The iBasso T4, tinier than the T2 and better . . with more new images page 1,5, 14 . . - Page 16

good idea - i might do that with some clear acrylic that I used to build up some custom IEM to fit tighter a while back - mine isn't scratched yet as it has only been sitting in one spot burning in.

Or you could put some cheap DealExtreme screen protector on it (like I did), which is a reversible "fix".

My T4 has 190 hours of burn in and it sounds much better that I ever imagined it would. The idea of a 3rd gen 8 Gb Nano sure sounds appealing.

My T4 didn't change at all since I got it... and it's truly a great amp (despite the hiss).

I tried that, but the corner where the protector can't reach still get scratched even when I was very careful with it. I actually applied plastic food wrap to the whole metal back plate and it works quite well. However, it doesn't last too long (two weeks or so).

I am very interested in taking this little amp for a test drive. If there are any aussies out there who would like to swap amps for a couple of weeks, let me know.

how would they sound with Westone 3s?

how do they handle mids?

how big is it compared to a mustang p51?

I finally had enough of that background hiss with the iBasso T4. Traced the lines with my multimeter, shorted some stuff here and there, and found the culprit for the hiss.

Removed the SMT parts from R9 and R14, and bridged it with a tiny piece of copper from a CAT5 cable. Result: perfect sound, no more hiss.



I don't really care how my soldering looks, it's really hard with my tools to get that 1mm tiny solder joint right. The only thing that counts is that the amp now sounds better than ever, without hiss.

Here's the RMAA tests for the new mod vs. the original T4: RightMark Audio Analyzer test: comparison

As you see, the THD, IMD, SNR are a tiny bit worse now - but that doesn't matter for 44/16 audio and human ears at all, it's just my professional sound card that captures these differences. The main advantage still is that the thing doesn't hiss any more with low impedance/high sensitivity IEMs. (So, in reality, the SNR is actually a lot better now than what the sound card sees.)

Pretty interesting mod you got there, dfkt. I wonder what those two resistors are for, they seems to link to an AD chip...

They affect the bass boost circuit. The bass boost is now much more audible with the two SMTs removed (actually, it didn't do anything before, was more or less inaudible to my ears). Which is a wonderful side effect for my needs, using the T4 with my Cowon O2 to watch videos. More bass, less hiss - iBasso should never had put those resistors there, IMO.



(Bass boost on high gain is too much, but I only use low gain anyways - and that's just about right for my taste, for a player without EQ or BBE in video mode...)

Got my T4 a few days ago, maybe I got lucky and they forgot to include the hiss. With T4 and my cleanest source -- a PCDP (line out, ESP turned off) there isn't hiss at all at volume 2, my typical listening volume; or 3, cranked up for favorite songs; with Klipsch X10's. My usual portable source is my Nokia N95 cell phone, which has a very hissy HP out. With the T4 I can turn up the Nokia's volume, improving the SNR ratio. I can still hear a little bit of hiss, but it's no longer enough to distract from the music.

The X10 are 50 Ohm, they shouldn't hiss indeed.

That IS a massive bass boost!