Aleph-X: High-Power Version

[grataku]

Macka,
-varnish- is what I meant, but anyway it sounds like you got that covered.

[macka]

This bunch of posts should be titled Retro Fitting The X Aleph to the Aleph but who cares, I just think everyone should be aware it's not that hard.

One of my 1st considerations was to determine if the exisiting matched fet sets for the Aleph 2 (2) x (6) , tested at 0.5 amp each, would still be a match for 1.00 amps for my design.

So with my trusty 22 volt lab supply (actually an unused 15 watt JLH supply regulator...(Mr Pass will growl at Me)) I carefully tested all the fets. To do this I made a jig so that I would not have to remove each fet from the exiting heat sink.

This entailed lifting one end of each of the 1.00 ohm source resisters from the board and carefully shorting the gate to drain of each fet with a bunch of crock clips. With a big precision 18 ohms resister in series with the drains all I had to do was touch the negative side of the test supply to the source on each of the fets (IRF 244's) individually.

Well, much to my relief the match was surpirisingly good, within 0.03 VGS, so a guess transconductance of this lot was quite similar!!. Typically I got a VGS of 4.85.

All that remains with this phsse of the project is to mount the additional parelleled source resisters to get 0.50 ohms, cut the tracks on the middle of the board for the gate , sense, source and drain to create 4 sets of 3 fets and Bob's your uncle (sorry Karen...not your uncle Bob)

( I have already done this for one channel)

regards

macka

[macka]

Oh, by the way.

While writing an Ombudsman complaint about my F@#$%^*( Gas supplier who has overcharged me $500.00, it occurred to me and no doubt many of you, how on earth would the chokes referred to above have measured up okay if I used un insulated wire.

I might be stupid, but I'm not that F^%%$## stupid..

Need I say more

Don't worry Grataku...we all Love ya. Muhahahaha

macka.

[macka]

Here is the modified power board for the X Aleph.

Note the 1 watt power film resisters (2.2 ohms), they were the only value readily available to reduce the value of the source resisters to 0.5 ohms.

I have also carefully cut the tracks using a small grinder wheel on my PCB drill.

I have also dressed the boards with new leads, colour coded to avoid potential mistakes.

macka

[macka]

Here's the old Antrim transformer from the Aleph 2, 1000 Va 35+35 Antrim.

You need a huge Iron to solder those wires (double secondaries)

I am not sure what to do with it, door stopper?,boat anchor? tranni for a potential X Pass amp?, or I may post it the the trading post, dont know yet.

macka

Her indoors would kill me if she saw that sucker on the dining room table... Muhahahah

[Taco]

Good work Macka you're working fast . But do you need the extra power of the larger X? You have very sensitive speakers I thought.

/Taco

[Andypairo]

I wish I had the time (and the space!) to complete my projects.... (Aleph X - Pass Xover as soon as it will appear - My loudspeakers....)....

Cheers

Andrea

[macka]

Thankyou,

Well it all happens late in the day....about 12.00 am!!

The new projects coming from Mr Pass are the reason for a move on.

I can't wait to see the Remote Pre amp and the Passover.

Yeah, that would be a big X Pass but they all are, and if I was to get way laid (poor choice of words) by that Gal, then I may have to consider smaller speakers of lower sensitivity..more waff friendly and a big amp like that would be real nice.

Beside, by then I could be making other things (hint hint) in the wee hours of the morning...a terrible thought...Muhahhaah

macka

Ps I anticipate at least one jealous email by morning!!

[macka]

Oooooops,

I hear a knock on the front door.......wait a sec Guys.

Oh know.....stung bad, Time for Bed I'm told.

bye for now

macka

[grataku]

Since many think that I am a "drop kick" whatever that is, let me take the full blame for this recent BIG misunderstanding.

-I am the stupid one-

I just thought they invented a new type of wire that was treated in some way as to render it insulated but without requiring the excess layer of combustible varnish.
In my work I see new type of materials I didn't know about on a daily basis.