[Young Spade]

Quote:

Hey folks... I may be too lazy or search-handicap but why can't I find info on how to DISASSEMBLE (remove cover, take apart, etc) the flo:2?
 
Wanna change the op-amp but I see no fastening cover/chassis screws to take the bloody thing apart??

Get something small/sharp, put it between the mid-line on the player and pry that baby open.

 

[Hero Kid]

^ Similar to opening an iPod. Be careful not to use a metal object or something that could easily scratch or bend the back cover. A hard plastic object is desirable (eg. Guitar pick).

 

[headfone]

Quote:

Get something small/sharp, put it between the mid-line on the player and pry that baby open.

Yeah, I figured that was the way to go and was trying to pry apart earlier but wussed out after cosmetically messing up the sides of the case. Too late (DUMB design mp4nation ... are screws that hard to design in??) Anyway, the Ebay value of this brand new unit just dropped by at least $15USD due to the cosmetic wounds that'll never heal ... But replacing the OPA2604 with a OPA2132 was well worth it! Yes, the OPA2132 is better than the OPA2134.
 
Not a whole lot of room in the unit, even for SMD mods, or else I'd bypass-tweak this opamp some more.

Oh well, grounded Cu tape on the digital ICs should improve things a bit. Anyone found better caps than those brown Panasonic polys (which are pretty good as is)?

 

[headfone]

Quote:

A hard plastic object is desirable (eg. Guitar pick).

Now you tell me !! Well at least it now sounds good.

 

[headfone]

Back to this player ...
 
Since my unit is less than 24 hrs old, I was wondering about break-in (burn-in) time for the S:flo2's SQ to optimize. It seems to be improving in the few short hrs I've had it, but still seems there's a long way to go. The caps are usually what take the most burn-in time. New and out of the box, the sound has plenty of detail -- and is bold, big and punchy (nice!) -- but the "bigness" is mostly a bloated big (i.e., little acoustic-image focus). What usually happens in break-ins is that the sound gets smaller but more focused (analogous to the optical lens version of this effect).
 
How about you long-time owners...how much does the SQ improve/change over time...and how long before improvement gains settle down (bottom out)?

 

[headfone]

Sorry folks, this may be old news to many of you -- haven't yet topically researched the issue in the archives or this thread. But...something else I noticed, at very low signal level (e.g., quiet passages in music), is a kind of pumping hiss. It MIGHT be dither, soft-/firmware-enabled in the Wolfson DAC, and that's a very reasonable "compromise" for the sonic gains / virtues of that attribute. Not sure, tho' -- it SOUNDS a lot like dither, anyway.

 

[ClieOS]

So I see you already have your s:flo2. The hissing is a known issue with s:flo2. The cause is the voltage step-up circuit for the touch screen. Once the screen is off, the hiss will go away.
 
Quote:

Sorry folks, this may be old news to many of you -- haven't yet topically researched the issue in the archives or this thread. But...something else I noticed, at very low signal level (e.g., quiet passages in music), is a kind of pumping hiss. It MIGHT be dither, soft-/firmware-enabled in the Wolfson DAC, and that's a very reasonable "compromise" for the sonic gains / virtues of that attribute. Not sure, tho' -- it SOUNDS a lot like dither, anyway.

 

[swanlee]

Quote:

So I see you already have your s:flo2. The hissing is a known issue with s:flo2. The cause is the voltage step-up circuit for the touch screen. Once the screen is off, the hiss will go away.
 

 

This issue is fixed in firmware version 2.3,  it's not hissing either it is a slight crackling at the start and end of most tracks and probably happen during the tracks as well it is just covered by the music. Dithering may actually be what is happening here but it is hard to properly describe cause it is not just standard background noise.

 

[ClieOS]

Haven't actually tried v2.3 yet. If it does fixed the hissing then it would be a good reason to try now.

 

[swanlee]

 
Quote:

Haven't actually tried v2.3 yet. If it does fixed the hissing then it would be a good reason to try now.

Yea it is greatly reduced if not totally gone, also the sound signature has changed a lot in 2.3. It seems some people on some chinese BBS discovered that they were overdirving the opamps and this firmware backed that off. So the volume is slightly less but the results are a much cleaner signal, better stereo separation more details, cleaner and more focused bass, with less bloat, that results in slightly less bass but over all everything is much cleaner. It is a major change in the sound with version 2.3. I really like it but some may be put off by the reduced bass.

 

[borrego]

 
Quote:

...But replacing the OPA2604 with a OPA2132 was well worth it! Yes, the OPA2132 is better than the OPA2134....

Did you ever think of using the latest OPA1642 (try ordering samples from TI). It's supposed to be the OPA2134 replacement. The best thing about the OPA1642 is its low power comsumption. Which could probably give another hour of battery run-time for the S:flo2 and make it running cooler
 
I have some OPA1642 in hand already. I will wait till the internal battery dies, and I will do the opamp swap together with the new battery installation.
 
Please let us know if the Cu tape would be effective for shielding.

 

[ClieOS]

I just spent the last hour writing and re-writing firmware (can't remember how many times, but it is probably around ten times or more) and listen for any sonic change. A few interesting finding: First, the hiss problem with the screen is still there and it didn't get better with the new firmware (v2.00 <-> v2.3). I test it with one of my most hiss sensitive IEM, the SE530, and pretty much can confirm the result. I think the observation of other who find the hissing becoming lesser has really more to do with my second finding, that is the change in sound signature has made the hissing less obvious in music. Here is my second finding (with ER4P) and it is very close to your observation: v2.3 does sound cleaner, better detail and stereo separation has been improved. I won't call the bass more 'focused', perhaps less body (or bloated, as you has said). I think 'tighter' is probably what we both mean. The overall volume is indeed just a tad lower, probably 1~2dB(?). I has noted in my s:flo2 review that the sound signature is b/w nano4 (cold) and fuze (warm), now it seems it is a little bit closer to nano4's colder sound, a little cleaner and a little drier. Haven't had the time to compare the LO though, since I already did too many firmware writing in one day. As far as I can tell It still sounds as clean as I can remember so it is not a big deal for me.
 
Quote:

Yea it is greatly reduced if not totally gone, also the sound signature has changed a lot in 2.3. It seems some people on some chinese BBS discovered that they were overdirving the opamps and this firmware backed that off. So the volume is slightly less but the results are a much cleaner signal, better stereo separation more details, cleaner and more focused bass, with less bloat, that results in slightly less bass but over all everything is much cleaner. It is a major change in the sound with version 2.3. I really like it but some may be put off by the reduced bass.

 

[headfone]

I have some 1642s in my kit but have not tried them -- an interesting suggestion, IAC, so thx.  (BTW: yup, TI has a great sample program -- that's how I got my 2132, which is not a cheap opamp. May try AD8620; I generally like AD sound better than TI/BB in most cases)
 
ClieOS: Definitely not screen noise in my case -- it's there when screen is off. Less sure about dither now as well; the wm8470 does not have it as an option (newer 8471 does, tho'). One can still add dither before the DAC IC, so maybe that's what's going on.

 

[borrego]

 
Quote:

I have some 1642s in my kit but have not tried them -- an interesting suggestion, IAC, so thx.  (BTW: yup, TI has a great sample program -- that's how I got my 2132, which is not a cheap opamp. May try AD8620; I generally like AD sound better than TI/BB in most cases)
 
ClieOS: Definitely not screen noise in my case -- it's there when screen is off. Less sure about dither now as well; the wm8470 does not have it as an option (newer 8471 does, tho'). One can still add dither before the DAC IC, so maybe that's what's going on.

The problem with AD8620 is its minimum supply voltage is +-5V, which is higher than the S:flo2 can supply. May be the AD8622 is a better option?
 
The power supply of the S:flo2 is its another weaknesses. So I think the suitable opamp replacement will be another low power FET opamp like yours OPA2132 or the OPA1642.
 
One fellow in the Chines forum did swap in a LME49722 and claim getting excelent result. But I just won't believe the S:flo2 circuit is ready for any bipolar opamp with much greater input bias current.
 
I actually quite like the sound from the stock OPA2604. I think it keeps the best quality balance for listening low bit rate MP3 and FLAC/APE.
 

 

[Anaxilus]

Quote:

Back to this player ...
 
Since my unit is less than 24 hrs old, I was wondering about break-in (burn-in) time for the S:flo2's SQ to optimize. It seems to be improving in the few short hrs I've had it, but still seems there's a long way to go. The caps are usually what take the most burn-in time. New and out of the box, the sound has plenty of detail -- and is bold, big and punchy (nice!) -- but the "bigness" is mostly a bloated big (i.e., little acoustic-image focus). What usually happens in break-ins is that the sound gets smaller but more focused (analogous to the optical lens version of this effect).
 
How about you long-time owners...how much does the SQ improve/change over time...and how long before improvement gains settle down (bottom out)?

I noticed the big bloatedness to settle down after about 36-48 hours of half day use/day.