After many time lost to explore the DAC world from the DAC 1.0 to the DAC Final I have found the end of this way.
The No Oversampling DAC give a more natural sound but if you ear the TDA1541 and TDA1543 seem to lose details.
The AD1865N-K with passive I/V give a perfect combination, natural sound and all the details.
So this project is the end of my DAC projects also if someone speak very well about the AD1862.
The AD1865N-K give the better performances with a 200ohm MK132 Caddock as passive I/V.
In this configuration the output signal is too low to drive any amplifier so I have design for the AD1865N-K the better output stage.
This DAC use a single ended vaccum tube amplifier with output transformer and no interstage capacitors.
To get the max sonic performances has been used the new amorphous C-core by Lundahl.
I have tested other output stages like the LL7903 used as voltage amplifier or as I/V conv. but the results was bad if compared to this.


  • Description


Crystal CS8414 used like receivers to obtain LSB signals from spdif input

Analog Device AD1865

74HC04 Hex Inverter used to create the latch signal for the right channel

LD1086V50 Positive voltage regulator similar to the LT1086

E182CC Mullard

LL1660AM/10mA Lundahl

 About wire forget the teflon ! use only stranded tinned copper wire with pvc isulator.

A very good quality stranded tinned copper wire could be buy directly from E-Z-HOOK that carries an extensive line of fine stranded and extra flexible wire.

The output transformers used in this project are the new Lundahl with amorphous C-core for the best sonic performances.

The LL1660AM/10mA has been configurated with the primaries in parallel (pin 13,16,18 e 21) to have a correct gap for a 20mA anode current.

In this configuration the LL1660AM/10mA have a primary inductance about 31Henry so the E182CC with a Ra about 2Kohm will give a ft(-3dB) = Ra / ( 2 * 3.14 * L) = 2000 / ( 2 * 3.14 * 31) = 10Hz (-3dB).

A valid alternative to the E182CC are the R5842 Raythoen and the D3A Siemens.

Thong ke