Group Buy for full ATX Linear PSU from Teradak

[fmak]

It is not meaningful to look at the performance of linear v switching PSs only wrt to ripple and effeiciency numbers.

 

What we have in a PC are several noisy power supply rails supplying reactive loads. If you forget 'ripple' at 50/60Hz and probe the rails with a fast oscilloscope (not cheap digital ones with limited bandwidth and capacity to ' hold over a wideband), you will see pretty horrific low frequency and high frequency pulses as the PS reacts to large and fast current demands from the various bits of hardware. 'Silencing' these pulses is for me one important aspect of improving sound quality from PCs.

 

Linear supplies may have 18 mV noise at high currents but well designed ones do not 'emit' large noise pulses like switching ones. There should also be less coupling between the various voltage supplies

 

Specmanship is a feature of PC performance claims. The claims for PC switching supply performance ae like the claims for SSD performance - loads of test figures that do not actually relate to performance or experience in use in a particular situation.

[fmak]

Does Switching PSU vs Linear PSU with the same ripple noise at 18mV provide a same sound? The answer is no because of pulse, transient etc which make Linear PSU still more superior, produce better sound even with a same number of ripple noise...... alright, this question has been answered.

 

Okay now moving on to the next question:

 

12VDC example

1) 2A (2.13mV) + 4A(additional load) = 6A (3.51mV) --> make sense

2) 6A (3.51mV) + 4A(additional load) = 10A (18.3mV) --> does not make sense

 

I would expect the ripple noise increase bit by bit accordingly to the load, not a sudden exponential increase. Probably I am expecting something like on Corsair AX860i chart in post #63. There you can see ripple noise increase bit by bit accordingly to the load given. My suspect still stand on the same exact capacitor which is use by all three models.

 

And other things to put in mind when comparing to the other linear PSU brand, they typically have 1mV ripple noise or even less than that. 18mV is simply off the chart. Unless somebody can says that "18mV, 3mV, 1mV in Linear PSU does not effect the sound or only subtle. Please ignore it", I would say we may have an issue.

 

is to quote some Corsair numbers with no qualification of how they have been obtained and over what bandwidth. Really it is pointless to pursue numbers like these.

 

The only valid method of comparison is to power with the two PSs and then measure wideband noise as well as record pulses under a defined set of conditions in the operation of the PC.

 

If people don't want to do this, they have to use their ears, and linear power supplies for PC audio do work in improving SQ.

[fmak]

If you look at the iFi data, the 2mV spec means nothing. What is important is their spectra, which shows spikes at around the switching frequency not reflected in the 2mV number.

 

The iFi USB Power sounds a lot better with a good linear supply (I use a superregulator with pre regulator), whatever they may claim

[fmak]

Hey Rurika, news about the DC cable.

 

Like I posted above, the default umbilical DC cable is 1m. They can make it 1.5m for + $20USD, you just need to attach a note to your order and the money. They WILL NOT make it 2m because they said it won't function dependably/correctly.

 

I myself am going to move some stuff around and make sure it'll work at 1m or less. I'd like to make that cable even shorter if I can :-D

 

Ben

 

I almost forgot in my PM. Rather than having a 1.5 m cable, it would be good to have 2, a 1m and a 1.5 m. Is this possible and what about the cost?

 

Fred

[fmak]

Tier 1 is CLOSED

 

Thanks a lot, guys. I'll now compile all the info, make it readable and unmistakeable, and forward it to Teradak for processing.

 

Michael will get back to me with final shipping quotes and then I'll let you guys know the totals you need to pay.

 

And I'll post Teradak's PayPal info here too.

 

 

nt

[fmak]

No 8 Payment made 29 Oct

 

Original Transaction

Date Type Status Details Amount

28 Oct 2014 Payment to Li Michael Completed ... -$548.75 USD

Related Transactions

Date Type Status Details Amount

28 Oct 2014 Charge from Credit Card CompletedYour transfer from your credit card to your PayPal account is complete.Your transfer from your credit card to your PayPal account is complete. Details £350.39 GBP

28 Oct 2014 Currency Conversion Completed Details -£350.39 GBP

28 Oct 2014 Currency Conversion Completed Details $548.75 USD

 

Sent to:

Li Michael (The recipient of this payment is Non-US – Verified)

[fmak]

Oops. Haven't thought about customs. What is wise / best practise here when importing into EU (Netherlands). Any tips (that might save me some?

