irfp240pbf or irf9240pbf for aleph 4

[slr 5000]

hi guys
as the tital says im going to purchase these from tech diy store for a aleph 4 project is either suitable and if so which is best

also what does the pbf on the end of the code mean ?

one more question if you please ,why does no one ever mention the aleph 4?
i hear and read heaps about the other alephs butr nothing about the 4 ,was its sound no good or is it just the forgotton brother.

im choosing the 4 becouse i already have 2x 1kva 40/0/40 toroids which seem perfect for the 4 but too much for the 2

regards sherafer

[Dennis Hui]

Hi,

For a standard Aleph, IRFP240PBF is appropriate.
(The PBF designates the part as lead-free.)

Cheers,
Dennis

[jacco vermeulen]

PB is the periodic list code/abbreviation for the Latin PlumBum, aka Lead.
PBF = PlumB Free.

The original Aleph-4 uses IRF244 TO3 N-channel MOSFETs.
IRFP240 is an N-channel, IRFP9240 is a P-channel device, all Aleph amps are N-channel only !

The Aleph-4 has an idle dissipation of 250W per channel, which is quite a lot of heat to get rid off with passive heatsinking only.
Most attention has gone to the Aleph3, Aleph5, 30 and 60 models, due to their manageable dissipation levels.
More than a few Aleph4s have been built and talked about though.

Oops, Dennis beat me to it, serves me right for taking a coffee break halfway through typo.

[slr 5000]

hi guys
many thanks for your help thats great
i just ordered 4x matched sextuplets of irfp240 from diy tech store so i guess im ok

regards sheafer

[slr 5000]

hi all
is there anything i should look out for when building the aleph 4

im using brian gt mini a boards that are populated for an aleph 5 so as far as i can tell i just have to change a few resistor values and run the 12 output devices per channel instead of 6

im going to hardwire the output stage directly on the heatsinks so i wont need to get output boards made and will be using 4x conrad mf sinks that are 350mm long and 150 high per channel

the toroids are 1x 1kva nuvotem 40/0/40 per channel and aussie amp psu3 with 90,000mf per channel so 180,000mf toptal for the stereo amp

ive noticed that the mini a i have (built by a forum member stones) thanks mate have r19 omited which as far as i can tell increases the bias to max

should i fit this resistor for the aleph 4 or is it ok to leave it out still

any advice or help would be much appreciated
and also any impressions about the aleph 4 sound

regards sheafer