aleph 1.2

:) hi guys- i am a very new newbie to this all and it's very cool! anyway- my question is- i want to build the aleph 1.2 ( its a manly thing) heh-heh! anyway i have been reading this forum for a while and i like the info and the help everybody gives. ok on to my question- the aleph 1.2 has 12 matched output devices per channel-does anybody know where i can get that many matched devices? i'm new to the electronics biz and don't have the time(read knowledge) top macth them myself! also does anybody have pcb boards for them? - ps i have visited the pass diy site and i don't see any 1.2's there, i know a couple of people have built them-why don't they post them on his site?(wow mr. Pass is such a great guy for starting that site and allowing the diy-er to build unobtainable (read unaffordable) equipment) THANKS MR. PASS- if anyone could help me i would greatly appriciate it-thanks again greg
 
The 1.2 requires 2 sets of 12 matched FET's per channel or 24 total. 48 for a stereo pair. You might be able to use some PC boards from this site: http://web.vip.hr/pcb-design.vip/ The hardest thing to obtain might be the huge heat sinks needed for the project. Do a search of the Pass forum to read about the required size. E-mail this guy for matched FET's [email protected]
 
thanks for your help! i know i'll need big heat sinks-i was going to build a 50W soz. but i saw the aleph 1.2 and thought it would be a better design! also more watts!! wow what a nightmare about matching mosfets! someone told me for every 100 i can get 10 matched? holy sh-- that means i need to buy 480 to get 48 matched! there has to be a better way!! maybe i'll start off slow-maybe an aleph 5!!
 
Not quite right, out of 144 you can get 12 matched sets of 12. The link I gave you is to a person that does the matching and can sell you the matched sets for a reasonable price. No need to go through all the bother yourself. Also, not all 48 need to be matched. You need 4 sets of 12 matched FET's. The sets of 12 need to be matched to themselves, not to the other sets.
 
hey thanks alot for your help!!!! i am new to this. i don't know too much about electronics-thats why i like this forum. i like all the help everybody give to everybody. thanks again and i will e-mail that link!! do you think i should start smaller? i want to build something that will last for a while. i want to build amps then maybe an aleph 1.7 pre-amp. what do you think?:D
 

xcel

Member
2001-09-12 3:23 pm
Almere
I suggest you try something smaller, because you've said so yourself, you're a newbie to electronics. My concern is that you going to build an amp that has a big power supply, lots of transistors, huge heatsinks and so on and so forth. All these elements will present problems (and lots of them) to the inexperienced DIY'er. I suggest you start with a more modest design, don't reach for the uiltimate goal straightaway.

I'm saying this to prevent you from frustration and disappointment, and my comments are certainly not meant to be degrading. If you still want to go ahead with an 1.2, go for it, but beware of a bumpy ride....

Xcel
 
ok here goes! first i have martin logan sequal II- electrosat/hybrid-i really love this speaker-very reveiling- my amps are b&k m-200's mono blocks. they produce about 360W into 4 ohms! they too sound good! i want more punch and detail- if thats possible? i have heard electrostats need lots of current? also i love this hobby but i don't want to get addicted like some of you ( nothing personal-just not for me) i only want to do this once! of course i haven't been exactly correct- many(read many many many) moons ago i took electronics in high school-i was good (not great/not bad) but haven't done anything since- so i figured i probably forgot almost everything. i use to solder,so i'm not afraid to do that(might need some practice)but i probably need to start smaller!! ANY SUGGESTIONS WOULD BE WELCOME- maybe aleph 5? i also have some no name speakers-8 ohm- in a di'apollo (did i get that right?) configuration. they sound very good for very cheap!! (just a note-there from canada). anyway- xcel is probably right- i don't want to get frustrated and give up!! i don't want to get in above my head-but i think from all that i have read-the aleph's are for me!!!! please if any one can help or has anybody gone through this- i will be encourgaged.. thanks alot everybody for all your help!! greg
 

Nakib

Member
2018-06-11 9:07 pm
Hello everyone!!!
After giving a lot of thought, I took the decision to build an Aleph 1.2 amp.

aleph-12.html


This is the diagram that I've found on the internet. Now here am getting a little conscious, looking at the circuit it seems to me that it will be costly. Therefore I want to protect my investments and want some help from you guyz!!!!

Question1: Will the circuit work as intended? I mean to say, is this the actual diagram of the Aleph 1.2 amp from PASS LABS?

Question 2: Looking at this thread earlier I've found that you guyz were talking about matching mosfets. Can anyone please explain further? I really quite didn't get the fact of 'matching mosfets'. My point is, how can a mosfet with the same IC number be different?

Question 3: The output devices shown in the diagram are IRF244. These devices are not available where I live. Can I use IRFP460 or IRFP4668 instead? These parts are available. ... :(
 
there are always some variations in parameters from devices of the same type due to semiconductor process variations. matching them helps by better sharing the current more equally between them. there’s much written on this topic if you search it out.

there are many suitable equivalents for these FET’s but to be asking such basic questions suggests you are new to this - it would be advisable to read widely before jumping in as the voltages, currents and energy stored in the power supply of this design are not trivial, there are many ways to get lost, to blow things up and to hurt yourself.