[Voyst]

Hi,
 
I plan to build a Beta 22 and I read almost all the posts of internet on the subject. I saw that there are some conflicts about the number of board, number of power supply, real utility of the ground channel etc. I am especially referring to JCX and Nwavguy who gave real engineering materials to make their point. I know there are lots of post on this forum (and other) which treat about this subject but I would like to do a summary and a clarification of all the informations.
 
I know there were some (very rare) listening tests between 2 boards vs 3 boards configurations and that the 3 boards configuration usually sound better in those. I am not here to say that it is not true but I am the kind of man who attache importance to the engineering aspect. That is why I want to know more on it. 

So if some people could talk about/compare the following configurations with only an engineering point of vue I would be really grateful:
 
2*B22 board + 1*S22 board
3*B22 board + 1*S22 board
4*B22 board + 1*S22 board
2*B22 board + 2*S22 board
4*B22 board + 2*S22 board
 
 
Moreover I would like to underline that the HeadAmp GS-X  which is considered as one of the best headphone amplifier is composed of 4 boards and 2 power supplies.
And that the HeadAmp GS-1 which is still a high-end amplifier is a 2 boards + 1 power supply configuration.
 
Also if someone could detail the wiring/connection for a 2boards configuration and a 4pin headphone connector it would be nice.

 
Sorry for my poor English and thank you to everyone who had taken the time to read this.

 

[Avro_Arrow]

The first question is are you going to use it balanced or not.
 
Two and three boards will give you a single ended amp.
Four boards will give you a balanced amp.
 
If you were going to use four boards, I would use two
power boards, one for the left channel and one for the
right.
 
Cheers!

 

[preproman]

 

[bidoux]

I think some people aren't convinced by the use of a third channel, especially if a nice dual power supply is used. I don't have a theoretical justification and certainly am not able to speak in their stead.
 
You will find details regarding the wiring on AMB's website. His support is very accurate, it truly is impressing.
 
(I didn't understand why you made a reference to headamp's product, as gorgeous and awesome as they are)

 

[Voyst]

Thank you for your answers.
 
 

The first question is are you going to use it balanced or not.

I will probably use it balanced with a Buffalo III.
 

You will find details regarding the wiring on AMB's website. His support is very accurate, it truly is impressing.
 
(I didn't understand why you made a reference to headamp's product, as gorgeous and awesome as they are)

I think I read a post of JCX which said that two boards with a 4pin output (not TRS) would be great, and that 4 boards does not worth it. I may have not well understood what he explained, but if I did the wiring is not the same that on the AMB's website. 
That is also why I talked about the GS-X, to show that this amp uses 4 boards, so it must be a reason ...

 

[preproman]

The reason is to be fully balanced.  1 board for each channel.  L+ R+ L- R- is how I understand it.

 

[bidoux]

If size, power consumption and price don't matter, just go with four boards + 2 sigma22. The whole reason of using a balanced topology, as done in the headamp GS-X, is to gain voltage swing thus to gain power (see here."[size=x-small]It has twice the voltage swing, twice the slew rate and 4 times the output power" )[/size]
 
Imho it is overkill with most headphones, even the power output of a simple 2 channel Beta22 is too much for most headphones. But if you want to build one of the best amp around, 4 boards + 2 sigma22 is the way to go. And it will be able to drive absolutely any headphone you feed him, well maybe not stats

 

[preproman]

May not be overkill depending on what you have the gain set at.  Well I guess it's still overkill but what the hay

...  I want to bump my gain down a few notches now for the TH-900.