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Is the Benchmark AHB2, in mono mode, really better than my Mark Levinson No. 536 monoblocks?

dlaloum

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JSmith
I have limited experience with metal dome tweeters...

In the mid-80's I worked in "Hi-Fi" and the store I worked at, stocked both Soft Dome Boston Acoustics speakers (A60 to A400) and several bookshelf Magnat speakers (cannot recall the model).

All I can say, is that back to back comparisons between similar size/price models between BA and Magnat supported some of the stereotypes around metal dome tweeters... somewhat harsh, overly bright high end, tiring to listen to for extended periods... etc...

I really loved those BA soft dome tweeters - sounded great - In some ways kept up with the Quad ESL-63's that we also stocked.

To this day I have not heard a metal dome tweeter that I loved.... but most of my exposure has been brief listening "en passant" typically at audio shows.
 

Kijanki

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JSmith
Interesting article. I'm sure there are some great metal dome tweeters, including Beryllium, but in my experience cheap metal dome tweeters are prone to sound brighter than cheap soft dome. I do not claim that all metal dome tweeters are bright - just stated that metal dome tweeter could be causing brightness (since I had one). I'm just trying to say that covering system brightness (whatever is the cause) with warm sounding amp is a bad idea.
 

Darkscience

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Recordings vary so wildly so using the amp as a tone control is futile use actual tone controls or EQ .

You know your getting close (IMHO) when you system sound very different with different recordings. If there is a sameness to everything even if it’s pleasant it ain’t rigth a s I see it ?

But it’s a kind of daft argument regarding the amps in question none of them seems to reach audible levels of distortion anyway :)
This is my experience with my AHB2. I can just hear what the record sounds like, they are all different.
 

Darkscience

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Since the OP's speakers are pretty sensitive and he also appears to be using a subwoofer is two AHB2's actually going to sound any different to one?
This is exactly why I am reading this thread. I have 1 AHB2, but am thinking of adding another.
 

Darkscience

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I upset my plans. After three weeks of waiting, I cancelled the AHB2 order. Benchmark told me the wait would be that long and they were just about to ship when I cancelled. I instead purchased the Dutch & Dutch 8c speakers. I can say the D&D are very nice but the software is not as good as it should be for a $15k pair. Also, the Revel F328Be are simply more powerful and just as clear. I may still get the Benchmarks at some point but after considering all the available data I suspect I wouldn’t notice an improvement over my ML monos. So, for now, I’ve got to busy myself likely returning the D&D and going back to my Revel+ML setup.
Ive been reading eagerly awaiting your impressions, this is a curve ball.
 

dualazmak

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Although quite belated, I just came to this interesting thread.

In August - September 2020, I rather intensively (mainly subjectively) tested and evaluated AHB2 in my multichannel multi-driver (multi-way) 5 way 10-channel stereo multi-amplifier project where I use the still-amazingly-excellent Yamaha Beryllium midrange dome; I intensively compared AHB2 with Accuphase E-460 and Rotel RB-1582 MkII;

- Benchmark AHB2 (class-A[H]B)_Part-1_Comparison with ACCUPHASE E-460 in Single-Amplifier + LC-Network full range reference sound system: #253
- Benchmark AHB2 (class-A[H]B)_Part-2_Incorporation in multichannel multi-amplifier system and Listening sessions: #258, #265
- Rotel RB-1582 MkII (class-AB)_Part-1_Comparison with AccuphaseE-460 and Benchmark AHB2 in single-Amplifier + LC-network full range reference sound system: #263
- Rotel RB-1582 MkII (class-AB)_Part-2_Incorporation in multichannel multi-amplifier system and listening Sessions: #264, #265

If you would be interested, you may find many of my subjective comparative impression on AHB2 in the above referred posts.

Unfortunately, at present, since the Japan domestic sales of AHB2 has just started in July 2020 through one sole import company and distribution channels/shops, the price of AHB2 is still rather high of ca. JPYen 462,000 (or USD 3,725 by JPYen 124/USD) inclusive of VAT and shipment. Even though the sole import company declares one-year warranty and possible repair arrangements (by sending back to Benchmark in NY?), we are not yet fully sure for these service system and arrangements on AHB2.

