Hi again.
would i need to build a dedicated preamp power supply like for example this: http://sound.westhost.com/project05.htm , or could i simply use a 2*15Vac transformer or something?
and if i have to make the power supply, would it do to use only a 4,5A trafo?
im going to use it on this project: http://sound.westhost.com/project99.htm
would i need to build a dedicated preamp power supply like for example this: http://sound.westhost.com/project05.htm , or could i simply use a 2*15Vac transformer or something?
and if i have to make the power supply, would it do to use only a 4,5A trafo?
im going to use it on this project: http://sound.westhost.com/project99.htm
Hi,skogs said:
I don't know the power requirement of your proposed pre-amp but most will require substantially less than 100mA @ +-15Vdc.
That amounts to just 3VA plus losses in the regulators.
If you over-rate the supply transformer by a factor of ten you still arrive at just 30VA. There may be a small gain in performance by over-rating the transformer by a factor of fifty, but most in this Forum would disagree with that philosophy. The only way would be to try and prove it is better, buy 30VA and 150VA and see what difference there is.
Hi again, thanks for the advices.
im quite a novice, a newbie in these things. Im also kind of poor at the moment, so i can only afford to buy the things i absolutely need.
but what do you mean by this over-rating? is it neccessary? or will it work to just use a 6A supply transformer?
Keruskerfuerst: what do mean with better power supply? could you give me an example or something? im on a reeeally tight budget. and im not capable of designing any of these things myself. i need schematics, i can make pcb layouts and such myself.
Thanks alot for the respons guys
im quite a novice, a newbie in these things. Im also kind of poor at the moment, so i can only afford to buy the things i absolutely need.
but what do you mean by this over-rating? is it neccessary? or will it work to just use a 6A supply transformer?
Keruskerfuerst: what do mean with better power supply? could you give me an example or something? im on a reeeally tight budget. and im not capable of designing any of these things myself. i need schematics, i can make pcb layouts and such myself.
Thanks alot for the respons guys
Hi,
without using rail to rail opamps, a +-15Vdc supply allows a maximum output voltage of about 10Vac into a high impedance load. With +-12Vdc the maximum output is reduced to about 8Vac, again into a high impedance load. Hi impedance is >=5k.
I do not recommend rail to rail opamps. The opamp's desirable characteristics are compromised to achieve rail to rail and worth avoiding if you can manage with the 8 or 10Vac quoted above.
without using rail to rail opamps, a +-15Vdc supply allows a maximum output voltage of about 10Vac into a high impedance load. With +-12Vdc the maximum output is reduced to about 8Vac, again into a high impedance load. Hi impedance is >=5k.
I do not recommend rail to rail opamps. The opamp's desirable characteristics are compromised to achieve rail to rail and worth avoiding if you can manage with the 8 or 10Vac quoted above.
ohkey... but now im almost there in finishing this 6.order filter. the steeper the better, so why make any changes now the parts have arrived and im just waiting to make the final pcb.. so the only thing i wonder is wether i should connect the ground from the source (which is subwoofer preout on my main amp) to the ground on the filter?
the parts have arrived and im just waiting to make the final pcb.. so the only thing i wonder is wether i should connect the ground from the source (which is subwoofer preout on my main amp) to the ground on the filter?- Status
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