Aleph 5 playing...

[Mark A. Gulbrandsen]

Then when you are all done with your amp and you think it sounds great , remove R-19 and things get about 5 times better! Be careful of the extra heat dissipated though!
Mark

[Lucas_G]

Originally posted by Duck-Twacy
(Sorry Lucas for the offtopic, you better post a new pic of your Aleph soon )


II)
With a bias of 3A it will dissipate 234 watt a channel and result in 76 watt/8 ohm. This requires 0.66 ohm resistors at the fets.

Anyway, this is a problem because I already bought 12 1ohm Vishay-Dales costing around 6 euro a piece.

Btw What will it mean for the 0.47ohm resistors at the output?? (Aleph5 has 4 in parallel, Aleph2 en 4 have 6 0.47 ohm resistors)

Btw Did I mention that I wil use a CLC filter using 4 2.2mH tritecs (with 0.24ohm DCR). This will influence the voltage I guess.

Hi Duck,

I have made some better photo's with the sides attached; now the ugly duck has found out it's a....
But it will take some time to develope/print these and scan them

Furthermore it was I who sidetracked this topic, so never mind!

Wow, these Dales cost 6 Euro a piece ?
You could of course put less pricey Intertechnik 4 Watt 2 Ohm MOX resistors in paralell with them. This wouldn't sacrifice the good sound of the Dales, bercause they still handle 66% of the current. The MOX are also quite good and precise and they cost only 60 Eurocent a piece.
Just go for the 0.66 Ohm, because it also means more efficiency.

Yes, you should go fot 6 time 0.47 then.

The Tritec are beauties! Almost too nice to be put in a PSU...
Maybe you should put a glassplate on top of the amplifier with some nice led throwing light on these coils...

With 0.24 Volt you will probably get a voltagedrop of about 1 Volt (I get 0.5 Volt with a 0.14 Ohm choke), so nothing to worry about.


Regards,

Lucas.

[Lucas_G]

Originally posted by Mark A. Gulbrandsen
Then when you are all done with your amp and you think it sounds great , remove R-19 and things get about 5 times better! Be careful of the extra heat dissipated though!
Mark

What do you mean with removing R19? What happens?
How much extra heat?

Lucas

[Duck-Twacy]

Originally posted by Lucas_G


Hi Duck,

I have made some better photo's with the sides attached; now the ugly duck has found out it's a....
But it will take some time to develope/print these and scan them

Furthermore it was I who sidetracked this topic, so never mind!

Wow, these Dales cost 6 Euro a piece ?
You could of course put less pricey Intertechnik 4 Watt 2 Ohm MOX resistors in paralell with them. This wouldn't sacrifice the good sound of the Dales, bercause they still handle 66% of the current. The MOX are also quite good and precise and they cost only 60 Eurocent a piece.
Just go for the 0.66 Ohm, because it also means more efficiency.

Yes, you should go fot 6 time 0.47 then.

The Tritec are beauties! Almost too nice to be put in a PSU...
Maybe you should put a glassplate on top of the amplifier with some nice led throwing light on these coils...

With 0.24 Volt you will probably get a voltagedrop of about 1 Volt (I get 0.5 Volt with a 0.14 Ohm choke), so nothing to worry about.


Regards,

Lucas.

Can't wait to see them. Did you play it a little longer? I was wondering why the red copper strip. Is it better then sticking the mosfests directly on the heatsink? Would you also do it if you would mount the mosfets p2p?

And the Seiferts are still cool enough? Its getting warmer outside

By the way what speakers are you using?

Anyway as for my amp. I guess I will attach al 8 mosfets, but maybe I start with a standard Aleph5 (so use only 6) and look what happens. I just am a bit to much a noob in electronics to redesign it to 8 mosfets (anyway if I would do that I would probably want to to it in the best way, so I would excange my trannies for higher voltage if neccessary and use different resistors if that is best. Will lose some money on that I think.

First I ordered Caddock resistors, but they took > 2 month delivery time and had a minimum order of a 100 or so (which is a bit expensive, given that they cost almost 10 euro a piece). The electronicshop than selected these Vishays which should be equally good (he said). I still havent got them, but they arrived at the shop.

The tritecs are in stead of torobars. I had already paid for the Caddocks and torobars before I heart the Caddocks were a problem, so I had some money to spare

[Edwin Dorre]

Originally posted by Lucas_G


What do you mean with removing R19? What happens?
How much extra heat?

Lucas

without R19 you are not limiting the amout of bias which the transistor sets. It will be a maximum based on the Hfe (a transistor parameter) of the transistor. So it will not blow out of the roof, however it will raise the bias out of my head between 10 to 40% ...

Edwin

[Mark A. Gulbrandsen]

It raised both of my 2's to about .68 volts drop on the source resistors. My sinks were about twice the amount of the factory units, perhaps even a bit more than that and they were coasting as fas as heat was a factor...now they are toasty warm....I can keep my hands on them for about 15 seconds max! Still not hot enough to fry an egg though so I doubt that I'll have any semiconductor problems for a long time. I ahve not measured them with my TEK DMM temperature probe but I will and get back to you on actual device case temp and sink temp.

Interestingly, a guy came over to hear them that designs loudspeaker systems professionally and he thought they sounded fantastic with the bias giving .55 volts drop.....they now sound far more detailed and are more involving than they were. He is ging to build a tri-amped system for himself using all Aleph amplifiction.

Mark

[Lucas_G]

I promised to post some more pictures with the (wooden) sides and (alu) top and bottom attached.
The only thing still missing are the frontplates which will be professionally made and inscribed.

Here is a view on the backside:

[Lucas_G]

Here a little closer:

[Lucas_G]

Here from the right side:

[Lucas_G]

Here from the left side: