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AK4490 USB Dac with dsd support.

Hi Sonny,

I'm really enjoying my USB dac + discrete shield setup. Thanks for the nice product.

But, I've ordered another USB dac board and I'm itching to build my own output stage (something tube-ish perhaps) that will not be powered by the +/- 14V supplies available at J10.

My question is, given that there will no output shield drawing power, how stiff do the power supplies to the USB dac board need to be? 100mA or less? And, do I even need to supply the +/- 15V or do I only need the +5.5V?

Thanks for the help,
John
 
No wonder printline closed, used them a couple of times for prototypes, but after my 2nd batch of significant substandard PCB's I gave up on them....

Now I use only PCBCART for my prototypes and sometime first series, they just work....

The PCB i showed above is from multi circuit. They are okay fast, and the Stencils are only ~85€ compared to the 200€ from Scanditron, Elprint, Printline...

Only Scanditron does know what they are doing, so the stencils are better from them.

I had a talk earlier with a guy from Rokoko (He is a member here) and he asked me about quality from pcbcart. So i will just pass you comment onto him.
 
Hi Sonny,

I'm really enjoying my USB dac + discrete shield setup. Thanks for the nice product.

But, I've ordered another USB dac board and I'm itching to build my own output stage (something tube-ish perhaps) that will not be powered by the +/- 14V supplies available at J10.

My question is, given that there will no output shield drawing power, how stiff do the power supplies to the USB dac board need to be? 100mA or less? And, do I even need to supply the +/- 15V or do I only need the +5.5V?

Thanks for the help,
John

Hi John. It is on the way with DHL.

You will need the +5.5 and the +15V. Just leave the -15V unconnected. The +15V is powering the AK4490 voltage references. You can feed it with an lower voltage than 15V.. for example 9V. But as soon as you get below 14.5 the first voltage regulator will not regulate. If your +9V to +15V is low noise than it should be okay.

Requirement is 40mA on +15V and 200mA on +5.5V (+5.1 to +5.5V)
 
Sonny, what voltage did you use to feed VDDR/L (analogue) on the AK4490?

You can find it on Page2 #18...it says 6.1。
BTW, I do enjoy the sound of Sonny's discrete opamp design. We are in a commercial vendor forum and have no right to force "vendor" to disclose schematics. Am I wrong? If someone wants to do some simulation or whatever, he'd better to buy one in advance. Fair enough?:D
 
Thanks guys

Phono stage missing gain modules

56e2357a2667c8ae562da2aafc81324d.jpg



Sent from my iPhone using Tapatalk
 
Please buy the discrete output shield and listen to it, it is really a musical piece of equipment. I have both output shield and although the ADA4898-1YRDZ version is truly remarkable, I find the discrete one just more musical.

I'm not too sure if the argument is about musicality/Sound reproduction or THD figures, but if it has something to do with THD then I cannot comment since I do not own equipment precise enough to measure this. Anyways, not going to war with anyone here, just my subjective impressions of the output shield.

High THD are often seen as musicality.. many famous companies survive on it for years..
 
I have tried Sonnys two outputshields, the one with 4627 sounds really good, but I ended up buying the discrete because it plays music and sounds amazing - I may admit since I don't finding pleasure in measuring the sound, I just enjoy listening to the music it makes..

High THD are often seen as musicality.. many famous companies survive on it for years..
I am convinced that we will never see 'real world' measurements for discrete output here.. simulation files too..
 
FFT measurements on the Graviton phonostage

Enjoy
 

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We are using Sonny's SITO Jfet amp1 opamp's as an option for our Purestream DAC. I'll be the first to vouch for the incredible musicality. Perfect balance of transparency and musicality. Dead black background as well.
 

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Last edited:
Hi John. It is on the way with DHL.

You will need the +5.5 and the +15V. Just leave the -15V unconnected. The +15V is powering the AK4490 voltage references. You can feed it with an lower voltage than 15V.. for example 9V. But as soon as you get below 14.5 the first voltage regulator will not regulate. If your +9V to +15V is low noise than it should be okay.

Requirement is 40mA on +15V and 200mA on +5.5V (+5.1 to +5.5V)

Thanks Sonny. Got the emails, should be here in another day or so.

Exactly the info I needed -- thanks.

Regards,
John
 
While waiting on me to get the new DAC board (I am working on the DAC today with SPDIF, optical, USB and a I2S header)and Graviton power amplifier ready i have uploaded picture of an example of an assembled Graviton phonostage.



On the picture below you can see that i have the PSU in the same chassis.

I would recommend to have it in a separate chassis or having a wall between the powersupply and the RIAA stage.

So in this example i have hum, but it is regardless of selected gain.

Even at 80dB gain the S/N is very good.
 

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While waiting on me to get the new DAC board (I am working on the DAC today with SPDIF, optical, USB and a I2S header)and Graviton power amplifier ready i have uploaded picture of an example of an assembled Graviton phonostage.



On the picture below you can see that i have the PSU in the same chassis.

I would recommend to have it in a separate chassis or having a wall between the powersupply and the RIAA stage.

So in this example i have hum, but it is regardless of selected gain.

Even at 80dB gain the S/N is very good.
Quite impressive. BTW can you list the basic specs (watts at 4/8 ohm etc) of the Graviton power amp vs the TSSA V2? Thanks. BR Per
 
Some comments.

Graviton power amplifier:

It will work with up to +/-50V. So output power depends on class A or class AB mode selected. Class A means less power as the dissipation is higher.

Output power is depending on the above configuration. I it uses 2 pairs of output transistor per channel to give good current drive.

And of course it has a build in SSR output protection circuit.

DAC:

The new DAC is compatible with the existing meaning they will fit into the existing configuration.

What new is that the Attenuator can be controlled by the frontpanel.