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folkeb 18th July 2006 11:36 PM

A baby giant is borne...
At last - after a lot of hassel we connected the Aleph 1.2 and fired it up. It is not finished. Actually, we only tested it up to 25 volts. The resistors (25 w 0,3 ohms) seemed very varm so we didn't dare up the voltage. But anyhow - we connected the amp - as of now occupying the whole living room - to a set of cheap speakers and flipped the switched. (Had checked for DC (0v) and 10k input). Music for all to hear!!! It is still a long way to the end, but at least the amp does play music. To early to say anything about the sound as I only have one amp running just over 1/3 of the rated voltage. The bass was deep, but it seem all a bit forward. Shouldn't even think about the sound yet!!

Still remains the issue of harnesing the voltage and keeping it below 60 volts. (see my other thread).

Good night and good luck to all - I'm one happy guy :D

folkeb 19th July 2006 07:06 AM

I'd thought I post some images of the test setup:

I know it looks like a mess, but it seems to work.

VT67 19th July 2006 11:37 AM


That amp is coming along nicely.
I have the same coark coasters (pic DCS_0155.jpg), didn't knew they were audiophile stuff! Gonna try them in my amp too:D


amelecsol2000 19th July 2006 12:01 PM

Watts rms ?
Just curious, how many watts (rms) are you pushing with this ?
I am building a 200W rms guitar amp for my son, am working on the pcb,s now. Power supply is done.
Your project is looking real nice.

folkeb 19th July 2006 01:38 PM

The Aleph 1.2 should be 200w pr channel(8ohms). It will be slightly less as I plan to reduce the voltage to about 58, instead of 60v. Each monoblock will draw just under 500w from the socket.

jasonlky 19th July 2006 05:12 PM

You are my inspiration. Its time for me to get off my butt and return to building my amp. In this day and age of Xs, XAs, Aleph Xs, ZENV9s.... its nice to know that there are still some out that that hold on to the original Alephs!

I am so glad that you have solved your other issues quickly. Have you done the calculations to determine the correct wattage for the resistor? As I also have the similar 25watt 0.39ohm Arcol resistors for my CRC filter.

folkeb 19th July 2006 07:01 PM

Thank you for your kind words. I have just tested the Aleph with 59 volts on the rails and 229 on the variac. This was with one 0,3 ohm resistor in the system. So I am getting close. I hope that one more in series will do the trick.

The sound:

It is not easy to evaluate the sound from one channel, but I will try. The bass went a lot deeper and was at the same time slightly more punchy as well as a lot more detailed than my Electrocompaniet 250R power amp. The midrange seemed very nice indeed and the top end I can't realy say anything about. Stereo was obviously not too good... It seemed to be a lot more rythm to the music.

After about 30 minutes playing the heatsinks were warm, but not hot as I expected. Maybe they need longer to heat up, or I have bought over the top heatsinks (maybe a combination of both). Anyhow, this is good as it enables me to place the amps out of harms way and eyesight (not mine...)! I have even bought 12 fans as precaution, no need for them anymore!!

The other problems will be solved, of this I am sure. It may take some time . I'll write more on this in the more techy thread I have going.

steenoe 20th July 2006 08:52 PM


The Aleph 1.2 should be 200w pr channel(8ohms).
Just to make sure; the 200 watts of an Aleph amp is rated at Single Ended Class A! That spell's: monster-amp!. A 200 watt guitar amp is next to nothing in comparison;) You can have those in any Discount-supermarket!! Hats off to Folkeb:) Quite impressive job!


moe29 21st July 2006 01:49 AM

...i was thinking those heat sinks don't look big enough! :)

if they stay reasonable after one hour of warmup you should be ok!

(reasons i stayed away from Aleph 1.2)

- way too many holes to tap for FETS!

- way too many FETS to match!


good job folkeb!

folkeb 21st July 2006 08:44 AM

The C/W ratio for each amp is 0,06. The heatsinks aren't your regular heatsink, they have ragged fins that greatly increase their efficiency. They should be sufficient. But then again....

The heatsinks are Fischer SK535 (500mm x 200mm x 85mm).

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