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

[sandchak]

Originally Posted by les_garten

I would make sure it is socked well. But it seems it is working, because your headphones are working. With everything you said here, it is leaning towards faulting switching of the line output from the HP Amp to the RCA's. The reset switch may fix this.

For COAX, any RCA cable will work for troubleshooting.

I am absolutely sure the cables I am using are fine and as you say, the opamps are fine too because I can hear the headphones..

What is this RESET switch?? and how can I use this switch to fix it????...

[sandchak]

Well Guys ! thanks for all the inputs, its close to 2AM out here and feel like just the Zero myself !

Tommorow morning I'll try and hook up my NAD C541i which does have coax connection and try my vandenhul RCA cable to act as coax and see if that works.. if not, well I just realized that I have crossed 10 posting and I can SELL!!!!.. kidding.. any further inputs will be highly appreciated considering this cost me around USD250 with DHL shipping and considering more that I aint rich but a freak for audio..

And to say honestly, I am now dreading if theres something majorly wrong and I have to ship back and forth.. by that time this might be the costliest Zero - well only if it works..

[les_garten]

Originally Posted by sandchak

Well Guys ! thanks for all the inputs, its close to 2AM out here and feel like just the Zero myself !

Tommorow morning I'll try and hook up my NAD C541i which does have coax connection and try my vandenhul RCA cable to act as coax and see if that works.. if not, well I just realized that I have crossed 10 posting and I can SELL!!!!.. kidding.. any further inputs will be highly appreciated considering this cost me around USD250 with DHL shipping and considering more that I aint rich but a freak for audio..

And to say honestly, I am now dreading if theres something majorly wrong and I have to ship back and forth.. by that time this might be the costliest Zero - well only if it works..

Actually you need 50 posts to sell. I got something and have to wait or do it on Fleabay. They slap these things together, and I guarantee you, they are not fired up and ran, no matter what any of them say. If they were, we wouldn't have the kinda problems we are seeing. I'm waiting on mine and I've got both my testicles crossed for good luck!

[Pricklely Peete]

Sandchak,

Double check the 627 opamp in the dac section socket. If it's the AU form factor (the small adapter with an over under chip arrangement) it's possible it's been installed backwards or was poorly assembled. If it was then it will cook itself when you turn the unit on with little or vastly distorted signal being passed to the analog outs or the H/Amp section. That's one possibility, another is checking to make sure the H/Amp opamps are also installed correctly. The crescent or cutouts on the IC's themselves should all face towards the rear panel. If you can take a pic of the opamps as they are now before taking them out that would be very helpful. Post the pic and maybe we can spot something obvious.

Another possibility, and this is a remote one, is the vol pot is bad or the relay used to engage the preamp is faulty. In any event the line out or line level should function if you are hearing faint music with the cans plugged in.

One more idea, do you have another amp to run that line level signal to (other than your computer speakers) to establish if it's a conflict with the computer speakers themselves. Like a cheap receiver or integrated amp with either a head phone output or hooked up to your speakers (a regular pair, not the computer speakers).

One other test to try....isolate your computer speakers completely from the computer and only run the RCA outs from the Zero to the computer speaker inputs (2 channel stereo only) Make sure you have selected the Front pair of speakers if it's a MC setup. The only connection to the computer being the optical out.

Another option to try is making sure you don't have a level in your CP mixer low or muted, a driver conflict or configuration problem (such as 5.1 vs 2.1 etc...).

That's a lot of things to try and I hope you can get your problem nailed down soon. It seems to me that if you can hear music than it's a possible easy fix that is being overlooked somewhere.

One last note...a blown opamp will pass some signal so that's no sign of them working properly. The gain level between a blown opamp and one working properly is huge.

One more I thought of...pull the pcbs to check for shorts anywhere...untrimmed legs touching the chassis, sloppy solder clean up causing a short...gently, ever so slightly, flex the pcb's to see if anything changes while passing a signal through the DAC and H/Amp sections. Another trick is wiggle the 1/4 in jack in the Zero's H/Amp socket...it may have a cold solder joint, check the solder joints on the pot as well with a gentle flex of the pcb while powered. Visually inspect the pots solder points.

