Problem Aleph 2

[jeclk]

I have a problem with the aleph 2 construction has verify several times. I manage to make function the amplifier with 2 240 of each dimensioned, it functions perfectly but when I start to add a transistor of each with dimensions,no walk more, I have a rise of voltage in HP.
the construction PCB :it's PCB Wayne Sankey
idon't undestand
thanks for all.

[Nelson Pass]

Please clarify what you mean when you use the
word "dimension".

[jeclk]

I carry out the test with 2 "240": 2 on the left and 2 on the right. and it functions well. but when I add transistors, I then have much voltage in the HP I am completely lost.
thank for infos
sincerely
escuse my english
it's very difficult for me

[nar]

I help,because jeclk has mailed me several times to get rid of the problem.

So here's what's happening:when powering up with the 12 IRFP240 hooked up,seems he has

1) 9.83 V on the 392 ohm driving the gates of the 240 outputs
2) a high offset rising at HP outlet,like 30,40V very fast.

When he stays with 2 IRFP240 for the CCS and 2 P240for the output stage,with the Sense pins linked to the whole circuit,seems to work well and produces music.

This seems hard to understand !!!

So Nelson,what do you thik it should be?

For me the CCS of the differential and differential itself work well,he got good measures on the 392 ohm drive and on the CCS 9610 resistor 221 ohm between V+ and source pin of the mosfet.

Thanks for help Nelson !!!

[Nelson Pass]

Sounds like either a bad device or a bad connection.

You should be seeing about 4.5 volts or so across the
392 ohm resistor, so the front end is proably driving
the negative power gain devices at maximum, trying to
lower the output voltage toward ground.

This would imply that the current source is driving far too
much current. It might be broken, misconnected, or oscillating.

Got 220 ohm resistors on every Gate? What is the value
of the Source reisistors and the DC voltage across them?

Oh, and get yourself a Variac.

[jeclk]

I do not know what it occurs in my assembly. however I assembled the alph2 correctly. I go tested the PCB of BrianGT.
I changed the 9610 and the ZTX450, but that still does not function.
thank for all

[nar]

Salut jean claude je pense qu'a ce stade si tu as essaye un autre PCB et que ca ne fonctionne pas,c'est peut-etreton alim qui n'est pas branchee correctement.N'oublie pas que l'alim est symetrique,alors que sur le Zen le cablage est plus simple:+ et -

Je pense que tu devrais utiliser un pont 25A/400V tout fait,et cabler comme il suit

transfo 4 fils.2 enroulements.
1er fil du 1er enroulement au symbole alternatif du pont.
2eme fil du 1er enroulement:ne va pas au pont.est relie au 1er fil du second enroulement.Ces 2 fils relies constituent la MASSE generale du montage,donc relier aussi aux condos de filtrage

2eme fil du second enroulement va a l'autre broche AC du pont

Le + du pont va au + du montage,du + il y a ton condo 33.000 broche +,l'autre a la masse

Le - du pont va au - du montage,du - il y a l'autre 33.000 broche -,broche + a la masse

Ta masse alim va a la masse PCB.

Voila.

Si ca marche tu peux tirer,la tension ne va pas varier avec le jus que tirent les 240 X 12

J'espere que ca aide.

Anael