I completely agree with Bob on this one. That is the stepped pot I've been using for some time and it's excellent.
Check the further up this thread (there a many pages). I think people have had similar problems when the are short circuits on the board. Check the chips with a magnifying glass.
Good luck
I like my NE 5532 to OPA827 change.
Has the OPA been on a scope as in the thread?
http://www.diyaudio.com/forums/analog-line-level/191389-swapping-op-amps-you-have-checked-see-its-stable-havent-you.html
Has the OPA been on a scope as in the thread?
http://www.diyaudio.com/forums/analog-line-level/191389-swapping-op-amps-you-have-checked-see-its-stable-havent-you.html
I have scoped my DAC2496 (AK4396), that uses a dual OPA627. It does not oscillate. I bought the OPA smt to dip board from vintage audio lab (from Taiwan.) I also use two Wima MKS2 (.22uF, 100V) caps to bypass the opamps. Using larger "boutique" caps could cause oscillations, because of the necessarily larger inductance associated with large caps. Besides, the MKS2s are designed as by-pass and decoupling caps. I assume that the OPA827 will also be stable if properly bypassed. Again, users of "boutique" caps, you will have to check for stability yourselves.
I just used the 0.22uF Wima MKS2s instead of the orange Chinese 0.1uF caps, on either side of the op-amp. The logic for using 0.22uF MKS2s was as following...
1 The specifications from TI recommend a minimum of 0.1uF for one OPA627 and I have two on the satellite board.
2 The 0.22uF, 100V MKS2s fit the available space perfectly (see picture.) The caps lie flush with the mainboard (so that the length of the leads is basically zero.)
3 I have have a lifetime supply of them.
Sorry for the poor focal depth of the attached photo. There is another Wima on the other side of the op-amp board, of course.
1 The specifications from TI recommend a minimum of 0.1uF for one OPA627 and I have two on the satellite board.
2 The 0.22uF, 100V MKS2s fit the available space perfectly (see picture.) The caps lie flush with the mainboard (so that the length of the leads is basically zero.)
3 I have have a lifetime supply of them.
Sorry for the poor focal depth of the attached photo. There is another Wima on the other side of the op-amp board, of course.
Attachments
I´ve lost my orientation in this huge topic..Can somebody tell me where i can find the post with the link with the BOM
apoo
http://www.diyaudio.com/forums/digi...kit-cs8416-ak4393-5532-a-169.html#post2993903
I´ve lost my orientation in this huge topic..
Hi apoo,
you can find my upgrade BOM, together with other relevant files, here.
Those 'Chinese' caps are actually Korean ones made by Pilkor (ex Philips Korea) and they're not so bad.
BTW I recommend good quality electrolythics (47uF) in those positions.
News from mee! I've almost finished the external power supply! Here are the extras
-Separate heater transformer
-Much better grounding, center tap for the heaters, beter cable paths, twisting
-Attenuator for the DAC (not done yet)
-New output caps (RIFA PME271M)
There is more to be done on the outside, it's just a matter of money and time
Pic 1
Pic 2
Pic 3
Pic 4
Pic 5
Pic 6
Pic 7
Pic 8
-Separate heater transformer
-Much better grounding, center tap for the heaters, beter cable paths, twisting
-Attenuator for the DAC (not done yet)
-New output caps (RIFA PME271M)
There is more to be done on the outside, it's just a matter of money and time
Pic 1
Pic 2
Pic 3
Pic 4
Pic 5
Pic 6
Pic 7
Pic 8
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atupi - Good Eye. The DAC is working great but I'll replace it (probablly both) on my next to-do list. I used all the parts from a build I messed up on a new PCB so I feel lucky it's working at all. I use double sided carpet tape for sorting parts and will avoid placing them upside down in the future. Could have been the cause.
Only thing I couldn't salvage were the LEDs. Popped in some Radio Shack generics.
BTW, Should get this package today. Bought it to compare the WM8741 to the AK4396
I use double sided carpet tape for sorting parts and will avoid placing them upside down in the future. Could have been the cause.
Only thing I couldn't salvage were the LEDs. Popped in some Radio Shack generics.
BTW, Should get this package today. Bought it to compare the WM8741 to the AK4396
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