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-   -   Some like it hot (and heavy),another boy toy. (http://www.diyaudio.com/forums/pass-labs/24711-some-like-hot-heavy-another-boy-toy.html)

joho 23rd December 2003 01:41 PM

Some like it hot (and heavy),another boy toy.
 
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In these days of the big Aleph-X boom, maybe my new Aleph 5 is a little bit old fashioned but i'm very happy with it.
The construction is around 4 old thyristor cooling heatsinks. Two heavy alluminium L-profile(6mm) connect the heatsinks and form the base for the power mosfets. A front,a back and a ground-plate makes it complete.(the top isn't ready)
I use a CLC powersupply with amplimo transformers(2x300VA),two standard 30A rectifier bridges,BC154 caps(352mF total) and two Mundorf foil coils(0.35R). For the powerstrips a used massif tinned copper. I know it's a little oversized but it was for free.
For the amplifier itself i used pcb's from Kristijan. For the components i used CMF55 and MPC71 resistors,Panasonic FC and silvered mica caps.
The mosfets and power R's are matched.
In fact a use the standaard A5 design of the master only a few bypasses with Vishay 1837 and Mundorf Suprime are different.

The most important thing ; How does it sound ???

I can use a lot of difficult english words to describe what i hear but in three words ; i like it.
There is a lot of rest and definition in the huge soundstage.

At the moment i'm almost ready with my Aleph 1.7 casework and for the future the Ono and Aleph-X are on the program.

Thanks to everybody on the forum and have a nice Christmas and a Happy Newyear.

Johan.

Feel free to give any commend on this creation.

ARAD 23rd December 2003 03:03 PM

Well Done
 
This looks very nice ! How hot does it get ? Do you have more pictures ?

Regards,
Andreas

cocolino 23rd December 2003 03:37 PM

Quote:

Feel free to give any commend on this creation.
Absolutely well thought out and wonderful craftsmanship - very professional looking!!

Yes, more pics please, I can`t get enough of those kind of beauties ;)

Tazzy 23rd December 2003 03:58 PM

Pretty NICE work!

Where did you get those heatsinks?

Taco 23rd December 2003 04:35 PM

Another Dutch Aleph, nice job. I like your case, but why you're using foil inductors, don't think it will improve the sound.

joho 23rd December 2003 05:36 PM

and another pic
 
I have the strange feeling that one of my answers goes wrong.

joho 23rd December 2003 05:53 PM

How hot is hot ?
 
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Hi Andreas,

A gave already a answer to your question but the cat was walking over my keyboard and i think the answer is not posted.
So again,
My Aleph runs a little bit to hot in my opinion. After an hour burning it becomes 59 degrees celsius at 20 degrees environment, measured at the top of the heatsinks.
To solve this problem i made a 35mm thick wooden base with four 80mm computer blowers exactly under each heatsink. Depending of the speed (and noise) of the blowers,the temperatuur goes down.

Regards,
Johan.

joho 23rd December 2003 05:56 PM

more pics
 
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I can't enough of posting pics

joho 23rd December 2003 05:57 PM

pics
 
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last pic

joho 23rd December 2003 07:09 PM

Heatsinks and foil coils
 
Hi Tazzy,

A good old friend of mine found the heatsinks on a dusty attic of the firm where he works for. Long time ago i worked for that same firm. They make very large regulation for engines and generators used in dregging,fishery offshore etc.
The type is K53 and normally a power thyristor is clamped between two of those heatsinks. So they build large thyristor units and bridge them like a rectifier bridge. It's all real power electronics and these days they also use "water"cooling for the units.
So maybe you can find them in a industrial electronics dumpshop.

Hallo Taco,

When a made my components choice i read some discussion about CLC, CRC etc. coils with ferriet ,without and so on.
In my opinion a CLC is superiour but don't use ferriet coils(saturation problem).So the best is a air coil or something like a big transformer but i didn't like the large dimensions.
The coil i use is 2.2mH and the R=0.35 and it's very compact. Normally they use these "kupferfolienspulen" in very expensive speaker filtering.
The material is OFC-copper and Mundorf wind them on a special way so the capacity is very low(please visit the Mundorf site).
For me it's a tryout but i don't think that i'm the only one who use them. My Aleph is super quiet. No hum no noise even when i put my ear in the speaker so i think the CLC filtering works well!
Also the sound is very three dimensional,detailled, musical and so on. I really love it.
The only disadvantage is the price(30-35Euro a piece).
Maybe a simple induction free power resistor is good enough...
Who knows ,i never try it.

Regards,
Johan.


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