Turntable/pre-amp hum

[margetti]

Only noticed this when the other day when I switched the amp to the TT input whilst the volume was at 12 o'clock and my ear was only about 6 inches from the speaker. Quite an audible hum, although at normal listening levels (9-10 o'clock) and position (at least 2 metres away) it is barely noticeable.

Playing with the ground connection wire and the pre-amp ground terminal changes the loudness of the hum, but at no point can I eliminate it altogether.

Questions therefore are...

1. Is this level of hum to be expected with the Debut? - I mean, whatever the accolades it has, it's still a budget TT at the end of the day...???

2. Can I try connecting the TT's earth wire to ANY ground point (eg the TT ground on the 876), or does it have to connect to the pre-amp it is attached to? I'm wondering if the 640p grounding terminal is a bit suspect, and just want to confirm or eliminate this theory...

thanks 

 

 

[plastic penguin]

You tend to get some hissing, but if it goes to a heavy drone as you crank it slowly then it's probably an earthing problem. Make sure the wires to the cartridge are secure.

 

[Anonymous]

Don't make an earth ring take your earthing from on point only and loop from that point to the next. Make sure you connections to the TT via the signal cables are not looped.

worth fitting a Tacima 6 Way Mains Conditioner and Radio Frequency Interference Filter £29 from Amazon worth every penny.

 

[margetti]

Thanks - it's clearly a grounding issue - have got the evening booked in to troubleshoot locating it and then eliminating it!