Hi all -- I recently dusted off an over 20 year old Entech Number Cruncher 203.2 to use as a starter DIY project. I'd like to try out implementing some mods, but--as you might expect--enthusiasm for modding these DACs waned a LONG time ago. As such, I can't find many images or schematics showing exactly how to apply some of the mods that folks have applied to the CS8412 chip over the years.
My primary issue right now is implementing one part of the wildmonkeysects loop filter mod to the CS8412 (detailed here: Audio Asylum Thread Printer).
In short, the mod includes--referencing the following picture of my unmodified board--replacing the resistor at R1, replacing the cap at C23, and adding a 3300uF cap between FILT (pin 20) and AGND (pin 21) on the CS8412.
Unmodified board with pins marked:
I have found one image of the finished mod, and it looks like that 3300uF cap is soldered directly to the AGND pin from the R1 resistor:
First, is that correct? Is that how this cap is mounted?
Second, if correct, does anyone have any tips/resources on how to solder a cap directly to a pin on an integrated circuit? Anything in particular I should know other than being cautious about solder bridges on the chip pins? I do know that I need to keep the leads as short as possible.
Apologies for the total newb questions--this is a steep learning curve for me.
Thank you.
My primary issue right now is implementing one part of the wildmonkeysects loop filter mod to the CS8412 (detailed here: Audio Asylum Thread Printer).
In short, the mod includes--referencing the following picture of my unmodified board--replacing the resistor at R1, replacing the cap at C23, and adding a 3300uF cap between FILT (pin 20) and AGND (pin 21) on the CS8412.
Unmodified board with pins marked:
I have found one image of the finished mod, and it looks like that 3300uF cap is soldered directly to the AGND pin from the R1 resistor:
First, is that correct? Is that how this cap is mounted?
Second, if correct, does anyone have any tips/resources on how to solder a cap directly to a pin on an integrated circuit? Anything in particular I should know other than being cautious about solder bridges on the chip pins? I do know that I need to keep the leads as short as possible.
Apologies for the total newb questions--this is a steep learning curve for me.
Thank you.
I would practice on a junk board first. You will need a decent iron with a small tip,
and no larger than #20 solder, preferably smaller.
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If that is truly a 3300µF capacitor, it's the smallest one I've ever seen. Maybe a 3300pF instead? In any case, it would be easier to do on the solder side of the board.
Yes -- 3300pF! Thanks -- I had wondered if the solder side of the board might be a good option. I believe there is a enough clearance under the board once it's mounted in the case. Are there any downsides to that implementation in a typical mod that I should know about? Heat, etc?
I definitely will practice on a junk board. Appreciate the advice on the right tools as well.
Sorry if this last question is better for another section, but I just wanted to check--the picture of the modded board that I included in the first post, does that appear to be a correct implementation of this mod?
Thanks again!
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