 

@Ben: was joking... I have (VERY) many thoughts on my next CAS design... Need to kill-off options though..

I have more or less decided on Single PC on Server2012 + AO + JRiver.

Need to decide on :

- Bay Trail vs Haswell.

- Details on battery config (how many batteries; do I share the Teradak 5VSB to trickle charge 2 batteries for both PPA and SSD, or should I bring in a separate 5V feed for one of them, or do I put the PPA on the 5V shared with the mobo...)

- relays to switch the batteries.

 

I don't really care for form factor. My CAS in on a bottom shelf in a rack besides my couch (not in sight). Heat is an issue, but 10W Bay Trail vs 35W Haswell pré underclocking should not give much difference..

 

Hans

 

no escape normally duty (12% from memory) + VAT

 

let's hope the Dutch Post doesn't do a DHL etc and charge you opn top for collecting the custom money.

 

Evil; EU should have a free trade agreement with China. I think Switzerland recently did this.

[fmak]

Hey guys, I've gotten a bunch of emails from Michael about adding units to an order or friends of buyers trying to get in.

 

#1 - I'm the liaison to Michael about the group buy. Due to the surge in emails, he and I have decided that any communication regarding it must come to me. He will not answer any questions.

 

#2 - Tier 1 is closed. Locked solid. Shut. We can't have a single more unit added, even from an existing buyer. Zero.

 

If all the new people jumped into Tier 2 there would probably be enough interest to send it through.

 

I know the idea of trying to slip in is attractive, but it's not gonna fly. Commit yourself to Tier 2, try to drum up interest, and it'll probably go ahead. That's really your only option for now.

 

Thanks guys.

 

Ben

 

You should be aware that there is an issue with posting here. You login, it's accepted then you click Reply,

the site says you are not logged in. Then you go to help, Notification is enabled and you are logged in. You can then go

to Forum and can post a reply. Weird.

 

I have flagged this up with Chris under General.

 

Fred

[fmak]

Ben

 

I sent you a PM with the title ATX175 which was wrong, sorry.

 

I need delivery to HK by Jan 15. Is this still on the cards as Xmas is in the way.

 

Thanks for all the work

 

Fred

[fmak]

Inspection shows good finish and good cables. However, I cannot try it until end of month.

 

Pissed off for being charged extra for 'express' delivery which I did not ask for. The amount

was small but it was the principle.

[fmak]

I still haven't get the tracking number yet. Is it just me?

 

Even if you ask for courier and tracking details. The thing just turns up and we were

asked for extra money for 'express delivery'.

 

I have to say, however, that it was very well presented and packed in a double box,

and puts some other vendors, especially Amazon, to shame.

[fmak]

That's good news, I had asked them that they be packaged extra securely. I'm not sure if this is anything special for us our if it's Teradak's usual style, but I'm happy to hear it's happening.

 

No pics for us?? It sounds like you're the first to receive yours, you can't leave us out in the cold!

 

It looks like the Pics you posted. There is a seal on the case which says that there

will be no warranty if broken. I'll only do so when I have tried the unit on a MB.

 

You posted elsewhere about the U12. I have and have modded the U10 with much improved

5V. I think that you will be better off with the e99 Luckit board powered by a good super

regulator PS.

 

The combo sounds a lot better than the U10.

PS such as a

[fmak]

Teradak said they paid for express shipping because of the delay with their supplier and they wanted to guarantee that you received your unit before the Jan. 15th moving date that you'd told them about. They said that they paid up front so that you wouldn't have to, but that if you did they can only guess it's because your address is off the courier's normal route.

 

 

Yeah, I definitely wouldn't recommend breaking that seal and taking any internal pictures for us either. I was just thinking of some extra pictures, but if they look the same then you're right and there's probably no point.

 

 

It's cool to hear that you also have experience with Gustard's convertors. I'm pretty excited to get my U12 and see how its I2s sounds into my PWD Mkii. I also look forward to modding it a bit with new Crystek clocks, some power caps, a new transformer, and whatever else I can think of.

 

I've seen the Luckit board and it looks pretty great and always has up to date Thesycon drivers too. I don't know much about the rest of it, but if I was really going the DIY route I think I'd try the newest Combo384 Amanero USB board. It sounds more advanced and skips using an XMOS chip all together. Do you have any experience or preference between the two?

 

 

Luckit has very good XOs and spdif as well as I2S. Lucian is excellent in responding

to queries.

 

I have the Amanero in my W4SDAC2 Se. It's fine but for diy I'd go for the Luckit.

[fmak]

Hi All,

 

Let me try to provide some information on the 'problem' and the 'fix'. In case you wonder I'm the guy raising the issue with Teradak after I received my unit.

 

First of all, the original unit works. After receiving it I setup it up and my PC boot without any issue. I ran it for a while and then I noticed that the 5V and 3.3V fluctuates a bit using the h/w monitor provided by my ASRock motherboard. I then proceeded to measure the ripple using my DMM and found that the 12V rail is fine but the 5V rail has ripple at ~100mV which IMO is higher than desirable. I didn't measure the 3.3V rail as I cannot find an easy measuring point with the PC running.

 

Teradak's engineer could not reproduce my observation but nonetheless they investigated further and did confirm that the 5V/3.3V ripples are higher than expected. After some more investigation Teradak developed a modification aimed to improve voltage stability and reduce ripple.

 

The modification involves replacing the voltage reference semiconductor (for each voltage rail) with a green LED (which has constant voltage drop so can serve as voltage reference). Teradak sent me the parts and I did the modification to my PSU. I measured the PSU's performance before and after the modification using a scope with the following results:

 

[12V Rail]

- Original ripple RMS: ~40mV

- LED-mod ripple RMS: ~40mV

 

 

[5V Rail]

- Original ripple RMS: ~110mV

- LED-mod ripple RMS: ~25mV

 

 

So it is clear that the 5V ripple performance improved significantly. Again I didn't measure the 3.3V rail but I believe it will have similar improvements. The voltage stability of all three rails are now very stable as well. I believe Teradak applied the mod to all unshipped units. If your unit has green glow inside the chassis then it has the LED mod.

 

Have fun with your new ATX-PSU.

 

Was it to replace the voltage references?

 

Can you please post details?

[fmak]

Hi All,

 

Let me try to provide some information on the 'problem' and the 'fix'. In case you wonder I'm the guy raising the issue with Teradak after I received my unit.

 

First of all, the original unit works. After receiving it I setup it up and my PC boot without any issue. I ran it for a while and then I noticed that the 5V and 3.3V fluctuates a bit using the h/w monitor provided by my ASRock motherboard. I then proceeded to measure the ripple using my DMM and found that the 12V rail is fine but the 5V rail has ripple at ~100mV which IMO is higher than desirable. I didn't measure the 3.3V rail as I cannot find an easy measuring point with the PC running.

 

Teradak's engineer could not reproduce my observation but nonetheless they investigated further and did confirm that the 5V/3.3V ripples are higher than expected. After some more investigation Teradak developed a modification aimed to improve voltage stability and reduce ripple.

 

The modification involves replacing the voltage reference semiconductor (for each voltage rail) with a green LED (which has constant voltage drop so can serve as voltage reference). Teradak sent me the parts and I did the modification to my PSU. I measured the PSU's performance before and after the modification using a scope with the following results:

 

[12V Rail]

- Original ripple RMS: ~40mV

- LED-mod ripple RMS: ~40mV

 

 

[5V Rail]

- Original ripple RMS: ~110mV

- LED-mod ripple RMS: ~25mV

 

 

So it is clear that the 5V ripple performance improved significantly. Again I didn't measure the 3.3V rail but I believe it will have similar improvements. The voltage stability of all three rails are now very stable as well. I believe Teradak applied the mod to all unshipped units. If your unit has green glow inside the chassis then it has the LED mod.

 

Have fun with your new ATX-PSU.

 

Please read and see if you can help

[fmak]

Hi JM,

 

it's not that I misunderstood you, it's that I was hoping you didn't see things that way. There have been issues, but I don't think they've been very bad or ones that would put in to question the overall quality and dependability of the units. But, that is my opinion and that's all. If anyone feels otherwise than that's alright.

 

As for the design problem adding 10-20x the ripple, that's actually not true. The reason the measurements were higher is because they were not done according to the Intel defined method of testing, like the first measurements were and all PSU company's ripple measurements are. The original ripple numbers and the second numbers you're talking about were both true.

