Review and Measurements of Benchmark AHB2 Amp

[anmpr1]

The Salon2's and Voice2 are bi-amped by 3 AHB2s.

The Studio2 rears are driven by a single AHB2.

My game room Revel M20's are driven by an AHB2...

Trying to follow your setup. You have 5 AHBs?

 

[graz_lag]

Trying to follow your setup. You have 5 AHBs?

His name is Rich, what else?

 

[Eljimador]

Not replacing anything. It will be used for my RAAL SR1a

Nice. I just got my SR1a and am still considering the amp to drive it (using an old power amp for now that’s too big to use in the desired location). I’d be interested to hear about your experience with the combo, including whether it has enough power to reach your desired listening level. I know Raal used the AHB2 in developing the SR1a, but it’s always good to increase the sample size.

As an aside: Schiit is releasing a DAC/Amp combo that is designed to drive the SR1a directly, without needing the interface box that consumes most of a normal amp’s power. I know I’m not buying the Schiit. But maybe we could get Benchmark to design one for us based on THX technology. Call it the AHB2SR1aTHXAAA direct drive amplifier for maximum confusion.

 

[anmpr1]

His name is Rich, what else?

LOL. I see his sig has the answer. Just didn't look there. Actually, I've known relatively poor audiophiles with expensive gear. Maybe that's why they are relatively poor. I would never say a discouraging word about anyone buying a six-pack 'o Benchmark. Besides, in the scheme of 'high end' audio, I'm sure you can find a five or six watt SET for comparable dollars as half a dozen AHB2s.

 

[DonH56]

In HS/college I knew lots of guys living hand-to-mouth with all their money going into their cars or trucks (mostly, for my country crowd). Me, I got by, but had an ARC SP3a1 and D79 sitting under my AR turntable and between my Maggies. I got the stuff at wicked low prices, though, and much bartering. Helped to be working for a couple of hi-end stereo shops. The guys with real money would dump the old stuff so I got some great deals. And got dealer's accommodation on the new stuffs so 40-60% off list. Can't decide if I miss those days or not; at least not being in the biz and being closer to retirement puts the impulse buys at bay. Usually.

 

[anmpr1]

In HS/college I knew lots of guys living hand-to-mouth with all their money going into their cars or trucks (mostly, for my country crowd). Me, I got by, but had an ARC SP3a1 ... Helped to be working for a couple of hi-end stereo shops.
.

Good catch. The old SP3 was the preamp anyone who knew anything about high-end owned, before there was really a thing called 'high end'. I don't know how many mods ARC came out with for this machine, but there were a lot... before they cooked up their 'analog module' shtick. And then went back to toobs. Speaking of mods, if I'm not mistaken, ARC began by modding Dyna kits, using their special magic (whatever that was) to make the good even better. Not working in a stereo shop, I was relegated to the real deal--building whatever David Hafler was selling at the time. I still have scars from burnt fingers. Probably have embedded solder in my nails, somewhere. Like you, not sure I miss those days, but they were certainly fun.

 

[SIY]

Sad truth: the SP-3 was a terrible preamp, especially the phono stage.

 

[RichB]

Trying to follow your setup. You have 5 AHBs?

Yes 5: 4 on my main system and one in the game room.

Friend 1 has 4.
Friend 2 has 5.

Edit: We bought them at the same time so that order was 13 amps

- Rich

 

[laidick]

Yes 5: 4 on my Main system and one in the game room.

Friend1 has 4.
Friend 2 has 5.

- Rich

Do you have Atmos or surround back ?
I wonder if you would have 3 more lol

 

[RichB]

LOL. I see his sig has the answer. Just didn't look there. Actually, I've known relatively poor audiophiles with expensive gear. Maybe that's why they are relatively poor. I would never say a discouraging word about anyone buying a six-pack 'o Benchmark. Besides, in the scheme of 'high end' audio, I'm sure you can find a five or six watt SET for comparable dollars as half a dozen AHB2s.

No I am not wealthy. It was an incremental upgrade that was mostly funded by selling my 3 AT6000 amps and various gear I had hanging around, some of it from Oppo. The achieved goal was to end my amp buying days.

I have one more upgrade looming for an HT processor. Right now, I am considering an Emotive RMC-1/RMC-1L or Monoprice HTP-1.
Emotiva is offering some excellent trade in value for the XMC-1 with V3 (HDMI 2.0b) board that are tempting. I have reason to suspect the SINAD of the RMC family is going to be excellent.

- Rich

 

[RichB]

Do you have Atmos or surround back ?
I wonder if you would have 3 more lol

I have no sides channels or Atmos. My room has large openings and an angled then flat ceiling with skylights and beams that makes Atmos challenging.
It also precludes up firing (IMO) nonsense speakers.

Sides would help but the tweeters for the Salon2 and Studio2 are at or above ear level so all sound is a bit up.
In the cinema, all there is up on the walls and the ceiling. I have a hard time noticing the difference

I have found that Atmos mixes make better use of additional channels that also benefit 5.1 systems.
For example, I compared Star Trek Into Darkness spear throwing for the original and Atmos mix.
The front to rear swish as the spear was thrown was clearly improved on my 5.1 over the original mix.
I suppose there could have been a better transition with more speakers but not something that I care about when watching video content.

I choose quality over quantity. Unfortunately, that means using processors that have a lot of extra channels that will not be used.

- Rich

 

[DonH56]

Good catch. The old SP3 was the preamp anyone who knew anything about high-end owned, before there was really a thing called 'high end'. I don't know how many mods ARC came out with for this machine, but there were a lot... before they cooked up their 'analog module' shtick. And then went back to toobs. Speaking of mods, if I'm not mistaken, ARC began by modding Dyna kits, using their special magic (whatever that was) to make the good even better. Not working in a stereo shop, I was relegated to the real deal--building whatever David Hafler was selling at the time. I still have scars from burnt fingers. Probably have embedded solder in my nails, somewhere. Like you, not sure I miss those days, but they were certainly fun.

The SP3 and all its ilk had the rep and in some ways really had outstanding performance, less so in others... I modified mine several times; need to put it back to stock and sell it, but not sure if the power supply is still working. The zener string and output transistor was prone to self-destruction; they ran the string pretty hot (too hot IMO) and needed more safety clamps around the circuit. I changed it to a different (still SS) regulator circuit and regulated the filament voltage. SNR got better but changed character; LF hiss/hum was gone so the HF hiss stood out a little more. Still pretty low. THD was ridiculously low, <0.005% at something like 5 V output. The phono stage was almost impossible to overload but they neglected Miller capacitance so loading was off, RIAA precision was not great, and it was very sensitive to the input tube. I made various tweaks through the years including rebiasing the input, switching tubes (even built a little nuvistor stage at one point), and trying a basic passive (not feedback) RIAA circuit. To me it always sounded good but I was always fiddling with it and it had a tendency to self-destruct if a tube arced or when a zener decided to go. I kept a bag of 47 V zeners.

I also had to fiddle with the D79 though not as often as the preamp. I finally sold the D79 some years ago; the guy who bought it had fond memories of it but said it did not match his current (recent) tube gear. Some memories best left as just memories.

I built plenty of Hafler kits for myself and others. Still have a DH-220 in the basement, someplace... I bridged it to drive my DIY subwoofer back in 1979 or 1980-something. And course modded them though I think some of the mods were not audible at all; still, I got paid by the hour.

 

[anmpr1]

Sad truth: the SP-3 was a terrible preamp, especially the phono stage.

I never heard anyone say that, but then again I never owned one, nor did I ever hear a system with one in it. It sure had a big following. It was the 'high end' thing, right before Mark Levinson came out with his 'consumer' preamp, the JC-2.

A mid '70s tube design... maybe folks were hearing tube 'softening' and taking that for quality. At the time ARC was distributing Magneplanar speakers, so maybe there was some kind of 'synergy' going on between the gear. I could never afford the stuff, back then. Dyna, Pioneer, JBL, Technics turntables. That was what I could afford in the '70s.

 

[SIY]

There's a lot of psychology involved. The SP-3 and later the SP-6 were basically slightly modified clones of a Marantz 7C and had most of the same performance issues. Poor noise performance, high input capacitance, poor RIAA curve conformance, slew limiting, high distortion especially at low frequencies, poor tube life... they were a mess.

