Pure class A power for the CA-2300?

[leo2498]

Hi I wondering if anyone would know how many watts in "class A" operation this amp will provide before it change to "class AB"?
thanks.

[Glen B]

You will probbably just have to ask Classé if you feel its that important. Whatever the figure, it will still not be "pure class A" (just pointing out the oxymoron in your post heading). That term is reserved only for amps that operate in class A up to full rated power, and never switch to class B at any time.

With the legacy CA series amps, class A operation was up to 20 percent of rated power, based on a dynamic biasing method. Output stage bias was set to idle at a relatively low level. As output increased under the load, bias was raised accordingly, remaining at about 20 percent of total output. This information came directly from Robert Adam at Classé.

[leo2498]

You will probbably just have to ask Classé if you feel its that important. Whatever the figure, it will still not be "pure class A" (just pointing out the oxymoron in your post heading). That term is reserved only for amps that operate in class A up to full rated power, and never switch to class B at any time.

With the legacy CA series amps, class A operation was up to 20 percent of rated power, based on a dynamic biasing method. Output stage bias was set to idle at a relatively low level. As output increased under the load, bias was raised accordingly, remaining at about 20 percent of total output. This information came directly from Robert Adam at Classé.

Hi thanks for your advice but I was confused because I thought a class AB amplifier will work in two stage, the first one is a "class A" amplification so I'm wrong to say that power stage is pure Class A operation, right? I have another doubt, this "class A" stage is different in an amplifier that is full rated in class A vs AB?

[Glen B]

There have been amps that claim to be class A, but switch to class B at some point. Such an amp is really just a high bias class A/B amp. A pure class A amp is biased so that it never switches to class B at any time.

[windshear]

I read somewhere that the CAM600 is biased into class A for the first 3 Watts. Im not sure if one can relate this to the CA2300 given they use the same basic topology.

[Glen B]

I just received a reply from Robert Adam at Classé in response to my e-mail last week, enquiring about the operating class of the CA2300. He said the CA2300 operates in the same way as the CA-XXX legacy models, "class A for the first 20% of rated power, then it will switch to class B". So there you have it, approximately 60 watts.

[leo2498]

for if someone want to know, I talked with classe and the response is 20% of the rated power so it's something like 60W in class A operation, I'm wondering if this class A operation will produce the same performance that a 50W class A pure amp and the result sound could be considerate like close to a pure class A amplifier.
if anyone know please enlighten me.

[mjb]

I'm wondering if this class A operation will produce the same performance that a 50W class A pure amp and the result sound could be considerate like close to a pure class A amplifier.

I think so, class A is class A, ie, there's no cross-over distortion, so it should be comparable operating within the linear part of the slope (first 20% of power - thanks for the info BTW).

[RebelMan]

Glen, are you quoting Robert literally? When I inquired about this a while back I was told, from a different but highly credible source, the first 20 watts was biased into Class-A. The new Delta amplifiers are a complete redesign from anything Classe' has done previously so when I heard the biasing changed I attributed that to the new design. It's possible I may have misunderstood him.

windshear, what you read in Secrets, as sometimes happens with republished specifications, was in error.

[Glen B]

Rebelman, I quoted Robert literally. He said "same thing" as the legacy models "Class A up to 20% of rated power then switching to class AB". The OP also received the same information in a separate communication. Here's also a previous direct quote from Robert on how the biasing system works: "The way it is done is that the output stage DC bias is set to idle at a relatively low level to minimize heat. As the output increases under the load, the bias increases, remaining at about 20% of the total power output, largely eliminating the switching distortion normally associated with a Class A/B design."

[RebelMan]

Okay and by "legacy" you (he) is referring to the pre-Delta series correct? As the first generation Delta amps biased at up to 1/3rd total output.

[Glen B]

"Legacy" refers to the pre-Delta models, CA-200/201/300/301/400/401, etc.