Make sure the 2 cables (of the 4 wires each) running to and from each board along the right hand side are fully seated and finally...make sure the two black power connectors are fully seated (one is the upper left hand side and the other a small 3pin on the H/amp board ).

A real quick test to see if the 627 is buggered is to try one of the H/Amp opamps in the DAC section's socket. Again this will only allow for a line level output to another amp (with speakers).

That should narrow a few of the possibilities that come to mind.

Good luck and report back...

Peete.

[les_garten]

Originally Posted by Pricklely Peete

Sandchak,

Double check the 627 opamp in the dac section socket. If it's the AU form factor (the small adapter with an over under chip arrangement) it's possible it's been installed backwards or was poorly assembled. .

SNIP>>>>>>>>>>

Peete.

Thanx Peete,
I saved this doc as a neat troubleshooting guide. I anticipated some of what you posted here, so when I ordered my Zero, I ordered 3 sets of OpAmps from Linear Tech just in case it came in with an amp screwed up. The smart plan seems to just pull both boards out and QC them before firing them up. That's been my plan. Shame you have to do this, but seems like not a bad idea.

[sennsay]

Originally Posted by les_garten

Thanx Peete,
I saved this doc as a neat troubleshooting guide. I anticipated some of what you posted here, so when I ordered my Zero, I ordered 3 sets of OpAmps from Linear Tech just in case it came in with an amp screwed up. The smart plan seems to just pull both boards out and QC them before firing them up. That's been my plan. Shame you have to do this, but seems like not a bad idea.

Yes, it is a shame to have to do that, especially since it might make noobies somewhat nervous pulling the boards, a good idea though.
I did pull mine, even though I've had my Frankie .... um, Zero once upon a time ago ... for some months now, fortunately all was well. Mine's been flawless from the beginning, other than the standard channel imbalance on the stock vol pot, since replaced with the upgraded ALPS.
PP is excellent with noobies to the Zero! Let's call him Daddy Zero!

S-Man

[sandchak]

Originally Posted by Pricklely Peete

Sandchak,

Double check the 627 opamp in the dac section socket. If it's the AU form factor (the small adapter with an over under chip arrangement) it's possible it's been installed backwards or was poorly assembled. If it was then it will cook itself when you turn the unit on with little or vastly distorted signal being passed to the analog outs or the H/Amp section. That's one possibility, another is checking to make sure the H/Amp opamps are also installed correctly. The crescent or cutouts on the IC's themselves should all face towards the rear panel. If you can take a pic of the opamps as they are now before taking them out that would be very helpful. Post the pic and maybe we can spot something obvious.

Another possibility, and this is a remote one, is the vol pot is bad or the relay used to engage the preamp is faulty. In any event the line out or line level should function if you are hearing faint music with the cans plugged in.

One more idea, do you have another amp to run that line level signal to (other than your computer speakers) to establish if it's a conflict with the computer speakers themselves. Like a cheap receiver or integrated amp with either a head phone output or hooked up to your speakers (a regular pair, not the computer speakers).

One other test to try....isolate your computer speakers completely from the computer and only run the RCA outs from the Zero to the computer speaker inputs (2 channel stereo only) Make sure you have selected the Front pair of speakers if it's a MC setup. The only connection to the computer being the optical out.

Another option to try is making sure you don't have a level in your CP mixer low or muted, a driver conflict or configuration problem (such as 5.1 vs 2.1 etc...).

That's a lot of things to try and I hope you can get your problem nailed down soon. It seems to me that if you can hear music than it's a possible easy fix that is being overlooked somewhere.

One last note...a blown opamp will pass some signal so that's no sign of them working properly. The gain level between a blown opamp and one working properly is huge.

One more I thought of...pull the pcbs to check for shorts anywhere...untrimmed legs touching the chassis, sloppy solder clean up causing a short...gently, ever so slightly, flex the pcb's to see if anything changes while passing a signal through the DAC and H/Amp sections. Another trick is wiggle the 1/4 in jack in the Zero's H/Amp socket...it may have a cold solder joint, check the solder joints on the pot as well with a gentle flex of the pcb while powered. Visually inspect the pots solder points.

Make sure the 2 cables (of the 4 wires each) running to and from each board along the right hand side are fully seated and finally...make sure the two black power connectors are fully seated (one is the upper left hand side and the other a small 3pin on the H/amp board ).

A real quick test to see if the 627 is buggered is to try one of the H/Amp opamps in the DAC section's socket. Again this will only allow for a line level output to another amp (with speakers).

That should narrow a few of the possibilities that come to mind.

Good luck and report back...

Peete.

Hi Peete,
I just woke and rushed here to see anything for me..
I will run all the tests and pics during the day and post the pics too..
I think I have to mention something which I overlooked and didnt mention earlier..
When I put on the amp for the first time which was the day before and hooked it to the headphones, it started off well, BUT within a minuite, there was like a noise (zzzzzzzzzzz) like something getting burnt inside or shot circuiting, and the lights of zero were kind of shimmered.. I got scared and switched off the Zero, (thought it was maybe the voltage problem), but then I switched on the zero and everything worked fine with the headphones on..
It was only yesterday that I tried to connect the speakers and found no sound comming out of it..
Like I said, I'll do all the tests and pics and report back in the evening, hopefully I'll find time because abnormally today is an extremely busy day for me..
Thank You Peete, You are a saviour for folks like me on the forum..

[Penchum]

With all this troubleshooting going on, I thought it would be a good idea to share some of what I know about the Zero, from a slightly different stand point. Many of you don't know this, but the Zero has been sold to members of HeadFi, dating clear back to August of last year. That is a year and three months!!

Late last year and early this year, Lawrence was the only trusted seller who was "bench testing" his Zero's prior to shipment. The Zero factory was putting out some decent units, and the failure rates were much better than we could get from a US manufacturer. Then, things just seemed to change somehow. Other sellers were popping up, selling quantity to make their profit. Once Lawrence lowered his prices and made deals to compete directly with them, I'm "pretty" sure bench testing went away, except in cases where soldering was involved, like when the Alps pot upgrade was done in house.

Then, we started to notice problems with the cleanup and QC of the boards, prior to final unit assembly. It looked like sloppy work, but I think the cleaning/QC was simply NOT DONE before assembly. It seemed like the assembly line just dropped this cleaning/QC step, opting to shove them out the door quicker. I wasn't impressed. The factory owns this problem 100%. Then, we started to notice the upgrade Opamps not being installed correctly, like they were an afterthought or something. Chalk this one up to final QC. The "seller" owns this problem 100%.

Considering all these things, it seems to paint a "not so hot" picture for the makers and sellers of the Zero. However, all of this is only ONE part of a much bigger picture.

The Zero factory sells Zero's in batches of 50 units, to resellers that sell on eBay or their own web site stores. We already know this part. The part we don't see, is the amount of Zero's that are sold to stores in China. According to two such stores, they are selling Zero's like crazy to the public in China! Way more than the amount of Zero's being sold around the world! So, when you think about production of the Zero's, you have to factor in a much higher quantity demand being put on the factory. Those boys must be jamming big time! We also have to consider what happens to our Zero's during shipping. It is the great unknown, but indicators show that smaller boxes are being tossed around pretty hard. We can't escape this variable, if we want a Zero.

At the end of the day, the failure rates on the Zero's as a whole, are very good. Of all the HeadFi'ers buying Zero's, we always hear about the ones that have issues. These amount to a very small portion of the overall HeadFi numbers. Add in the units that need help after shipping, and you still have a very small number.

So I guess what I'm trying to say, is that the majority of us who order a Zero, will have a decent Zero without problems. The problems noted above were spread out over an entire year! Considering it is a budget DAC/Amp and it was shipped half way around the world to our door steps, it is great that the Zero has had so much success. The price point has saved us a bunch of cash, and the Zero's performance has put higher priced units on notice!

I still believe buying a Zero is a safe bet. Thanks to everyone's hard work in this thread, the small number of problem Zero's identified here, get fixed by the owners, and very, very few will ever have to return their Zero's to China for a fix. This thread has just about every fix known, and the help you can get here is some of the best I have seen on HeadFi. With this kind of backing, I would buy another Zero in a heart beat! You guys are the best!!

Pench

[sandchak]

Originally Posted by Penchum

With all this troubleshooting going on, I thought it would be a good idea to share some of what I know about the Zero, from a slightly different stand point. Many of you don't know this, but the Zero has been sold to members of HeadFi, dating clear back to August of last year. That is a year and three months!!

Late last year and early this year, Lawrence was the only trusted seller who was "bench testing" his Zero's prior to shipment. The Zero factory was putting out some decent units, and the failure rates were much better than we could get from a US manufacturer. Then, things just seemed to change somehow. Other sellers were popping up, selling quantity to make their profit. Once Lawrence lowered his prices and made deals to compete directly with them, I'm "pretty" sure bench testing went away, except in cases where soldering was involved, like when the Alps pot upgrade was done in house.

Then, we started to notice problems with the cleanup and QC of the boards, prior to final unit assembly. It looked like sloppy work, but I think the cleaning/QC was simply NOT DONE before assembly. It seemed like the assembly line just dropped this cleaning/QC step, opting to shove them out the door quicker. I wasn't impressed. The factory owns this problem 100%. Then, we started to notice the upgrade Opamps not being installed correctly, like they were an afterthought or something. Chalk this one up to final QC. The "seller" owns this problem 100%.

Considering all these things, it seems to paint a "not so hot" picture for the makers and sellers of the Zero. However, all of this is only ONE part of a much bigger picture.

The Zero factory sells Zero's in batches of 50 units, to resellers that sell on eBay or their own web site stores. We already know this part. The part we don't see, is the amount of Zero's that are sold to stores in China. According to two such stores, they are selling Zero's like crazy to the public in China! Way more than the amount of Zero's being sold around the world! So, when you think about production of the Zero's, you have to factor in a much higher quantity demand being put on the factory. Those boys must be jamming big time! We also have to consider what happens to our Zero's during shipping. It is the great unknown, but indicators show that smaller boxes are being tossed around pretty hard. We can't escape this variable, if we want a Zero.

At the end of the day, the failure rates on the Zero's as a whole, are very good. Of all the HeadFi'ers buying Zero's, we always hear about the ones that have issues. These amount to a very small portion of the overall HeadFi numbers. Add in the units that need help after shipping, and you still have a very small number.

So I guess what I'm trying to say, is that the majority of us who order a Zero, will have a decent Zero without problems. The problems noted above were spread out over an entire year! Considering it is a budget DAC/Amp and it was shipped half way around the world to our door steps, it is great that the Zero has had so much success. The price point has saved us a bunch of cash, and the Zero's performance has put higher priced units on notice!

I still believe buying a Zero is a safe bet. Thanks to everyone's hard work in this thread, the small number of problem Zero's identified here, get fixed by the owners, and very, very few will ever have to return their Zero's to China for a fix. This thread has just about every fix known, and the help you can get here is some of the best I have seen on HeadFi. With this kind of backing, I would buy another Zero in a heart beat! You guys are the best!!

Pench

I AGREE with everything you said Pench, I am sure one off problems always crop up and even though I might be the unlucky one out here, I can vouch that the Zero is a terrific value and does sound fantastic for its price (even the way it is now on the headphones only ), and I also very confident with all the help around this place, my Zero will come alive SOOON !!

[les_garten]

Hello,
Don't know if you guys know about this utility, but it is what I am using to burn in stuff now. Freeware that has rest periods that you can set.

Download section for Burninwave generator

Les

[les_garten]

Originally Posted by Penchum

I still believe buying a Zero is a safe bet. Thanks to everyone's hard work in this thread, the small number of problem Zero's identified here, get fixed by the owners, and very, very few will ever have to return their Zero's to China for a fix. This thread has just about every fix known, and the help you can get here is some of the best I have seen on HeadFi. With this kind of backing, I would buy another Zero in a heart beat! You guys are the best!!

Pench

Hi,
I had also thought these were aberrations and read over LC's Ebay FB to see who complained about what. I didn't find any Zero problems. He had some other complaints for some other stuff, but if you've sold anything on Ebay, you know that can happen. However, it is disconcerting to fire up a box and have it go "poof" because the Opamps were installed backwards or the HDAM was connected backwards on one end.

I think he's doing well on these boxes if you look at what Chinese workers make. He should eat the shipping both ways if something has to go back to the Motherland due to ineptitude. That would kill his profit I am sure and that's why he doesn't want to do it.

Les

[sandchak]

Originally Posted by les_garten

Hello,
Don't know if you guys know about this utility, but it is what I am using to burn in stuff now. Freeware that has rest periods that you can set.

