Review: ZERO 24 BIT/192KHz DAC/Headphone Amp/Pre-Amp - Page 400

U are the most generous guy around. Me too. I spend a lot of $$$ to be the first to try things.

I have some info on the Power Supply issues with 3 OPA. be back.

Power supply issues with 3 OPA.

Well the rating on zero dac is only 10W (read the specs behind the dac).

That means only about 100MA is available at about 110V.

Now OPA Earth and 2*Sun add up to 56+2*44 = 144mA say 130mA (not fully loaded all the time)

On top of 130mA, there is DAC, receiver and other power supply requirement.

This will strain the tranny to work, though it will not spoil the tranny.

For power supply, typically u need to have 3-4 times the headroom to have good stable sound quality.

At this high current demand, if the voltage regulator (3 pin) is premium grade, it can still give good sound. What if the regulator is just the normal grade !

Hope to hear PP mod of the power supply. 1A = 1000mA would be great for the power hungry OPA.

Furthermore different voltage regulator also can affect the sound quality. Some diy also change the OPA connector with 4N and it gives good sound as well.

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...

Excellent job with this info...that pretty much confirms my suspicions CC.

I've been talking back and forth with Lawrence about this very subject all morning and he has suggested hi speed schotky (SP?) voltage regs...but I was/am concerned the stock transformer doesn't have the heft (in current) to deliver what the 3 HDAMs really need. The volt reg board and 1 amp transformer are on the way as we speak...in addition to that I have requested from LC additional part numbers for all 8 stock volt regs on the stock pcbs of the Zero...For a few bucks more it can't hurt to go to hi speed regs anyway...I highly doubt it will allow the 3 HDAM equipped Zero to function at it's best...but you never know. I will also ask what max rating the stock toroid delivers (at CC's preferred loading %) in case it's more than 100VA. I'm hoping it's 200VA.... but I doubt it...otherwise the bass wouldn't have leaned out, SQ suffered like it did (when 3 HDAMs are installed).

If the number is 100VA as CC suggests (and it most likely is) then a separate reg/transformer set up will be the cure for the 3 HDAM Zero config...I hope

Between CC,Alex, Pench and I we'll get this all figured out guys

Peete.

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.

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.

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.

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.

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.

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.

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.

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