[leo2498]

I auditioned the ca2300 in a awful room 15 days ago and although the sound was not good I can rescue some good thing of the classe combo(cp800+ca2300) like the perfect bass and the excelent presentation of each instrument so I'm motivated to get one but I just wondering if this class A could give the same sweet sound of something like a pass lab pure class A or something similar (I have not heard it but when I changed from a receiver to a class ab rotel the sound was a lot better so I'm guessing that a class A will be better acording I have read). for that reason I did the question, what do you guys think about this last statement? :roll:

[RebelMan]

Nelson Pass has gone on record stating that it is fairly easy for engineers to build amplifiers that sound similarly neutral and that the real challenge lies in how to make them sound distinct or unique. The aspect of voicing/tuning in a manner that shifts what could be, should be, a transparently performing amplifier into one that is purposely colored can be viewed with a bit of irony for the audiophile. I am not a fan of engineers that take this position and any potential misgivings involving crossover distortion inherent with push-pull designs are largely mitigated with good execution. Thanks to Alan Clark's philosophy to stay true to the signal, one which I share, the CP-800 and CA-2300 combination he designed was made to sound superb.

[wkhanna]

Was it not Nelson who also said, "It is the first watt that matters most" ?

[RebelMan]

Actually it was Dick Olsher but Nelson Pass was inspired by the remark.

[wkhanna]

Thank you for the correction!

[RebelMan]

Update

Since the Delta Series II amplifiers are products of a completely redesigned architecture they DO NOT I repeat DO NOT vary the quiescent current (bias) like the previous Delta Series I amplifiers do. Amplifiers such as the CA-2300 only output about 3 watts of pure Class-A power before engaging Class-A/B operation. NOT 20% as we were first led to believe, that information was regrettably in error! The advantage though is that it only dissipates about 46 watts at idle for doing so. Amplifiers such as the CA-2200 run Class-A output up to one third (1/3rd) total output in the manner as referred to by Glen B but the penalties for doing so are much higher power consumption at idle, 166 watts to be exact in this case. So there is no free lunch as they say. Pay now or pay later.

[windshear]

So the Secrets Review was correct then with their 3w.

[RebelMan]

It appears that Secrets was indeed correct.

[leo2498]

good to know, thanks.

[BWLover]

Just out of curiosity, why would the 2200 output more class A then the 2300?


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[mjb]

... but the penalties for doing so are much higher power consumption at idle, 166 watts to be exact in this case. So there is no free lunch as they say. Pay now or pay later.

My SSP800 draws 60 watts regardless of being on or off, then a couple of amps, man... I hope Classé can nail Class D because with the price we have to pay for our "eco" wind-power, I'm almost afraid to turn it all on.

[BWLover]

What do you pay per kilowatt hour?


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[mjb]

29 euro cents per kilowatt hour. So keeping the SSP800 and CA2200 idling (220 watts) costs me 1.53 euro's a day, or 558.45 euro per year! Gosh, I just worked that out to reply to your question, and now I'm in shock :E

[RebelMan]

Just out of curiosity, why would the 2200 output more class A then the 2300?

Both Delta Series I and II power amplifiers are Class-A AND Class-B designs (combined). The quiescent current (bias point) determines when the operation of the amplifiers (actually the transistors) switches from one mode (Class) to the other. Because crossover distortion is more of a problem in low to medium Class-B power amplifiers the biasing point is set higher with the Delta Series I amplifiers than it needed to be with the Delta Series II amplifiers.

[RebelMan]

I keep my SSP-800 powered on all the time for the reason that it doesn't save much in standby mode. It also eschews some of the HDMI handshaking issues (really HDCP issues) that are more prevalent with the TiVo Premiere 4 than they were with the TiVo HD which loosely supported the protocol. I keep the amplifiers powered off until I need them but then they need to get the warming up treatment before critically listening, i.e., maximum enjoyment.

[slauten]

Think the Classe Omega Mono blocks draw a few watts of juice in stand by?

[BWLover]

Anybody on the forum own the omega mono blocks?


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[leo2498]

I turn off my gear always and I unplugged the power cord, I did this for protection and avoid damage for peaks of current; it is not recommended do this?

[RebelMan]

Think the Classe Omega Mono blocks draw a few watts of juice in stand by?

