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Old 23rd May 2010, 04:01 PM   #261
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Location: Vienna
A bit off topic here, but here are the step by step instructions I compiled:

For me they worked, I had only one minor explosion :-)



INSTRUCTIONS

1) Determine operating voltage (Vload) and MAX load current (Iload). This come from your project, what do you want to power with the regulator?


2) If Vload>300 V and Vload < 400 V
Q2=MPSA94 or Toshiba A1626. NOTE that MPSA94 is NOT pin to pin compatible with MJE350. Some rework is needed
R3= 82K/5W
R4=220K/2W
If Vload< 300 V
Q2=MJE350
R3=56K/5W
R4=120K/2W
3) Iload+25mA < Iccs < 2 * Iload or 1.2 * Iload < Iccs < 2 * Iload

Vload + 25 V < Vccs < Vload + 50V

(NOTE: higher values of Iccs and vccs improve performances, but increase the heat production, I would start with a minimum needed difference between Iload and Iccs and vccs)

4) Make a first estimate of R1 using the following table
Iccs=40mA >>R1=56R/1W
Iccs=50mA >>R1=47R/1W
Iccs=60mA >>R1=33R/1W
Iccs=80mA >>R1=22R/1W
Iccs=100mA >>R1=20R/1W

5) Use PSU2 to determine the AC voltage needed considering the chosen topology of the filter. The transformer should be rated for 2 *Iccs.
If a center tapped transformer is used, populate only D10 and D12
If a normal transformer is used, install all the diodes and use the two contacts marked AC to connect the transformer. CT do not need to be connected

6) Set the trimmer R8 to 100 ohm

7) connect as dummy load (Calculate the value of the resistor Rdummy= Vload / Iload Wdummy= 2* Vload* Iload) I used some 20 K 20 W connected in parallel to adjust the values

8) connect two voltmeters, set on DC, one on the dummy load and one on R1, they will measure Vload and Vr1.

9) power the circuit (For a first test it can be safer to pre-heat the filaments, so that the load comes up faster)

10) with extreme care, and the left hand behind your back, adjust the output voltage to Vload.

11) Note the voltage Vr1 measured on R1 (should be in the range of few volts). The real Iccs can be calculated Iccs=Vr1/R1

12) Compare Iccs calculated with the project Iccs and reduce or increase the value (reducing R increase the current) so that they match. To do that iterate the process.

13) power off the circuit and wait for all the capacitor to discharge.

14) When Icss and Vload measured are OK, power off the circuit and wait for all the capacitor to discharge, disconnect the dummy load, disconnect the volt meters, and connect the real load.


HEAT DISSIPATION

Q1[mW] =Iccs * (Vccs-Vload) in any condition

Note (Vccs-Vload)< 200 V otherwise you fry Q1

Q3[mW] = 1.2 * Iccs * Vload when the regulator is unloaded (conservative in the worst case scenario. Avoid to operate the circuit without load, but the heat sink should be capable of the maximum dissipation, that can occur in case the load has a failure, e.g. burned filament )
Q3[mW] = (Iccs - Iload) * Vload when the load is draining current

NOTE 1: Current are expressed in mA, voltages in V and power in mW

NOTE 2: I you use a single heatsink for both components, you must electrically insulate them from the sink.



COMPONENT CHOICE

D9-D12 FRED diodes 1000 V 1A
R2 and R6 Carbon Composite (gate stopper)
Other resistors metal film, rated for 400 V
C2 and C3 WIMA MKP
C4 and C5 High ripple current, low ESR
R8 Multi turn trimmer, replace with a low ppm fixed resistor for final build
R4 Choose a resistor with low ppm as this is the voltage reference


TIPS

The pads are not tinned. To avoid oxidation put a thin layer of tin on them.



PLEASE NOTE THIS IS A DRAFT

Have fun,

D.
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Old 23rd May 2010, 04:49 PM   #262
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Thank you
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Old 24th May 2010, 11:53 AM   #263
vzs is offline vzs  Europe
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Quote:
Originally Posted by sampler View Post
Second option is to stop using any compensation and reclock using MCK from your I2S source to put everything in perfect sync. Good example would be Eric Juaneda’s decoder
I took the ideas from Eric Juaneda's decoder and this is it (see attachment).
The MSCK from 8414 which is Fsx256 is divided by two and it's used to latch all signals used by the AD. Everything is in perfect sync now.

As I will do my tests on perfboard I'm not sure the >11MHz MSCK will be happy. What do you think?

Thanks.
Attached Images
File Type: png sim6_schematics.PNG (41.0 KB, 850 views)
File Type: png sim6_timing.PNG (24.7 KB, 820 views)
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Old 24th May 2010, 01:16 PM   #264
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What do you use to see the digital signals ?

D.
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Old 24th May 2010, 02:29 PM   #265
vzs is offline vzs  Europe
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Quote:
Originally Posted by Nikon1975 View Post
What do you use to see the digital signals ?
D.
I'm using an evaluation Multisim 11 and the files sampler shared with us in post #233.
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Old 24th May 2010, 04:27 PM   #266
sampler is offline sampler  Lithuania
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Join Date: Jan 2010
Quote:
Originally Posted by vzs View Post
I took the ideas from Eric Juaneda's decoder and this is it (see attachment).
The MSCK from 8414 which is Fsx256 is divided by two and it's used to latch all signals used by the AD. Everything is in perfect sync now.

As I will do my tests on perfboard I'm not sure the >11MHz MSCK will be happy. What do you think?

Thanks.
Nice

Run a shielded wire as short as possible from 8414, center pin - MCK, shield - AGND. Connect only center pin at logic side, don't make any ground loops, should be ok then.
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Old 2nd June 2010, 01:27 AM   #267
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I have new up dat for AD1865:
http://www.diyaudio.com/forums/group...-buys-169.html

http://www.diyaudio.com/forums/group...-buys-168.html

http://www.diyaudio.com/forums/group...-buys-167.html
__________________
Group buy DAC-END R (ES9018) full assembled board
update 06/14/2013 :http://www.audiodesignguide.com/DAC32/index2.html
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Old 2nd June 2010, 07:58 AM   #268
vzs is offline vzs  Europe
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Quote:
Originally Posted by quanghao View Post
I have new up dat for AD1865
It's nice that you removed the TL431 and used a separate salas reg for the analog part of the CS8141. I also like that the psu and dac are on the same board

Even if not asked I will say what I would have done:
- on DAC side: which is more important, I would have used smds for the CS PLL part (as in CS8416 data sheet) and solder the CS directly to the DAC board.
- on the PSU side: in my opinion, only one Salas reg would have been more than enough for the digital part, or even a simple LT1086. This would reduce board size and costs.
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Old 5th June 2010, 12:37 PM   #269
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Location: Vienna
Dumb question: I want to add a toslink connector to the CS8414. From the documentation it looks like you just need to stick the output of the torx connector to the chip through a coupling cap. Is it correct ? It sound too easy. The toslink has TTL output.

Thanks,

Davide
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Old 7th June 2010, 10:23 AM   #270
tassosk is offline tassosk  Greece
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Davide,
You could also buy one from TP TOSLINK Optical Input Module
Fairly priced and needs only +5 to 12VDC and GND
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