Looking for alternative to Peavey dual diode SZ-13886

[mikeydee77]

I was trying to find a replacement for the above part which now cost just less than £6 from Peavey in the UK; AFAIK MZ-2361 is the part which peavey select from and its a tight tolerance dual diode but I haven't found a source for that either. So just for the hell of it I thought I would try to measure the characteristics since I have a pair of new ones from Peavey on my bench right now.

Peavey SX-13886 Dual Diode Test.pdf

If anyone has experimented with subs would love to hear how you got on.

Cheers, M

[Jazz P Bass]

As far as I know, Peavey selects that part from a batch.

So there likely is not a proper substitute.

[soundguruman]

I was trying to find a replacement for the above part which now cost just less than £6 from Peavey in the UK; AFAIK MZ-2361 is the part which peavey select from and its a tight tolerance dual diode but I haven't found a source for that either. So just for the hell of it I thought I would try to measure the characteristics since I have a pair of new ones from Peavey on my bench right now.

[ATTACH]26964[/ATTACH]

If anyone has experimented with subs would love to hear how you got on.

Cheers, M

The diode, from peavey, costs $11.86. hand selected...I bought 2 of them and still have 1 left.

AND, as a tech at the peavey factory told me, many many years ago, stick in 1N4007.
will you notice any difference? I doubt it.

The diode is supposed to hop up the bias when the amp gets HOT.
But why not just hop it up all the time, even when it's cold?
You might as well try it...

[gbono]

Your data shows that the Peavey diode is 2x forward voltage the BAV21. The 1N4007 might be a better choice as stated. I'm also assuming this diode has less than 100mA going through it in the application?. Today a silicon PN junction diode, of the same date code, would probably be very close in forward voltage - The temperature coefficient (forward voltage/silicon) is -2mV/C.

[soundguruman]

OR you can buy the one I have!
Only $11, what a bargain!!!
hahahahahahahhhahahhhahahahhahahhahahahhaha!

[Mark Black]

From the Peavey Transistor Cross Reference:
"SZ-13886 is a special selection from MZ-2361 for voltage drop characteristics. Commercially available parts may not
perform to these specs."

Now according to the datasheet from the maker (Microsemi), the MZ2361 is pretty tightly controlled anyway with a listed forward voltage drop of 1.24V to 1.38V. Then again that is only at 10mA current and 25C temp, and Peavey may be testing/using at a different current/temp range.

[gbono]

The Microsemi data sheet for the MZ2361 states that 1 to 4 diode die (chips) are stacked in series to build this stabistor. That's why the BAV21 has a forward voltage 1/2 of the Peavey part (which is probably fabricated with 2 diode chips stacked in series).

How is this device used in the Peavey circuit?

[mikeydee77]

Well I decided to go for the correct part but am always curious to see what is possible. The BAV21 was just something I was using to compare, I wasn't suggesting that this could be a suitable replacement. The MZ2361 doesn't seem to be available here in the UK.

The diode itself is used in a string of diodes setting the bias conditions on a power amp output transistors. In this case it is 1993 PV4.5c amp but I think it is commonly used in other pv products and the same idea seems to be also used in hifi. The diode is mounted through the heat sink to pick up the temperature of the amp. As I understand it, the diodes maintain a separation between the output device bias. When the temperature goes up that gap gets reduced I guess as vf goes down.

This amp I am working on through is my own so I may be tempted to experiment with subs.

I will attach the schematic later on for those that are interested.

[TIM R]

Hi, Do you still have the extra MZ 2361 diode? If so do you want to sell?

[Jazz P Bass]

Call Peavey & buy it from them?

As noted, it is a 'selected' part.

[TIM R]

Hi, Thanks for the info. I did not realize Peavey still stocked them. I ordered two, hopefully they are what I need.