There should be no issue with disconnecting a secondary winding from ground

Disagree.
As Dave noted, the transformer is presently generating a negative voltage referenced to that ground.

 

Disagree.
As Dave noted, the transformer is presently generating a negative voltage referenced to that ground.

Hi Crutschow,
You are correct. There is a - 24vdc to earth circuit.
Dave

 

To produce a negative rail with reference to earth, you need a centre tapped transformer, and cannot use the single secondary winding as originally proposed.

 

To produce a negative rail with reference to earth, you need a centre tapped transformer, and cannot use the single secondary winding as originally proposed.

You can if it's half-wave rectified.

 

Yes, but you’ll need to double the reservoir capacitor value for the same ripple voltage.

 

Yes, but you’ll need to double the reservoir capacitor value for the same ripple voltage.

Of course.

 

What you said is what I intended. To be completely clear, the -ve end of the capacitor should go to the same 'ground' as the centre tap of the transformer. You should get about 31V DC out in theory. I would go for a capacitor rated at 50V or higher. It would be good to check the output voltage with a multimeter before you connect your amplifiers to it.

Hi Dave. Thank you for all your advice you really know your stuff. It worked a dream. Tried to send quick video but wont upload.

What you said is what I intended. To be completely clear, the -ve end of the capacitor should go to the same 'ground' as the centre tap of the transformer. You should get about 31V DC out in theory. I would go for a capacitor rated at 50V or higher. It would be good to check the output voltage with a multimeter before you connect your amplifiers to it.

 

It worked a dream.

Thank you for letting us know the outcome. Often the original posters just don't come back and the regulars here just have a discussion amongst themselves about the problem.
Are the new amplifiers outputting sound okay now?

 

Thank you for letting us know the outcome. Often the original posters just don't come back and the regulars here just have a discussion amongst themselves about the problem.
Are the new amplifiers outputting sound okay now?

Hi Dave yes the sound is perfect absolutely no hum. Just to fit a tone/volume board and job done. Thanks again.
Dave