Download section for Burninwave generator

Les

Thanks Les, its going to be a great utility for me - just bought a pair of 701s 4 days ago..

[sandchak]

Originally Posted by Pricklely Peete

Sandchak,

Double check the 627 opamp in the dac section socket. If it's the AU form factor (the small adapter with an over under chip arrangement) it's possible it's been installed backwards or was poorly assembled. If it was then it will cook itself when you turn the unit on with little or vastly distorted signal being passed to the analog outs or the H/Amp section. That's one possibility, another is checking to make sure the H/Amp opamps are also installed correctly. The crescent or cutouts on the IC's themselves should all face towards the rear panel. If you can take a pic of the opamps as they are now before taking them out that would be very helpful. Post the pic and maybe we can spot something obvious.

Another possibility, and this is a remote one, is the vol pot is bad or the relay used to engage the preamp is faulty. In any event the line out or line level should function if you are hearing faint music with the cans plugged in.

One more idea, do you have another amp to run that line level signal to (other than your computer speakers) to establish if it's a conflict with the computer speakers themselves. Like a cheap receiver or integrated amp with either a head phone output or hooked up to your speakers (a regular pair, not the computer speakers).

One other test to try....isolate your computer speakers completely from the computer and only run the RCA outs from the Zero to the computer speaker inputs (2 channel stereo only) Make sure you have selected the Front pair of speakers if it's a MC setup. The only connection to the computer being the optical out.

Another option to try is making sure you don't have a level in your CP mixer low or muted, a driver conflict or configuration problem (such as 5.1 vs 2.1 etc...).

That's a lot of things to try and I hope you can get your problem nailed down soon. It seems to me that if you can hear music than it's a possible easy fix that is being overlooked somewhere.

One last note...a blown opamp will pass some signal so that's no sign of them working properly. The gain level between a blown opamp and one working properly is huge.

One more I thought of...pull the pcbs to check for shorts anywhere...untrimmed legs touching the chassis, sloppy solder clean up causing a short...gently, ever so slightly, flex the pcb's to see if anything changes while passing a signal through the DAC and H/Amp sections. Another trick is wiggle the 1/4 in jack in the Zero's H/Amp socket...it may have a cold solder joint, check the solder joints on the pot as well with a gentle flex of the pcb while powered. Visually inspect the pots solder points.

Make sure the 2 cables (of the 4 wires each) running to and from each board along the right hand side are fully seated and finally...make sure the two black power connectors are fully seated (one is the upper left hand side and the other a small 3pin on the H/amp board ).

A real quick test to see if the 627 is buggered is to try one of the H/Amp opamps in the DAC section's socket. Again this will only allow for a line level output to another amp (with speakers).

That should narrow a few of the possibilities that come to mind.

Good luck and report back...

Peete.

Hi Peete, I had some free time, so I took these 2 pics (sorry I have a horrible camera..).

I think by the pics you can make out the the opamps are the type you mentioned and placed rightly.
Actually from the beginning I have not involved the PC, just the CD player > Zero> Speakers (klipsch 2.0 active), I also ran the same setup minus the Zero from the headphone out of the CD player to the speakers and it worked fine.

I should exclude problem with digital cables or speakers because it works fine in other setups.
I also pulled out mt NAD C541i CD player and attached the ZERO useing the vandenhull RCS as coaxial - NO Sound again..
All the wire connections you said to check, are placed as it should be.. I havent yet opened the board to see the stuffs behind, But I am waiting for the sellers reply, and I want to hear what he says before taking things apart..
Well, its bad because I bought this ONLY for the speakers as the PH100 is on its way that I would use for the headphones..
BTW, I just heard from a courier that 3 pcs of LM4562NA opamps should reach me tommorow?? Can I do anything with that? I have no clues about single and dual opamps, so I dont know if those can be placed on the ZERO opamps socket just to see if it makes any difference..

I dont know how to thank you.. but then.. Thank you..

[Sganzerla]

Sandchak, check if the voltage switch at Zero's back is correct.

[sandchak]

Originally Posted by Sganzerla

Sandchak, check if the voltage switch at Zero's back is correct.

checked - its on 220 ( which is correct..)
Thank you