Review and Measurements of Benchmark AHB2 Amp

[amirm]

Does this indicate that the sweep was performed high frequency to low and shutdown at about 45 Hz?

Correct.

 

[zalive]

Louder than I care to listen.
I have used Lorde Royals as a test track with Oppo UPD-205 -> Benchmark LA-4 -> AHB2 (low gain) -> Salon2's.
The AHB2 base amp clip indicators blink at about +14 and the upper section amp clips at +15.
I would bridge these amps if I wanted more.

I appologize in advance for the OT but jeez...why not use some decent music for a test track...

Out of curiosity: is there still a critical mass of manufacturers who adhere to this FTC rule in 2019? I remember in the golden age of car audio there was CEA-2006...

Personally speaking, doesn't matter if the AHB2 doesn't meet FTC. It's current rating for real world musical transients (a few seconds?) is a whole lot already given it's size, price and measurements. I think doing 190W @4 ohms for 5 mins while staying clean will already defy physics given the size of this amp. The declared specs doesn't say "FTC" so IMO no deception here.

Nothing wrong with the performance and a real music, the real problem are claims. AHB2 keeps low distortion numbers because it's measured with protection on. But continuous measurements are with protection off (which doesn't apply to a consumer product). It gives a false impression that this amp can perform with the lowest distortion up to its rated power at 4 ohm, while in reality it's not likely so - and you can't verify because you can't measure (yet we know protection kicks in for a reason). I've no objection with the performance, to me it's clear nevertheless, continuous power ratings which don't apply to the product being sold are false ratings.

If one looks better and thinks a bit, this one really doesn't look like an amp for a heavy load speakers. At least I myself wouldn't trust it in this respect.

 

[restorer-john]

Does this indicate that the sweep was performed high frequency to low and shutdown at about 45 Hz?

It wouldn't matter whether the sweep went high to low or low to high, as John_s mentioned it would shutdown at the high end instead.

 

[svart-hvitt]

I appologize in advance for the OT but jeez...why not use some decent music for a test track...



Nothing wrong with the performance and a real music, the real problem are claims. AHB2 keeps low distortion numbers because it's measured with protection on. But continuous measurements are with protection off (which doesn't apply to a consumer product). It gives a false impression that this amp can perform with the lowest distortion up to its rated power at 4 ohm, while in reality it's not likely so - and you can't verify because you can't measure (yet we know protection kicks in for a reason). I've no objection with the performance, to me it's clear nevertheless, continuous power ratings which don't apply to the product being sold are false ratings.

If one looks better and thinks a bit, this one really doesn't look like an amp for a heavy load speakers. At least I myself wouldn't trust it in this respect.

The first watt is what counts:

https://benchmarkmedia.com/blogs/application_notes/power-amplifiers-the-importance-of-the-first-watt

 

[RichB]

I apologize in advance for the OT but jeez...why not use some decent music for a test track...



Nothing wrong with the performance and a real music, the real problem are claims. AHB2 keeps low distortion numbers because it's measured with protection on. But continuous measurements are with protection off (which doesn't apply to a consumer product). It gives a false impression that this amp can perform with the lowest distortion up to its rated power at 4 ohm, while in reality it's not likely so - and you can't verify because you can't measure (yet we know protection kicks in for a reason). I've no objection with the performance, to me it's clear nevertheless, continuous power ratings which don't apply to the product being sold are false ratings.

If one looks better and thinks a bit, this one really doesn't look like an amp for a heavy load speakers. At least I myself wouldn't trust it in this respect.

It's not music I listen to, but it has tremendous bass and like much popular music it provides compressed, slammed volume.

Specifications that potentially do not match the shipping product are discouraging.
From John's posts it appears that this amp performs up to the performance specs into 4 Ohms until the protection is triggered condition and then mutes.
Once triggered, the AHB2 must be manually powered on to reset.
Users experiencing shutdowns would have something to complain about but I have not heard of any such reports.

- Rich

 

[restorer-john]

There's plenty of good reason to have user defeatable protection, not the least of which means the amplifier can be confirmed by third parties to actually hit its rated specification.

