Ground Loop Hum

[nige2000]

heres kens amps with the rectifier earth gnding

[Cyndale]

heres kens amps with the rectifier earth gnding

I am just a novice, can you point out exactly where it is connected on the pic, thanks!

I got some information from a guy who has built valve amplifiers...
As long as the pre-amp is earthed then the power amps will be earthed through the interconnects. The 'health and safety' way to do it is to fit an earth lift circuit on the power amps then they can be earthed to the mains with no earth loop hum problem.

What say you?

[nige2000]

Cobblers children have no shoes in this case
One of my amps and dac I use every day is still not earth grounded they were built a year and 3 yrs ago
That's out of laziness
Voltages aren't crazy but nobody going to advise against earth grounding
Bit like riding a bicycle without a helmet fine as long as all goes to plan

The green wire at the bottom of the pic is the gnd wire going to rectifier

You'll have to make your own decision on it

[sima66]

I just replaced my Audio Aero Prestige mono's wit Pass Labs XA100.5 and I get the hum (more like zzzz) in both speakers and ONLY when I connect the ground wire from Entreq Tellus to the ground terminal of the amps! All my components are connected the same way and the Audio Aero worked with no problem!!
Without the ground wire from Entreq, perfect silence!

[nige2000]

so youve already found the solution?

you can try back to back 1n4007 diodes in series with the tellus wire
thats the two diodes turn one upside down and join them together

dunno if the tellus will work under those conditions?

[sima66]

so youve already found the solution?

you can try back to back 1n4007 diodes in series with the tellus wire
thats the two diodes turn one upside down and join them together

dunno if the tellus will work under those conditions?

Thanks Nige, but the ground cables make a huge difference and with this the cables will be affected very much.
I will try to use XLR instead of RCA, since the Wadia and Pass Labs are true balanced and both recommend using XLR 's!
That might solve the problem!

[nige2000]

not sure xlr will fix it `as gnd/shield is still passed through xlr

[sima66]

not sure xlr will fix it `as gnd/shield is still passed through xlr

Then I will have to not connect the amps to Entreq!
Tomorrow I will get the XLR cables

[Diapason]

I had a pair of amps that always hummed single ended but were fine via XLR. See how you get on!

[jkeny]

I Haven't read all of this thread so forgive if this has been said before but the problem is that the signal ground is being corrupted with ground return currents from the power supply. Nige has dealt with this in his amp design from early on. The idea of allowing the interconnect ground or shield being the ground return is wrong thinking - it should never be used in this way.

From my reading of the first post, It looks like when you plug in your preamp or second amp, it is giving a lower impedance return path through your interconnects for these PS ground currents. So I would suggest to look at the ground return in your amps & make them lower impedance i.e thicker wire or double up the existing wire. Are your amps/preamps using tube rectifiers or solid state rectifiers?

A quick test of this would be to try an interconnect cable with a higher gauge ground wire i.e one that is higher impedance & resist these return currents flowing in it rather than in the correct route to ground in the amp. It may be just one amp that needs this modification?