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When does my class Atoll IN200 A/B integrated switch from class A to class B?

I have an Atoll IN200 integrated amp (earlier version of this: https://www.atoll-electronique.com/en/products/integrated/integrated-in200sig/)

Having read a lot of praise about class A power, I’m wondering how to tell from specs when my integrated likely needs to switch from class A to class B?

The reason I’m curious is that I’m still wondering how my speakers might sound with a pure class A amplifier (such as Pass, etc.) but perhaps the integrated I have is already demonstrating much of that if there is a long enough delivery of class A power from it already? My speakers are 8 ohms, 87 db sensitivity, standmounts.

I apologize if this question is too simple; I hope I’ve posed it clearly.

P.S. This is not about dissatisfaction with my integrated or other gear (I have tubes, too). It's really just part of a longer term attempt to understand how different power sources change the character of a system, particularly the speakers.
128x128hilde45
robertrs
17 posts
 
Coda uses three different taps on the transformer to achieve their versions. I have the CSiB integrated in V1 which is 150 watts into 8 ohms but with class A up to 18 watts, the V3 is 400 watts into 8 ohms and class A to 8 watt. So a unit can be adjusted to one of three versions, the correct transformer tap soldered in place and the bias set, all performed at the factory, not a user adjustment. 

I also have a Pass INT-60 which is class A to 30 watts, both wonderful units. Weighs in at 90 + lbs.

I agree with what most have said that your unit is likely class A to 10 watts or less.

The most important thing is how it sounds to you!
georgehifi's avatar
georgehifi
10,312 posts
 

hilde45
When does my class Atoll IN200 A/B integrated switch from class A to class B?

Looking at the size of the heat sinks https://ibb.co/1LXDhKt and the rail volts needed for Class-B 120w output, your lucky to have a couple of watts of Class-A

Because of the high rail volts needed for 120w of class-B, the heat dissipation of Class-A goes up exponentially as the rails volts rise for Class-B.

Think this way, if you have a 10w Class-A "only" amp (no B) the heat is X
If that same amp is still 10w Class-A ((but 120w of B) then the heat is far far higher.

Like I said your lucky to have a couple of watts of Class-A (sorry probably not what you wanted to hear) 

Cheers George
hilde45's avatar
hilde45 OP
4,783 posts
 
Thank you George and others. You have told me what I wanted to hear, namely the truth with explanations. I did not buy this amplifier with the expectation that it would be class a for very many watts.

I think this inquiry has taught me something also about what this company is willing to say even when they know that it is being repeated into a forum.

If I have more dialogue with them I may just share it with you because it's kind of amazing how long they are willing to stick with this line of bs.
georgehifi's avatar
georgehifi
10,312 posts
 
"The IN200 works in Class A up to about 40W under 8 Ohm. The switch to Class AB is quite slow."
BTW this is BS, that they claim for a 120w rms class-B they say it is.
If it were true the thing would huge with external heat sinks and weigh 30kg+ not 12kg
https://www.atoll-electronique.com/en/products/integrated/integrated-in200sig/

Cheers George
hilde45's avatar
hilde45 OP
4,783 posts
 
It seems proved as BS. What I'm amazed at is that I confronted them via email with the evidence it couldn't be true and they just repeated the BS. I may give them one more chance to come clean but nothing really hangs on it -- I'm just a berserker-against-BS.
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