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Review and Measurements of Benchmark AHB2 Amp

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amirm

amirm

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Now Amir you are providing food for the speaker cable manufacturers ?? ... I can see them jumping on this , I quote:
So now you can see why the Palladium Tellurium Platinum Silver compound with 99.99999 percent OFC laminated under a vacuum, quantum tunneling and cryogenic-ally treated can make a huuuuuuge difference in the sound with blacker blacks and a Milky Way wide soundstage while remainint 100% organic .. Mark my words!! S someone will quote you and their speaker cable will suddenly become 15% more expensive !
:) The thought definitely occurred to me.

The combination of AHB2 and APx555 analyzer makes an excellent test bed here! The issue though is that one side needs to be bare to connect to the load resistor to see the difference. Would be fascinating to see how many high-end cables actually make this worse or better.
 

restorer-john

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What I like about the brand and the products themselves, is they let the gear speak for itself.

In a previous thread, we looked at the interior shots and found nothing of significance to complain about- it's a glorious looking design.

Also nice to see a currently available reasonably priced product that puts paid to the hype, surrounding Hypex. "Ncore® is the first Class-D amplifier not just to nudge the best linear amplifiers, but to surpass them in every aspect relevant to sound quality."

@amirm Did you precondition the Benchmark for an hour and have you run the full power tests for 5 minutes?
 

RayDunzl

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Even the quality of the metal used in the connectors matters

Sometimes a bare wire just won't work.

As everyone already knows, I use (now defunct) BellCore approved power cable (we are delivering power, aren't we), terminations, and antioxidant...

1558649339653.png


Scale reference: The nuts are 1/2"/13mm

Ok, it's stupid, but it was all in my scrap pile. The cable was manufactured in 1992, the connectors at least the same vintage.

Same thing at the amplifier, a whole five cable feet away.
 

restorer-john

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As everyone already knows, I use (now defunct) BellCore approved power cable (we are delivering power, aren't we), terminations, and antioxidant

Only takes one of those cables to slip sideways and you'll have a nice fireworks show in your lounge room.

Why not make a few small perspex plates with two holes that slips over the two grub screw threads, then they can never touch?

1558651558382.png


Almost like a flat lego plate with two holes.
 
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amirm

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@amirm Did you precondition the Benchmark for an hour and have you run the full power tests for 5 minutes?
I did not. Since damaging another amplifier, I no longer subject them to this kind of stress. My dummy loads would also cook real good with that kind of power dissipation.

I did run it for 60 watts or so continuous in the process of testing the dummy loads. It did just fine there.
 

tpaxadpom

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Amir, at what power level did you measure IMD with 19+20kHz tones? 5W? I see your results looking vastly different from those published by JA at 50W. It would be interesting to see how they look at 1/2 or full rated power.

Any comments on how it sounds in comparison to your ML amps?

PS: as always thanks for the review.
 

FrantzM

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I'd like to see the Devialet tested here. Their specs are are pretty interesting.

Idle draw is of importance for me, using Solar and an AC to DC UPS system (Inverter Charger Charge Controller , Diesel Generator, etc ,...) these days ... That the Benchmark matches Class D efficiency is a proof of superb engineering.
 

RayDunzl

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Only takes one of those cables to slip sideways and you'll have a nice fireworks show in your lounge room.

I keep a long vertical wooden divider crammed in there.

It doesn't go anywhere.

I'm careful with the amps. I don't want anybody trying to fix them.

Possible Schematic: http://www.tubebbs.com/thread-266201-1-1.html - (some assembly required)

Six pages. Think signal input, DC power regulation, output drivers, and output sections. differential input and ouptut, so, most everything is doubled.

At least 145 transistors of various capacities in a channel.

350/700/1400W @ 8/4/2 rated... Stepped Class A bias

14 years old now, I'm not the original owner.
 
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amirm

amirm

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Amir, at what power level did you measure IMD with 19+20kHz tones? 5W? I see your results looking vastly different from those published by JA at 50W. It would be interesting to see how they look at 1/2 or full rated power.
Sorry, should have mentioned they were at 5 watts. JA's graph is at 8 ohms by the way and I don't see what power he used for that.
 
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Any comments on how it sounds in comparison to your ML amps?
If I get a chance I plan to hook them up to my main system and see. The MLs have much more power so at the extreme, it won't be able to match them.
 

D700

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I've only seen the name Benchmark in passing. I had no idea their amp was that good and that compact. I might have splurged had I known. I am going to take a hard look at trading up. Thanks for the review.
 

Kal Rubinson

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A bunch of people are using a pair bridged mono to drive speakers like Salon2's that are ~4 ohms nominal. I believe Kal tested into speakers that dip a bit low and had no problems.
Yes. I am now using three of them as monoblocs for L/C/R.
 

RayDunzl

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tpaxadpom

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estuardo4

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If I get a chance I plan to hook them up to my main system and see. The MLs have much more power so at the extreme, it won't be able to match them.

Maybe connecting the two amps that benchmark loan you bridged can give you the power you may need.
 
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