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

[Pricklely Peete]

Originally Posted by fugimax

I'm confused on exactly how this would end up being wired. You cut the neutral / primary wires and insert the blokker in there?

Also, do you think there's a place for this to sit / mount in the Zero case?

Originally Posted by LeBuLLeT

Yea I am confused like fugimax. First I am going to try a good power cable then if that doesn't show an improvement then I will get this "blokker."

Guys it simply connects off the IEC Neutral connection (in between the N terminal and the neutral wire to the toroid primary inside the Zero) in series (google series connections) as follows......here's the direct quote,

Just connect the red wire in series with the neutral of your mains supply, blue wire to transformer primary side and kill DCv dead. Also removes destructive harmonic content created by other electrical devices loading your power matrix. Most AC supply has some DC offset present. DC is the enemy, robbing a power transformer of efficiency and often making it hum. Blok it, and the transformer can do its job, Sound improvement can be major depending on your line conditions.Small enough to fit in most chassis. 5cm x 5cm x 2.4cm. 3A/240V.


It sounds far more complicated than it is. You could even do this outside the chassis as long as the wiring is where specified. It should fit in beside the toroid though quite easily. The 240V 3A rating makes it suitable for worldwide use.

Peete.

[RedSky0]

This may not be the best place to ask, but is there a guide out there to op-amp rolling? I'm not quite certain what it physically involves, and how technical it is. Sorry if someone's asked this question already, but going through 600+ pages is impossible.

[Pricklely Peete]

Originally Posted by dario

But how much cost the power supply? And it can be changed "plug and play"?

I think also the if we know how much power require the opa627 and lt1364 we would do a much more realistic analysis, becouse if the opa rate is 15v they would require a maximum of:
0,66W for the Sun
0,84W for the Earth
If we know how are hungry the "standard" opa we can understand how much is the difference...

Unfortunately this modification comes under intermediate to expert level on the difficulty scale...not because it's actually hard to wire up and solder in...because you need to know what your doing and have a digital multimeter and other tools necessary to do the job properly...which means measuring things with lethal voltage levels applied.....not safe in other words for a beginner who has trouble finding the opamp socket.. ( I don't mean anyone in particular...it's just an example).

The wattage isn't the real concern...it's the current delivery capability of the stock toroid and volt regs...they are close to max ratings with 1 HDAM in the dac section and LT1364's in the H/Amp section.

If I had to guess what the draw of the stock Head Fi deal opamps are I'd say no more than 50 - 60 ma in total...if that.


Once I get my reg/transformer kit and install it I'll post pics through Pench and instructions how I did it for anyone else that want to try it. The cost from Welborne labs for this kit (15 V DC @ 1 Amp ) is 75US including shipping....so it's not cheap. The actual volt reg board itself is rated to handle a maximum of 3A so it's got tons of headroom to run 3 HDAMs easily....The percentages work out to 1/9 th loading on the 1 amp transformer and about 1/40 th load on the reg board max capacity. If I have made a mistake...please correct me...it's off the top of my pointy , cement filled head

If a person were to build the reg from scratch and source the transformer I'm sure that cost would drop to 30US or less...but that is beyond my abilities at the moment (give me a few months ).


Peete.

[ccschua]

Now the OPA works in +15 and -15, i.e. 30V dc.

multiplying the 30 by 130mA, we have, 4W for the OPA alone.

Beside OPA, there is DAC , receiver chip, logic circuit, relay (each relay 50mA !), other little component that drains power as heat.

So it looks like 3*OPA is more or less confirmed to drain the the tranny hard.

[Pricklely Peete]

Originally Posted by RedSky0

This may not be the best place to ask, but is there a guide out there to op-amp rolling? I'm not quite certain what it physically involves, and how technical it is. Sorry if someone's asked this question already, but going through 600+ pages is impossible.

google "opamp rolling"...I'm sure that will help. Also go to page 1 and look at the pics and info on most of popular types used in the Zero.

Peete.

[Pricklely Peete]

Originally Posted by ccschua

Now the OPA works in +15 and -15, i.e. 30V dc.

multiplying the 30 by 130mA, we have, 4W for the OPA alone.

Beside OPA, there is DAC , receiver chip, logic circuit, relay (each relay 50mA !), other little component that drains power as heat.

So it looks like 3*OPA is more or less confirmed to drain the the tranny hard.

Thanks CC...that would explain the loss of bass and other SQ issues I ran into with Earth and 2 SUNs config a few days back...and reported soon afterwards...

Interesting... Hi speed regs wouldn't solve the fundamental issue of current starvation would it CC....?

Do you concur with my assertions thus far on the matter (reg/tranny kit solution) ?

BTW thanks a million for filling in the blanks , your info is invaluable to my understanding of things (limited as it is) !!!!!!

