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DIY Stompboxes => Building your own stompbox => Topic started by: Pushtone on April 14, 2007, 01:58:13 PM

Title: 1N4454 suitable replacement for 1N34A?
Post by: Pushtone on April 14, 2007, 01:58:13 PM

Will a 1N4454 work in place of the 1N34A in the Fox Tone Machine and Jawari ciruits?

http://www.mouser.com/search/refine.aspx?Ntt=1n34a

I'll find out in a few hours.


Looks like I cheaped out way back when I ordered parts for a bunch of projects and got the 1N4454s.
Funny how a desciion made several months ago dosn't seem well thought out now.  :icon_redface:

Here is what Mouser has to say regauding the 1N34A. (Of course this text wasn't there when I ordered the 1N4454)

*********************************************************************

FROM MOUSER...

GERMANIUM DIODE
610-1N34A, a DO-7 75V 50mA Germanium Diode has been discontinued
by Central Semiconductor, and once stock has been depleted, it
will no longer be available.

The closest replacement available for this item is 610-CDSH270.
The 610-CDSH270 is specifically designed to replace Germanium
diode manufactured with 1950s technology with a product that
uses 1990s technology. Some of the advantages of this new
technology are lower forward voltage, lower leakage, faster
switching speed, and a more robust package.

The major differences between these items is shown below:
                          610-1N34A            610-CDSH270
Case Type                    DO-7                 DO-35
Peak Repetitive
Reverse Voltage              75V                  100V
Peak Forward
Surge Current               500mA                 750mA
Power Dissipation            80mW                 100mW
Reverse Current             500uA                 100nA
Forward Voltage          1.0V @ 5.0mA          1.0V @ 200mA
Juntion Temperature    -50 to +75 Deg C      -65 to +125 Deg C
Storage Temperature    -50 to +75 Deg C      -65 to +150 Deg C
5-1098-28
Title: Re: 1N4454 suitable replacement for 1N34A?
Post by: Pushtone on April 14, 2007, 02:11:30 PM

From the Fairchild 1N4454 data sheet.

Symbol       Parameter                                     Value    Units
WIV            Working Inverse Voltage                   50       V
IO               Average Rectified Current                 200     mA
IF               DC Forward Current                         400      mA
if                Recurrent Peak Forward Current       600      mA
if(surge)      Peak Forward Surge Current
                   Pulse width = 1.0 second                 1.0       A
                   Pulse width = 1.0 microsecond         4.0       A



The slightly different names for the specs is confussing.
Title: Re: 1N4454 suitable replacement for 1N34A?
Post by: R.G. on April 14, 2007, 02:31:14 PM
Will it work? Sure.

Will it give the same results? No.

The CDSH270 is a silicon schottky diode. The V-I curves for turn on of shottky is not the same as germanium.

The 1N4454 shows a forward voltage of 0.5V at 100uA at 25C. It's silicon. It may be shottky, can't tell from the Fairchild datasheet.

This is not to say you won't like the sound. It will do clipping. It will not be identical to a 1N34A. That may or may not be a bad thing.
Title: Re: 1N4454 suitable replacement for 1N34A?
Post by: Pushtone on April 14, 2007, 02:49:18 PM
Quote from: R.G. on April 14, 2007, 02:31:14 PM
Will it work? Sure.

That's all I was hoping for. Something to rule out when de-bugging.

Quote
Will it give the same results? No.

I expected that.

Quote
This is not to say you won't like the sound.

I love the sound of all my pedals.  :icon_wink: :icon_redface: :icon_wink:

Thanks RG, take the rest of the afternoon off  :icon_wink: