Before I start, I want to thank the representative from Shozy for giving me an opportunity to review the Zero free of charge in exchange for a honest, unbiased review.  In my opinion I want to say that I had not much hope when I was approached because Shozy is very terse with specifics on the IEM. When I got it from him when he was in Singapore he told me I will really like it and I should give my opinions after 200 hours of burn in. That's waaay too long so here's my opinion after spending a week (and getting into trouble for having my IEM on while...

          I was looking for a cheap tube headphone amp and I came across the BM A1 and it was better than I thought :   Design : It has PCB faces for the back and front, not entirely a fan of that but it works but to see the fiberglass is really quite a turnoff so a 5/10 I suppose. Other than that it isn't blocky instead it has a oval metal chassis that resembles a NASCAR oval? Tubes stick out and thank god they do because the 6AH6s I put in there after I swapped the 6J5s out for run alarmingly warm. Blue LEDs are on the socket so...

      It is brilliant, having been based on a OPA2134 as input amp that is wired to a TPA6120A2 as buffer (Current amp).   It uses a TDA2030 as a rail splitter. Using a power opamp as a rail splitter has it's advantages, mainly you will notice bass on this amp is much more defined than the original sApII. It DEFINITELY will improve SNR if you use a better power supply than standard, standard power supply is pretty junky. It runs on 24V so if you want peak headphone power (or lower distortion at lower outputs and also higher voltage has a...

*The soundstage is pretty good for the price but only so-so in a grand scheme of things. It's very "listenable" or rather, enjoyable. It doesn't disappoint in any genres or even gaming although ... yeah. Don't want to do that.   At first it was rather harsh on mid-treble but after burning it in it is very smooth on the treble now. It does lack bass once you listen to a neutral headphone in comparison on the other hand which is strange given it's a closed headphone but the details are not perfect and it's not flat.     The best part is the...