Consequently, I felt it would be better for me to postpone my purchase of AHB2 in Japan for some while, about one or two years, to see the business continuity and the real implementation of the service system on AHB2. It may be also possible that updated new version of AHB2 MkII (?) would be released during the coming a few years, I would really expect it.

(Just for your reference, you would please find my present exact system configuration in my post here.)

As I wrote in my post #292 there (the Plan-3 diagram in that post), I still have my dream amp plan to use two of AHB2 dedicatedly and directly driving each of L & R woofers in my multichannel multi-amplifier system, or I would hopefully use four of AHB2 in that plan-3 diagram.

I do hope the price-down of AHB2 in Japan and its reliable and speedy warranty and repair services would become reality in the near future.
 
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Darkscience

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Guys, I came here because I was feeling like I needed a change. I was thinking of selling the Cornwall and AHB2. Cleaned up my listening room, cranked my system up and I am in heaven again. No change needed, the AHB2 paired with the Cornwall is magic to me. I just needed to make my space more enjoyable and that did it. For anyone on the fence with the AHB2, all I can say is it works amazing for me. I am thinking of experimenting with a PS Audio S300 for variety, but only for that, not because I need it. Love the AHB2!
 

Darkscience

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0410221252_HDR.jpg
 

anmpr1

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This is exactly why I am reading this thread. I have 1 AHB2, but am thinking of adding another.
It's a dilemma, for sure. Can my experience help? We should learn together.

My main loudspeakers are (plus or minus) 105dB/watt sensitivity. I always thought how one stereo AHB2 might be too limiting. Did I need mono amps? Was I choking the signal? Although I never saw the clip LED flash, I always worried that I needed more power. Perhaps my hearing was too fast for the LED? A reasonable worry, for sure. But was it reality based?

Investigating the literature, I found my condition was listed within the Fifth Edition, text revised version, of DSM (I always keep a copy handy, for both friends and relatives, as a precaution). At first I didn't want to face it, but I had to eventually admit that I suffered from the dreaded Audio Nervosa NOS 3.15, (unspecified with acute situational features).

It was then that I knew that I had to either confront my disease, or go involuntary to the ward.

How did I solve my audio anxiety? Well... in my main system I changed out the AHB for a twelve watt/ch 6v6 push-pull tube amp, and moved the AHB to my secondary system, one using only 95dB/watt speakers.

Now I sleep better at night. My nightmares have subsided, and when the Pink Floyd alarm clocks go off, I'm entirely rested, ready to face the new day.
 

Darkscience

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My wonder is if adding a second AHB2 will make the sound different. I am going to assume if it is different it must also be better because 2 is more than 1? But not really sure, I think a year or so ago when I was first going down this path I had read that two AHB2 will actually not make the sound better but worse. Only way I will ever know is to try it. I love the aesthetics of 2 mono blocks and that in itself might make the sound better, or it could make it worse knowing it did nothing but cost money. I have little to complain about though, the sound today was terrific. I do feel like I need to really get the speakers loud to make them sound their best, I do not know if this will still be the case with mono?
 

kongwee

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My wonder is if adding a second AHB2 will make the sound different. I am going to assume if it is different it must also be better because 2 is more than 1? But not really sure, I think a year or so ago when I was first going down this path I had read that two AHB2 will actually not make the sound better but worse. Only way I will ever know is to try it. I love the aesthetics of 2 mono blocks and that in itself might make the sound better, or it could make it worse knowing it did nothing but cost money. I have little to complain about though, the sound today was terrific. I do feel like I need to really get the speakers loud to make them sound their best, I do not know if this will still be the case with mono?
In youtube, someone compare stereo and monoblock AHB2. Eventually, how much do you drive you speaker? If you able to achieve half volume at your pre with AHB2 gain setting. That is loud enough for you. Properly, you won't need mono bridged.
 

dlaloum

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Just a reminder - when you run an amp "bridged" (aka- "monoblock")- you get twice the power, but it is equivalent to halving the impedance of your speakers... so the current demands on the amp will double...

If your speakers are 8ohm+ that probably won't be an issue. But if your speakers are 4ohm (or less) - then the amp may well "run out of steam".

