1. ohshitgorillas

    ohshitgorillas Friend

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    I recently (finally, after making a series of stupid mistakes) completed an AMB γ1.5.

    [​IMG]
    [​IMG]

    Here's a little write up of my thoughts on the thing.

    Build

    The total cost of the unit, using Vishay-Dale/Beyschlag resistors for the analog stage and other higher quality components, comes out to about $200 (half of this cost is in the zeta1 USB receiver board, $60, and the faceplates, $40). The build itself is very straightforward (as long as you read the instructions carefully): AMB provides a list of parts, you order those parts and put them in their holes labeled clearly on the PCB itself. This was my first project involving surface mount devices, but that wasn't actually nearly as hard as I was anticipating (excepting the tiny metal film capacitors did give me some trouble, I think I melted a couple on my first try...they stick to your soldering iron if you're not careful).

    My unit is low gain, and HD600 push full volume (with zero audible distortion) on quiet classical recordings or TV shows. On the other hand, it is capable of deafening volumes with modern music through the ASG1+, which are not terribly sensitive.

    Build Quality

    I have used the equipment available to me as a graduate student at a well-funded research program to subject the γ1.5 to a range of extreme conditions. These include being frozen at 8 degrees Kelvin (that's 8C above absolute zero), contained within a floating sphere of plasma, subjected to temperatures as high as 220 C while contained within high-pressure vessels while simultaneously submerged in hydrofluoric acid, subjected to pressures and temperatures similar to those within the molten outer core of the earth, and being fired as a projectile at a wall at nearly 200 kmph.

    Disappointingly, the γ1.5 did not appear to function after any of these tests. This unit would definitely not be fit for transport or use outside of the confines of our planet or day-to-day existence.

    Sound Impressions/comparisons

    These impressions are made using the HD600 (and the Aurisonics ASG1+ to a lesser extent). The only other solid state amp I have to compare the γ1.5 to is the O2, and most of my listening is done on the Crack (or a FiiO X1). The only DACs I have to compare the γ1.5 to are the γ2 (USB), Audioquest Dragonfly, and the iBasso DX90.

    That said, the γ1.5 has really impressed me, especially given its size. If I had to describe the sound in three words: clean, natural, great_soundstage. My ideal sound is natural and realistic, and this thing does that very well. It is very good as a DAC, or to power the HD600 with surprisingly dynamic results. It's certainly not perfect: there is a hair of a reduction in noise floor by the γ2. To my ears, it bests the γ2/O2 combo (4x the size), but loses by a slim margin to the γ2 when used as a DAC for the Crack.... then again, I've always been a little biased against the O2 and towards the γ2/Crack. It wins easily against the DX90 and Dragonfly in clarity and just overall.

    Concluding thoughts: The combination of carefully implemented asynchronous USB, a great-sounding D/A chip, and a well-implemented but minimalist analog stage that maintains linearity while outputting a shitload of current, is a god damn winner. Bravo with a standing ovation. Something so small shouldn't sound so good.
     
  2. Armaegis

    Armaegis Friend

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    Dude, I've played with stupid things in the lab before. Heck, I've had molten aluminum splatter through a face shield because I wasn't careful*... but even I don't touch hydrofluoric acid :confused:


    *ever blow bubbles in a thick milkshake and the whole thing rises before it goes pop? it's kinda like that
     
  3. ohshitgorillas

    ohshitgorillas Friend

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    Haha, HF isn't so bad if you take the necessary precautions. I've come close to having a drop on me though (which would have resulted in a hospital visit), it landed on one of my arm hairs...
     
  4. Aelms

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    Nice to see more AMB reviews. I've always been curious how their amps stack up in today's market.
     
  5. Armaegis

    Armaegis Friend

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    Yeah... some acids will burn horribly and make your eyes tear up or make you puke, but something about HF's ability to quickly seep into your body and harvest calcium from your bones over an extended period of time is a whole bucketload of nopes for me.
     

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