Transistor question: IRF9610 vs SFP9610?

[PolishedSteel]

Hello, finally the first part of my components for an Aleph 5 arrived, including 20 pieces of 9610 series Transistors. Now I actually specified IRF9610s and made the comment on my order that I'd love to have them from the same lot, but in any case from International rectifiers, but what I actually received were nevertheless Fairchild SFP9610. My question now: Are they also suitable for use (of course they are in a technical sense, since they are the same transistor type, but what about the musical qualities?), or should I return them without looking back?

Thanks a lot in advance,

Chris

 

[Nelson Pass]

My experience is that the Fairchild P channel devices are superior
to the IR (and seem to be equivalent for N channel). I don't see
any reason you shouldn't use them.

 

[PolishedSteel]

Ok, thanks a lot... So I think I will start to get into the business of matching them now!

Chris

 

[wrenchone]

Nelson, are you referring to the "funny" (we're not laughing) linear region behavior you documented for some of the IR devices? Is this behavior unique to IR?

 

[flg]

I thought I had a bk-mrk of that thread, the exchange with N.P. and a couple other "Guru's" of the subject... Very interesting reading. I'll look more later.
I have never heard an IR 610 part I always get Faichild... If I remember correctly, the gain of the Fairchild 610 is a tad higher and C a tad lower??? Everything I ever expected, always worked just like I expect. Or maybe more correctly, Just like N.P. said... But I also wonder about the P ch weirdness thing??? I have a few of those 9610s still in a bag...

 

[Mad_K]

I have used Fairchild SFP9610 for Aleph 3, and they worked very nicely

 

[Nelson Pass]

Nelson, are you referring to the "funny" (we're not laughing) linear region behavior you documented for some of the IR devices? Is this behavior unique to IR?

Yes. The IR P channel parts have a slightly odd gain shelving
behaviour. It's not a big deal, but the Fairchild and others
don't have it, so they get the nod in Common Source applications.

 

[yup]

Well, now the Fairchild part has been discontinued...

They list the FQP3P20 as a replacement. Unfortunately I do not have the ability to measure the frequency response of this device.

Can anyone make any reccomendations or have any experience with this part (or another brand)?

I am building the Aleph-x with the 044's (slightly dark top end), so I am guessing that the frequency response of the IRF9610 is not a good compliment.

Thanks,
Jeff

 

[Nelson Pass]

We used them successfully for years, but the Harris or
Fairchild versions have proven to have a little less distortion
as input devices. It is not at all a given that the amp will sound
darker.

This could change at any time if IR changes its process, as
no other mfr seems to have this phenomenon on what are
supposed to be the same parts.

 

[mpmarino]

On the same topic I grabbed a tube of IRF9610 with the Samsung 3 star logo (-Korea-) a while back.

Junk?

Edit: Oh, a quick search turns up that Fairchild bought the semi stuff from samsung ~1998. All good I guess.

 

[yup]

FYI

Mouser now has some inventory of the SFP9610 parts...

 

[metalman]

Originally posted by yup
I am building the Aleph-x with the 044's (slightly dark top end), so I am guessing that the frequency response of the IRF9610 is not a good compliment.

I built my Aleph-X monoblocks using the IRF9610 for the input differentail and 044's for the output FET's, with +/-15V rails and 5A (total) bias, and it is not in any way dark sounding. IMHO The IRF9610 / 044 combination makes for a spectacular sounding amplifier.

The "darker sounding" reference needs to be taken in the strict context of when being compared directly against an Aleph-X built with 244 output FET's. The difference is very subtle, and may be due to the higher voltage and bias across the output FET's, or to having more devices paralleled, as to the output device type.

Cheers, Terry

 

[GRollins]

I was sent an Aleph 3 by a generous member. On listening to it, I noted that the two channels didn't sound the same. So there I was, wearing a puzzled frown, trying to figure this out. Nothing would do but to crack the case and see just what the hell was going on. B'gosh and b'gorrah, the output devices were different. One channel had (I think) IRFP260 and the other had something entirely different--they were IRF parts, but with wildly different voltage and current ratings, not to mention capacitance.
I won't bore you with the whole thing, but the punchline was that I preferred the treble on the channel with the higher capacitance and not by a small margin, either. I was looking for my notes as to what the devices were the other day, as I'm trying to select a device for a project. Couldn't find them. They'll surface again one of these years.
The moral of the story is: Don't be so sure that you know what you want. The numbers aren't the whole story.
(And '044s don't sound half bad...I've used one or two of them...ahem...)

Grey

 

[MikeW]

IRFP254

 

[GRollins]

Is that what it was? Cool. Saves me from having to dredge around and find those confounded notes. Thanks.
(For those who aren't adept at reading between the lines, Mike was the generous member I mentioned.)

Grey

 

[GeorgeBoles]

IRFP254 ...

Hi Grey and MikeW,

I had an order in with futurlec for IRFP140N (they were cheap +++ and the spec were good) but they were out of stock However they do have some IRFP254, and IRFP150N. I was thinking about getting the latter.

Now the question is: was the IRFP254 the "good" channel or the "bad" channel when compared to the IRFP260?

To save you dredging your data bank:

254 input capacitance = 2040; g fs = 15; r ds (on) = 0.125 ohms
260 input capacitance = 4057; g fs = 27; r ds (on) = 0.04 ohms

By the way, how important is r ds (on) if it is SO FAR away from the normal of the mosfets we generally talk about?

(The attraction of the IRPF254 is its price ... $1.75 down to $1.35 for 100.)

I will probably go for the 150N as it is well trusted, unless you advise otherwise - going to play with Babelfish J (similar to aleph 3) and Babelfish J - X'ed ...

The other technique, as you always suggest, Grey, is to build it annd see!

Regards,
George.

 

[Nelson Pass]

One channel had (I think) IRFP260 and the other had something entirely different

I am presuming that this was a DIY version of the Aleph 3,
as we have never used other than IRF244 in that product.

 

[GRollins]

I am presuming that this was a DIY version of the Aleph 3...

Unquestionably.
It was from MikeW. I imagine he hit his 10 amp limit and needed to lighten the load. So in comes a box with heatsinks for front and sides, thick metal for a partial bottom (just think of it as improved ventilation), and plexiglas for the top and back. I've been slowly modifying it as time permits and ideas strike me. At the moment, I have a backlog of Evil Experiments to be performed on the poor thing, as my imagination has ranged far ahead of my available time.
Bummer.
On the bright side, everything I've done so far has turned out okay.

Grey

 

[Nelson Pass]

Yes, I know the ones.....

 

[Samuel Jayaraj]

Gray, if you are looking for IRFP parts, why not have a look at IRFP264. The specs are far better than IRFP 260, 460, 450, 250, all of which I have used.