Aleph 5 Help

[PedroPO]

Need some help.

just finished my aleph 5 with Kristijan Boards.

Problems:

very low sound, heavy distortion.

no hum.


The irfp240 fets don't heat up - what is supposed to be their terminal voltage?

only the irfp9610 get a bit warm

I've got 34V on each rail, IRFP240 and ZTX450 instead of MPSA18.


didn't mount the led.

all other components are like the schematic.

Is there any test to find out the fault?

Should I try out the other channel?

thanks,

 

[jleaman]

i would like to know them answers too as i have a aleph 5 soon to be powered up..

 

[PedroPO]

never mind!

I confused R17 221k with 22k.

dam red stripe look alot orange

my baby has run now for 3 hours.

It looks ok.

the fets are at 57ºC ( hey Peter Daniel hit the spot in that!)

the sinks are at 49ºC.

looks good I guess.

When I build the other channel I'll post another pic

 

[jleaman]

so how did yuo solve the problem just let it warm up ??

 

[Mad_K]

Hi!

I am also building an aleph with Kristijans A5 boards -they are really nice!

Only I am doing it as an A30 because of my powersupply
(+/- 25V).

I've had lots of problems, but they where caused by me.

Waiting for new parts now

Try to measure all the voltages from the A5 service manual, and tell us what you get. There is a fault in the manual; there should be something like 0,66V across the source resistors.


Maybe then we get a starting point for fault finding

-careful with those probes

 

[Mad_K]

Congratulations!

May we get your voltages anyway?

 

[jleaman]

PICTURES

PICTURES

PICTURES

:O)

 

[PedroPO]

pics tomorrow when the hole amp is on.

you can see a preview in


http://www.diyaudio.com/forums/showthread.php?s=&threadid=6712&perpage=15&pagenumber=3

volts tomorrow too

 

[jleaman]

you should email me some photoes pedropo

jleaman@citytel.net

im thinking about making a webpage about aleph amps..

 

[roddyama]

Good Job Pedro,

Keep us informs of the progress.

Rodd Yamas***a

 

[protos]

Are you sure your fets measure only 57C? You should not measure the plastic case but ideally on the metal tabs on the two sides or alternatively on the middle pin. Mine as I mention in a related thread are well into 90C.

 

[skaara]

Great job pedro!

So its ok if I dont use led in my aleph2 which Im building?

 

[kristijan-k]

Hello skaara,

The LED and the 10 K resistotr, which is in the series
with the LED, are serve only for visual indication
that the amplifier is ON.
They can be leaved out without problems and any
serious sound degradation.

Best regards,
Kristijan Kljucaric
http://web.vip.hr-pcb-design.vip

 

[PedroPO]

here are some other pics of my incomplete aleph 5

the first one is a side view.

there you can see the PCB the caps, trafo, bridge and on/off relay.

 

[PedroPO]

here is the place where I put the Thermo probe.

It was the hottest place I could stick it. 57ºC

 

[PedroPO]

In this one, the bottom sink is the coldest of them all.

after 3 hours of operation, it became about 35ºC

the other two were at 49ºC in the pcb side. the opposite side was 40ºC or so.

 

[MikeW]

Heat

Beautiful amp. The reason the bottom sink is staying cooler is because it is the farthest awy from the heat source. The heat can only get there by traveling throuh the the connecting bars and where the sinks touch. Try putting some bars vertical along the heat sink seams. Aluminum if you have it. Good luck, Mike.

 

[nar]

Hey PedroPO where did you get those super-sinks?
Do you know their thermal resistance?

Regards,

Anael

 

[kristijan-k]

Hello nar,

Those heatsinks can be founded at :
http://www.fischerelektronik.de
They comes in bare aluminium or black eloxated.

Best regards,
Kristijan Kljucaric
http://web.vip.hr/pcb-design.vip

 

[nar]

where to order them? ....PLEASE