A Review On: JDS Labs Assembled Objective2 Headphone Amplifier

JDS Labs Assembled Objective2 Headphone Amplifier

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Pros: Noticeable improvement in some cases, very little improvement in other cases

Cons: Everything is on front panel


So, this amp makes the signal just a bit cleaner. It was pretty noticeable on my Q701s, noticeable for general clarity, separation, esp cymbals got a bit clearer. For my HD 558 (w/ foam mod), slightly noticeable, but not that much. For my closed-back headphones->very minuscule, you might notice if you listen really hard. When I bought this, I just needed power for my Q701s so I was surprised the quality actually improved, thus I might have exaggerated my initial impressions a tiny bit. Overall the difference minor even for the Q701, but still pretty noticeable. It's not OH WOW I CAN'T BELIEVE THIS, IT'S LIKE DAY AND NIGHT kind of difference.


I bought this amp for my Q701s (Which I won't receive until Friday). When it came I took it out just to make sure it works (All my current headphones are low impedance and don't require an amp). I hooked it up with probably one of the worst possible sources you can imagine: a Nintendo DS (I was in the middle of playing a DS game when it arrived). Of course there was volume, but I also almost immediately noticed that the soundstage got bigger and the instrument separation became better. This was on my AD700s. I thought to myself it must be me imagining things. Just to make sure I switched back to directly plugging into the DS and the DS->Objective2->Ad700 setup. There really was an improvement, not just volume, I adjusted the knob so that the volumes were the same. The improvement is definitely real and doesn't require careful listening to notice, it was almost immediately noticeable. Needless to say, I am impressed as I have always been skeptical of headphone amps, but this one made me believe all the hype.


"I hooked it up with probably one of the worst possible sources you can imagine: a Nintendo DS"
I feel your pain, but with a 3DS, hahaha. It really does have a lame audio system. The O2 helps it quite a bit.
Thanks for that review. i was on the fence as i don't have Golden ears and can't tell minute differences. But I may have to pull the trigger now. ;)
It will also depend on your headphones whether or not you will hear a difference. On my Sennheiser Amperiors, the difference wasn't as noticeable.
I have Grado SR80's myself, also V-Moda M80's. Easily drivable with low impedance. Would they offer more potential for improvement with such an amp?
I can't really say because I haven't tested the O2 with those headphones (though I do have an M80 myself so I might do that later).
It depends on a lot of factors, such your original source also and the output impedance of that. Generally the 1/8 rule applies in which the output impedance should be at most 1/8 of the headphone impedance, otherwise the frequency response can get screwed up a bit. In this case you would hear a very noticeable improvement with the O2, since the O2 has near zero output impedance. On power hungry headphones improvement would also be very noticeable, since if the headphones are under-powered, it wouldn't sound right as well. I've heard out of an ipod, Q701 is more of a sidestep compared to AD700, however it's generally accepted and common knowledge that the Q701 is a big upgrade compared to the AD700. On my AD700 (32ohms same as SR80), sound was definitely cleaner. I think since my Amperiors have a much smaller soundstage, the difference was not as noticeable. There's a lot of factors, but I think you will definitely hear an improvement. The M80 and SR80 both have a bigger soundstage than the Amperiors. I can't guarantee substantial improvement, but I think it's better to just buy the amp. You should at least hear a small improvement and in case you want to upgrade to better headphones later, this amp will make a huge difference compared to an unamped source. I'm trying to be as helpful as I can since many things said here are subjective and you don't really know until you judge with your own ears.
How is the O2 with the Q701? Does it have enough power to drive it well?