High hfe 2n5133s???

[Giglawyer]

A few years ago, I ordered some 2n5133s, so that when I "had time", I would get to building a proper Ram's Head Big Muff.  Well, I have had the board populated for a while, and and am soon going to do the finish wiring and box it up.  On an off chance, I saw some other posts on 2n5133s, and saw that the hfe for these should be in the 50-100 range, but that many people were using other transistors to get a higher hfe and more gain.  On a whim, I tested the hfe on my 2n5133s (which bear the Motorola "M" and were purchased form a reputable dealer, I think). 

Strangely ,the 4 tested were 334, 367, 389, and 407.

Huh?

EIther I am testing them wrong, these aren't really 2n5133s, or something else is going on.  I am excited to hear how they sound.

Any thoughts?

[Giglawyer]

On a side note, these are in the "metal can" transistors, not the TO-92 plastic ones.

[duck_arse]

well, I  wuz gunna say check the datasheet, but they are hard to find. so, read this, instead ....

http://www.diystompboxes.com/smfforum/index.php?topic=46281.0

[Giglawyer]

So I could be insanely lucky?  LOL...

I should have taken a picture, but mine look like this: 



And I am assuming the E-B-C layout as related to the tab on the case is the same.  Could it be different?

I really have to get this boxed up and tested now...

[smallbearelec]

The factory spec for the 2N5133 was Hfe 50 minimum, which means that it can be Anything above that. All the old-stock parts  I have seen are epoxy "dots",   but it was made by so many shops that I'm not surprised that you found a TO-5 can version. Many people prize the high-gain lots, so enjoy your build.

[Giglawyer]

Thanks.  BTW, I don't know if mine are actually a TO5 build.   This is a better image of what mine look like, except mine don't have gold leads:



Again, I assume the tab marks the emitter lead.

[smallbearelec]

Thanks.  BTW, I don't know if mine are actually a TO5 build.

That looks like TO-18, and you say it has the Motorola "M". Yea, probably good stuff. BTW: If you want to try some of the kind of parts that EH was using back-in-the-day, I have found numerous Fairchild and National "Dots" that hit gains of several hundred.

http://www.smallbearelec.com/servlet/Categories?category=Transistors%2C+Bipolar+Si+%26+Unijunction%3ATO-106%2C+TO-109+and+TO-110+%22Dots%22

[Giglawyer]

Thanks for the info!

[Giglawyer]

BTW:  Just received my latest order from Small Bear in RECORD time.  Thanks for the excellent service.

[CodeMonk]

I've got a few NOS metal can 2N5133's
IIRC, they had hFE's of around 500.

[PRR]

> factory spec for the 2N5133 was Hfe 50 minimum, which means that it can be Anything above that.

A sheet I found (from a secondary supplier) shows:
Min 60
Typ 220
Max 1000 (all at 1mA 5V)

Typ 50 (at 50uA 10V)

Also 20V and 60MHz.



I agree that this says "more than 60" for all practical purpose. (If any significant number were really hFE near 1,000 they would sort-out and sell these at high price.)

The Gregg-observed 330-400 numbers are "better than typical" but not enough to matter in any well-behaved circuit.

[Giglawyer]

At this point, all 8 of the 2n5133s I have test between 300-430.  Should make for a nice Muff, I hope.