[worldman]

Quote:

Originally Posted by eiraku /img/forum/go_quote.gif Thinking of velcro-ing a 2200mAh/1800mAh USB battery pack (these can be very small indeed) -> to the back if this is possible, would negate the ONLY problem I have with the S.Flo2: battery life. Anyone? I MIGHT just cave depending to the answer to this.

Your idea above will work fine with the S:flo2.

"Charging/Data Transfer Mode" kicks in only when connected to a computer.

 

[worldman]

Quote:

Originally Posted by FLACvest /img/forum/go_quote.gif There are two different opamps in each output channel... The Headphone Output has a (will fill in later) and the direct line-out ouput has a (will fill in later) (need to confirm specs) and - can at this point confirm higher SQ (cleaner sound, less distortion, more bass, more crisp) from the direct line-out output port evewn via a 9.99 USD part. I will be lookming into getting a higher quality extewnsion cable with an inline volume attenuation wheel in the near future.

FLACvest, to give you a little help, I think you are referring to the following:

"There are two different opamps in each output channel... The Headphone Output has a NXP (Philips) TDA1308 and the direct line-out ouput has a Burr Brown OPA2604 and - can at this point confirm higher SQ (cleaner sound, less distortion, more bass, more crisp) from the direct line-out output port evewn via a 9.99 USD part. I will be lookming into getting a higher quality extewnsion cable with an inline volume attenuation wheel in the near future."

 

[AnAnalogSpirit]

Quote:

Originally Posted by worldman /img/forum/go_quote.gif FLACvest, to give you a little help, I think you are referring to the following: "There are two different opamps in each output channel... The Headphone Output has a NXP (Philips) TDA1308 and the direct line-out ouput has a Burr Brown OPA2604 and - can at this point confirm higher SQ (cleaner sound, less distortion, more bass, more crisp) from the direct line-out output port evewn via a 9.99 USD part. I will be lookming into getting a higher quality extewnsion cable with an inline volume attenuation wheel in the near future."

worldman: THANK YOU for the assistance, I triple checked mp4nation.net, and you are spot on! I crafted that post sitting on couch at Grandma's watching Ultimate Fighting Championships! She likes "Wrestling"... HAHA

Appreciated!!

 

[theom4353]

I hate you all. I caved in and bought one today, i hope you are all happy, my virtual wallet is a little less heavier now. I was holding out, but your feedback and the $10 price drop pushed me over. Splurged on ems, i can't wait to listen to it. Got my fingers crossed that it gets to me by monday.

 

[headfever]

Quote:

Originally Posted by theom4353 /img/forum/go_quote.gif I hate you all. I caved in and bought one today, i hope you are all happy, my virtual wallet is a little less heavier now. I was holding out, but your feedback and the $10 price drop pushed me over. Splurged on ems, i can't wait to listen to it. Got my fingers crossed that it gets to me by monday.

You will really hate us after you get it. it is too early now.

 

[a_tumiwa]

usually line-out means bypass internal amp, but why the line-out still can use opamp???

 

[theom4353]

Quote:

Originally Posted by headfever /img/forum/go_quote.gif You will really hate us after you get it. it is too early now.

I hope not, more like i will like you all the more

They already shipped it

so happy.

 

[ClieOS]

Quote:

Originally Posted by a_tumiwa /img/forum/go_quote.gif usually line-out means bypass internal amp, but why the line-out still can use opamp???

As mentioned before, it is because WM8740 (the DAC) only outputs balanced signal (+/- left and +/- right), so you need an extra opamp to convert the balanced signal to single ended regular analog signal (left / right vs. ground) for typical headphone.

 

[Kees]

Quote:

Originally Posted by ClieOS /img/forum/go_quote.gif As mentioned before, it is because WM8740 (the DAC) only outputs balanced signal (+/- left and +/- right), so you need an extra opamp to convert the balanced signal to single ended regular analog signal (left / right vs. ground) for typical headphone.

