[Vandal]

I'm looking to try the X-Fi mod on my Platinum next weekend.

Found details on this thread - http://www.head-fi.org/forums/f46/ho...no-56k-226975/

I've managed to secure silver solder, and four National LM4562 opamps

Now I'm in Mumbai (India), and I cannot locate Blackgate caps at all here, let alone the 16v 2200uF one suggested.

What are my alternatives? What effect would each alternative have to the sound sig? I want something really top notch, price no issue.

Also can I get something solid state? Or will electrolytic do?

Please suggest something soon as I'm going to the electronics market tomorrow!

 

[LawnGnome]

You really don't need blackgates for the power section. In fact, super low ESR caps probably will be much better for a power section.

UCC's PSA series is good if you want polymer. And the common panasonic FM series always a great choice for power sections.

 

[Vandal]

What power rating should I look for? Any other brands you can suggest? These should be low ripple, low ESR right?

 

[stormcloud]

Voltage rating you mean? 16V typical or higher. That single power cap next to the Creative CA20K1 DSP is on a 1.2 volt rail (see the X-Fi details from bichi in that Layman's guide) output from TI TPS54352 VR ... so a typical 6V rating would be more than adequate. It's also rather "special" cap. Replacing with a super-low ESR cap isn't recommended.

I'm still trying to figure out a good capacitance & ESR value for that single cap and also whether it might be better to replace with 2 cap of same value in parallel, based on the details in the TI TPS54352 datasheet. A bit overkill, but it's something to think about

Other good brands are Nichicon, Rubycon, United Chemicon, Sanyo and possibly a new player, Samxon. Just to note, this applies to the power section. For the coupling caps, it's a different story.

 

[Vandal]

Yes I'm talking about the single large cap that has been changed in the picture, which I'm guessing will be the main power cap.

So a 16v would be good. The issue is Blackgate's aren't available in India (Mumbai), Nichikon I don't know - will have to ask and find out.

As of now I just plan on changing the op-amp(s) and the main power cap. Will check improvements after a hundred or so playing hours and then see later...

What rating? over 1000uF? The blackgate used in the mod is 2200uF

Quote:

Originally Posted by stormcloud /img/forum/go_quote.gif Voltage rating you mean? 16V typical or higher. That single power cap next to the Creative CA20K1 DSP is on a 1.2 volt rail (see the X-Fi details from bichi in that Layman's guide) output from TI TPS54352 VR ... so a typical 6V rating would be more than adequate. It's also rather "special" cap. Replacing with a super-low ESR cap isn't recommended. I'm still trying to figure out a good capacitance & ESR value for that single cap and also whether it might be better to replace with 2 cap of same value in parallel, based on the details in the TI TPS54352 datasheet. A bit overkill, but it's something to think about Other good brands are Nichicon, Rubycon, United Chemicon, Sanyo and possibly a new player, Samxon. Just to note, this applies to the power section. For the coupling caps, it's a different story.

 

[michelhack]

what effect would it make if I used higher voltage capacitors say 25v or higher

would it cause a problem in the long run?
would the sound signal improve?

 

[Logistics]

You don't want to increase the voltage rating A LOT higher when dealing with electrolytics, but 25V is no problem where a 16V was. The only problem you may have is that it may be physically larger. In some cases you may see a bit higher ripple handling than in the lower voltage counterpart, which is a plus, but you're not likely to notice a difference.

Your PC's power-supply is not going to produce anything over 12V so 16V is already a pretty good buffer.

Great brands are Panasonic, Nichicon, UCC, Samxon, Rubycon

 

[Apocalypsee]

If you wanted to replace capacitor labeled C177, don't use super low ESR caps like Sanyo OS-CON, it will make some ringing noise from the regulator chip, the voltage there is 1.2V, so 6.3V is suffice. I forgot the ripple limit, I think trodas knows it, you can PM him

Anything branded is good enough to replace the stock one, I use Sanyo WG 1500uF 6.3V

 

[Logistics]

Hmm, this is interesting. Is the cap before or after the regulator? And does this happen only with solids/polymers or do normal electrolytics cause it, too? Solid caps tend to have loads of leakage compared to normal electrolytics; I wonder if that is the problem.

