FET Equivalent required

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timbo - 23 Jul 2008 05:27 GMT

Hi,

need an equivalent for a SPF558 N-channel FET, havent been able to locate
any info on it via google, hoping someone here might have an old data book
with a few specs to give me some idea of what to replace it with. It's in an
old Peavey Deuce guitar amp.

thanks,

tim.

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Phil Allison - 23 Jul 2008 06:04 GMT

"timbo"

> need an equivalent for a SPF558 N-channel FET, havent been able to locate
> any info on it via google,

** That would be because the part number is a Peavey " in house " one.

Means it is a selected part.

hoping someone here might have an old data book

> with a few specs to give me some idea of what to replace it with.

** No published data exists.

> It's in an old Peavey Deuce guitar amp.

** Comes right after the treble control ( in each channel) - right ?

You have two options:

1. Contact the Peavey importer;

http://www.audioproducts.com.au/ContactUs.aspx

2. Buy a few 2N5459s and try them.

When you get the drain pin to sit at about 10 to 12 volts DC - you have it.

Possibly trim the value of the 15k in the path from source to ground.

..... Phil

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Phil Allison - 23 Jul 2008 07:41 GMT

"Phil Allison"

> 2. Buy a few 2N5459s and try them.

** You can also use 2N5457s or MPF105s.

Try Farnell or eBay for 2N5459s.

..... Phil

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Electronics Forum / Electronics / July 2008

FET Equivalent required