I'm developing a tube filter/buffer for use with a modified Sony XDR-F1HD (replacing its audio stage).
I've been looking around at new and kit buffers which I could quickly repurpose, and surprised to discover that all that I've looked at have IEC grounded A/C connection.
I figure that they do this for safety (if power transformer has failure, it could put A/C or HV on the chassis). But this wasn't done in the golden age of tubes, virtually all such equipment has no A/C ground. So is this because of improved safety standards, or low quality transformer and construction quality now?
It's a huge inconvenience for me. I have an exceedingly complex whole house audio system and I am constantly struggling to eliminate ground loops. It has come to this: only one component per interconnected system can have earth ground. Period. Everything else must float. I figure greatest risk is with power amplifiers, so those generally get the ground connection, line level gear gets ground lifted.
One way around this is to use small wall wart power supplies, as Musical Fidelity does with their X components. The small UL-listed AC transformer does not apparently need a ground connection (as it doesn't have one). Unfortunately, this does put a severe limit on available power and usually requires rectifying and complex voltage doubling and tripling circuits in the chassis itself (so much for getting the PS out of the unit).
Another way might be double insulation. The transformer itself should not be directly mounted to chassis, but indirectly through insulated washers, etc. Also all HV wire must be insulated. But it seems like typical Chinese manufacturers do not do this, and I have not yet found a buffer kit that takes this approach.
I've been looking around at new and kit buffers which I could quickly repurpose, and surprised to discover that all that I've looked at have IEC grounded A/C connection.
I figure that they do this for safety (if power transformer has failure, it could put A/C or HV on the chassis). But this wasn't done in the golden age of tubes, virtually all such equipment has no A/C ground. So is this because of improved safety standards, or low quality transformer and construction quality now?
It's a huge inconvenience for me. I have an exceedingly complex whole house audio system and I am constantly struggling to eliminate ground loops. It has come to this: only one component per interconnected system can have earth ground. Period. Everything else must float. I figure greatest risk is with power amplifiers, so those generally get the ground connection, line level gear gets ground lifted.
One way around this is to use small wall wart power supplies, as Musical Fidelity does with their X components. The small UL-listed AC transformer does not apparently need a ground connection (as it doesn't have one). Unfortunately, this does put a severe limit on available power and usually requires rectifying and complex voltage doubling and tripling circuits in the chassis itself (so much for getting the PS out of the unit).
Another way might be double insulation. The transformer itself should not be directly mounted to chassis, but indirectly through insulated washers, etc. Also all HV wire must be insulated. But it seems like typical Chinese manufacturers do not do this, and I have not yet found a buffer kit that takes this approach.