As a rule of thumb, if an amp can handle 4 ohm speakers, then bridged, it can handle 8ohm speaker, if an amp can handle 2 ohm speakers, then bridged it can handle 4 ohm speakers.

If you have speakers that are "difficult" (eg: impedance curve drops below 3 ohm or 2 ohm) - then running an amp in "monoblock"/bridged mode can actually take you backwards.

Your amp will only provide the bridged level of power, if its power supply can provide the current required at half the impedance (which doubles the current required) - the higher the impedance of your speakers, the less current is required - and vice versa.
 

DonH56

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Bridging doubles the voltage and thus quadruples the power. Whether or not the amp's power supply and thermal management can support the power is often a question. The load as seen by the amplifier is effectively halved and current requirement doubled as stated above. Output impedance is doubled (damping factor is halved), noise is increased by ~1.4x (sqrt(2)) but voltage doubles so maximum SNR increases by 3 dB, some distortion products may be reduced and others increased, etc. Seems like this has been said before.

The AHB2 has very sophisticated monitoring and clipping indicators. If they are never flickering now, you do not need to bridge your amps.
 

sarumbear

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If you have speakers that are "difficult" (eg: impedance curve drops below 3 ohm or 2 ohm) - then running an amp in "monoblock"/bridged mode can actually take you backwards.
I’m not sure I’m following you. How can two amplifiers in series be worse than a single amplifier?
 

avanti1960

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Some people place a great deal of significance on "Class A" amplification, even for just the first few watts. I don't understand why.
For the two class A amplifiers I have owned / currently own, there is something about their speed and micro dynamics that set them apart from my other class AB amplifiers. They also seem to keep complex music better organized and timed.
Hard to imagine until you compare amplifiers back to back like I did but it is very noticeable once you hear it.
Something about the "always on" nature of an inefficient class A design which I am not qualified to comment about technically.
I am sold.
FYI it is this speed and immediacy that prevents me from trying the Benchmark amps, which have been somewhat maligned for not being the top of the class dynamically.
 

avanti1960

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I have limited experience with metal dome tweeters...

In the mid-80's I worked in "Hi-Fi" and the store I worked at, stocked both Soft Dome Boston Acoustics speakers (A60 to A400) and several bookshelf Magnat speakers (cannot recall the model).

All I can say, is that back to back comparisons between similar size/price models between BA and Magnat supported some of the stereotypes around metal dome tweeters... somewhat harsh, overly bright high end, tiring to listen to for extended periods... etc...

I really loved those BA soft dome tweeters - sounded great - In some ways kept up with the Quad ESL-63's that we also stocked.

To this day I have not heard a metal dome tweeter that I loved.... but most of my exposure has been brief listening "en passant" typically at audio shows.
Great sounding metal domes are out there- it takes a more complex crossover to make their breakup modes inaudible but it can be done.
See Harbeth for example. Super smooth metal domed tweeters with natural detail.
 

Darkscience

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For the two class A amplifiers I have owned / currently own, there is something about their speed and micro dynamics that set them apart from my other class AB amplifiers. They also seem to keep complex music better organized and timed.
Hard to imagine until you compare amplifiers back to back like I did but it is very noticeable once you hear it.
Something about the "always on" nature of an inefficient class A design which I am not qualified to comment about technically.
I am sold.
FYI it is this speed and immediacy that prevents me from trying the Benchmark amps, which have been somewhat maligned for not being the top of the class dynamically.
Speed and immediacy? Can you explain what you are talking about? My AHB2 reproduces the music with no distortion, it comes out at the same speed as any other amplifier. You sound like someone who likes the colored sound of whatever amp/speaker combo you own, (perfectly fine with me). Dynamics come from the music, the band/singer plays soft or loud, this has nothing to do with the amp.

If your speakers are hard to drive and the amp is losing power that is something else, but I do not think that is what you are talking about. Until the amplifier is clipping you are getting full dynamic sound.
 

sq225917

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Try a very good class A amp against a middling ab amp and the crossover distortion might be audible. Though I know of no class A amp that manages thd and noise within 20db of the benchmark amps, so you might just be enjoying the harmonic noise profile of the class A amp vs the lack of any on the ahb2
 
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