Aleph 5 playing...

[Edwin Dorre]

Very nice!!!!

I am looking forward to see it with all the side panels on!

Keep up the good work!

Edwin

[trigon]

Nice.

Trigon.

[grataku]

Is it just me or the pictures? I have been looking at these for the past five minutes and I have almost no idea of how this amp looks or it's put together.

It works, so very nice I guess.

[Peter Daniel]

Originally posted by grataku
Is it just me or the pictures? I have been looking at these for the past five minutes and I have almost no idea of how this amp looks or it's put together.

I had a good laugh reading your comments, which as usualy, are right to the point. I guess too many close ups and not enough wide angle photos.

I also noticed unique way of mounting output devices, very practical.

So, it is nice.

[Taco]

And another Dutch Aleph is born . Your chasis is very different, but I think very rigid too. Are you using the amp balanced?

[Lucas_G]

Originally posted by grataku
Is it just me or the pictures? I have been looking at these for the past five minutes and I have almost no idea of how this amp looks or it's put together.

It works, so very nice I guess.

Originally posted by Peter Daniel


I had a good laugh reading your comments, which as usualy, are right to the point. I guess too many close ups and not enough wide angle photos.

I also noticed unique way of mounting output devices, very practical.

So, it is nice.

Hi Grataku and Peter,

I already had this fear when I posted them... , but you DIY guys like puzzling, don't you?

I had a very simple camera at my disposal and the light conditions weren't very ideal, I guess.

I will make some more (and hopefully better) pictures with the sidepanels attached.

BTW, I thought that you DIY guys are more interested in naked photography than external cosmetics....

Anyway there seem to be no questions, so it can't be that much confusing. (Or it is too confusing to invoke questions... )

Peter, I used 30 mm M3 bolts that went into the heatsink up to the maximum end. Then I could easily raise tension on the mosfets by turning the butterfly nuts. This way you can use the maximum available thread within the heatsink and it doesn't put pressure on the thread while turning around...

Anyway, thanks for all your attention!

Regards,

Lucas.

[Lucas_G]

Originally posted by Taco
And another Dutch Aleph is born . Your chasis is very different, but I think very rigid too. Are you using the amp balanced?

Hi Taco,

Yes it is very rigid. Aluminium is always a wonderful tool to play with, even if you have to do with L-profiles instead of the wonderful solid bars of Peter Daniel....

I have tried the amp both un- and balanced, however with my current preamp I get a somewhat better and more dynamic sound with unbalanced. Maybe the balanced outputs of my AVM evolution V3 are not so good. They also seem to have the same outputlevel as the unbalanced outputs...

I will built an Aleph P1.7 later. Maybe with that preamp the balanced inputs will sound better.

Regards,

Lucas.

[Franz]

Hi!

I wonder how you manage to get only 47 °C at the heatsink with this size and 39 V DC rail voltage !?
Your heatsink seems to be pretty small.
Also I wonder if a 330 VA rating of the trafo is adequate.

However I beliefe you that all is working well.

cheers

Franz

[Lucas_G]

Originally posted by Franz
Hi!

I wonder how you manage to get only 47 °C at the heatsink with this size and 39 V DC rail voltage !?
Your heatsink seems to be pretty small.
Also I wonder if a 330 VA rating of the trafo is adequate.

However I beliefe you that all is working well.

cheers

Franz

Hi Franz,

I was also sceptical at first when I saw the diagram at

http://www.seifert-electronic.de/eng/prod/index_p.htm

When you look at it you find at 150 mm a C/W of 0.15

The heatdissipation in my Aleph 5 is appr. 2,4 x 39 x 2 = 187 watt per channel. The above room temperature is 47 - 20 = 27 degrees. 27 / 187 = 0.144
Therefor we can conclude that Seifert is quite honest in their value of 0.15 C/W
One of the secrets of this heatsink is that they have long cooling-fins that have an extra surface because they are curved.
Furthermore I have them some 5 cm lifted from the underground so that air can freely go through the "chimneys".

With a dissipation of 187 Watt you could also do with a 220 VA
transformator, provided it is of good quality. The 330 VA has enough reserve, especially if you consider that a good quality toroid can easily provide 1.5 up to 2 times the nominal value without going into saturation. A 500 VA won't hurt either of course, but that is up to you...

BTW: I tried also a 750 VA (which I will use for Aleph 2s) but I could definitly not hear any difference with the 330 VA type! (Not so good news for all those who spent money on oversized toroids, I guess...)

Regards,

Lucas.

[Lucas_G]

Here are the measures of the heatsink: