NM

0 Members and 1 Guest are viewing this topic. Read 1040 times.

Folsom

NM
« on: 19 Dec 2014, 06:16 pm »
NM
« Last Edit: 26 Aug 2015, 03:29 am by Folsom »

gychang

  • Jr. Member
  • Posts: 90
Re: TDA7297 - Best w/ Shielded Cable (Balanced Outputs)
« Reply #1 on: 19 Dec 2014, 07:13 pm »
Hey guys, here's something you can try now (before I get a kit out :thumb:)

I'm using 20ga Belden 8412. Furutech makes some fancy expensive XLR cable too.

Anyways, the TDA7297 has balanced outputs. Without the shield the amps can never reach near it's full potential. In fact the close the shield is to the outputs, the better. On my own board I went from being 2-3in away to 1in away and the effect was quiet large, actually. This was a coiled wire, on my test rig. The PCB I've got in the works includes an output for the shield, but as is here's the easiest way to do it right now.

You may want to switch to XLR connectors for the speaker outputs, or add a third binding posts to continue the shield.

You'll notice the shield isn't connected anywhere to the speaker or the outputs of the amplifier. Doing so will either ruin your amplifier or it'll sound broken if you get anything at all.



Lastly if you've come to explain how you don't think you need shielding, save it. This isn't a "mod" to improve just RF susceptibility, it is entirely necessary for exercising the best your amp can do. There are a few other things that improve it. The amp benefits highly from a zobel on the outputs as well.

this is great, want to make the amp-speaker as quiet as possible, improving to ten-tec 937 linear PS was surprising.  Does this work also for t-amp?, is the ferrite ring on the speaker wire helpful?


Folsom

Re: TDA7297 - Best w/ Shielded Cable (Balanced Outputs)
« Reply #2 on: 19 Dec 2014, 07:25 pm »
I wouldn't bother with other amps in this fashion. Single ended amplifiers won't get the benefit. They can used two conductor wire for lower noise.

This is specific to this amp that is unique because of the balanced outputs. The shield doesn't function how you think it would for noise; in this case it's simply a drain and lower radiation. What you'll get is a much improved consistency in sound so details will come through better. Also bass improves.