Anyone know what component this might be?

[solderspongebob]

Hi,

Looking at the schematic below (taken from the Symetrix 527 schematic here: http://www.symetrixaudio.com/kb/527e_sch.pdf), does anyone know what D4 might be?

I've googled 'dual diodes' but come up with devices where the diodes are connected by a common cathode (such as the BAV70-V) and not 'center tapped' as shown in the diagram.

Any suggestions welcome.

 

[Curtis]

I'll take a stab and suggest a 3 terminal voltage reference.  Dunno about a part number in your example, but perhaps something similar to an LM336

 

[gyraf]

I do not think they are critical in any way - they just up the 47V zener by a bit, allowing ca. 48V after the b-e drop of the transistor. Use 4001's or even 4148's - or even simply short them out if you can live with ca 46.4V Phantom power voltage (which is still well within specs.)

Jakob E.

 

[solderspongebob]

Thanks Curtis/Jacob - I'll sub a couple of 4001's and see how it works out.

 

[JohnRoberts]

+1 it looks like a simple dual diode to get circa 1.2V higher V.  I recall getting dual diodes from Motorola selected for voltage drop to use in amplifier biasing stages but that was years ago..  IIRC they weren't in a 3 pin package.

I'd just drop in some 4001s .

JR

 

[bcarso]

I've googled 'dual diodes' but come up with devices where the diodes are connected by a common cathode (such as the BAV70-V) and not 'center tapped' as shown in the diagram.

Any suggestions welcome.

http://www.fairchildsemi.com/ds/BA/BAV99.pdf

 

[solderspongebob]

Thanks also to JohnRoberts and bcarso.

I'll drop in some 1N4001's. Cheers to all!  ;D