different hfe's on these transistors

A good electronics engineer will design his circuit to tollerate worse case parts. The spec says hfe can be as low as 40 or 30 and yours are higher than that so you should be ok.

I forgot.... sometimes it is necessary to use parts with a specific minimum hfe. Normally in such cases the designer will specify you need the C version of a transistor. For example they will specify you need a BC109C rather than just a BC109....however this is very bad practice. It's much better to design out the need for a specific hfe.

So you are saying that all your transistors are within datasheet limits.

hfe is not a very well controlled parameter (typically varying over a

Johan Wagoner: Your actual test results of the transistors were well within the manufacturer's specified range that you posted. If you need matched pairs for push-pull or parallel circuitry considerations then you can use selected transistors based on the results of your tests, otherwise they all meet specifications.

-- Best Regards, Daniel Sofie Electronics Supply & Repair

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They're in spec.

Depends on what you need.

Decent circuit designs are beta-variation-tolerant. Fixed base current linear design is called "suicide bias"... some transistors may work, and some may not. Design to work over the transistor's spec'd beta range, or worse.

John

This is for use in the leach amplifier.

I never heard of CDIL, but that markings usually screams "GENERIC"! Didn't you got them for good price? If so that's the reason and and are faked.

I got few stuff made by NSC and few of them looked real and had correct brands too marked and I don't trust them either because of too good to be true prices.

In audio stuff, close hfe values usually is preferred to get smaller

The large transistors made for high power audio stuff are in 20 to 40 dollars range not 5 bux range that generics abounds.

Cheers,

Wizard

Hfes from one transistor lot should be close. Variations are to be expected between lots. That's why the range in the spec is so high. If you want them close, you will pay extra for it. And most likely the mfgr will just select them for you.

As an example, years ago, we tested a large lot of resistors of one value we had purchased. The purchase tolerance was +-5%. Yes, They were all in that range. But...there was a big hole in the plot at +- 1%. It looks like the mfgr had separated out all the resistors that were +- 1% from the lot and sold them as such. We got he +- 5%, which is what we had asked for. We were too stupid to specify a normal distribution in the resistor values.

The same will hold for almost any component you buy.

Al

Oh, audio. In that case, all rational design considerations are void. File the corners off the packages or dip them in red wine or whatever makes it sound best.

John

ROTFLMAO!

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

Yous guys should start circulating a claim among the audiophiles that only amps and other audio electronics sound excellent if they were designed and drafted with pencil and drafting board. Any audio component won't have the right sound if it was designed with a lowly computter program!

What do you mean start circulating a "claim", it's TRUE ;-)

...Jim Thompson

The best audio interconnects are gold-plated, custom-bent hardline coaxial cables with SMA connectors.

John

Not necessarily so!

I had a fellow working for me that bought a Heapshit Preamp Kit many years ago.

He didn't like the looks of the audio coax included with the kit, so he substituted some nice ultra-small diameter teflon cable (shielded) that we had in the lab.

Bye, bye, high frequency response.

...Jim Thompson