New Aleph Mini PCB GB

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Hi Everyone,

Sorry for the threadfart, but I wanted to see if anyone is interested in some heatsinks to go with all of those Aleph 30 component kits (or any other projects...)

Given sufficient interest, I will arrange a group buy for large heatsinks (0.18c/w each) for folks in North America. The thread is here.

Now back to your regularly scheduled programming...
 
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Here is my first idea for a chassis for a low power amp with these small boards :)
http://www.briangt.com/gallery/aleph-briangt-mini

I like how the red of the table reflects on the front of the amp:
An externally hosted image should be here but it was not working when we last tested it.


I will push the power as far as these heatsinks will allow, which I still expect to be < 10w, but good for a simple amp.

As for the power supply board used, I cropped down the power supply board to use 4 caps and to fit in the chassis, leaving room for the wiring up the connectors on the back. I will make a mounting bracket to sit it over the transformer, which will fit rather well with the low profile caps and heatsinks.

I will try to work on this soon, as I have shipped out all of the current pcb orders, except for 2 (one recent arrival, and one waiting for the new chipamp boards to arrive). I still have a 3" high stack of power supply boards and a 5" stack of amp pcbs, if anyone wants to get them.

--
Brian
 
This is probably not the best place to ask, but where can i read about the first Mini-A with SMD?

Using the search resulted in me :dead: :xeye: :mad:

I´m trying to make my own A60 layout and thinking about using SMD. Would like to know the pros/cons of Brians SMD Mini-A and for instance if there was any problems using 0,5W resistors.
 
Thanks Brian!

Got the board today.

So I'm thinking of making an aleph 60 on the boards I have a few questions:

The Mark Finnis aleph 5 used 6 output mosfets per channel. Could I use 6 for the aleph 60 ? They seem to have most of the same specifications.

Apart from the obvious changes . I am thinking the ratings of the 3w resistors in the aleph 30 should be upped to 9-10w for the aleph 60.

any other differences I should look out for please dont hesitate to mention.
regards
dave
 
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dhole said:
Thanks Brian!

Got the board today.

So I'm thinking of making an aleph 60 on the boards I have a few questions:

The Mark Finnis aleph 5 used 6 output mosfets per channel. Could I use 6 for the aleph 60 ? They seem to have most of the same specifications.

Apart from the obvious changes . I am thinking the ratings of the 3w resistors in the aleph 30 should be upped to 9-10w for the aleph 60.

any other differences I should look out for please dont hesitate to mention.
regards
dave

If I understand correctly, the sum of the currents through the output devices is greater for the Aleph60, but the current per device is the same, which should allow for 3W resistors to still be used. Correct me if I am wrong. The Aleph60 manual indicates 3W resistors. There is also room on the output resistor section to wire 6 resistors in parallel through stacking. (7 = max possible)

The output boards will allow you to cascade them and use multiple boards per channel. I am going to make an Aleph 5 with the boards, once I finish initial mini Aleph amp. Here are my chassis size estimates:
http://www.briangt.com/gallery/aleph-briangt-mini/chassis5
silver one = stereo Aleph 60 or Aleph 5
bigger one with black heatsinks = Aleph 30 (might be able to up the bias here, since the same 4 heatsinks were also used for an Aleph 2 monoblock: http://www.passdiy.com/gallery/aleph2-p1.htm )
small one = mini Aleph

Attached a picture of the output resistor configuration for the Aleph 60. (more output boards needed, boards attached in possible Aleph30 configuration. For my Aleph 30 amp, I will put 1 output board on each of the 4 heatsinks [attached from the board], allowing for more heat dissipation)

--
Brian
 

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Brian,

I know ive asked this before, but never got a definitive answer and im still trying to get a hold of all this stuff.

Im planning A5 for a friend of mine, other than obvious component changes, source resistors etc, am i just raising rail votages and changing bias?

regards
 
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MEGA-amp said:
Brian,

I know ive asked this before, but never got a definitive answer and im still trying to get a hold of all this stuff.

Im planning A5 for a friend of mine, other than obvious component changes, source resistors etc, am i just raising rail votages and changing bias?

regards

Exactly. If you combine the Aleph60 and Aleph 5 service manual schematics, you will get what you need. Most of the components will match the Aleph 60 values, except for the number of output devices, and the value of the bias resistors.

--
Brian
 
thanks for the advice Brian. I am considering the aleph 5 aswell. As ihave a parts list. I do however on the parts list for the 5 have the higher wattage resistors as 10w is this really needed ? It isnt marked on the schematic as with the 60.
also would I need to put a heatsink on the 9610s ?
dave
 
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dhole said:
thanks for the advice Brian. I am considering the aleph 5 aswell. As ihave a parts list. I do however on the parts list for the 5 have the higher wattage resistors as 10w is this really needed ? It isnt marked on the schematic as with the 60.
also would I need to put a heatsink on the 9610s ?
dave

I think that 3w should be fine for the resistors. You don't need a heatsink for the 9610 devices. Nelson didn't use them in the Aleph 30 or Aleph 60 amps.

--
Brian
 
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Peter Daniel said:
Pass Labs are using Panasonic resistors there, and those resistors are available in 3W maximum rating only (from D-K), so go figure ;)

Besides, you can use equasion: P=U2/R, both valuse are given in schematics, so power can be calculated.

Panasonic makes the same resistors in 5w, although, I haven't seen a supplier that sells them:
http://www.panasonic.com/industrial/components/pdf/AOA0000CE18.pdf

--
Brian
 
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In Aleph 5, max. 1A will flow through each source resistor. This means that max. power dissipation across each source resistor will be 1W. Even if my estimation includes certain error, I think that the 3w grade resistor is still acceptably enough.

The four current-sensing resistors of 0.47Ohms 3W will be equivalent to one 0.12Ohms of 12W. Here also, the 3W grade is big enough. Good luck.

Regards
 
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