iBasso DX50 MODS
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jazzwave

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So, which you prefer to change for 1st mod; LO or HO caps? I have 32 Ohm and 300 Ohm cans
 
~ron~
 
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post-11661581
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babs

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  Wow babs, this is some bad-ass testing! You made me curious about those POSCAP`s now.
And I`m glad I`m not hearing "wrong" things. Your tests are much more "scientific & hi-tech" than my simple breadboard-fast-switch listening tests but You also rate FC caps on top - thanks for confirmation :wink:
 
In DX50 FW thread I was talking about oxicaps - I was talking about HO amps decoupling caps which I still wish to change for those (Yes I know room can be problem but I think I can fit them :wink: ): http://www2.mouser.com/ProductDetail/AVX/NOJD107M010RWB/?qs=%2fha2pyFadugxym376v1PCTxYMG83g6bUcOX5cpt8tb5fh%2fu5IBzi%2fA%3d%3d
You are still running 3x47uF 10V oxicaps there?
 
Also thinking about changing HO output amplifiers or DAC differential amp but I need Your advice - which way should I go with my gear (12-36 Ohm IEM`s and Fidelio X1) and FC caps (atm probably going to leave them in place, I like them)? Is changing only HO output amps enough SQ improvement or is differential a "must have"? Or should I go for both mods?

I am already changed the HO decoupling cap; the 3x47uF oxicaps are gone and I put one 330uF 10V POSCAP (#10TPE330M)
This cap fit nicely to the original pads
Bass seem tighter, and go definitively lower
 
For the HO OP amps, I recommend the model I put on my DX50: the ADA4897-1ARZ
For the LO OP amp, I don't recommend the model  I have installed on my DX50 (ADA4896-2); too difficult to solder correctly this small package
But the ADA4841-2YRZ seem equivalent and have the good package (SOIC-8)
 
Changing HO OP amps give me more punch and bass
Changing LO OP amp give me lower distortion and better imaging
 
But its just me...
 
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post-11662207
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CoiL

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I am already changed the HO decoupling cap; the 3x47uF oxicaps are gone and I put one 330uF 10V POSCAP (#10TPE330M)
This cap fit nicely to the original pads
Bass seem tighter, and go definitively lower
Thanks! This will be first thing I do. Next will be HO opamps and then lo opamp.
But the ADA4841-2YRZ seem equivalent and have the good package (SOIC-8)
Have You tried this Yourself on Your modded DX50 or just recommendation?
 
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post-11663163
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babs

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I have not try the ADA4841-2, just a recommendation
 
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CoiL

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Thanks again! :wink:
 
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post-11707086
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CoiL

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I am already changed the HO decoupling cap; the 3x47uF oxicaps are gone and I put one 330uF 10V POSCAP (#10TPE330M)
This cap fit nicely to the original pads
Bass seem tighter, and go definitively lower
Any particular reason why You went with 330uF 10V POSCAP (#10TPE330M) instead 220uF 10V (stock caps spec) POSCAP (#10TPE220MIL) ?
 
330uF vs. 220uF poscap:
 
ESR - 25 mOhms vs. 18 mOhms
Leakage current - 330uA vs. 220uA
Ripple current - 3000mA vs. 2800mA
 
http://www.mouser.com/ds/2/315/TPE_OS-262406.pdf
 
Anyway, I ordered #10TPE220MIL and will report back after installing.
Another worthwhile modification, in the same circuit, is the replacement of the differential opamp decoupling Cap (see picture, yellow rectangle), placed just over the Amplifier I just changed.
The original capacitor is a standard 100uF 6.3V tantalum in a 3528 case
I replace it with a 22uF 6.3V Oxicap (AVX #NOSB226M006R0600)
Are You still using oxicap there or also replaced it with POSCAP?
 
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polyrhythm

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Regarding change of Dual Differential Amplifier I think this might be a worthy upgrade:

JRC: MUSES8820E

http://uk.mouser.com/ProductDetail/NJR/MUSES8820E/?qs=sGAEpiMZZMtxdzBvM0rKcdcB8W9ucxBQ8hRkSqFfJ7c%3d

maybe it is not suitable though to be positioned in the circuit straight after the DAC? Babs any thoughts.....?