Remember the standard is only 5 minutes, not 1 hour or continuously forever. If a power amplifier cannot achieve its rated power into specified rated loads for a measly 5 minutes, the ratings are false.

Plenty of you guys drive cars with top speed limiters that are not defeatable (easily). But the car makers do not advertise top speeds you cannot achieve, they just fit speedoes with numbers the dial pointer never quite reaches...

As for throwing out the FTC amplifier rule proposed a few pages back, it's the only thing keeping manufacturers partially honest. Without it, you'd be back to the Wild West of amplifier ratings in the early 70s.

Hopefully we'll get to see an AHB-2 properly tested into all its rated loads, stock standard, as per the long standing rules. If I had money to burn, I'd buy one because I think it's a fabulous amplifier and I'd test it, report the results and put the whole thing to bed.

 

[cbnbmore]

First post in this forum although I followed the DAC3 thread for quite a while before deciding to buy one and I thank you all for the indirect guidance.
I really like the Benchmark product philosophy. A lot of this talk is over my head but I thank you all for helping to further my education in audio.
My question is I was really considering picking up a AHB2 when finances allowed.
Are there now any reservations that I should consider?
I doubt I will push the amp to its’ limits and likely will not even make it sweat. It looks like a great addition to me. Am I missing something?

 

[restorer-john]

Am I missing something?

Nope. You aren't missing anything. It'll be a great amplifier for you.

I don't think there's a soul in this thread who doesn't secretly want an AHB-2.

The heated discussion in this thread is about honesty in specifications, FTC standards and adherence to them along with the need or not, to protect users from themselves.

 

[Jim777]

don't think there's a soul in this thread who doesn't secretly want an AHB-2.

Me. I secretly want two, not one.

 

[cbnbmore]

Thanks RJ. I was a bit worried. I always thought Benchmark was upfront with their specs. I’m really only concerned with the sound and it looks like the AHB2 should be a non factor in the noise department and will provide plenty of power to my SMS1 speakers. Thanks!

 

[cbnbmore]

Me. I secretly want two, not one.

I’d love two but one for now would be great. Unfortunately they are really in high demand. Looks like August now for current orders.

 

[DonH56]

I don't think there's a soul in this thread who doesn't secretly want an AHB-2.

I am one counter example. No secret about it.

 

[cbnbmore]

I’d love to hear your negatives on the AHB2 Don. Care to share?

 

[DonH56]

You misunderstood. I want one. In fact, I want seven, one for every channel. I have said it before thus it is no secret.

Negatives? Output impedance is a little high. I don't like the apparent specsmanship; seems very un-Benchmark, and I am hoping for a good conclusion. The biggest negative? It is too much for me to afford.

 

[cbnbmore]

Sorry I thought when you said counter example you were going anti AHB2. I know what you mean, one is enough to afford. I recently joined the retired numbers. I have to watch my expenditures now. I want to get good value now.
Do you all think the AHB2 provides that?

 

[Sal1950]

I don't think there's a soul in this thread who doesn't secretly want an AHB-2

I’d love to hear your negatives on the AHB2 Don. Care to share?

I can do without them.
Not that there's a darn thing wrong with them, but there's no reason to replace my current classic Adcoms, they more than fill the bill for me.

 

[cbnbmore]

I absolutely understand. Now I have a Proceed amp from about 20 years ago. 150w/ch if I’m correct. Granted this was a decent amp in it’s time. Will the AHB2 make me forget the Proceed?

 

[Kal Rubinson]

I absolutely understand. Now I have a Proceed amp from about 20 years ago. 150w/ch if I’m correct. Granted this was a decent amp in it’s time. Will the AHB2 make me forget the Proceed?

So, here's my question: How will you answer yours?

 

[cbnbmore]

Kal, I’m not sure what you mean? I’m asking if I’ll notice a difference between the
Proceed and the AHB2. I’d like to get some opinions before dropping 3k on an amp.
Just trying to get some feedback on

 

[cbnbmore]

Sorry it was asked incorrectly. I know you can’t say what I’ll notice but I’d like to hear your opinions on the two pieces of gear if you can.