Review: ZERO 24 BIT/192KHz DAC/Headphone Amp/Pre-Amp - Page 550

mhhh ok that makes sense, what if they send me an 'old' unit? Do they just differ in regard of this switch, or is the build different? (the seller advertises it as an upgraded version so i find it surprising if they would send 'old' version with the opa627)

by the way thanks for quoting audiophile china, i didn't know about it, maybe it's a cheaper solution for me, i'll check the shipping fares....though it's not the opa627, do you know if they allow you to chose an 'upgraded version'?

thanks

Some changes have been made regarding the enclosure (added vent bars) but I am unaware of other changes, most sellers sell the opa627 "upgraded" but they do the change themselves, not the manufacturer as far as I know (this may have changed since the opa627 became the popular choice).

The manufacturer may have changed the transformer to one that is not capable of dual primary voltage, this change may or may not have been a result of some problems with "humm" reported here and elsewhere.

I had the version with switch and had no Hum problems, but... you never know, better to ask and confirm.

As far as I know audiophilechina does not provide a version with the OPA627, but you can always ask, still, you can get the OPA627 elsewhere and upgrade the unit yourself, or maybe go for the better option, an Audio-GD HDAM, it is a very simple thing to do, remove one, place another.

So choosing a version which doesn't allow to switch would be a safe choice regarding the humming? Maybe it's because the power supply is solely designed for a dedicated current which enhances a steady signal? (i looked a bit in the previous article posted regarding the humming and electro-magnetical noise due to alternative current, though i wonder if i would be able to hear it, even with my HD650, i mean i am not sure to have golden ears lol) btw, if any of you know of a way to test your audition, i'll be interested, like a web based test maybe?

If such a change was really put in affect with the newer versions, yes, I suspect that would be the reason, but I do not know this for a fact, only the manufacturer (or the seller because he probably was informed by manufacturer as to why) would be able to confirm.

Mine has a voltage switch and it does not hum.

From what i read, it's quite normal if you don't, it's just that there is a kind of 'standard deviation' with the zero, therefore though you buy the same zero as another, one will have a humming sound to it, or a shortened life....i don't know how much this is through though, because one will be more likely to post his experience with a product if it was bad than the opposite :s...but still around a 100 bucks for this good a quality it's worth the risk i think. (i intend to push it a step further with the franken mod, do anyone know of a good soldering iron on ebay, or available in Canada? thanks)

-DaMnEd k well i'll ask the seller about that...smells fishy, you don't know what you've paid for in advance...i'll try my best to get the 'switch' version

I suspect the new versions are the one with the switch actually (cuts cost), and the sellers on ebay just have old pictures, if you look at the first post in this thread, the Penchum pictures, his unit has no switch, and his unit is older than mine was, much older, and probably one of the first batches.

This is why you should ask your seller if the current units he stocks have the switch, they probably do and you won't have to buy a power converter.

Just got my Zero with Moon and Earth HDAMs plus some LT1364s. Jesus, it's a phenomenal improvement compared with the Sigmatel HD audio chip in my XPS. Initial comparison between the 2 HDAM modules reveal that the Earth is more forward sounding that the Moon. Right now I'm not sure which one I like better, gonna burn-in the Moon first for the next few days.

I guess I didn't really pose a question here...should the unit be considered defective, or should I just learn to live with the hum?

I've seen here one case where the Hum was present (few pages back), and after a new transformer was installed, the hum was gone. The new transformer was given by a member that had a broken ZERO laying around, and offered the transformer to this member with the Hum problem.

So, given that the "new" transformer was the same model and had no Hum, yes, that should be considered defect, ask your seller if he can send you only a new transformer, from what I understand wsz will do this for you at no cost to you. And ask him to test the transformer and confirm no hum is present before shipping it, just to be safe.

I got my 50W WELLER soldering station from Active Compoments (www.active123.com) and have been pretty happy with it.

thanks X lk, but it's an overkill for me, i just intend to buy one for modding the zero (10hours labour if i am correct) and won't use it afterwards, but do you think a 30w iron is enough for soldering components?

You're welcome. 30W should be enough. I even used 15W before. From my experience, a bigger one actually helps when doing desoldering - not sure if this is just for me WELLER may be a bit expensive, but Active Components does carry economy soldering tools.

so i was looking into dedicated headphone amps.. and i stumbled upon the headroom ultra micro amp which boasts the opa627 bb. how would this headphone amp sound quality be different than a modified zero with the same op-amp? i suppose that the 700 dollar price tag is not related to the op-amp alone but the cross-feed function and with the different inputs, but still.. seems like a big price difference.

The price tag is related to much more than a cross-feed, opamps, inputs, it is related to every aspect of the unit, that is in a completely different league.

You can find audio equipment costing thousands of dollars what will have the same opamp the ZERO has or can have, this by no means means they will sound even close to each other, their is so much more to an amp. The amp on the ZERO is a OK amp, does the job, but it is nothing special or even good really, specially when comparing to a dedicated amp like the headroom amps.

The opamps cost you 30$ out of the 700$ if that..