe that the subtle small differences in imaging and impact detail come from the power output linearity of the unity gain stage. I am very interested in reading what the experts here at ASR that have super strong skills in this topic have to say and please dissect my ideas if you will and set the record straight for me and all here.

Apparently, no one has run that test, however, if you read most of the power amps tests and comments from the most qualified members on this forum, (I am not one) you can pretty much deduct the folowing:

Class D amps are not a easily repaired as other classes of ampliers, if at all.
Contrary to a lot of comments, the good ones are not cheap.
Top sinad on this site has been awarded to a class H-G amplifier.
Also keep in mind that some experts, consider that the amplifier problem has been solved years ago.
My conclusions:
I can see no good reason to buy a class D amplifier despite all the hype.
In fact I would not buy a class D amp even with your money.

 

[SIY]

I am all about the power output linearity of the unity gain stage

What exactly does that mean?

The control over the varying loudspeaker impedance (Z) comes from the power output linearity

That comes from source impedance. Good class D amps have vanishingly low source impedance.

Owning an ML would be for non-auditory reasons. There's no reason to do a direct comparison, they'll both work fine, the Class D will just be much smaller, cooler (temp wise), and more efficient. It will also have lower distortion and noise, but since the ML is already more than good enough, that's just testmanship rather than something actually useful to an owner.

 

[Doodski]

In fact I would not buy a class D amp even with your money.

Thank you very much. I like a honest opinion.

I can see no good reason to buy a class D amplifier despite all the hype.

The total power consumption efficiency is a attractant but I have not seen what the efficiency ratings for class D amp are at varying total power draw levels are. Is it most efficient at low power consumption, high etc? Compared to the No. 23.5 the class D devices should be much more economical to operate.

Also keep in mind that some experts, consider that the amplifier problem has been solved years ago.

Yes, it has been solved although now with the recent expensive electrical power consumption rates that are only going up changes are occurring again.

Top sinad on this site has been awarded to a class H-G amplifier.

I am not a believer that SINAD is the end all of specs. I am as mentioned before all about input to output linearity and power output linearity.

Contrary to a lot of comments, the good ones are not cheap.

Yes, again you are correct. I thought wow these things are a great deal but the reality is that to get a nice linear power output model assembled unit with proper buffering and protection(s) and LEDs for indicators of features and operation costs a lot.

Class D amps are not a easily repaired as other classes of ampliers, if at all.

Yes, I agree repairs are at the master expert level if a technician can be found and although the protection circuitry in the better class D amps really beats the heck out of something like the No. 23.5 and the current limiting makes for some stable operation without releasing the smoke when under duress. The class Ds if done properly should be pretty reliable over the long term compared to a No. 23.5 and if the manufacturer uses proper and good quality caps with proper cooling the life expectancy can be doubled and tripled.

 

[Ron Texas]

I won't be around in 30 years.

 

[Doodski]

What exactly does that mean?

In reference to quoting me from this comment.>

Doodski said:
I am all about the power output linearity of the unity gain stage.

What I mean by that quote is that the output power transistors with the emitter resisters and the power supply of the amplifier (Unity stage.) make for the source impedance and I believe that the lower the source impedance the better more accurate imaging and detail occurs. This is where things always get to me because expert peeps here @ ASR stated that the linearity of power output does not matter that much. So I am questioning my thoughts versus the peeps thoughts.

 

[Theta]

Thank you very much. I like a honest opinion.

The total power consumption efficiency is a attractant but I have not seen what the efficiency ratings for class D amp are at varying total power draw levels are. Is it most efficient at low power consumption, high etc? Compared to the No. 23.5 the class D devices should be much more economical to operate.

Yes, it has been solved although now with the recent expensive electrical power consumption rates that are only going up changes are occurring again.

I am not a believer that SINAD is the end all of specs. I am as mentioned before all about input to output linearity and power output linearity.

Yes, again you are correct. I thought wow these things are a great deal but the reality is that to get a nice linear power output model assembled unit with proper buffering and protection(s) and LEDs for indicators of features and operation costs a lot.

Yes, I agree repairs are at the master expert level if a technician can be found and although the protection circuitry in the better class D amps really beats the heck out of something like the No. 23.5 and the current limiting makes for some stable operation without releasing the smoke when under duress. The class Ds if done properly should be pretty reliable over the long term compared to a No. 23.5 and if the manufacturer uses proper and good quality caps with proper cooling the life expectancy can be doubled and tripled.

Regarding power cosumption/ Class H-G amplifiers are more efficient then class AB like the Levinson. How many hours a day are you listening to music? And at what volume? If you realy want to be economical, better look at your AC or you sub-zero refrigerator.

I agree SINAD is not the "be all" judge of quality and musicality, but very useful and quite dependable when awarded by Amir.

 

[Doodski]

Regarding power cosumption/ Class H-G amplifiers are more efficient then class AB like the Levinson.

Yes, I forgot that while I was replying to you. I don't think that much about class H-G but now that you mention that and I know this already I agree.

How many hours a day are you listening to music?

Between 5 hours and >15 hours per day.

And at what volume?

As loud as can be without damaging my ears. Pretty loud.

If you realy want to be economical, better look at your AC or you sub-zero refrigerator.

That reminds me that I must decide if I am going to purchase a new floor standing model AC unit before the mad rush occurs when the heat hits this summer. My fridge is a brand new efficient model.

I agree SINAD is not the "be all" judge of quality and musicality, but very useful and quite dependable when awarded by Amir.

I do use SINAD to judge but not when purchasing. I look for total power output when purchasing and low load impedance amp power output comparisons.

 

[Mikig]

Questo mi ricorda che devo decidere se acquisterò un nuovo modello di unità CA da pavimento prima che si verifichi la folle corsa quando il caldo colpisce quest'estate. Il mio frigorifero è un modello efficiente nuovo di zecca.

think that I don't use air conditioning....it bothers me!! I have a problem, convincing my lady for the umpteenth year that the strong heat only lasts 10 days!!!

 

[Doodski]

think that I don't use air conditioning....it bothers me!! I have a problem, convincing my lady for the umpteenth year that the strong heat only lasts 10 days!!!

AC is a major game changer for personal comfort and life expectancy I think.

 

[Mikig]

AC is a major game changer for personal comfort and life expectancy I think.

yes, but it bothers me at home, especially in the bedroom!! I prefer open windows, but above all I prefer being outdoors! I get back into the audio world, generally from May to September, I no longer listen to music with my system. I'll start again with the first cold weather!! When I had the smallest music room, the tube, the Levinson 332, were stoves!! impossible to stay in there in July to listen!!

 

[pantera_rapida]

Class G as in NAD 2200 power amps? I have a pair of those I use regularly.

I was pondering whether to recap my 2200 power amps as they sound excellent with my current setup, but are about 40 years old. Or whether I'd be better off looking at a newer Class D amp? If possible I'd want to A/B a newer one of those amps with my setup first to understand if I can see the benefit of going that route. The ML amp, even at it's age, is still out of reach $$, and I'd be leery of how much it would cost to recap that behemoth....

 

[SIY]

I was pondering whether to recap my 2200 power amps as they sound excellent with my current setup, but are about 40 years old. Or whether I'd be better off looking at a newer Class D amp?

If the amps you're using have enough power, then no reason to change them. Yeah, replacing the electrolytic caps is good for PM, but be wary of increasing the capacitance in the power supply (as is often recommended by people who don't understand why that's a really bad idea)- use original values and make sure the rectifier bridge is up to any additional peak current with newer, lower ESR caps.

 

[Mikig]

Class G as in NAD 2200 power amps? I have a pair of those I use regularly.

I was pondering whether to recap my 2200 power amps as they sound excellent with my current setup, but are about 40 years old. Or whether I'd be better off looking at a newer Class D amp? If possible I'd want to A/B a newer one of those amps with my setup first to understand if I can see the benefit of going that route. The ML amp, even at it's age, is still out of reach $$, and I'd be leery of how much it would cost to recap that behemoth....

Many speak very highly of Zerozone mono. I would say that for 400 euros you get a pair. Absolutely, MLs are either perfect, and guaranteed to be perfect, or else they could become a bad experience. If you open one, you realize that there are "thousands" of components inside, and some parts of devices that are now 30 years old are starting to deteriorate. Furthermore, they often use Camacs, or you have special cables or there are plugs from RCA to Camac. However, if in good conditions they sound good, they are very pleasant, but clearly like many other modern amplifiers. If you like collecting, with the 23.5 you'll take home a pleasant and enjoyable piece of history, all there...

 

[Mikig]

replacing the electrolytic caps

it took me some time, but in the end I managed to change the capacitors on my 332.

I ask you a question: it still has a problem, but no, I think I can solve it myself: only on some frequencies, typically piano, high notes, right channel distorts. They told me it could be the right power board. Do you have suggestions? Thank you!!!

 

[SIY]

I ask you a question: it still has a problem, but no, I think I can solve it myself: only on some frequencies, typically piano, high notes, right channel distorts. They told me it could be the right power board. Do you have suggestions? Thank you!!!

That will take some close board-level diagnostics. Sorry I can't help remotely.