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Author Topic: FET selection BC264  (Read 5301 times)

electricpress

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FET selection BC264
« on: August 02, 2015, 10:56:20 AM »

Hello Klaus

I was reading about the FETs you have found to be good starting points in place of the 2N3819. I cannot find any Texas Instruments 2N3819 and have tried other makes with varying degrees of success and noise.
You mentioned the BC264 was up there, I was wondering which version? BC264A, B or C?

Kind regards,
Mark
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klaus

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Re: FET selection BC264
« Reply #1 on: August 03, 2015, 04:04:37 AM »

Correct, T.I. 2N3819 are obsolete. But Fairchild has recently taken up production of that FET and, so far, I like their 3819. I have only had a couple of less than perfect ones (they would not properly bias up) but that has been the exception to an otherwise very reliable series at an affordable price.

(I don't use the BC264 anymore, but will check which version suffix I used and post it here).
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Klaus Heyne
German Masterworks®
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mwurfl

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Re: FET selection BC264
« Reply #2 on: August 27, 2015, 06:41:38 PM »

I just checked both Digikey & Mouser's websites, and both indicate that the Fairchild part is "obsolete," and unavailable.  Instead, they both only show that a version from Central Semiconductor is available.  Klaus, do you have any experience with the Central part?  Or, any idea where the Fairchild part is still available?

Thanks!

Mark
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klaus

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Re: FET selection BC264
« Reply #3 on: August 27, 2015, 09:02:22 PM »

You are right. It says on their home page "obsolete as of 2012"
I guess Neumann bought them all up???
How many do you need?
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Klaus Heyne
German Masterworks®
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mwurfl

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Re: FET selection BC264
« Reply #4 on: August 28, 2015, 12:06:55 AM »

I'd be more than happy if I could even get six (that were all usable).

MW
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klaus

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Re: FET selection BC264
« Reply #5 on: August 28, 2015, 10:09:12 PM »

Please contact me privately.
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Klaus Heyne
German Masterworks®
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Uwe

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Re: FET selection BC264
« Reply #6 on: September 07, 2015, 09:45:34 PM »

In some previous thread about alternate FETs for high-end microphones (either here or in the Neumann Forums the following types were recommended:
from Linear Systems - LS 846 and LSK 170
form various other manufacturers: 2N3819, SK 107, 2N4302, BC 264A, 2N3066 and S2436.
Any of these will work as long as properly biased. According to their respective manufacturers' specifications, the two Linear Systems types should have the lowest self noise, but any FET should be tested for this parameter after careful biasing.
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Jim Williams

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Re: FET selection BC264
« Reply #7 on: September 08, 2015, 11:17:37 AM »

Don't forget the venerable J305, a very fast fet with low input capacitance.

Linear Systems has also released a new jfet series, the low stray capacitance LSK189 and the LSK489 dual. Those are 4 pf stray capacitance, a bit better than any of the commonly used jfets. The spec at 1.8 nv noise a tiny bit higher than the 1 nv noise of the LSK170. The benefit in a 3 to 10 gig input impedance would most likely wash out the noise differences.
www.linearsystems.com
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