TSSA - The Simplest Symmetrical Amplifier

[AndrewT]

Originally Posted by Idefixes

The blue led i have ............needs 20mA / 3.5v ........

Are you sure?
Have you read the datasheet correctly?

[Lazy Cat]

Originally Posted by Idefixes

The blue led i have VAOL-3LSBY4 needs 20mA

LED is intended to be PS +/-50 V indicator not a room ambient light, which blue LEDs at If=20 mA quickly become.

So 5 mA will be more than enough (see diagram) to do the indicating job properly and certainly we don't want two resistor-heaters on PCB just to feed the indicator LEDs - nonsense.

[Idefixes]

New progression....

[Idefixes]

Originally Posted by AndrewT

Are you sure?
Have you read the datasheet correctly?

May be not....

[Idefixes]

Originally Posted by Lazy Cat

LED is intended to be PS +/-50 V indicator not a room ambient light, which blue LEDs at If=20 mA quickly become.

So 5 mA will be more than enough (see diagram) to do the indicating job properly and certainly we don't want two resistor-heaters on PCB just to feed the indicator LEDs - nonsense.

Ok i trust you without any condition... will eliminate the unnecessary resistor

Marc

[Idefixes]

Here with half led resistor

[Lazy Cat]

Originally Posted by Idefixes

New progression....

OK nice one

Do you allow some more changes or is it considered as final for you?

[Idefixes]

Originally Posted by Lazy Cat

OK nice one

Do you allow some more changes or is it considered as final for you?

Ever ready to play....I like the look the board take and the methode to align things

Marc

Note : 0R22 MPC71 and 2N5486/2N5462 are ordered

[Lazy Cat]

Minor changes, more or less aesthetical ones:
- yes, MUR460 are as big as 2 W resistor, correct size as now
- wire jumpers of correct lenght, aligned to grid with resistors
- 1 mF and 2,2 mF have a little more space around, not all producers have exactly the same diameter for given voltage
- four 15 V zeners move to the side, to have more thicker output track, more current capability
- feedback tracks conducts only mA, so no problem as they are thiner now
- parts alignment to drawn grid lines is now OK

Until now I didn't make any connections check according to sch, that job will be performed when you'll make this final correction.

Regards, Andrej

P.S. For VAS 2SA/2SC transistors you can use Fischer heatsinks SK75 37,5 x 32 x 14 mm with two soldering pins for fixation and GND connection

[Idefixes]

Thanks LC i go on work to evolution. I drawn schematic under eagle and than switch to board. At ths level without any componant placement Eagle present thin yellow line between components pins according connection drawned in schematic. When you done modification in schematic it affect board....Consequence is that normaly there is no mistake in connection if schematic is correct and if parts library are right, but even that i check every time the roting job accordig schematic.