another Aleph5 (Upgrade from ZEN)

[ARAD]

...and here is another Aleph5 clone

As an 'upgrade' project I converted two stereo ZENs into two mono Aleph5s using Kristijan's boards, new heatsinks and most of the rest of the ZENs.

The ZENs were build in '97 and worked without any problems bi-amping my Beck BK3 (4Ohm) speakers. The desire to have some more power and the daily temptation reading about all the projects in this forum got me started.

As you can see in the picture, bottom, back & front remain the same (also top), the sides are entirely new. I have mounted one FET per heatsink element (but coupled the heatsinks via a massive (40x12 mm) aluminum bar). The FETs are matched. I will take temperature measurements to check if the temperature of the heatsinks is similar. The gate resistors are soldered to the FETs. Since the Alephs have to drive 4 Ohm speakers, I followed 'wuffwaff's' direction and sure was glad that he shared his findings.

The picture shows an intermediate step - one ZEN down, one Aleph to go...

In the meantime I completed the second unit and started to listen.

My first impression is that the music is clearer and more dynamic. It seems that the speakers are better controlled - a certain 'preciseness' without being sharp or harsh is a weak attempt to express my initial findings. Listening is pure fun (especially after removing the small but noticeable noisefloor by separating signal ground from 'protective' ground via a 10Ohm resistor...).

Thanks to all who contribute to this forum - especially to Nelson Pass for sharing his knowledge and experience. I am most impressed by your patience and willingness to discuss your designs !

Best regards,
Andreas

[roddyama]

Hi Andreas,

Great job. How about some more pictures?

Happy listening,
Rodd Yamas***a

[jleaman]

Those look NICE.. great job Man.

[jleaman]

Are your powersupplys external.. Can we have a pic.?

[cowanrg]

looks like he stacked cap bank over the transformer. if you look close, its the blue thing under the caps at the front of the chassis.

Originally posted by JasonL
Are your powersupplys external.. Can we have a pic.?

[ARAD]

here is another picture of the Aleph - you are right, the caps are on top of the transformer (toroid, 300VA 2x30V). I made some temperature measurements - temperature at the heatsinks is approx. 42.5C after one hour (temperature is within 1 centigrade when measured at the same spot on each heatsink). The caps surface measure 26C at the same time (ambient temp is approx. 19 C).

Regards,
Andreas

[jleaman]

How come there are 2 transformers in one case..?

[ARAD]

there is just one transformer with two secondary windings (primary 230Volts, secondary 2x30Volts)

[jleaman]

LOOK

[roddyama]

Andreas,

How much inductance do you get out of your little toroid coils? They look so cute.

Rodd Yamas***a