XTZ Class A100D3 Amplifier - partial report

[Effem]

So I have something to look forward to then Frank

Nothing I hate more than kit packing in before say 10 years use at least. That's one of the reasons I use so much Sony gear, it rarely lets you down.

Had a really good vinyl session on the XTZ last night - it does miss some of the magic of the Croft on the phono stage, in particular guitar and vocals are not quite as vivid or real as with the Croft. What continues to please me is the lower mid and bass - this amp just burbles along un troubled, like a V12 powering a milk float.

It might well be that yours being a later vintage Martin that these minor issues have been sorted out now.

Had a fair few Sony components with dry joints through my hands too and what annoys me is that flow soldering is not a new build technique that has yet to be refined so why after all these years do we still find dry joints?

At least you have confirmed that the phono stage works a darn sight better than my experience of it, so hopefully at the next bakeoff I attend there will be a better class of vinyl rig to feed into it, which might spur me on to invest a few quid in another deck

[Macca]

Let's hope so! Incidentally, do you use the amp in class A mode?

[Effem]

Let's hope so! Incidentally, do you use the amp in class A mode?

It is permanently set to Class A mode Martin and have yet to have it switch to AB by itself when the going got tough My speakers are not power hungry anyway and my listening room isn't cavernous either to be honest, although at a couple of bakeoffs I took the handbrake off and still wouldn't switch when left on auto.

[Macca]

: My speakers are not power hungry anyway and my listening room isn't cavernous either to be honest, although at a couple of bakeoffs I took the handbrake off and still wouldn't switch when left on auto.

Just been looking your speakers up. Interesting review here (although you probably read it already):

http://www.theabsolutesound.com/arti...v-loudspeaker/

[Firebottle]

I've just looked up the Focal Chorus 706V and can get a pair in France for €189.
That sounds like a very good buy

[AlfaGTV]

It is permanently set to Class A mode Martin and have yet to have it switch to AB by itself when the going got tough My speakers are not power hungry anyway and my listening room isn't cavernous either to be honest, although at a couple of bakeoffs I took the handbrake off and still wouldn't switch when left on auto.

Since the construction allows the amp to operate in a sliding bias mode, how would you be able to tell whether is running in Class A or AB?
The switch allows you to force the amp into a low bias mode when set to Class AB, does it not?

Think i published measurements on this amp somewhere... Hm....


You'll figure this out i think!

Regards //Mike

[Effem]

No doubt the graphs are indeed true Mike

My only point of reference as a listener is what the display says as it switches between classes A and AB, even though in reality it may have long since switched out of Class A mode in the background due to it's sliding bias arrangement

[Mike - H]

It is permanently set to Class A mode Martin and have yet to have it switch to AB by itself when the going got tough My speakers are not power hungry anyway and my listening room isn't cavernous either to be honest, although at a couple of bakeoffs I took the handbrake off and still wouldn't switch when left on auto.

Since the construction allows the amp to operate in a sliding bias mode, how would you be able to tell whether is running in Class A or AB?
The switch allows you to force the amp into a low bias mode when set to Class AB, does it not?

Think i published measurements on this amp somewhere... Hm....


You'll figure this out i think!

Regards //Mike

Effem as I understood it from the guy who sold me the XTZ they switch from A to AB when under used, not when driven hard.
AlfaGTV, the amps tells you on the front screen which mode it's running in

[AlfaGTV]

AlfaGTV, the amps tells you on the front screen which mode it's running in

I would say the amp tells you what mode it's set to, not what its currently running in...
But i wouldn't swear to that!

Regards //Mike

PS
Effem, i agree with your writing fully!
And let me also add; the amp is a brilliant one, when looking at the cost, it becomes a steal!
The measurements are way better than the cost suggests! I mean, 58 Amperes current in both polarities, thats excellent engineering!

[Macca]

Interestingly XTZ quote 50 watts power output when used in class A wheras the Hi-Fi World bench test states that the amp outputs the same power whether in class A or AB.

Personally I have never found the big claims that some make for class A operation have any basis in audible reality. With this amp crossover distortion in AB mode is so low it should not be audible anyway.