+-35v POWER SUPPLY

[synthius]

hey guys,

here is my attempt at a +-35V power supply, it is a a mix of a couple different designs i've seen around.

Please critique/offer suggestions!

 

[luka]

Hi

You could/should add fuse on primary side, replace that resistor with NTC and I think that you don't need 1ohm resistors on output

 

[synthius]

You could/should add fuse on primary side,

I couldn't find a fuse in pspice but I do have a
4 amp Slow blow fuse on the primary.

replace that resistor with NTC

what resistor and what is a NTC?

 

[luka]

what is a NTC?

http://en.wikipedia.org/wiki/Thermistor

And I was talking about R1, this is probably fuse, but do use fast one... What is your trafo power rating?

 

[synthius]

oh I see,

R1 is needed in the design to simulate the traffo's internal resistance(schematic is from a PSPICE simulation).

I am in looking into NTC's right now.

I'm using a Avel Y236652 250VA 25V+25V Toroid.

 

[GregoryD]

C1 and C3 need to be reversed in polarity.

 

[TNT]

This is an advice I would strongly follow!

C1 and C3 need to be reversed in polarity.

 

[arunsoundar3]

hey guys could anybody tell me how many amps power supply should i buy for +- 35v and 100 w power output subwoofer amplifier

 

[AndrewT]

hey guys could anybody tell me how many amps power supply should i buy for +- 35v and 100 w power output subwoofer amplifier

Don't try to work out the amps demand.
All the transient demand of the amplifier is met by the smoothing capacitance and the amplifier decoupling.

The transformer only has to be sized to not overheat on "Party" use and to hold a reasonably small range of voltage over a wide operating range.

The easiest method is to adopt a transformer size that is directly related to the maximum power of the amplifier.

A 100W ClassAB amplifier will run well from a 100VA to 200VA transformer.

100VA 35+35Vac transformer is effectively a 1.4Aac transformer.
200VA 35+35Vac transformer is effectively a 2.8Aac transformer.

Two channels running off a common transformer, would work on a transformer from 200VA to 400VA.

However, what does this mean?:

+- 35v

do you have a 100W into 4r0 amplifier that requires +-35Vdc when fully loaded, or +-35Vdc when in the quiescent state, or do you require a 35+35Vac transformer to power a 100W into 8r0 amplifier?
Don't be ambiguous.

 

[arunsoundar3]

thank u so much andrew ...this uw dhelp me building ma first amplifier ....