buying shielded cable

General discussion area for tube amps.

Moderators: pompeiisneaks, Colossal

User avatar
Structo
Posts: 15446
Joined: Wed Oct 17, 2007 1:01 am
Location: Oregon

Re: buying shielded cable

Post by Structo »

Let us know how you like it.
Do you know what the spec is if you twist the two conductors together and use it as single conductor coax?

On my 50w amp I initially had coax from the Master to the loop jacks and back to the PI input.
It was the white 20ga Teflon from Apex.
I removed that and replaced it with single 20ga.
Seemed to lift a bit of dullness or mud from the tone.

I still have it on the four runs from the OD Drive and Level pots and on V1 grids.
Tom

Don't let that smoke out!
ApexJr.
Posts: 225
Joined: Tue Apr 11, 2006 2:46 am
Location: Torrance , Cal
Contact:

Re: buying shielded cable

Post by ApexJr. »

mad_dog wrote:I'm looking at the coaxial cable from this guy on ebay

stores.ebay.com/QualityChinaGoods

He has RG174 that looks pretty cheap, would any of the other cables be ok??

I know I could get some stuff from Steve at Apex Jr but don't really need anything else and don't want to have to bulk up an order to make it $20 plus shipping to Australia

If you still need some coax, I also have RG 174/U and both 22 Awg
and 20 Awg PTFE wire 1 conductor shielded and I can send you
some at no charge .... Contact me thru a PM thru this forum.

Steve @ Apex Jr
User avatar
rp
Posts: 2528
Joined: Sun Apr 25, 2010 4:21 am
Location: Italy

Re: buying shielded cable

Post by rp »

I knew shielded cable had capacitance but I never worried much about it, I just knew not to go crazy with the stuff, but 70pf/ft is a lot - There's no way I'd just start soldering 50-70pf caps around the amp. My default has been to put it in where it should go, now my default will be to leave it out and see what happens and use the gs4 if needed. As long as I'm doing p-t-p I doubt I'll have trouble.

A question: If I disconnect the shield from ground will the capacitance equal that of unshielded wire?
User avatar
Structo
Posts: 15446
Joined: Wed Oct 17, 2007 1:01 am
Location: Oregon

Re: buying shielded cable

Post by Structo »

As I mentioned I went a little overboard because I didn't know the effects of too much coax in my amp.

Now I only have it to V1 and on both runs of the OD Drive and Level pots. (4 runs)
Not sure about the capacitance if you don't connect the shield but that kind of defeats it's purpose, no?
Tom

Don't let that smoke out!
User avatar
rp
Posts: 2528
Joined: Sun Apr 25, 2010 4:21 am
Location: Italy

Re: buying shielded cable

Post by rp »

Structo wrote:Not sure about the capacitance if you don't connect the shield but that kind of defeats it's purpose, no?
Just for testing, to see if I can hear any difference.
Post Reply