Peete.

[fugimax]

Being that the 3x HDAM probably won't happen for me anytime soon (I'll let Peete experiment, first!) where's a good place to pick up some LT1364s?

I'll probably just experiment for now with Earth v. Sun and potentially picking up that blokker if I'm hearing line noise once my Zero comes.

[DaMnEd]

Originally Posted by fugimax

Being that the 3x HDAM probably won't happen for me anytime soon (I'll let Peete experiment, first!) where's a good place to pick up some LT1364s?

I'll probably just experiment for now with Earth v. Sun and potentially picking up that blokker if I'm hearing line noise once my Zero comes.

Directly from linear, you can get free samples, just search for samples/linear on this thread.

[fugimax]

Originally Posted by DaMnEd

Directly from linear, you can get free samples, just search for samples/linear on this thread.

Thanks, samples requested. I was at least expecting to pay ... geez!

[Penchum]

Originally Posted by Pricklely Peete

The wattage isn't the real concern...it's the current delivery capability of the stock toroid and volt regs...they are close to max ratings with 1 HDAM in the dac section and LT1364's in the H/Amp section. Snip-O-rama!

Peete.

I totally agree with your assessment of this PP. I just did a test to confirm how many HDAMs it takes to finally observe the drain on resources. It worked out like this:

Earth in DAC, LT1364's in headphone amp = Plenty of resources, headroom.
OPA627s in DAC, 2 "Sun" HDAMS in headphone amp = Resources peaked, headroom questionable.
Earth in DAC, 2 "Sun" HDAMS in headphone amp = Resource drain obvious, no headroom, bass punch gone.

So, the third HDAM is one too many for the resources on hand.

This isn't necessarily a bad thing. Keeping "low cost", "simplicity" and "flexability" in mind, one HDAM in the DAC section, giving you a super clean and dynamic signal, and your favorite Opamps in the headphone section, will result in some serious quality sound, while keeping the Zero in a "happy camper" operating state. When you think about it, it really isn't a trade off at all. Having the superior DAC signal is the best possible upgrade overall. It gives both the DAC output (RCA's) and the internal headphone amp an improvement at the same time. This also leaves room for you to further customize the headphone amp with different Opamps, to match with personal tastes and differences in headphones.

[Trax416]

Finally got my tracking number for the Zero DAC/AMP. Will be ordering a set of Denon AH-D2000's on Friday to go with the Zero.

Looking forward, as the best headphones I have ever used was a $25 Cyber acoustics headset. lol

[alxwang]

Originally Posted by Trax416

Finally got my tracking number for the Zero DAC/AMP. Will be ordering a set of Denon AH-D2000's on Friday to go with the Zero.

Looking forward, as the best headphones I have ever used was a $25 Cyber acoustics headset. lol

I do not think you will be happy about D2000 with zero headphone Amp.

PP: Computer PS test failed. It looks like just get right volt and current is not enough.

My power board is hold LA. I do not know how can a shipment from China to Canada can ever be hold in LA for 1 weeks.

[dario]

but the zhaolu has a sufficient power supply for a 3 hdam configuration?
I ask becouse I will have 3 sun hdam in the next weeks and I would want to use all...(I have not bought the zero yet than I have free choice)

[Pricklely Peete]

Originally Posted by dario

but the zhaolu has a sufficient power supply for a 3 hdam configuration?
I ask becouse I will have 3 sun hdam in the next weeks and I would want to use all...(I have not bought the zero yet than I have free choice)

Which one the 2.5 or 3.0 ? It's a different amp and I don't know anything about it. The 3.0 is 300 US and I don't know what the 2.5 cost...200US is a guess.

Can't tell by looking at it from pics...the transformers are covered up and there is no real details posted unless I need to find a better source page.

100VA is a pretty standard size power supply rating for most compact DACs of this class. I don't see the Zhaolu packing anything bigger than that in that size chassis...I could as always be wrong

Peete.

PS LC by the way used to work for Zhaolu IIRC. That's why the two are similar in design and philosophy...with the Zero being the lesser cost option with the better H/Amp in it. the 3.0 has no headphone amp I think...so that's no good for you ? Can you check that dario please...thanks. I've got to look up specs on the Zero's stock volt regs and see it there is better hi speed, higher current parts. The toroidal transformer has to be uprated to maybe 300VA...need to check all this out and gets prices and such...

[Pricklely Peete]

Originally Posted by alxwang

I do not think you will be happy about D2000 with zero headphone Amp.

PP: Computer PS test failed. It looks like just get right volt and current is not enough.

My power board is hold LA. I do not know how can a shipment from China to Canada can ever be hold in LA for 1 weeks.

Figures eh Alex....oh well it was worth checking out at least. Hmm, in LA...WTF ?

Peete.