 

Lucky for us, though, because of _JL_'s testing and non-Intel motherboard measurements Teradak was able to find a fault with their batch of supplied voltage references and apply a fix. This wasn't a design issue, it was an out of spec part issue. In the end we actually got a PSU that performed better than the ones they'd originally offered us.

 

Anyway, I'm not trying to stop anyone from sharing their concerns, I just didn't agree that there were tons of issues with the supplies or anything calling in to question their overall quality.

 

I received one of the first units in January and was surcharged for delivery 'out of area' in Tiny Hong Kong after having paid over $110 from China to HK. The explanation I got for this was simply ridiculous. This unit was one of the 'faulty' ones. Michael knew well that I was taking the unit away to use, and so I gave Teradak the address to post the components to. Apparently they sent these to the

wrong address (the original delivery one).

 

Two months after I got the unit, I still had nothing. So, after Terdak returned to work,

I chased Michael with many exchanges of emails. I was after two things. First the diagram for connecting the bypass capacitors wasn't clear as to where one of the legs went, and

second, I needed the LEDs and Capacitors sent to me in the Med. However, after many exchanges, all I got was no answer about the Caps and repeated regurgitations that they sent the parts and that postage to the Med was expensive. I offered to pay and still got no comprehensible answer. Note: Most China eBay merchants sell parts delivered to the Med without fail and at no cost!

 

Annoyed by the fact that Teradak had totally failed to provide any after sales service, I asked Ben M to intervene. This time, I did get an answer on the Caps and I thought I was going to receive the two LEDs and Caps. It is now April and I have still not received anything.

 

Anyway, I have now fixed the problem myself but wish to point out to further potential Group Buy or single buy posters that:

 

1. Either Michael is unable to comprehend requests via email, or he has no control over what happens to customer service at Teradak.

 

2. The way that Teradak had behaved over sending a few dollars worth of parts is reprehensible and all of the China sellers I have dealt with value service much more than they have done. A Western seller of over $500 worth of gear would have provided the parts and answered my query with little delay. They would also have refunded my ridiculous 'out of territory' delivery surcharge.

 

As I told Ben, it seems to me that Michael has a Mind Set Issue. Throughout my exchange of emails with him, the answers had been: LEDs were cheap and postage was expensive for them. This was just a fob off as I had offered to pay for both. Incidentally, getting LEDs with the right forward voltage range has been a major problem. Neither Farnell or RS do it and Mouser has a minimum order

of $100 or expensive e20 delivery. So, I had to resort to spending e10 on eBay UK for 'premium' LEDs that turned out to be faulty and that failed after a minute of use. Eventually I had the right ones, which Teradak should not have expected me to go to the trouble of getting.

 

Michael is welcomed to give his interpretations to the events, although I have kept emails so that what I said could be verified.

 

So, my message to readers here is: Caveat Emptor.

 

Having said all this, I do acknowledge that the ATX unit is well finished, with premium quality cables. As for performance, I shall do listening and measurement tests on load.

[fmak]

Hi JM,

 

 

I had a feeling that many people have left this thread, they are enjoying their PSU and the deal is done.

 

I can update a little bit, now that I have completed 300 hours burn-in time. The harsh sound is now gone, it now sounded very fluid and expanded sound stage, well that's my first impression. Other things also improve, better focus, detail etc. But i mind you that power cable and any power filter or power distribution you use to feed this PSU is effecting a lot. I believe some of us are actually have different outcome due to these factors, but would rather agree that Teradak PSU is an upgrade especially compare to switching PSU.

 

I believe Teradak PSU would do poorly on environment where there are many electrical problem such as EMI, RFI, poor grounding, voltage instability etc. I believe on such environment and combine with poor power cable plus without any power filter, Teradak would sound harsh and makes your ear easily fatigue, muddy bass etc.

 

I notice that an input filter is missing and therefore kick-back into the mains can be an issue.

 

I intend to try one out but this will take time.

[fmak]

''I was considering to write to Teradak to ask for an time estimation for tier 2 but I prefer to ask you first''

 

Teradak is doing serious business in monetary terms. I find it incredible that they do not respond promptly

and meaningfully to customer requests and enquiries. This has certainly been my experience from Day zero (order process)

to day 60 before getting 2 leds and two capacitors to make good their own mistake. The Chinese New Year thing

was just a poor excuse as other China vendors didn't do this.

 

Why should Ben have to take on the burden as intermediary?