2. digital
  3. 187864-173494

Class A, A/B vs Class D amp Soundstage

Good evening. 
i just upgraded my Cambridge 850R Class A/B to Cambridge EVO 150 Class D with integrated streamer. I use B&W Diamond II with good cables and interconnects. So, there isn’t really a weak link in my system to be uncovered or exposed when going to a. Class D amp. 
There actually is nothing I changed other than the amps

I lost all front to back soundstage. I lost 50% of my right to left soundstage (speaker position has not changed at all and is 6 ft from the back wall. 
I stream hi-res from Qobuz.  The mid-range sounds a tad bit muffled. The base drivers distort and lower top power than my other amp which remained tight in the base even at ear hurting volume. 
 

The only and I mean only thing I did was change amps. So, I am wondering, does going from a class a/b to a class d amp cause a significant decrease in soundstage?  So far, whatever it is, I don’t like it at all, not one kilo-bit

128x128geworthomd
northbeach
61 posts
 

I agree with Erik Squires suggestion of checking out NAD Class D amps, but Zlone also nailed it on three separate items being changed by going to the CA all-in-one. Did you consider the all-in-one offerings by Naim? My Seattle Dealer carries both the EVO models and the full line of Naim all-in-ones and steered me clear of the Cambridge offerings if I could somehow go with Naim [even if used over new for the Cambridge].

northbeach
61 posts
 

The Naim all-in-ones are not Class D, however. NAD does have all-in-one offerings with Class D.

marco1's avatar
marco1
519 posts
 

I’m not that familiar with the Cambridge models you speak of but be careful lumping  all Class D amps together.  I own the Atma-Sphere Class D amps which I have directly compared to my Conrad Johnson Class AB amp in exactly the same system (like you did).  The CJ amp although older is no slouch, but the A-S amps are still better in soundstage and all other respects as well.

geworthomd's avatar
geworthomd OP
98 posts
 

Thank you gentlemen. The reasoning is good behind your questions

1. B&W 802, 8 ohm, measured 6.7. Not changed.
2. 6 ft from the wall unchanged

3. Cambridge CNX into the Cambr 851a before. Similar streamer build in to Cambr EVO 150 second

4. The DAC’s are the ones inside each Cambr unit

5. Excellent idea on burn in. Bugger though, 4 days of 24 hours per day and no change

6. Double checked speaker wiring polarity

7. Highs on class d are fine. Mid is muffled like 1980’s technology. It isn’t distorted. Can crank it up but sounds like listening to an old K-mart as soon as plugged in. This is the mid section. Not noticed in the highs at all. They are crisp.
8. I have an older Red Rose Music, tube, no DAC inside. Plugged it in. Soundstage comes back (not such a powerful amp though. Plugged in a McIntosh 2100 that I also had (in the dust downstairs). No dac. Good soundstage. Not as good as tube Red Rose Music. Borrowed a Levinson with dac and changed to an older pre-alp using tubes. Best soundstage yet. Similar to the Red Rose but more noticeable than Red Rose bec it cranks up more and ears can hear the subtle timber. Plugged EVO 150 all-in- one back in (has dac and streamer) flat sounding. Limited power noticed in the base drivers. More power than Red Rose Music, More power than McIntosh, less power than Cambr 851a. Woofers flutter before ears bleed lol

9. Lots of people saying the switch to class d in their other set ups are flat i reached out to a manufacturer of high end tube class d with built in dac if I get the chance I will review for now I’ll keep that card close to my chest anxious to hear if it does work out Not too many class d, tube and modern dac inside

So, similar streamers by sane company. Burn in complete. Banana plugs on speaker wires. Qobuz hi res same songs. I have ideas but will wait for more replies first.

More to discover