23 replies to this topic

[Dev]

 

That’s interesting I think. I will make the comparison you are asking about. I already have the necessary stuffs for to do it. I will use two types of pico, one for 12V and another for 16-24V. They will be fed by different power sources to determine possible differences. And I will do this test on both my AudioPC and my ControlPC. I will also make a direct comparison of the sound as it’s right now when I run both computers with LiFePO4 batteries, where all rails are totally separated. It will probably take some time to complete the test, but I promise no matter what the result will be, write it down here.

 

Best regards
Tomas

 

Hi Tom,

 

Awesome and I really appreciate doing this. Its not an easy task but I am very eager to hear what you report back. Thanks much.

[sfkyzu]

Cabling from a separately LPSU to two ATX connectors is all what you need . It will take less space than yours DC-ATX, and will be much better sound.

Thanks.My problem is that there is no large hole on the chassis and the only choice is left the cover open.

[sfkyzu]

Hi Thomas,

 

Yes, I got the picture and you probably meant to exclude as much as smps psu as possible within our reach - I whole heartedly agree.

 

On the CPU power, the pico from mini-box passes the 12v as is without touching it. with the hd-plex dc-atx, since it accepts 16-24v, it must be regulating as some point for the cpu power.

 

I had a small discussion/email exchange with Paul Pang couple of months back and he thinks that if the linear psu (non-atx) has a good a/c transformer and regulator, their is no need for going linear atx route and a pico will just work fine. Incidentally, two other well known psu company (Uptone & Mojo audio) believes the same. It is also surprising that their products, including PPA, cost most or less same and very well above Teradak and hdplex.

 

I was wondering how much of a difference does it make going the full atx route versus a quality linear with pico ? has anybody compared this so far ?

I will do it later.I will use linear PSU linked to MY HIFI DC-ATX PSU or simplicity. 

[Tomslin]

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That’s interesting I think. I will make the comparison you are asking about. I already have the necessary stuffs for to do it. I will use two types of pico, one for 12V and another for 16-24V. They will be fed by different power sources to determine possible differences. And I will do this test on both my AudioPC and my ControlPC. I will also make a direct comparison of the sound as it’s right now when I run both computers with LiFePO4 batteries, where all rails are totally separated. It will probably take some time to complete the test, but I promise no matter what the result will be, write it down here.

 

Best regards
Tomas

 

The test has been done.

 

Initially, I would say that it’s almost two years since I last used a pico in my setup permanently. And it’s far from the same as stand in my signature now. I have had time to forget a lot since then, so it was fun and interesting to go back with pico. But if it becomes permanent again: No, I don’t think so.

 

In practical terms, it was harder than I thought to perform this test. ATX slot in my AudioPC was blocked by heatpipes and any pico didn’t fit, I had to do a little rebuilding there first. Differences was also not so easy to evaluate as I first thought. But now has it been done, and I hope you have some advantage of it.

 

I tested with two types of pico (12V and multi 16-24V) and it was quite difficult to hear any difference between these. However, it was sometimes a clear difference when they was driven by different power sources. I tested with two transformer, one with 24V 250VA and second one 24V 75VA. I couldn’t hear any difference between them. I use voltage regulator based on LT1083 for both 12V and 20V for 16-24V version of Pico. I also tested 12V Pico with a regular 75Ah lead/acid battery. I couldn’t hear any big difference between this power feedings either. Then I change transformer and voltage regulator to a switched device ((Power Brick) HD-Plex 100-240/12V 150W) I heard a clear deterioration.

 

The mainly difference I perceived in SQ between Pico and the LiFePO4 battery system I use and is accustomed with, are that Pico had more digital gloss in its sound and I don't think it was attractive. A bit boring and tiring in the long run acutally. It always went through and I heard it in all different test configurations. When I heard it first, I even thought that this new, glossy sound was better and that despite all my doubts maybe had introduced an improvement in my setup. But the longer I listened, the more clearly I could hear other differences too; less soundstage, less dynamic, thinner and more sharpened for to mentioned some.

 

My experience after this test is that Pico doesn’t sounds better, but I must admit that the differences was of another kind than that I expected me. I also have a very revealing and natural sounding headphone system, who does not hide anything, can I say without to brag. Of course many differences are system dependent, and what I hear is not obvious that others can hear. And vice versa too, certainly.

 

I haven't finished this test completely yet. I will get home some other transformers and cables, among other things, for to evaluate the impact of the internal impedance of the power source, if this would have any effect. If it would be that my impressions changed, I will write it here.

 

I also took some photos of the stuff I used. You can see them here.

 

 

Best regards
Tomas