Archive for March, 2007

Step Attenuator

Wednesday, March 14th, 2007

This is a ladder type step attenuator used in my pre-amp.  The switch is a 23 throw 4-pole and thus it is good for one balance channel.

Resistor value for 10K volume


Friday, March 9th, 2007

D1V1 was the first revision of clone NP D1 DAC.  It has CS8412 or CS8414 (on daughter board) digital receiver, no 2nd PLL, SM5842 digital filter, 4 x PCM63 in balance mode and Jfet IV (not mosfet IV).  All regulators were using normal 78/79 series 3 pin regulator ICs in digital and DAC section.  Two discrete low noise regulators were used in the Jfet IV section.  This DAC was made as a trial version on jfet IV back in 2007.  The benchmark of this DAC at the time was a Lite DA-50 DAC with PCM63P-K and 6922 tube IV.  This D1V1 won the Lite DAC in smoothness of sound, noise level and image.

Silkscreen Top view:

D1V3 Silk top