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Discrete Preamp to be used with DAC and Frontpanel.

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sonnya

sonnya

Member
Joined 2001
mirand-audio.dk/?post_type=product
Just to give you all an teaser. I will of course make an seperate thread for the Discrete preamp but here is an picture of the PCB.

The board has servo but also in this case we have decided to use an discrete approach. The servo can pull the output with +/-20mV. It is mainly the JFET vgs mismatch that sets the limit here.

Feature list:

  • Discrete Servo
  • JFET input discrete opamps
  • Volume control based R2R DAC 16 bit from TI (DAC8812)
  • +12dB Gain
  • 5 channel DIFF/SE input
  • Balanced output.
  • No relays, only MOSFET switches.
  • All stages runs in class A.
  • Small size : 140x100mm

The price for this board is 389€. To get it functioning it needs the frontpanel and +5.5V,+15V and -15V supply.

No information will follow the next days.
 

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sonnya

sonnya

Member
Joined 2001
mirand-audio.dk/?post_type=product
rogerchou said:
Much better than my expectation. Please count me in for preamp & frontpanel (the pre-order of frontpanel would be canceled automatically? )
May I dismiss my SE output shied and connect to this preamp board directly?
Click to expand...

I will cancel the frontpanel order. (The other that have paid frontpanel should only pay difference of course)

You will need the output shield to connect to the preamp or any other selector.

BR

Sonny
 
sonnya

sonnya

Member
Joined 2001
mirand-audio.dk/?post_type=product
rogerchou said:
May I know what is "any other selector'? That means I cannot wire to preamp board from J10(pin3-5-7-9)? Why?
Click to expand...

You need to filter the signal (The DAC puts out HF noise on those pins. Also they have an offset voltage of approx. 3.1Vdc).

That why you need an output filter in some form here. All you need to handle the +3.1V offset.
 
sonnya

sonnya

Member
Joined 2001
mirand-audio.dk/?post_type=product
I have got an chassis constructed for our Phison Brand. But we can change the box to accommodate Frontpanel, Encoder, Preamp, LPS and DAC.

It is 215mm wide, 117mm high and 312mm deep.

The thing is. Are there any interrest in this? To keep the price down we would have to produce 25 units in total.

The frontpanel will blank anodized, the back will be painted with in black structure paint. This black paint has high scratch resistance and is relatively easy to clean.

It is an all aluminium design.

If it is something that has interest we will this week order the changes to the box and get them made.

BR

Sonny
 

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