audio-talk

Thermionic Idler wrote: ↑Sat Feb 09, 2019 10:17 am Those power supply boards from Australia look very interesting, it seems that they have a little less noise on their output than the AMB ones I used for my preamp, yet take up less real estate. Actually if you have the dimensions of those boards that would be really helpful!

Without the transformer, the boards are about 100mm x 62mm. Height is dependent on your choice of heatsinks, I used tall ones for maximum cooling, which are around 60mm tall.

Space considerations in my Masterpiece headphone amp mean I won't be using the Acko supplies in that project so, if of interest, we could cut a deal? I have two of the boards, each carrying two supplies. All the supplies are configured for 5V.

Thermionic Idler wrote: ↑Sat Feb 09, 2019 11:33 am That said, if I put the NUC into a separate case (might not be a bad idea anyway) that opens up the possibility of configuring the dam1941 with a balanced tube output stage. Also, looks like no USB to I2S conversion is needed.

There's a thread on the 1941 over on DIY Audio;

https://www.diyaudio.com/forums/vendor- ... odule.html

and if you go for the 1121 you may find this of interest;

https://www.diyaudio.com/forums/vendor- ... ntrol.html

Its the control arrangement I use in the images at the start of this thread, which is now resident in my headphone amp project.

Oh, and you can stack two 1121 boards to operate in stereo differential mode.

Ray P wrote: ↑Sat Feb 09, 2019 4:47 pm Space considerations in my Masterpiece headphone amp mean I won't be using the Acko supplies in that project so, if of interest, we could cut a deal? I have two of the boards, each carrying two supplies. All the supplies are configured for 5V.

Oh definitely. I've decided to go back to my original single-chassis idea, again for reasons of available space. Having poked about with the design this afternoon, I've worked out that I'd need three boards:

- one for [2 x +5V] to power the USB to I2S generators and reclock on the JLSounds module, and the digital side of the Soekris
- one configured for [+/- 5V] to power the analogue side of the Soekris
- one configured for [+/- 10V] to power the AMB output stage (because of course the voltage requirements for that are different!).

So out of the two you have, certainly one of them would match my needs - I don't know how easy it would be to reconfigure the second for +/- 5V?

Looking again at the dam1941 though, this one would negate the need for a separate USB to I2S board and has the SPDIF input built in as well.

Thermionic Idler wrote: ↑Sat Feb 09, 2019 6:42 pm

Ray P wrote: ↑Sat Feb 09, 2019 4:47 pm I don't know how easy it would be to reconfigure the second for +/- 5V?

Very easy.

And, should you decide to go with the DAM1121, I have some PCBs that connect a JLSounds USB board to the input headers on the 1121 and another that plugs into the 1121 output header to make it easy to connect the power supplies etc. You would be welcome to a set.the DAM1121, I have some PCBs that connect a JLSounds USB board to the input headers on the 1121 and another that plugs into the 1121 output header to make it easy to connect the power supplies etc. You would be welcome to a set.

Your one box approach will make it hard to try different DACs and also means that you'll have the noise of the NUC right next to your AC and it's analogue output. A seperate NUC box can be very small, meaning it can be discretely tucked away somewhere, here's a nice NUC case;

https://www.quietpc.com/akasa-newton-s7d

Ray P wrote: ↑Sat Feb 09, 2019 11:21 pm Very easy.

And, should you decide to go with the DAM1121, I have some PCBs that connect a JLSounds USB board to the input headers on the 1121 and another that plugs into the 1121 output header to make it easy to connect the power supplies etc. You would be welcome to a set.the DAM1121, I have some PCBs that connect a JLSounds USB board to the input headers on the 1121 and another that plugs into the 1121 output header to make it easy to connect the power supplies etc. You would be welcome to a set.

That all sounds good to me, I'll send a PM later on today.

Ray P wrote: ↑Sat Feb 09, 2019 11:28 pm Your one box approach will make it hard to try different DACs and also means that you'll have the noise of the NUC right next to your AC and it's analogue output. A seperate NUC box can be very small, meaning it can be discretely tucked away somewhere, here's a nice NUC case;

https://www.quietpc.com/akasa-newton-s7d

Yeah, noise was something that I did have a concern about, I must admit. My design was for a 430cm wide chassis with the NUC and analogue output buffers positioned at either end, to try and put as much distance between them as possible, with a couple of aluminium panels down the centre internally to act as a screen - would that actually work? I suppose I could do two separate half-width cases, then there would be proper galvanic isolation.

By the way, I appreciate greatly all the input and help, with this being my first foray into proper digital.

Dave, very happy to offer any help I can. I've responded to your PM about the supplies.

Ray

Hi Ray,

I find your building very interesting. First of all, I would be very interested in whether the buffer is definitely sufficient in front of a very powerful output stage with the little low output voltage (SE 1.4V RMS, Bal 2.8V RMS, Zout 640R). Current gain and power increase is indeed given. Or would you build it up today with the classic Aikido entry part, which brings gain into play.

Regards
Thomas

Hello Thomas. I didn't complete this project as I repurposed the Soekris DAC into my 300B Headphone amp.

http://www.audio-talk.co.uk/phpBB3/view ... =11&t=7124

Thomas, I am using the dam 1021 (raw output) with a 300B buffer with gain (10dB/Zout about 800R). This puts the volume control of the HQ player between -30dB and -10dB for absolutely satisfying dynamics and loudness in a really big room (listening distance about 9 feet).

If I use the raw output without buffer it works only for 95% of my recordings with volume control between -15dB and 0dB.

My amp has about 15dB of gain and needs 1,2V input for full output. I use Lowther DX4 with 97dB/1W/1m.

Thomas, one of the reasons I changed direction with the project was because of reports of hum problems with the Broskie ACF2 buffer (due to tolerance issues in the power supply caps resulting in some imbalance) , however, if you search DIY Audio you'll find a fix or this. If I were to build an ACF2 now I would probably use a regulated B+/- supply though. The ACF2 is well regarded for sound quality when the hum is fixed.

BTW, my Soekris DAC module is the DAM1121, which only offers raw output.

@Wolfgang
Thank you very much for this reference points!

@Ray
Thank you, too! It is very interesting to know in advance! I am amazed that JB publishes it like this ...
Even when I think of my own power supply units ...