Industrial AlephX High Power version

[cocolino]

originally posted by grataku
The only thing I would change is the placement of the voltage drop resistors from where they are to the base plate. That should increase the life span of the caps.

Another thing I would change is placement of the speakers!
They are far too near the wall on the side. You`ll get some early reflections which can spoil everything.
I understand that You might not have enough space for this but just for a try move them away from that wall - at least another half meter - more is better - I bet this will make a HUGE difference(towards positive).

[Netlist]

Originally posted by grataku
Hugo,
looks very good. what was the story in the end with the measurements? Do you still hear the distortion? What do the rail end up to be after the resistors? What bias do they run? What mosfet did you use?

The only thing I would change is the placement of the voltage drop resistors from where they are to the base plate. That should increase the life span of the caps.

Thanks Grataku
I still think there is space for improvements, playing with resistors. The distortion is nothing more than plain clipping. I cranked up the bias to a total of 7.5A and that's HOT!!!
The 0.5ohm resistors drop about 3.7V. That's more than 27W.
I'll have to get rid of them one way or another.
I'll definitely place them on the base plate later on, because the cap plate also cools the rectifier.
I now have +/-21 rail voltage.
A small calculation tells me that 21+3.7=24.7V. Safe enough for the caps, but in reality, without the resistors I end up with 28V no matter how high I set the bias. With the lowest possible bias the voltage climbs to 32V!
The mosfets are IRF9210 for the diff-pair, and IRFP240 for the power transistors. All others are BC550C. The current source is made with the TL431CLP.

Peter, that’s a good idea. We’ll see. The rigidity is surprisingly good for the moment. The whole amp is bolt together only with 24 M4 screws.
BTW, how could I possibly inspire you???

/Hugo

[Bricolo]

are those feets copyrighted? :d

I never thought about using this as feets, the easyest solution is ever the last that comes to my mind...

[Netlist]

Originally posted by cocolino

Another thing I would change is placement of the speakers!

Thanks, I noticed that in the past. The living room where they stand is very nice (thanks to my wife) but is in no way good for sound. There is a high ceiling that ends in a ^-shape (don't know the name of those ceilings). Besides that there is a big lamp (1m diameter) hanging between the speakers which has a dramatic influence on the sound. And last but not least, there's the WAF

Originally posted by Bricolo
are those feets copyrighted? :d

I never thought about using this as feets, the easyest solution is ever the last that comes to my mind...

They can be ordered in any amount.
Part of the 'industrial' look
/Hugo

[grataku]

Originally posted by Netlist


Thanks Grataku
I still think there is space for improvements, playing with resistors. The distortion is nothing more than plain clipping. I cranked up the bias to a total of 7.5A and that's HOT!!!
The 0.5ohm resistors drop about 3.7V. That's more than 27W.

I was using the same scheme to lower the voltage of my bench PS: 50 W ohmite resistors bolted on a plate of about the same size as your current one. I did measure some crazy temperatures like 150 C. At turn on they where making some metal sizzling noise.

I'll have to get rid of them one way or another.

The easyest way out that I see, if you want to keep the transformers, is to go all out. Make each monoblock with 4 heatsinks and use the full voltage swing from the trafo, sell the caps and buy a new set with higher voltage. Basically, make it a fully fledged XA200.

[Bricolo]

Originally posted by Netlist


They can be ordered in any amount.
Part of the 'industrial' look
/Hugo

OK, but before, to be sure they are good quality, I'll order you 4 free samples

[Netlist]

Originally posted by Bricolo

OK, but before, to be sure they are good quality, I'll order you 4 free samples

They will be available soon, via Karen from PassDiy
She knows how to take care of people who ask for "free samples".

/Hugo

[Bricolo]

Originally posted by Netlist


They will be available soon, via Karen from PassDiy
She knows how to take care of people who ask for "free samples".

/Hugo

[Netlist]

Originally posted by grataku

The easyest way out that I see, if you want to keep the transformers, is to go all out. Make each monoblock with 4 heatsinks and use the full voltage swing from the trafo, sell the caps and buy a new set with higher voltage. Basically, make it a fully fledged XA200.

Could you give me your bank account?

/Hugo

[Taco]

Nice job! As Peter suggested, add the extra bar for extra strenght. The same feet I am using for my rack (tnt-flexy).