regarding shielding

Okay, I'm using unshielded cables from both, my TT and preamp. The phono preamp is plugged into the wall using a c-7 cable. It's very quiet, no RFI. I did the star grounding with other cables and it worked okay, but why with non-shielded cables do I get better sound without them acting like antennas? Also, I have four dedicated circuits which everything is plugged into.

mt10425, could you provide a little more detail:
What is the construction (or brand) of your (single-ended?) interconnects? Just because cables are unshielded doesn't necessarily mean they will be noisy if they don't pass near power cords (or equipment transformers) and if there is no strong RFI coming from your system (usually digital gear) or from fluorescent lights or dimmers in your home, or broadcasting stations in your area.

What is a c-7 power cord? Is that a brand?

Dedicated circuits are good, but you still have to observe the same grounding techniques as with any wall citcuit.

thx

Sure. The cables are Music Metre with a single silver wire in a semi-flat transparent tube. 1m from TT to TTVJ Hybrid phono stage - 1/2m from phono to Sophia Baby amp. With the amp turned all the way up there is no tube rush or any noise.i thought phono cables had to be shielded against RFI. Apparently not. C-7 is the two pronged end of some power cords. I use Furutech outlets on my dedicated circuits. Let me know if that's enough info.

Hi Mt10425:

I checked and found that the Music Meter cables are constructed of TWO wires in a "twisted pair" configuration. This works well for rejecting RFI (with no shield) but not so much for 60Hz hum (although hum is more easily controlled by careful cable placement.) Twisting the + and - conductors together though, creates other issues that might negatively affect performance (or not) depending on the cables' application.

The Vinyl Junkie phonoamp is actually solid state for the first gain stage (first and second gain stages if you're using a MC cartridge.) That's where tube hiss would happen if tubes were used there.

The unit's power supply is a (transformerless) "switching" power supply providing high voltage to the tubes, and the 12V DC is provided by a wall wart transformer. Neither of those devices require a third ground conductor, as would be required for a more conventional power supply which is often housed in a separate chassis away from the sensitive phonoamp circuits.

Thanks much Nsgarch! I've looked hard for that info without any luck. I
knew the hybrid phono was not all tube, but didn't know when SS kicked in.
It's very hard to tell there are two wires just by looking at the cable. The
phono power supply isn't the plug into the wall type, but the type a
computer printer uses (2 piece) with a separate cord (in this case a c-7
Pangea) to the wall. As far as the 60Hz hum, all cables are placed away
from each other, none touch. The cart is MM, a Grado Sonata. Again, this
is much appreciated info and helps to explain my questions.