 

[Nocturnal310]

Hey dude..where are u getting all the parts from in mumbai? i had a friend who was asking... did u buy from Lamington road?

 

[Apocalypsee]

Quote:

Originally Posted by Logistics /img/forum/go_quote.gif Hmm, this is interesting. Is the cap before or after the regulator? And does this happen only with solids/polymers or do normal electrolytics cause it, too? Solid caps tend to have loads of leakage compared to normal electrolytics; I wonder if that is the problem.

AFAIK the caps is after the regulator, since all the voltage from PCI is PC standard 3.3V, 5V or 12V only. I forgot where did I read it, I need to dig deep on X-Fi hotrod thread to look for it

 

[bichi]

Link to original post, Sept 17, 2007:
http://www.head-fi.org/forums/3269637-post1295.html

*****

Did some verification fun on TI TPS54352 switching section, C177 cap change from low-ESR (Jamicon WL) to ultra-low ESR (OSCON).
- both TI and OSCON discuss design differences between ultra-low ESR, as opposed to low-ESR. (see ref below)
- did some simple validation with TI's design calcs, using Creative's 100uh inductor and guessing at the rest. (no public CA20K1 specs)
- compared theoretical with practical measurements below:

+1.2vdc waveforms, SB0460, C177, stock Jamicon WL 220uf @ 16vdc vs., OSCON 330uf @ 6.3vdc:
- taken while WAV playing looped, output max'ed into 50ohm resistor load.
- OSCON might be causing a bit of "ringing," compared to standard low-ESR.
- will have measure with better scope and possibly change 100uh inductor to smaller value.
- OSCON remains steady, while stock Jamicon "wanders" as load changes. (very small deltas, in reality)
- OSCON does attenuate noise coupling on analog sections, small deltas...
- did not find any "catastrophic" negative changes.
- recommend staying with standard low-ESR caps for C177 for now.....


REFS:
Comparison Waveforms:
X-FI-MOD-064b - eSnips, share anything

TI TPS54352 Datasheet, pages 22~23
http://www.ti.com/lit/gpn/tps54352

OSCON TechBook v14, pages 70~86
http://www.edc.sanyo.com/english/pdf/oscon/E70.pdf

 

[michelhack]

thanks bichi
i see you are using socket for the caps where you get them? that would make swapping a lot easier for me

 

[bichi]

I get mine from local electronics surplus store.
- they are SIP sockets, screw machined, 0.100" spacing, pin diameter 0.018", breakaway.
- made with tin or gold platings.
- maybe take specs/picture to your local electronics/surplus store?

Cautions:
- capacitor lead diameter and lead spacing are key, too large and it will not fit.
- capacitor lead material is also key, too soft, plated or tinned, can jam/foul the socket.
- usually use machined pin header, soldered to capacitor, for use with sockets. (reliable, gas tight without jamming/damaging socket)

If your question is about socketing switching regulator filter capacitor for CA20K1 (C161, SB0550 or C177, SB460)
- used RS232 pin/socket, heatshrink and a bit of epoxy (added for rigidity)
- have since directly soldered with good quality, low-ESR capacitor, 470uF @ 25vdc, ie., Panasonic FC.
- did not find significant audio quality improvement by changing this capacitor.

Typical online surplus store offer:
Online Product Offering SOCKETS SIP MACHINED

Machined Pin Header (soldered to capactor):
Online Product Offering HEADERS-MACHINED-PIN BREAKAWAY .1SP

Picture of SIP sockets on SB0550, output capacitors, Line Out:
X-FI-MOD-092b - eSnips, share anything

Picture of headers soldered to capacitors:
X-FI-MOD-100a - eSnips, share anything

Sample datasheet of one of MANY makers of SIP socket strips, 0.100 spacing, thru Hole, gold plate:
http://www.arieselec.com/products/12013.pdf

Another maker, same spacing, but in TIN plating:
http://portal.fciconnect.com/res/en/...arch/58805.pdf