same transformer, different voltages?

[calx44]

Hi,
I had a post on here not so long ago about making a guitar amp. I have a preamp schematic that runs off 15 volts and a power amp chip that works best off about 25V. Can i use the same transformer/power supply? If so how?
Really basic question i know...

Thanks in advance
Callum

 

[sreten]

Hi,

You tap off and regulate the high current 25V rails down to 15V
for the low current supplies for the preamp, leaving the 25V rails
directly connected to the power amplifier.

rgds, sreten.

Assuming you don't use a multitapped transformer ...

 

[calx44]

OK, thaks for that. Makes sense really when I think about it.
Cheers
Callum

 

[calx44]

I should have asked this before really, but how can i do this? with a voltage divider?
Thanks
Callum

 

[sreten]

Hi,

Zener diodes or regulators, you can't use a voltage divider for power
supplies. Look up some schematics of amplifiers to see how its done.

rgds, sreten.

 

[calx44]

Thanks. I have never really done anything with power supplies before, but I thought a divider wouldnt really work.
Cheers
Callum

 

[Minion]

Depending on yer preamp you might be able to run it off of 25v.
If it is an opamp preamp and runs off a single supply you can most likely run it off of 25v , most opamps can run off of 30v or more and you will get increased headroom useing a higher voltage supply.

Cheers

Maybe post a schematic of your preamp design.