New Aleph Mini PCB GB

[Dennis Hui]

Originally posted by applebook
Yep, I purchased a pair. Shipping is cheap too. Thanks again.

Just curious, how much was shipping for a pair?

Cheers,
Dennis

[applebook]

Hi, Dennis, shipping is $16 for a 12" x 5 3/8" piece.

[yoke]

Hi ...
I have two questions ;
- how do you connect unbalanced signal to input ? do I need to short ground to - ( of XLR ) ( place jumper from SG to -In )
- and is there way to optimize Aleph Mini for 10W on 4 Ohm ( I need mini to drive 4 ohm tweeter ( scan speak 2904/7000 )

Thanks

[jleaman]

Originally posted by yoke
Hi ...
I have two questions ;
- how do you connect unbalanced signal to input ? do I need to short ground to - ( of XLR ) ( place jumper from SG to -In )
- and is there way to optimize Aleph Mini for 10W on 4 Ohm ( I need mini to drive 4 ohm tweeter ( scan speak 2904/7000 )

Thanks

See Picture

And with the min alephs the best thing about them is you can just change heatsink / psu voltage up / down to get more less power.

if you want 10watts id do about 15-Volt rails. Transformer before recitification is about 12-0-12 They sell them on ebay for about 32$

[yoke]

Thanks Jason for replay

I have Aleph Power and Dissipation Spreadsheet from wuffwaff and when I enter 15V or 18V ( small diference in power at 4 Ohm ) I get around 8W ...

The picture below show 15V and 1A ...

From the sime spreadsheet, if I would like more power at 4 Ohm I would nead to rise bias ...

Is this right ? ...

what is the minimum recomended voltage for IRFP044 operation ?

my heatsink could only take up to 18-19W ... so if I would rise bias I would nead to lover voltage to stay inside those 18-19W

[jleaman]

I once had my alephs running at 9V Rail's It worked ok.

[applebook]

I have another question, will this EI 15W 80Ma transformer work? http://www.rpelectronics.com/English...ems/125ESE.asp

I've seen another builder make his/her Mini with those exact specs but want to be sure.

Toroid transformers are ideal with audiophiles, but Antek is taking ridiculously long and is asking for an additional $16 shipping even though I've already paid $25 for shipping (as per their original request).

[hayenc]

Might doublecheck your link. It brings up an output transformer for a tube amp.

[applebook]

You're right. Here's the correct one: http://www.rpelectronics.com/English...ems/166R12.asp

[Dennis Hui]

Originally posted by yoke
Thanks Jason for replay

I have Aleph Power and Dissipation Spreadsheet from wuffwaff and when I enter 15V or 18V ( small diference in power at 4 Ohm ) I get around 8W ...

The picture below show 15V and 1A ...

From the sime spreadsheet, if I would like more power at 4 Ohm I would nead to rise bias ...

Is this right ? ...

what is the minimum recomended voltage for IRFP044 operation ?

my heatsink could only take up to 18-19W ... so if I would rise bias I would nead to lover voltage to stay inside those 18-19W

Hello Yoke,

As Jason mentioned, the best thing will be if you can
use larger heatsinks. (Perhaps use a fan?)
However, if you can only to dissipate 18W per
mosfet then I would perhaps try
12V @ 1.5A. Mr. Pass' mosfet testing article
( http://passdiy.com/pdf/mos.pdf ) shows that the
distortion goes up with decreasing
voltage and goes down with increasing bias.

Then there's the matter of the circuit itself. IIRC,
the biasing circuit of the front end differential
pair will stop working below a certain voltage.

You're right about connecting an unbalanced
signal. Simply short the negative connection
of the XLR to ground and you're all set.

Cheers,
Dennis