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suggestion for a SS class AB amp that sounds like a class A ... if such a thing exists

Looking for an amplifier below 2K for my Altec 620A (99 db efficiency). My actual amp is a Sugden A25B, which has 34 watts/chanel in class AB. Although quite musical, it lacks transparency and details. Of course, the best amplifier would be tube or class A but I'm trying to avoid these because of the heat and the electricity bill (my amp is on all day long). My short list include :

  • Audio by Van Alstine Set-120
  • Ayre AX 7e (used)
  • Sugden Mystro (class AB)
  • Benchmark AHB2 (used)

NOTE : please, no class D since I'm not familiar with it (and pretty skeptic too).
128x128alaindexe

Showing 2 responses by georgehifi

georgehifi's avatar
georgehifi
10,312 posts
 
a SS class AB amp that sounds like a class A
This thread is going nowhere. As it doesn’t address the OP’s thread title

Nothing repeat nothing! solid state A/B (low bias A) sounds like a 20w> high bias Class-A amp.
As there is no xover distortion in Class-A when the top and bottom transistors switch over from each other, because they’re still both biased into Class-A.
The transistor xover distortion is most noticeable in the highs, (strings, piano, tops of female high notes etc) on a low bias Class-A/B amp when it switches to B, after a couple of watts.

You need around 20w of Class-A to make it disappear on a A/B amp, then it gets too hot because of the rail voltage to get it to be 100w in Class-B. The A’s heat goes up exponentially. compared to just having a 20w class-A push pull with no Class-B

So go back to my first post, bi-amp with a simple 20w Class-A for the highs (no B and not very hot). Then an A/B for the bass.
https://forum.audiogon.com/posts/2065044

PS: last weekend we listened to Wilson Alexia MkII’s driven by a Class-A/B Gryphon Antillion Evo (it’s got 3 Class-A bias settings 10w 30w and 100w, switchable on the fly), we were listening mainly to streaming v cd, and at the end of the session we decided to go from 30w to 100w, all of us heard the improvement within seconds, and felt the room heat up after 1/2hr. (Didn’t change the streaming v cd outcome though).

Cheers George
georgehifi's avatar
georgehifi
10,312 posts
 

alaindexe OP
Suggestion for a SS class AB amp that sounds like a class A ... if such a thing exists
Great way that will sound very good, would be a $799 Schiit Aegir 20w Class-A for the highs and a $699 Schiit Vidar 100w a/b for the bass, horizontally bi-amped. Which if you look at the Altec xover is a snack to do.

Before
http://i10.photobucket.com/albums/a137/actke/Capture2_1.jpg
After
https://ibb.co/jVpKGvy

You will need though a Schiit $49 Sys passive on the Vidar input as it has more gain than the Aegir and needs to be lowered just a bit, and this will allow you to tune the sound a little to your room or yourself.
https://ibb.co/SwfGBm5

Cheers George

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