Phono Pre Amp

[Malcolm woodhouse]

Hello I have a old Cambridge audio A1 amp. There is a place in the amp for a Phono stage board but these are no longer made. There is enough room to fit one I have that connects via a wall transformer. It is 12v.
Question Can I take the 12v required from the A1 PCB board? there are 5 pins in a row marked Gnd Gnd Gnd -V +V.
When I check the voltage across them I get 31V.
Can I step down the voltage? also which PINS would I use to power the 12v phono amp?
Thanks Malcolm

 

[dorke]

Welcom to EP Malcolm.

Here is a schematic of the A1(seems to be various mks.)
Is it like the one you have?
There is the connector CN6(phono PSU) with ±28V,
Looks like inserting a phono board requires some mods,
read the remarks on the schematic.

 

[Malcolm woodhouse]

Thanks for the info. The picture is the same all I was going to do was take the power from the PSU phono plug and use it to power a phone amp I already have. I was ether going to cut the connections from the original plugs and hard wire them into the phono amp I have. Its quite small and there is plenty of room for this to be done. I need to know on the plug socket (One Phone PSU) which pins to use to power my 12v phono amp and if I can reduce the voltage by adding some resistors