Continuing pursuit of power supply improvements and improved Dac performance.

[budy]

Well, it has been a while, but I followed your suggestion Jim and invested in the TeraDak, and I am not dissatisfied. What a difference in sound quality. I am not too game to go the DIY experiments that you and 4est have embarked upon, at the moment. maybe because I think it might just be magic. Anyway, thanks for the information. You have increased my enjoyment of music all over again.

 

Regards Bill

[sjoc2000]

Well, it has been a while, but I followed your suggestion Jim and invested in the TeraDak, and I am not dissatisfied. What a difference in sound quality. I am not too game to go the DIY experiments that you and 4est have embarked upon, at the moment. maybe because I think it might just be magic. Anyway, thanks for the information. You have increased my enjoyment of music all over again.

 

Regards Bill

 

Hello Bill;

 

Glad to hear that posts at CA have helped in improving your enjoyment of this great hobby. Magic has served well for thousands of years as an explanation for many things. Whether you want to learn to do a little magic yourself, or just sit back and watch the show is not as important as - Enjoying the music :0)

 

Jim

[mcandmar]

Hi Jim,

 

Your thread was a great inspiration for me to experiment with 5v power supplies for a USB DAC. In my case the ODAC.

 

I have most of my power supply chain built, mains filter (copy of felix filter) > toroid > rectifier board > 7812 based rectifier board > LT1764 based regulator @5.1v > USB isolator > USB DAC. I basically have it as clean as i can make it using a scope to measure noise.

 

My question to you is in relation to grounding, specifically mains earth referenced. Do you have the - rail of the DC power supply tied to mains earth or floating?

 

I'm conflicted as to which is the better option, i could swear the floating DC sounds much better, and looks cleaner on the scope. I would love to hear what way you have your setup configured?

 

Cheers,

 

Mark

[sjoc2000]

Hi Jim,

 

Your thread was a great inspiration for me to experiment with 5v power supplies for a USB DAC. In my case the ODAC.

 

I have most of my power supply chain built, mains filter (copy of felix filter) > toroid > rectifier board > 7812 based rectifier board > LT1764 based regulator @5.1v > USB isolator > USB DAC. I basically have it as clean as i can make it using a scope to measure noise.

 

My question to you is in relation to grounding, specifically mains earth referenced. Do you have the - rail of the DC power supply tied to mains earth or floating?

 

I'm conflicted as to which is the better option, i could swear the floating DC sounds much better, and looks cleaner on the scope. I would love to hear what way you have your setup configured?

 

Cheers,

 

Mark

 

 

Hello Mark;

 

I am a ham operator, so I have a nice, deep ground rod set up for the radio gear. Like you, I looked at the scope to establish differences between using the earth and a floating ground.

 

Here, the earth ground looked cleaner on the scope, but I could not differentiate between the two conditions by listening. In any event, I left the earth ground in place.

 

Congratulations on your work. Can you report significant differences in the sq of your system as a result of the improvements? It made a big difference here.

 

 

Jim

 

P.s. Mark - Adding a 47 ohm resistor (1/4 watt is fine), and a 2 uh inductor (radio shack), placed in ground at point closest to dac ground, made a significant difference to the ears. Here, any noise or ripple is attenuated from the pc as a source, as well as any anomalies from the ground in general. I used the little 2 component addition in series. You can get some improvement with just the resistor.

[mcandmar]

Hello Mark;

 

I am a ham operator, so I have a nice, deep ground rod set up for the radio gear. Like you, I looked at the scope to establish differences between using the earth and a floating ground.

 

Here, the earth ground looked cleaner on the scope, but I could not differentiate between the two conditions by listening. In any event, I left the earth ground in place.

 

Congratulations on your work. Can you report significant differences in the sq of your system as a result of the improvements? It made a big difference here.

 

 

Jim

 

P.s. Mark - Adding a 47 ohm resistor (1/4 watt is fine), and a 2 uh inductor (radio shack), placed in ground at point closest to dac ground, made a significant difference to the ears. Here, any noise or ripple is attenuated from the pc as a source, as well as any anomalies from the ground in general. I used the little 2 component addition in series. You can get some improvement with just the resistor.

 

Thanks Jim,

 

I have been looking at various amp/dac schematics and seen all sorts of solutions from direct grounding to resistors, caps/resistor in parallel, diode pairs, and even bridge rectifiers/resistors/caps in parallel. Seems everybody has a differenent answer to the question. A low value resistor did seem the most popular so i might experiment with that, and i should have some inductors salvaged from ATX power supplies, in fact i know for sure i have seen some in the earth wiring circuit now that you mention it. I'm still really conflicted on if i should bother with ground reference at all to be honest.

 

At the moment i have the +, -, and chassis earth totally isolated from the PC itself by means of a USB Isolator board (pic below) so in my case the grounding will only be connected to the casing of the PSU box. (DAC in separate enclosure)

 

 

As for SQ, there is a considerable difference IMO. For me it was the smoothness and full bodied sound of bass guitars and drums that was immediately obvious, and after more time listening i noticed the high end frequencies are much cleaner and better defined.

 

On a somewhat related note, this is the quality of the USB 5v power i started with, hence my journey into a dedicated supply... Just how noisy is a switched mode power supply? - diyAudio