iBasso D42 "Mamba" with dual dacs! !! Hey Hey! Improved Starting on Page 76 .
Mar 12, 2010 at 1:41 PM Post #856 of 1,153
I've had very good service from iBasso, even on a product they don't officially support: the FiQuest. My case was stripped and they replaced the case for me without telling me they would - it was a surprise, and a damn good one too! I was checking how much it would cost and it arrived with my nice new P3+ (favourite so far).
 
Mar 12, 2010 at 1:58 PM Post #857 of 1,153
Sorry for silly question: where can I get the parts for D4 to roll by opamps? Is it plug-and-play or do I need soldering iron and deep knowledge to do it? I'm ready to order D4 and I was thinking if I can order somewhere ready rolled amp?

Johann

Quote:

Originally Posted by supern0va /img/forum/go_quote.gif
finally rolled by opamps! now my d4 sounds much warmer!
smily_headphones1.gif


here's a pic:
jipch4.jpg


thanks to madwolf for his advice, svenmz8 from jaben forums for more advice and help in soldering, and qusp for his detailed pic in d10 thread!
smily_headphones1.gif


my d4 works slightly differently from larry (headphoneaddict)'s in terms of the connection:

With USB power from my Macbook, i can use:
1. "AUX">>IEMs to bypass the amp, using only the DAC
2. "headphone">>IEMs to use both DAC and AMP
3. "AUX">>LOD>>IPOD and "headphone">>IEM, i can play from the macbook (much softer), or play from my ipod, or both!

All these without a battery!



 
Mar 12, 2010 at 10:11 PM Post #858 of 1,153
Quote:

Originally Posted by trentino /img/forum/go_quote.gif
I'm so busy enjoying the D4's dac/amp-combo with HD650's I don't have time to surf head fi. Feels good to actually enjoy the gear for a change, head fi usually makes me chase new gear more than enjoying what I have
smily_headphones1.gif



That sound amazing,the D4 ,the HD 650 don't they need more juice then the D4 could provide.
 
Mar 13, 2010 at 12:31 AM Post #860 of 1,153
Quote:

Originally Posted by dongringo /img/forum/go_quote.gif
The D4 is good for 300ohm. As far as my DT880/600ohm is concerned though, forget about it.


yeah, i sort of agree with that. i'd say 250 or 300 ohms is pushing it a bit, though. of course, it depends on the sensitivity as well.

i've heard the 250ohm dt880 through the D4, and it wasn't half bad...

the 600 ohm dt990, however, sounded like an alarm clock radio.
wink.gif
 
Mar 14, 2010 at 6:23 PM Post #861 of 1,153
Does anyone have a few extra 2.2k resistors? I'll pay for the stamp, just don't want to buy 200 of them for $10. (TIA)

I thought I noticed a bit of clipping on a few songs, and turned down itunes - that seemed to get rid of it but would rather have full resolution on the dac.

Quote:

Originally Posted by madwolf /img/forum/go_quote.gif
Initial Solution, quick remedy, (Have not spend much time thinking of the best solution). I decided the quickest solution to the problem is to reduce the gain of the AD8616. It original gain of the AD8616 is 2, by adding a resistor from the output of the 8616 to the negative input we could adjust the gain.
The original resistor across is 2.2K ohm.

ClippingModD4.jpg


The Gain resistors are located on the top side of the board, and to solder on that you need to remove the Big Nichicon HZ cap (On my case it is Rubycon ZL) to troublesome, to fix this way.

So instead of changing the resistor, I found a compensation capacitor beside the AD8616 which is connected in parallel to the feedback resistor. By adding a 2.2K ohm across this I reduce the gain to about 1.5. From the Picture the 2.2K resistor is sitting on top of the capacitor. label C26 and C28.

You could also solder the resistor directly on PIN 6,7 and PIN 1,2 on the AD8616. (If I do that I would be tempted to change the AD8616! )

I so happened to have a 2.2K 1% SMD 0805 resistor at home. How lucky.
So after adding the resistor I test it again and the Clipping would not occur.
Now I could feed signal at 100% resolution to the D4 instead of just 80%

It should be placebo, on initial testing I could hear more details from the DAC now. Sweet. Well in theory it is 100% now instead of 80%, so might not be placebo.