Given that the Delta Series is the Omega Series offspring, I would venture to say so. 8)

[RebelMan]

I turn off my gear always and I unplugged the power cord, I did this for protection and avoid damage for peaks of current; it is not recommended do this?

It's not really necessary to unplug in times of calm weather and stable AC mains though it shouldn't pose any problems if you do.

[Glen B]

Given that the Delta Series is the Omega Series offspring, I would venture to say so. 8)

In the Stereophile Magazine March 1999 review of the stereo Omega, it was described as running in class A up to 110W, before transitioning to AB. So, yes it would likely draw a few hundred watts of power at idle, and ditto for the Omicron and mono Omegas as well.

[slauten]

In the Stereophile Magazine March 1999 review of the stereo Omega, it was described as running in class A up to 110W, before transitioning to AB. So, yes it would likely draw a few hundred watts of power at idle, and ditto for the Omicron and mono Omegas as well.

The way I have my systems set up. I'm using a PS Audio P10 power regenerator that controls power ports separately. This allows me to power down circuits as desired via an iPad, cell phone, laptop, etc. The P10 controls all of my audio system with exception of my mains amp and subs. Those have stand by button on the side I can push, but they also are controlled by the Classe Can bus. If I know I will not be using for an extended period I can simply flip the breaker off. I have dedicated circuit for each main amps, plus 1 more 20 amp circuit for everything in the audio rack, center/ rear speaker amp and projector.

Summary 3 20 amp dedicated circuits feed the entire system

See Ya,
Steve

[Kobus]

Summary 3 20 amp dedicated circuits feed the entire system

Steve

You are an audiophile.

[mjb]

You are an audiophile.

For sure.... I only have one dedicated 20 amp breaker :cry:

[slauten]

For sure.... I only have one dedicated 20 amp breaker :cry:

Fortunately my house has a sub panel with spare circuits. In addition it's a 2 story home and and the HT is on 2nd floor, but the panel is located where attic is open above it. Fairly simple to run wiring for the system from panel to HT. It certainly eliminates any questions regarding electrical power to the HT system, nor any issues with overloading circuits. On this forum and many others a lot of discussion about top shelf amps, 500 watts and up but little discussion about properly feeding them. I also used upgraded outlets rated for 20 amps each.

Update...I also am fortunate my HT wall where speakers and mains amp is located with an open wall to the attic, and my equipment room is too. Very easy to run cable, make changes, etc and everything still looks good.

See Ya,
Steve

[RebelMan]

If I know I will not be using for an extended period I can simply flip the breaker off. I have dedicated circuit for each main amps, plus 1 more 20 amp circuit for everything in the audio rack, center/ rear speaker amp and projector.

Dedicated circuits are the way to go, I run 20A as well. Unfortunately, not all neighborhoods will benefit nor will all be capable. Fortunately, for us the quality of our AC mains is rock solid (this can be tested by the local power company, btw). In two years we haven't observed one blip in power delivery not even a hint of one has occurred. In our other place it was a very different story and I ran dedicated 20A circuits there as well. To protect your system consider a whole house surge protector if you haven't already. And as long as your power amplifiers are put into standby mode when not in idle/active use power loss will have negligible consequences on your bill.

[nikos]

I've owned the ca-5200 ssp-800 combo for years and never bothered to question the 1/3 class A power rating until it was the first thing that came to mind waking up today....

The question was so at what volume does my amp switch from A to A/B?

Then I ran into this thread.

My quick math and online conversion gives roughly 200/3=65 (rounded down)

65 watts = 45db

My 803D is 90db sensitive

With my trusty db meter what should I read at 1m to find the rough max limit of class A operation?

Can someone please connect the dots?

Thanks

[Glen B]

The class A output is approximately 20% not 33 1/3%, so with the CA-5200 it is about 40W, not 65W. There are so many factors that affect sound level at the listening position. This simple calculator may provide a good approximation of SPL at 40W: Peak SPL Calculator

[bigburner]

Was it not Nelson who also said, "It is the first watt that matters most" ?

Was it not Ritchie Blackmore who also said "Learning to play with a big amplifier is like trying to control an elephant."?

Totally irrelevant I know.

Nigel.

[nikos]

The class A output is approximately 20% not 33 1/3%, so with the CA-5200 it is about 40W, not 65W. There are so many factors that affect sound level at the listening position. This simple calculator may provide a good approximation of SPL at 40W: Peak SPL Calculator

Since the Delta Series II amplifiers are products of a completely redesigned architecture they DO NOT I repeat DO NOT vary the quiescent current (bias) like the previous Delta Series I amplifiers do. Amplifiers such as the CA-2300 only output about 3 watts of pure Class-A power before engaging Class-A/B operation. NOT 20% as we were first led to believe, that information was regrettably in error! The advantage though is that it only dissipates about 46 watts at idle for doing so. Amplifiers such as the CA-2200 run Class-A output up to one third (1/3rd) total output in the manner as referred to by Glen B but the penalties for doing so are much higher power consumption at idle, 166 watts to be exact in this case. So there is no free lunch as they say. Pay now or pay later.

So who is right here for the
ca-5200 Glen or Rebelman?

[Glen B]

Rebelman is right. In my effort to correct your percentage mistake, I forgot that your CA-5200 is Delta II series, which is of different architecture from original Delta and earlier models. However, as I said, Classe amps that operate in adaptive bias, run 20% class A, not 33 1/3%.

[nikos]

The class A output is approximately 20% not 33 1/3%, so with the CA-5200 it is about 40W, not 65W. There are so many factors that affect sound level at the listening position. This simple calculator may provide a good approximation of SPL at 40W: Peak SPL Calculator

Since the Delta Series II amplifiers are products of a completely redesigned architecture they DO NOT I repeat DO NOT vary the quiescent current (bias) like the previous Delta Series I amplifiers do. Amplifiers such as the CA-2300 only output about 3 watts of pure Class-A power before engaging Class-A/B operation. NOT 20% as we were first led to believe, that information was regrettably in error! The advantage though is that it only dissipates about 46 watts at idle for doing so. Amplifiers such as the CA-2200 run Class-A output up to one third (1/3rd) total output in the manner as referred to by Glen B but the penalties for doing so are much higher power consumption at idle, 166 watts to be exact in this case. So there is no free lunch as they say. Pay now or pay later.

Glen , Sorry if I'm beating a dead horse here... Yet I'm either not reading Rebelmans reply correctly or you're contradicting yourself.

I'll point out this specific phrase... Just as Rebelman wrote "Amplifiers such as the CA-2200 run Class-A output up to one third (1/3rd) total output "
This 1/3rd instead of 20% is what is listed on reviews even on the Classe site for the ca-5200.

Since ca-2200 same family tech as ca-5200 I figured Rebelmans point still stands and for this family(ca-2200, ca-5200) it's 1/3rd. Legacy is 20% and latest (ca-2300) the first 3 watts etc

Thanks for clearing this up for me

[Glen B]

Glen , Sorry if I'm beating a dead horse here... Yet I'm either not reading Rebelmans reply correctly or you're contradicting yourself.

I'll point out this specific phrase... Just as Rebelman wrote "Amplifiers such as the CA-2200 run Class-A output up to one third (1/3rd) total output "
This 1/3rd instead of 20% is what is listed on reviews even on the Classe site for the ca-5200.

Since ca-2200 same family tech as ca-5200 I figured Rebelmans point still stands and for this family(ca-2200, ca-5200) it's 1/3rd. Legacy is 20% and latest (ca-2300) the first 3 watts etc

Thanks for clearing this up for me

Looking on the Classe website, the CA-5200 is one of the Delta I designs. The CA-2300 and CA-5300 are Delta II designs, with the ICTunnel system. Draw your conclusions accordingly. In what reviews or where on the Classe site did you see any mention of a percentage class A operation ? I have never seen this information published. In fact, it was quite by accident that I found out from the Classe factory, about the class A output up to 20 percent of rated power.