MTW35N15E mosfet in Aleph?

[2002tii]

I have a lot of this Mosfet (840pieces...).
Can I use it in Alpeh amplifiers?
(or any other amplifier)


Datasheet:
http://www.onsemi.com/pub/Collateral/MTW35N15E-D.PDF

 

[Nelson Pass]

I think it'll work, but it's a big chip, I would say equivalent
to 2 of the 240's in the original.

I would consider using fewer of them in parallel than
240's, in light of this and their higher input capacitance.

 

[2002tii]

That`s great!

I noticed the higher capacitance, but was not sure what the consequence would be.
I also noticed lower voltage range, but it`s still high enough for Aleph.

Since I have so many I can match them quite easy.

Sometimes it pays of working at a electronics manufacturer😀

Thanks for your answer.

I really like what you are doing for the DIY community.
Makes me hope that I someday can give something back.

 

[Hamish]

other alternatives

Hi all,
i am gathering together parts to begin my first diy amp (an Aleph 5) on a paupers budget. i was wondering what the cost of the irf244 mosfets is overseas. if these are costly😱 (i am STILL waiting for prices in Aust.), are there any other cheaper substitutes that anyone can recommend? (it will be updated as funds allow).

thanks also to Nelson for allowing us his designs
a great sound and the satisfaction of having built it yourself is completely irresistable😀

 

[UrSv]

I think IRF244 is going to be hard to get. Most people use IRFP240 and that you can get from Farnell Australia and from RS Components.

RS sells them at AUD 10.11 at quantity 1, AUD 6.67 at quantity 25 and at AUD 5.77 at quantity 100.

/UrSv

 

[Hamish]

UrSv,
thanks. i've been trying to find irf244's. that should make it alot easier. and cheap too!

i know this is off the thread, but how would you use a single toroid for the power supply, and what sort of rating would you recommend?
🙂

 

[UrSv]

For the supply question the answers are in numerous previous threads.

Try the search.

/UrSv

 

[Hamish]

another silly question

i've since decided to build an aleph 3 (much cheaper and better first project). i've also found out that the electrical store at uni has bulk quantities of irf520v which they gladly hand out free. would these be suitable for an aleph? it looks like i might have to run twice as many, but i'm no expert on this. as they are free and a bottomless supply, i'd really like to use them.

any opinions?

 

[Andypairo]

I think there should be no problems related to gate charge, but you should take in account not only the maximum current but also total power dissipation. IRFPs can dissipate almost three times the device you want to use, but I think that 4+4 devices per channel can be enough. You can also go for 6+6 but it's probably overkill.

In Aleph 30 there are 3+3 IRFPs per channel while the power rating of the amplifier is almost identical to Aleph 3.. so you have to choose the "stress rating" of each mosfet and then use as many as you need.

Regards

Andrea

 

[Cobra2]

Hi.
I have been thinking of building a Aleph 1,2 and use MTW35N15E mosfets.
As I understand:
I can get away with half the number of these mosfets, compared to the original 24pc. IRF244/IRFP240 (pr.channel)?

What other parts need to be changed? (not thinking of the "removal" of "surplus" resistors).

Arne K
NORWAY

 

[Andypairo]

If you plan to use the half number of mosfets you should also half the value of source resistors, or simply use 2 in parallel.
This way you have half tolerance for free.
The voltage value on these resistors is the same as with original devices, since thay have half value but double current.

Regards

Andypairo

 

[Cobra2]

Different mosfets

Would it be a problem using different mosfets for gain and cc?
-If I my understanding of the amp-circuit is right, we could get away with much cheaper/less audiophile mosfets for the constant-current stage?

Arne K
NORWAY