I'm not alone here. From (IMO) the best modern text on tube designs, Morgan Jones's Valve Amplifiers, 4th edition:

When we investigated power amplifiers, we looked at some classic designs to see how the goals were achieved. There were no classic RIAA stages, they varied from mediocre to plain awful.

 

[etc6849]

I don't have Atmos either, and my system sounds many times better than any of the atmos systems that I've heard.

One suggestion though: if all you are needing is decoding to 5.1 or 7.1, a PC and a sound-card outputting multiple digital AES channels to decent pro-audio speaker processors will beat the XMC-1 and provide the flexibility to tri-amp, time align multiple subs, etc...

I use the RME HDSPe AES-32 (up to 16 channels in and 16 channels out). I then feed the digital AES signals into 3 Xilica XD4080's which drive 5 powered subs and 10 AHB2's (amps are driving 5 three way speakers that are fully tri-amped using FIR filters).

I would never go back to an AV processor. I say this having owned both the AV8805 and XMC-1 like you have. I'm sure there are some >$20k home theater processors that have similar performance to the pro gear I use, but these are well outside my price range and not worth it when you can pick up used units like the Xilica XD4080 for $900 each.

I'm not rich, but saved up and sold previous gear and other stuff to own the AHB2's. I consider my setup to finally be world-class though. With the 20 drivers all time aligned and level matched, it sounds is incredible. I also built a lot of room treatments too which definitely helped. There is nothing more to improve except build an addition on my house (not going to do that).

I have no sides channels or Atmos. My room has large openings and an angled then flat ceiling with skylights and beams that makes Atmos challenging.
It also precludes up firing (IMO) none-sense speakers.

I choose quality over quantity. Unfortunately, that means using processors that have a lot of extra channels that will not be used.

- Rich

 

[cequalspid]

well i’ve joined the club. bought an AHB2 for a pretty good price and hopefully it will arrive in a week or two.

 

[RichB]

I don't have Atmos either, and my system sounds many times better than any of the atmos systems that I've heard.

One suggestion though: if all you are needing is decoding to 5.1 or 7.1, a PC and a sound-card outputting multiple digital AES channels to decent pro-audio speaker processors will beat the XMC-1 and provide the flexibility to tri-amp, time align multiple subs, etc...

I use the RME HDSPe AES-32 (up to 16 channels in and 16 channels out). I then feed the digital AES signals into 3 Xilica XD4080's which drive 5 powered subs and 10 AHB2's (amps are driving 5 three way speakers that are fully tri-amped using FIR filters).

I would never go back to an AV processor. I say this having owned both the AV8805 and XMC-1 like you have. I'm sure there are some >$20k home theater processors that have similar performance to the pro gear I use, but these are well outside my price range and not worth it when you can pick up used units like the Xilica XD4080 for $900 each.

I'm not rich, but saved up and sold previous gear and other stuff to own the AHB2's. I consider my setup to finally be world-class though. With the 20 drivers all time aligned and level matched, it sounds is incredible. I also built a lot of room treatments too which definitely helped. There is nothing more to improve except build an addition on my house (not going to do that).

Sounds like a killer system.
I am not up to rolling my own at this time. Also, I need a family friendly operation and aesthetic.

- Rich

 

[etc6849]

For mine, you can pick up an iPad, pick content in the JRiver iPad app, and everything comes on automatically. Also, I have a remote setup I programmed, display readout showing volume and what's playing, etc... However, you do probably need to be a very techie to get controls to work seamlessly like that.

The aesthetics are very subjective, but I think it looks pretty good (but I'm biased ):

I am not up to rolling my own at this time. Also, I need a family friendly operation and aesthetic.

 

[Totoro]

I'd suggest that the review has absolutely zero credibility - the language gives it away completely. Was the review properly conducted to eliminate cognitive biases, double blind with matched levels etc etc? If it was not (& it doesn't look like it), then it is invalid. The language is also full of the usual hifi reviewer gobbledygook, it's nonsensical. It looks like the reviewer simply confirmed their biases...

Wtf is plankton? Holy shit.

 

[anmpr1]

For mine, you can pick up an iPad, pick content in the JRiver iPad app, and everything comes on automatically. Also, I have a remote setup I programmed, display readout showing volume and what's playing, etc... However, you do probably need to be a very techie to get controls to work seamlessly like that.

What is the preamp/digital source in the top left--with the round (volume?) knob?