I'm not technically educated, but I can't for the life of me figure why you'd need an opamp to convert a signal from balanced to se. You only need left and right channel + signal from the DAC and use the ground that you already have (for the headphone out). Or am I missing something here (as I said, I'm not technically educated)?

 

[ClieOS]

Quote:

Originally Posted by Kees /img/forum/go_quote.gif I'm not technically educated, but I can't for the life of me figure why you'd need an opamp to convert a signal from balanced to se. You only need left and right channel + signal from the DAC and use the ground that you already have (for the headphone out). Or am I missing something here (as I said, I'm not technically educated)?

I am not technically educated as well, but I do find out that if you use + signal with the ground for single end output, you will lose about 6dB of headroom from the signal due to lack of noise rejection.

Also, after reading the data sheet, I find out the in dual mono setting, WM8740 doesn't output balanced signal anymore. All 4 + and - signals in each DAC are required for creating the single left / right channel. Even if you look at single DAC configuration, you still need multiple opamps to output balanced as suggested in the default circuit design.

 

[SoupRKnowva]

Quote:

Originally Posted by ClieOS /img/forum/go_quote.gif I am not technically educated as well, but I do find out that if you use + signal with the ground for single end output, you will lose about 6dB of headroom from the signal due to lack of noise rejection. Also, after reading the data sheet, I find out the in dual mono setting, WM8940 doesn't output balanced signal anymore. All 4 + and - signals in each DAC are required for creating the single left / right channel. Even if you look at single DAC configuration, you still need multiple opamps to output balanced as suggested in the default circuit design.

the teclast t51 has two of the WM8940's in it, one for each channel, so they are both running in mono mode...

wonder if with some DIY work we could get a balanced output of this thing, using rays new connector...

 

[isao2k8]

I got mine a few days ago. LO SQ is awesome, better than iMod+PVcap combo, and HO sound is very similar to iQube imo. I'm very satisfied with this.

 

[Get_Zwole]

Im gonna hold off i think ClieOS review kinda made me wanna wait till some new firmware comes out or something. Not recognizing all id3 tags or songs is just a huge pet peeve of mine so i guess ill hold off.

 

[zzkatsuyazz]

Based on the 2 Wolfson Dacs, can the S:flo2 be compared against other budget DACs on the market? e.g: MF Vdac, CA Dacmagic 2, Beresford,...

I want to upgrade my *crappy" Asus Xonar U1 to a proper DAC, but for my money sake, I hope I could save a bit by using the S:flo2 instead of my Macbook as source?

 

[randytsuch]

Quote:

Originally Posted by SoupRKnowva /img/forum/go_quote.gif the teclast t51 has two of the WM8940's in it, one for each channel, so they are both running in mono mode... wonder if with some DIY work we could get a balanced output of this thing, using rays new connector...

EDIT
Does this have a 8940 or a 8740 DAC? Not all Wolfson DACs are created equal, the post below is based on a 8940. The 8740 does have a balanced output, and would require an opamp to create a single ended signal.
End EDIT

If the block diagram in the 8940 datasheet is accurate, this DAC does not have a balanced output, it is single ended. If you compare it to the 8741, the 8741 does generate balanced outputs in its block diagram.

Just from looking at the 8940, it looks like it is intended to be a fairly low cost DAC, for portable devices. It is a built in amp for driving small speakers and headphones, so it makes it easy for a designer to use it, no external parts required. Not the type of DAC where they add a balanced output.

So then why the opamp. I'm guessing that they use the DAC signal labled monoout to drive both the headphone amp and the opamp for LO. The opamp is to buffer the signal. Opamp's are pretty robust, so somebody could accidentally short out the LO, and not hurt the opamp. The DAC monoout may not be so robust. Plus, the designer does not know what the LO is driving, the monoout is not intended to drive a long cable, but that's no problem for an opamp.

Randy