My latest modding enterprise

[Andrea]

Not much to laugh about in fact

I've switched all chips in my Xenos 0HA-REP. The OPA2134 for and AD8620BR, and the two LMH6642's for two LT1363's.


I'm superhappy!!

I've always loved the LT1360/1/3/4 series of chips, and their goodness is more than confirmed once again.

With these LT1363's in particular, there's some really exuberant power with both my HD650 and (the more so) my HD485, but not just. The sound is so musical (warm in timbre), so immersive, so smooth and resolving, so punchy and deep-controlled down low.

As for the AD8620 (gain stage), it's like the perfect partner. But I'd like to hear the AD8066 in there, as well.


Recommended to all the daring

 

[Andrea]

Forgot a small detail

There's almost nothing more to do than desoldering the SMD chips and soldering the new ones.

Almost -- pin 8 of both LT1363's needs to be lifted so that it doesn't make contact with the trace below. That's it.

 

[Andrea]

Forgot another small detail

The DC offset at the output is 0.1 to 0.2 mV on both channels.

 

[Andrea]

No interest? This is my best sounding portable amp so far

Better than the Portaphile even, for my headphones, in that it's clearly richer sounding, & every bit as subtle without suffering from slightly harsh transients & treble..

 

[bperboy]

Pics?

 

[mrarroyo]

Yes some before and after side by side would be nice.

 

[Andrea]

I'd have wanted to take pics when all was finished, but selfishness & laziness won over public responsibility so...

But you could reproduce them mentally, just imagine the same pcb (as in www.aptecpro.com ) with different chips and no apparent damage

Actually it was a fine desoldering-soldering job, much to my own surprise

(helped by the Cardas solder and my trusty Weller soldering iron)

 

[Andrea]

Btw, if anyone was curious, I saw what the virtual ground driver chip is in the 0HA-REP. It's a Motorola MC33201, an op-amp with a high (80 mA) short circuit current output, and 13V 'absolute maximum' supply voltage. So the appropriate supply voltage for the modded amp is still 12V, despite the higher limit of all chips in the signal path. No problem -- the AD8620 works absolutely fine with +/- 6V, and the LT's are specified for +/- 2.5V, +/- 5V, and +/- 15V so again it's fine.

 

[cosmopragma]

Quote:

Originally Posted by Andrea Actually it was a fine desoldering-soldering job, much to my own surprise (helped by the Cardas solder and my trusty Weller soldering iron)

Aren't you italian?
Where did you get the Cardas solder in Europe?

 

[Andrea]

I had a small quantity shipped directly from the US (together with some female Cardas RCAs) some time ago. I can't remember what was the online shop

 

[Andrea]

When the Go-Vibe v5 arrives I'll probably post some comparative impressions...

 

[Andrea]

Listening to "Dance Hall at Louse Point" by PJ Harvey and John Parish was pure magic - this (modded) amp just sounds so 'genuine', so "analog" in that it is so smooth yet so subtle; all flavored with a solid, dynamic and tight bass... yum!

 

[Andrea]

This amp ROCKS.

Who'd have expected so much power (there's almost a too forceful bass with the HD650

), along with all this finesse, from such little chips

 

[Andrea]

One little downside -- there's an AD8620 inside, and it hears. The midrange sounds much like that of my Portaphile (albeit somewhat clearer). Just a little bit more presence & 'meatiness' would be welcome for me, at least with my headphones. One could consider leaving the OPA2134 in and simply changing the output drivers (the LT1363 have boosted the amp's musicality & refinement IMO). Or else, I was thinking that an AD746 could do some good in there...

 

[Andrea]

On the other hand, it's evident that the AD8620 is helping the amp to deliver what is the greatest micro- resolution & texture that I've had the chance of hearing from a (portable, but not only) amp.