The power is definitely stronger on the dark side.



 
Mar 14, 2010 at 7:28 PM Post #862 of 1,153
Quote:

Originally Posted by stevier5000 /img/forum/go_quote.gif
Does anyone have a few extra 2.2k resistors? I'll pay for the stamp, just don't want to buy 200 of them for $10. (TIA)

I thought I noticed a bit of clipping on a few songs, and turned down itunes - that seemed to get rid of it but would rather have full resolution on the dac.



If you would PM me with your address, I will send you a few.
Ron
 
Mar 19, 2010 at 12:16 AM Post #866 of 1,153
I just ordered my first hp amp ever, the D4, and I'm stoked! Gonna use with my macbook pro and dt770/80. Have always been listening to 128kbs and 160kbs mp3's and I'm now reripping my music library to flac's and mp3 v0's (to find what suits me). Not sure what kind of "sound" experience lays ahead of me. Pretty excited :)
 
Mar 23, 2010 at 11:06 PM Post #867 of 1,153
I found a good test to demonstrate the clipping on the ibasso d4 DAC section - play Radiohead, In Rainbows, 15 Step, right about 2:30 - 2:36, there's a quick kick drum section. When i have the itunes volume turned up to 100%, there's definite clipping/artifacts. If I turn it down to ~70%, and turn the volume control on the ibasso up, voila, no clipping.

Anybody else have this song and amp, care to test? I'm planning on soldering on the two 2.2k resistors tonight, will re-listen and update.
 
Mar 24, 2010 at 5:16 PM Post #868 of 1,153
I did the fix and I no longer hear clipping, haven't had too much time to evaluate but I like what I hear. This was my first experience soldering SMD's, it was pretty easy - at least after watching a couple how-to videos on youtube. I did spend a good bit of time practicing on some old computer hardware though.


Quote:

Originally Posted by stevier5000 /img/forum/go_quote.gif
I found a good test to demonstrate the clipping on the ibasso d4 DAC section - play Radiohead, In Rainbows, 15 Step, right about 2:30 - 2:36, there's a quick kick drum section. When i have the itunes volume turned up to 100%, there's definite clipping/artifacts. If I turn it down to ~70%, and turn the volume control on the ibasso up, voila, no clipping.

Anybody else have this song and amp, care to test? I'm planning on soldering on the two 2.2k resistors tonight, will re-listen and update.



 
Mar 25, 2010 at 2:31 AM Post #869 of 1,153
Quote:

Originally Posted by TheWuss /img/forum/go_quote.gif
yeah, i sort of agree with that. i'd say 250 or 300 ohms is pushing it a bit, though. of course, it depends on the sensitivity as well.

i've heard the 250ohm dt880 through the D4, and it wasn't half bad...

the 600 ohm dt990, however, sounded like an alarm clock radio.
wink.gif



I think we all have different thresholds for pain/pleasure. The DT880 600Ω sound great with the D4 for me. There are some older songs which are a bit too quiet, but they sound amazing still. If it sounds like an alarm clock radio, something must be wrong with the connection as the sound is as good as anything I've heard at that volume, if flat and neutral in comparison to some hot/warm tube and mains amps I've used with them.
 
Mar 25, 2010 at 2:34 AM Post #870 of 1,153
Quote:

Originally Posted by shigzeo /img/forum/go_quote.gif
I think we all have different thresholds for pain/pleasure. The DT880 600Ω sound great with the D4 for me. There are some older songs which are a bit too quiet, but they sound amazing still. If it sounds like an alarm clock radio, something must be wrong with the connection as the sound is as good as anything I've heard at that volume, if flat and neutral in comparison to some hot/warm tube and mains amps I've used with them.


I would want to know about what you feel about its DAC only section, what does it compare to.
 

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