Phillips Preamp Mod

[Jonathan Kristian]

Hi all,

This is my first DIY post and i have almost zero electronics experience but im very keen to learn.. so please go easy.

Ive got an old phillips preamp and wanted to have a go at modifiying so i am able to use it with my current setup and for a bit of fun.

It has 2 intputs which are 5 pin din plugs so im going to have to convert them to XLR but no sure how to wire it up.

Also the output is via 2 bannana plugs (red and black) intended to be conected to a speaker which im guessing will have an impedence of 8 ohms. So im going to to have to get it to an impedence my Digi002 can handle (2kohms???). Will i need an output transformer for this or can i just use some resistors??

Any help would be greately appreciated.

Cheers

Jonathan

[rob]

Jonathan
a good starting point is to start looking for a schematic, this will help remove lots of guess work.
do some reading on impedance, would a very low output impedance intended to drive a speaker be happy driving a high input impedance into your 002 ?
Are the inputs balanced?
Does it work as it stands at the moment? Jimmy up some temporary hook up to test it.

Rob

[Jonathan Kristian]

Thanks for the reply rob,

Unfortunately i was unable to locate any schematics, i scoured the net but as there is no model number or anything else of the like on the pre i was hard pressed to find anything.

Im guessing that the output of the pre would be to hot for my 002 to handle and am trying to find away to overcome that which is why i was wondering what the best way to do it was...

From what i understand 5-pin DIN plugs are unbalanced. Just having trouble working out which wires to connect to a 3 pin XLR, think i might need some trial and error

I havent been able to test the unit as i dont have any 5-pin DIN connectors but i have a mate that has a 5-pin DIN to RCA cable which im hoping to get hold of so i can at least test it with a tape deck and a set of speakers.

Any other suggestions would be much appreciated,

Cheers.

[rob]

don't worry about the output being too hot. If it is designed to drive a loudspeaker then i will probably not be hot enough. Bear in mind that a +20dBu level equates to about 8 watts into 8 ohms and that +30dBu equates to 72 watts into 8 ohms.

First up try to pass signal, you may need to experiment with the wiring on the DIN socket ..... looking at the back of it may yield clues as to the wiring

Rob