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Review and Measurements of Benchmark AHB2 Amp
- Thread starter amirm
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gfinlays
Senior Member
I have a 2-way sealed version of the Zaph Audio ZRT, at present, though I have a 3-way wide baffle build in the pipeline.
restorer-john
Grand Contributor
Interesting looking speaker. Just an 8" bass driver too.
misterdog
Addicted to Fun and Learning
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With the current strength of the Dollar/weakness of Sterling and Euro it's hardly worth doing.
Indeed, unfortunately, you are right. Can pick them u pin the UK for £3k now so not worth the travelling faff... Can't see the GBP recovering that much before Christmas neither.
gfinlays
Senior Member
Ex-demo/review units appear on eBay from time to time. Snagged mine from eBay this week for £2600 with a 2 year international Benchmark warranty.
restorer-john
Grand Contributor
What exactly does that entail? They fix it in the UK somewhere or they pay for it both ways back to the US?
gfinlays
Senior Member
You ship it back to Syracuse, they repair (or replace) and then return it to you - https://benchmarkmedia.com/pages/wa...-IW0hD4OGizWdsS1ygeSkDA3oHMbPndIaAqSpEALw_wcB
According to my dealer, failures of Benchmark components are very rare, so it's not something I'm overly worried about. The amps aren't particularly big or heavy either, so shipping shouldn't be that costly.
According to my dealer, failures of Benchmark components are very rare, so it's not something I'm overly worried about. The amps aren't particularly big or heavy either, so shipping shouldn't be that costly.
gfinlays
Senior Member
One of the guys who built it, went up to a 10" http://www.troelsgravesen.dk/PMS-Rik.htm
Haha
These are the best amps I’ve owned, including some that cost 10x what these cost. There is simply no distortion or noise, right up until they clip and turn off. And that only happened once for me, on a techno track accidentally playing at full volume.
I’m using 4 in an active biamp on TAD R1s. Andrew Jones designed the R1 and coincidentally his twin brother was one of the key designers of the AHB2. Andrew helped me set up the active crossover, otherwise it would have been impossible for me to do this.
If you can somehow biamp your system, I expect you will find 4 AHB2s sounding even better than 2, especially with the woofers connected directly to the amps with no inductors in the circuit. You could even try this with 2 amps using two channels per side, or even 3 amps with bridged mono only on the woofers. You don’t need that much power for the higher frequencies.
In my case, the TADs are 3 ways. We are only biamping actively between the woofers and the mid/tweeter. The stock passive crossover that divides signal between the mid and tweeter is still in place. This saves one amp per side and also at these higher frequencies the passive crossovers are easier to build using only air core inductors.
gfinlays
Senior Member
I did an experiment the other day. I got fed up of all the audiophool networking aficianados telling me that I needed audiophile switches and cables because ethernet noise pollutes the DAC output. Yeah, whatever....
So I recorded a -120dBFs noise track in REW, converted it to flac and loaded it into Roon. With the DAC3 HGC in calibrated (0dBFS mode), I wound up the volume on the HPA4. At 0dB, there was nothing, zip, nada, SILENCE. At +4dB, I could hear a fain hiss from the tweeter (with my ear against it).
What was I hearing? Noise? A -120dBFS track? So I made another test track, this time with a -120dBFS 1 kHz 50% square wave.
Lo and behold, @ about +4 dB gain, I could hear........
wait for it........
the 1 kHz test tone!!!!!
Need to hook up my digital 'scope to the amp outputs and see what it looks like. Sure, there was some hiss with it, but the tone was unmistakeable. I'm honestly flabbergasted that a Benchmark DAC3 HGC, HPA4, and bridged AHB2s can pull an audibly recognisable 1 kHz tone out of a -120 dBFs test track.
Categorically proved that all this network noise/fibre isolation/LPS stuff is a load of hooey. Not only that, my endpoint is a humble RPi 4B with touch screen running Ropieee and powered over PoE by a PoE HAT which has a little SMPS on it.
Hats off to Benchmark Media for absolutely stunning performance!
So I recorded a -120dBFs noise track in REW, converted it to flac and loaded it into Roon. With the DAC3 HGC in calibrated (0dBFS mode), I wound up the volume on the HPA4. At 0dB, there was nothing, zip, nada, SILENCE. At +4dB, I could hear a fain hiss from the tweeter (with my ear against it).
What was I hearing? Noise? A -120dBFS track? So I made another test track, this time with a -120dBFS 1 kHz 50% square wave.
Lo and behold, @ about +4 dB gain, I could hear........
wait for it........
the 1 kHz test tone!!!!!
Need to hook up my digital 'scope to the amp outputs and see what it looks like. Sure, there was some hiss with it, but the tone was unmistakeable. I'm honestly flabbergasted that a Benchmark DAC3 HGC, HPA4, and bridged AHB2s can pull an audibly recognisable 1 kHz tone out of a -120 dBFs test track.
Categorically proved that all this network noise/fibre isolation/LPS stuff is a load of hooey. Not only that, my endpoint is a humble RPi 4B with touch screen running Ropieee and powered over PoE by a PoE HAT which has a little SMPS on it.
Hats off to Benchmark Media for absolutely stunning performance!
My hero!
gfinlays
Senior Member
Is that a hint of sarcasm I'm detecting there?
Not at all! I have a benchmark AHB2, and your meticulous method of measuring and calculating to show noise levels is well… audio heroics! I would love for people to do that with a Hegel or Accuphase amp and see how badly designed they really are
gfinlays
Senior Member
Ah, my sincere apologies and thank you for your kind words! It's never easy to detect the tone in written communication!
Indeed. I love how audiophools defend their inferior products with expressions like warm, liquid, musical, engaging, PRAT etc. and call well measuring equipment cold, clinical, analytical, harsh etc.
If the AHB2 makes a system sound cold, clinical or harsh, it's not the AHB2 that's the problem!
As far as amplification goes, I've reached my endgame, unless of course, I go to a fully active system in which case I'll be buying more Benchmark gear!
Indeed. I love how audiophools defend their inferior products with expressions like warm, liquid, musical, engaging, PRAT etc. and call well measuring equipment cold, clinical, analytical, harsh etc.
If the AHB2 makes a system sound cold, clinical or harsh, it's not the AHB2 that's the problem!
As far as amplification goes, I've reached my endgame, unless of course, I go to a fully active system in which case I'll be buying more Benchmark gear!
Martini
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You need to turn it up +4 dBAh, my sincere apologies and thank you for your kind words! It's never easy to detect the tone in written communication!
gfinlays
Senior Member
You need to turn it up +4 dB
I have a single AHB2 powering my KEF Reference 3 and it sounds wonderful. But I’ve started wondering, with the incredible Class D amp coming out lately, 4 and 5 way speakers don’t need to be in the purview of 100K+ USD territory anymore.Ah, my sincere apologies and thank you for your kind words! It's never easy to detect the tone in written communication!
Indeed. I love how audiophools defend their inferior products with expressions like warm, liquid, musical, engaging, PRAT etc. and call well measuring equipment cold, clinical, analytical, harsh etc.
If the AHB2 makes a system sound cold, clinical or harsh, it's not the AHB2 that's the problem!
As far as amplification goes, I've reached my endgame, unless of course, I go to a fully active system in which case I'll be buying more Benchmark gear!
No need for ultra expensive crossovers. And yes, I have a friend who has definitely been cable-snagged and outlet fooled
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