FET Audio | Hi-End Audio & Electronics DIY Electronics & Repair

This converter board is to replace CS8412 in my DAC project D1.  This is designed to be used in the D1V2, D1V3 and D1V33 versions.  There are other DIYer who is interested to use this to replace the CS8412 in their DAC.  I have tested that it can be used to drive SM5842, SM5847, PMD100 and TDA1541 etc…  Take note that even through it is working fine but the output logic for DIR9001 is only 3.3V while all the old ICs are at 5V logic.  ACT logic should be used if 3.3V logic is needed to buffer up to 5V.

Another important note is the EMPH (pin 3) output in DIR9001 Converter BD is High when the data has pre-emphasis data added.  In a CS8412 or CS8414 chip, the pin 3 is LOW when the data has pre-emphasis data added.

The major improvement in DIR9001 is the lower jitter of 50ps (200ps for CS8412/14).  The improvement is very obvious in sonic performance of any DAC.

Sorry all sold out!

DIR9001 converter board Manual

DIR9001 converter bd BOM

9001 to 8412 V3 Circuit Diagram

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* * Sold OUT in 2009 and no more selling * *

This Jfet IV board was released in 2007.  The purpose of it is to modify a DAC or CD player IV converter.  It can be used for most current output DAC chips like PCM63, TDA1541, AD1862, PCM1702, PCM1704 etc…  NOS DAC is not recommend to use this Jfet IV due to excessive high frequency noises.

During the time of release, 2SK170 is used as the active device for IV.  It is now recommended to use 2SK369BL as the active device due to its higher gain around 40mS for better result.

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Jfet IV Circuit

Jfet IV BOM

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Update on Dec 31, 2009: Add photo on D1V33 jumpers setting with 24 bit input upgrade.

The converter board use SM5847 to replace obsoleted SM5842 digital filter.  It can be used in any version of D1Vx pcb.  Photo is on a D1V2 pcb.

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Circuit

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This is D1V2: Changes from D1V1 is listed below.

1. Add a super clock (11.2896MHz) output socket pad (J20).  This is reserve for the clock to feedback back to CD transport.
2. Allow more space and add holes for all TO-220 heat sink (total 15 T0-220 parts).
3. Add one more relay to select digital input (K2).  Use jumper to select either XLR or RCA input (J8).
4. Short circuit the PCM63 Iout to BPO and thus no more jumper is required (J1-4 are eliminated).
5. Enlarge all hole/pad sizes.
6. Add a ground connection for the ground plan on top near main filter capacitors (J19).
7. Jumper to select the “clock regulator” or “5842 regulator” for the 8414 IC (J17).  Thus the regulator for 8414 will be isolated from 5842 when the on board clock is not used.
8. Use LM317T and LM337T regulators (better noise performance) for all DAC chips.
9. Add de-emphasis LED indicator (D32).
10. Split the ground plan in sections: 8414, 5842, Input relay and logic IC, DAC left and DAC right.
11. Relocate the rectification section (diodes and caps) of the 30V supply so that the last few filter caps will be closed to a centre ground point J19.
12. Add “+” mark for all E-capacitors for easy polarity identification.
13. Add resistor and VR for all PCM63 to trim the MSB (this adjustment is optional and reserve for DIYer to play around the trimming of MSB).
14. Add Trimmer pot (R8, 9, 17 & 18) to adjust Jfet IV output level to match “+” and “-“ cycle.  This is also optional and need an accurate voltmeter and test CD to do the adjustment.  Do not solder the parts if not use.

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Documentation:

D1V2 Silk Top

D1V2 Assembly Manual

D1V2 Circuit Diagrams

D1V2 BOM

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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.

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Silkscreen Top view:

D1V3 Silk top

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