Head-amp PS question

[bm_mode]

Hello,
I'm looking at building one of Prof. Leach's head-amps from the link below. Would there be any danger of damaging my MC cartridge if I ran the head-amp from a 9V regulated power source supplied by a wall-wart, instead of from a 9V battery????

Cheers,
Joseph.


http://users.ece.gatech.edu/~mleach/headamp/

 

[SY]

It'll work fine as long as you don't mind a lot of noise.

 

[peranders]

When you have these one (or two) transistor solutions you must have a very very quite supply voltage. I can see only one problem (maybe) that the transformer introduce hum via capacitive coupling but it's no harm in testing.

EDIT: Oh I forgot, you probably add 1000-10000 uF in decoupling plus 100 nF after the wall-wart but add also 1-100 ohms in series. By this you create a LP-filter. It's possible the wall-wart deoesn't like to much caps at the output..

 

[peranders]

It's possible the wall-wart doesn't like to much caps at the output.

...therefore you must insert a resistor but the value is rather uncritical. Start with 100 ohms.

 

[peranders]

When I have had a look at the schematics, you probably must have two resistors, because the battery is used as a totally floating voltage source. I'll doubt that you can make this circuit hum free but no harm in testing.

 

[bm_mode]

Ok, Thanks for your help Peranders and SY. I'll make the head amp so it can be powered from either a battery or a wallwart-based regulated supply. That way the battery will work fine until (if ever) I get adequate results from the wall wart.

Cheers,
Joseph.