Bias Diode SV04F - Replacement through Vbe Multiplier (Sony TA-3650)

tiefbassuebertr · 12:11 PM

In most cases the thermal compensation for the idle current (quiescent current) in the output buffer from power amp sections was determine by an ordinary BjT small signnal transistor - mounted on the heatsink.
In older models there are often to find an also good known version, where are integrated circuits in use consist of an array from two until four diodes.
The SV04F seems to be such an integrated circuit (drawed as an ordinaty single diode symbol).
What to consider when replacing this part through a Vbe Multiplier ?
Thank you for your advices.

this threads are not helpful in this matter:
STV-3 bias diode replacement...
quad silicon bias diode
STV-4H AND STV-3H diodes array

Mooly · Yesterday, 06:40 PM

I remembered this thread which used similar (but different type number) diodes.

Sony TA3200f Issue

tiefbassuebertr · Today, 07:42 AM

Thank you for this advice. Similar kind of diodes are to find in follow datasheet from General Semiconductor.
http://www.datasheetcatalog.org/data...or/mXusrut.pdf
In the reverse direction, these devices show the
behavior of usual forward-biased silicon diodes (in opposite to usual zeners).

The question for me is, whether there is any advantage by the use of such voltage stabilizer diodes to a usual Vbe multiplier, which consist normally of a small signal transistor and two resistors.

Yesterday, 12:04 PM	#1
tiefbassuebertr diyAudio Member Join Date: Jul 2005 Location: D-55629 Schwarzerden	Bias Diode SV04F - Replacement through Vbe Multiplier (Sony TA-3650) In most cases the thermal compensation for the idle current (quiescent current) in the output buffer from power amp sections was determine by an ordinary BjT small signnal transistor - mounted on the heatsink. In older models there are often to find an also good known version, where are integrated circuits in use consist of an array from two until four diodes. The SV04F seems to be such an integrated circuit (drawed as an ordinaty single diode symbol). What to consider when replacing this part through a Vbe Multiplier ? Thank you for your advices. this threads are not helpful in this matter: STV-3 bias diode replacement... quad silicon bias diode STV-4H AND STV-3H diodes array Last edited by tiefbassuebertr; Yesterday at 12:11 PM.

Yesterday, 06:40 PM	#2
Mooly diyAudio Moderator Join Date: Sep 2007	I remembered this thread which used similar (but different type number) diodes. Sony TA3200f Issue __________________ ------------------------------------------------------- *A simulation free zone.* *Design it, build it, test it.*

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Today, 07:42 AM	#3
tiefbassuebertr diyAudio Member Join Date: Jul 2005 Location: D-55629 Schwarzerden	Thank you for this advice. Similar kind of diodes are to find in follow datasheet from General Semiconductor. http://www.datasheetcatalog.org/data...or/mXusrut.pdf In the reverse direction, these devices show the behavior of usual forward-biased silicon diodes (in opposite to usual zeners). The question for me is, whether there is any advantage by the use of such voltage stabilizer diodes to a usual Vbe multiplier, which consist normally of a small signal transistor and two resistors.