Any Alchemist Users!!

[hemantwaghe]

Hi All
Th constant quest of finding used equipment took me to untraded path of class - Class A Amp!
Someone says he can arrange alchemist APD-6 Mk II for me . Prce is yet undecided.


Alchemist HiFi Products | Kraken Range | Alchemist Kraken APD6 Integrated Amplifier

Looks too stylish with fins and external power supply!!

Now internet reviews are good and impressive but first the amp becoms too hot ---and also I remember reading somewhere it cannot handle 4 Ohm speaker load . Initially I am partnering it with Solis Mini Bookshelfs & Passive Subwoofer ( Solid is low prised brand of B & W)

Any member can help me??

 

[vivekam]

Hi hemantwaghe,

Personally I have never heard a class A amplifier. But I can say about class A Amplifier from my theoritical back ground.
First thing they are very inefficient.
The reason for it being inefficient are:
1. Class A amplifying devices operate over the whole of the input cycle such that the output signal is an exact scaled-up replica of the input with no clipping. Class A amplifiers are the usual means of implementing small-signal amplifiers. They are not very efficient; a theoretical maximum of 50% is obtainable with inductive output coupling and only 25% with capacitive coupling. You need to check this out what Alchemist does.

2. For every watt delivered to the load, the amplifier itself will, at best, dissipate another watt.

I guess you can't even touch its knobs when it is playing. And I am very sure it will reach to temparatures of 50C quite easily. If you add Indian summer to it, then you might feel that your amp is being played at equator.

Meanwhile, you can get more information on Class A amplifier from our dear Google.

 

[soundsgreat]

Hi,

Vivek although on the whole what you've said might be True !

I guess you can't even touch its knobs when it is playing.

But this is quite far fetched !! you can very easily operate without any issues ! they have solid heatsinks to dessipate the amount of heat generated by these class A amps !!

I have heard/Seen many such Class A amps and this is far from the truth !!

Now coming to the other stuff, Hemanth you have to be very sure of this decision coz, The Class A amps are a different breed of Amps and requires the same kind of maintenance and other stuff !

First off it requires some warmup time before you can actually start to listen !

Second as you said some of them are not Kind enough to take the low impedance speakers !

Third some of them are not to switched on without a load !

Next Some of them requires you to keep it switched on to attain the Optimum Bias always !

There are many such things,This is not to scare you away from the buy that Am mentioning it here, but to just inform the Real world Implications of choosing them !

Having said that I'd like to tell you this, Once you hear a proper class A amp you'll never ever want to even peek at any other types of Amp ! The sound is Magical :thumbsup:!!

There is a guy in the forum who uses Alchemist Nemesis ! His ID here is "stephan9" try Pming him and see what he has to say !!

Any other doubts please do let us know !!

Regards.

 

[vivekam]

Hi soundsgreat,

That is why I said it is all theoretical knowledge. And that too from college, which was mostly bunked.

Thanks,
Vivekam

 

[arj]

Hi hemantwaghe,

Personally I have never heard a class A amplifier. But I can say about class A Amplifier from my theoritical back ground.
First thing they are very inefficient.
The reason for it being inefficient are:
1. Class A amplifying devices operate over the whole of the input cycle such that the output signal is an exact scaled-up replica of the input with no clipping. Class A amplifiers are the usual means of implementing small-signal amplifiers. They are not very efficient; a theoretical maximum of 50% is obtainable with inductive output coupling and only 25% with capacitive coupling. You need to check this out what Alchemist does.

2. For every watt delivered to the load, the amplifier itself will, at best, dissipate another watt.

theoretically it looks bad but sonically Pure Class As are amazing in terms of fluidity of sound

the efficiency is usually at 10-15% and they run pretty Hot but not hard to touch..they need ventilation space all around though.

but the concept is simple..if the amp is say 10W at an efficiency of 10%, th pure class A will draw 100W all the time. any power needed by the speaker will be given and the rest dissipated as heat. so the tougher the load the cooler it runs.

Most A/B amps also have some % biased at class A ie a 100W amp may be biased upto 10W in class A after which it will switch to A/B mode.

 

[square_wave]

Most A/B amps also have some % biased at class A ie a 100W amp may be biased upto 10W in class A after which it will switch to A/B mode.

The odyssey stratos is class A till 30 watts then switches to Class A/B. Some amplifiers like the Plinius has a toggle switch for Class A/ AB