12 vdc step up to 19 vdc

[conntaxman]

I need to 19 vdc 400ma. Im putting a small per amp on my motorcycle and the pre-amp is running at 19 vdc.would anyone know an easy way to do this with useing as little room as possible.
Thank you
Johnny

 

[Nigel Goodwin]

Can you give more details on the pre-amp?, it might be simpler to just run that off 12V (certainly 19V is a VERY strange figure?).

 

[hentai]

yes indeed it should be able to run at 12V.... and getting 19V at 400 mA from 12V might be tricky

 

[Hero999]

You can use a small switching regulator to get 19V from 12V but they're often too noisy for an audio amplifier. Running it from 12V is probably your bet bet.

 

[conntaxman]

12 vdc/19 vcd

The pre-amp and speakers are the "Philips MMS321 Multimedia Speaker System "80 watt rms.
They run off a step down transformer must be 21volts ac.Then changed to DC.
I think that Im lossing some wattage,[rms] Not much but with only 80 watts to play with a little is a lot.
HERRO99 said a "switching regulator " That would need a circ.
I know that I could use a Small inverter [100 watt] and use the step down transformer.120 vac to 21 vac.But then I have the two extra peices.
I was thinking of just a small step up transformer.
TKS in advance.
Johnny

 

[hentai]

hmm are u sure thats 80W rms? seems 2 much... anyway if the transformer has 21V output when u convert it to dc u will have more than 21V i would say 25V mb higher.

 

[conntaxman]

hentai

when I measured the voltage + and - I was getting 18.75
Im not sure but I seem to think it was just a little bit louder with the AC stepDown transformer.I could be wrong.Im going to hook it up both ways again and try it and see if the sound level is the same.I don't know if the 5 volts would make that much of a difference.
There 80 watts rms,but its broken down 20x2 for the tweeter and mid-range and 20x2 for the woffer.I think that is how they are doing it.But they sure do sound real good.Better then any bike speakers I have ever heard.
TKS
Johnny

 

[hentai]

hi about the power supply is that a full wave rectifier?
about the speaker if they have 20W on tw and mid-range and 20W on woofer than the total is 20W u cant sum those 2.

 

[conntaxman]

12 vdc /19 vdc

I tried it both ways,hooked it up to 12vdc and with the power supply that came with the amp, and I can't hear a difference in loudness.So ill just use the 12 vdc.Pluse it's much easier,need to do nothing else.
Thanks anyways guys.
Johnny.
Love riding my bike !