2 x HO single amps will probably still be:

ADA4897-1ARZ

Like you Coil I am going to do the HO decoupling cap next and then tackle the main amp section.

Cheers
 
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post-11723937
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CoiL

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For differential opamp decoupling cap I ordered POSCAP in both cases D2E (# 6TPE100MI ) and B2 (# 6TPE100MPB).
Will try to fit D2E in that position because it has very good specs: ESR 18, ripple current 2800.
 
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polyrhythm

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For differential opamp decoupling cap I ordered POSCAP in both cases D2E (# 6TPE100MI ) and B2 (# 6TPE100MPB).
Will try to fit D2E in that position because it has very good specs: ESR 18, ripple current 2800.
 
so are you experimenting with these as well as the ones you stated earlier?:
 
Anyway, I ordered #10TPE220MIL and will report back after installing.
 
100μF vs 220μF
 
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post-11724118
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CoiL

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No, for HO decoupling cap I`m going straight with # 10TPE220MIL. I prefer to stay in original values and it has littlebit better specs than the one babs used imo (better ESR, lower leakage current and ripple is almost same). I already have it ready on my table for soldering but will wait for HO opams.
The original HO decoupling capacitor is a standard 220uF 10V tantalum in a 7343 case
Previously I was thinking about using 2x100uF 10V (# NOJD107M010RWB) http://eu.mouser.com/ProductDetail/AVX/NOJD107M010RWB/?qs=E%2F%2FhvbtCqpPbHFa5iD7IhQ%3D%3D
but my local electronics parts dealer doesn`t offer them and I don`t bother to order from internet and pay for transport.
Now I discovered POSCAP thanks to babs and going to use # 10TPE220MIL Poscap.
 
For DAC differential opamp decoupling cap I`m trying to fit # 6TPE100MI (larger D2E case) first. If I don`t succeed, then going to use # 6TPE100MPB (smaller B2 case).
Would try some oxicaps also but I can order them only by 5pcs min and cost is going to be too high. 
For that place babs used #NOSB226M006R0600 (he hasn`t answered to my question yet if he is still using it or also changed to Poscap):
The original DAC differential opamp decoupling capacitor is a standard 100uF 6.3V tantalum in a 3528 case
I replace it with a 22uF 6.3V Oxicap (AVX #NOSB226M006R0600)
NOSB226M006R0600 vs. 6TPE100MI vs. 6TPE100MPB vs. stock TAJB107M006RNJ
 
ESR- 600 mOhm vs. 18 mOhm vs. 25 mOhm vs. 1700 mOhm
Leakage current - 2.6 uA vs. 63 uA vs. 63 uA vs. 6.3 uA
Ripple Current - 412 mA vs. 2800mA vs. 1600mA vs. 224mA
 
I`m not sure if those Poscaps leakage current will be a problem? I know that in coupling application leakage current should be low as possible but with decoupling?
I hope babs has time to answer. 
 
Another option would be TA series Poscap # 6TAB47M which has half lower leakage current than TPE series Poscap: http://eu.mouser.com/ProductDetail/Panasonic/6TAB47M/?qs=r271rpOLewslPGukLYfMHA%3D%3D
This one has following specs: ESR 70 mOhm, Leakage Current 29.6 uA, Ripple Current 1100 mA
But it is new product and again my local dealer has problems - not offering it atm, so no go for me ;(
 
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post-11724828
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babs

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  Any particular reason why You went with 330uF 10V POSCAP (#10TPE330M) instead 220uF 10V (stock caps spec) POSCAP (#10TPE220MIL) ?
 
330uF vs. 220uF poscap:
 
ESR - 25 mOhms vs. 18 mOhms
Leakage current - 330uA vs. 220uA
Ripple current - 3000mA vs. 2800mA
 
http://www.mouser.com/ds/2/315/TPE_OS-262406.pdf
 
Anyway, I ordered #10TPE220MIL and will report back after installing.
Are You still using oxicap there or also replaced it with POSCAP?

No, I change de LO decoupling cap for a POSCAP: 6TPE220MAZB  (220uF, 6.3V)
this is more capacity than the original cap (100uF) but all seem OK, power supply didn't crash at all
 
Not sure of the improvement, maybe better separation, but Its just an impression
 
I buyed 10 of these caps, so I decide to try to change the decoupling caps of the DAC analog power supply; same case, same voltage
There is 3 analog power supply pins on the DAC: AVDD (pin 15), AVDDR (pin 9) and AVDDL(pin 20)
These caps are located at left on the photo:


The LO decoupling cap is just above the differential amplifier
The 3 DAC decoupling caps are vertically aligned on the left of the picture
No possible error; these 4 black caps have an big (+) on it
 
I didn't expect lot,but I am surprised; there is a clear improvement: less noise and better separation of instruments
 
I keep it!
 
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babs

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Regarding change of Dual Differential Amplifier I think this might be a worthy upgrade:

JRC: MUSES8820E

http://uk.mouser.com/ProductDetail/NJR/MUSES8820E/?qs=sGAEpiMZZMtxdzBvM0rKcdcB8W9ucxBQ8hRkSqFfJ7c%3d

maybe it is not suitable though to be positioned in the circuit straight after the DAC? Babs any thoughts.....?

2 x HO single amps will probably still be:

ADA4897-1ARZ

Like you Coil I am going to do the HO decoupling cap next and then tackle the main amp section.

Cheers
 
The dual differential OP amp must be an RRIO (Rail to Rail I/O) low voltage amplifier, the MUSE8820 is a high voltage amplifier (+/-3.5V to +/-16V)
And he is not RRIO at all, so I don't think it will work, and if it work, it will be at the limit, not recommended...
 
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post-11725481
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CoiL

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  I decide to try to change the decoupling caps of the DAC analog power supply; same case, same voltage
There is 3 analog power supply pins on the DAC: AVDD (pin 15), AVDDR (pin 9) and AVDDL(pin 20)
These caps are located at left on the photo:


The LO decoupling cap is just above the differential amplifier
The 3 DAC decoupling caps are vertically aligned on the left of the picture
No possible error; these 4 black caps have an big (+) on it
 
I didn't expect lot,but I am surprised; there is a clear improvement: less noise and better separation of instruments
 
I keep it!
LOL, every time we are dealing with "old" capacitors change, You already have new mods ;D
Since You used 6TPE220MAZB for LO differential amp decoupling cap then I assume leakage current isn`t problem
because the one You used has it 138.6 uA which is over double higher than the one I`m going to use (# 6TPE100MI or 6TPE100MPB).
 
Now I have to order some more Poscaps for  decoupling caps of the DAC analog power supply :wink:
 
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babs

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  LOL, every time we are dealing with "old" capacitors change, You already have new mods ;D
Since You used 6TPE220MAZB for LO differential amp decoupling cap then I assume leakage current isn`t problem
because the one You used has it 138.6 uA which is over double higher than the one I`m going to use (# 6TPE100MI or 6TPE100MPB).
 
Now I have to order some more Poscaps for  decoupling caps of the DAC analog power supply :wink:

For the LO decoupling Cap, I don't think that the value of the cap will be so important, I change an 68uF Oxicap for an 220uF Poscap without big sonic différences
These amplifiers drive an high impedance load, no need for lot of current
I think that the main différences will be the ESR and the DF of the caps, and your 100uF have lower ESR that my 220uF
Try your 6TPE100MPB before buying more caps
 
For the HO decoupling Cap, the value is more important, and affect directly the bass response
 
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CoiL

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Ok. Thanks for the information!
 
Will give little summary so that other readers/modders don`t get so confused who and what caps are going to use. Here are all the caps I`m going to use:
 
***
HO decoupling cap - # 10TPE220MIL (7343 case)
The original HO decoupling capacitor is a standard 220uF 10V tantalum in a 7343 case
***
DAC differential amp decoupling cap - # 6TPE100MI (7343 case) or # 6TPE100MPB (3528 case)
I ordered both and trying to fit larger with better specs.
The original DAC differential opamp decoupling capacitor is a standard 100uF 6.3V tantalum in a 3528 case
***
 DAC analog power supply decoupling caps - # 6TPE100MI (7343 case) or # 6TPE100MPB (3528 case)
I ordered both and trying to fit larger with better specs.
The original DAC analog power supply decoupling caps are standard 100uF 6.3V tantalum in a 3528 case
 
Lol, I think we can call this whole capacitor overhaul as PANAMOD because all caps (LO&HO coupling caps also) are Panasonic`s ;D
 
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