Looking for shielded hookup wire for tube preamp

[grindfix]

Greetings everyone,

I'm building Tube Line/Phono preamp combo and can't seem to settle on what shielded wire to buy for final assembly. Currently whole project is mounted on prototype chassis made of masonite board.
All transformers are remotely fitted into aluminum enclosure and connecting with preamp via shielded 18 conductor cable.
I used old (70's) shielded stereo interconnect cable for hookup. Phono input wires are placed inside of grounded shielding tube.
I got all hum figured out in the line stage and it is totally quiet but phono is stubborn.
Looks like I may have to build metal dividers around phono PCB if amy hum is still there after everything is assembled into aluminum chassis.
I'd like to use single shielded wire for line level signal and 2 conductor shielded wire for Phono signal.
I'd prefer combination of thin diameter and low capacitance if such exist.
Would 24g be what I should be looking for?

Thanks for your help

Below are pics of the transformer box completed. There are 2 relays. Main is controlled by power switch and second is controlled by source selector when Phono is selected. Small transformer in the middle is for remote control volume board. Dabs of silicone aren't holding anything, just for redundant protection. Last picture shows connectors that will be at the preamp end of metal chassis.




Bottom plate

 

[sKiZo]

microphone cable?

https://www.parts-express.com/mogami-w2552-superflexible-microphone-signal-cable-1-ft--103-1016

Two 25awg conductors, but you can just use the one. I'd also consider hooking up the second wire as a drain ...

 

[grindfix]

I looked at this one. It is 5.0mm OD and will be difficult and bulky to use for source inputs in preamp. capacitance is not that low either. I suppose it would work for a short run of phono input.
Any other suggestions?
Thanks,

 

[grindfix]

I misread specs. Capacity isn't a problem here. Diameter is

 

[I LIKE MUSIC]

There is a fair amount of sub miniature coaxial cable available with diameters as small as around 1.12 mm, but the capacitance can tend to be higher.

Below is just one example.

 

[whoaru99]

I keep several feet of RG179 on hand for small shielded wire with reasonable capacitance.

 

[whoaru99]

@grindfix

I have a bunch of RG188 if you'd care to use that. it's a little higher capacitance (~29pf/ft) than the RG179. Has stranded SCCS core if that matters. It never has to me, FWIW.

I'd pull half-dozen feet off the spool and send if you want RG188.

 

[grindfix]

@grindfix

I have a bunch of RG188 if you'd care to use that. it's a little higher capacitance (~29pf/ft) than the RG179. Has stranded SCCS core if that matters. It never has to me, FWIW.

I'd pull half-dozen feet off the spool and send if you want RG188.

Thanks for your offer. This is my first new build and I want to make best out of it. RG179 low capacitance is very attractive but 38g conductor size will make it difficult to work with. What cable would be a good compromise? Also, wouldn't it be better to use 2 shielded conductor cable for Phono input?

 

[whoaru99]

Guess I don't know if it would necessarily be any better to use a a pair vs. two single for phono.

Belden 1800F is pretty low capacitance and not too big, but maybe still bigger than you want.

 

[grindfix]

Guess I don't know if it would necessarily be any better to use a a pair vs. two single for phono.

Belden 1800F is pretty low capacitance and not too big, but maybe still bigger than you want.

I will use it as Phono pre input. It will be too bulky for line preamp signals. Unless I find the way to mount selector switch close to source inputs and use a shaft extension to faceplate. That way I would only have 2 cables going forward to volume/gain pots. Capacitance spec is impressive. I think it is the lowest I've seen so far. Thanks,
Dmitriy

 

[maxhifi]

If your layout is good, twisted pair works fine for line level signals.

 

[grindfix]

Does anyone use Mogami W2330 for line signal?
https://www.redco.com/Mogami-W2330.html

 

[N8Nagel]

I use Mogami W2694/2695 for ICs for old stuff, would that work for your app?

Looks like 2947 is even smaller with not much more capacitance...

 

[grindfix]

If your layout is good, twisted pair works fine for line level signals.

My layout is complicated. I'm combining Phono and Line preamplifiers in the same chassis. I can't avoid interference since input wires are going to run beside B+ regulator section. Old section of vintage shielded interconnect cable takes care of interference but I don't think twisted pair will suit me well.
Dmitriy

 

[grindfix]

I use Mogami W2694/2695 for ICs for old stuff, would that work for your app?

Looks like 2947 is even smaller with not much more capacitance...

Do you have a link? Google did not find it.

 

[N8Nagel]

Do you have a link? Google did not find it.

https://www.redco.com/Mogami-Video-Cable/
http://www.mogamicable.com/category/bulk/video/yc_separate/
http://www.mogamicable.com/category/bulk/video/subminiature_miniature/

and I'm dyslexic. it's 2964/65 (65 is just two 64s in a zip cord type config)

 

[maxhifi]

My layout is complicated. I'm combining Phono and Line preamplifiers in the same chassis. I can't avoid interference since input wires are going to run beside B+ regulator section. Old section of vintage shielded interconnect cable takes care of interference but I don't think twisted pair will suit me well.
Dmitriy

In this case I suggest BELDEN 8216 RG-174/u. It is well shielded, low capacitance, well made in USA, stranded for flexibility, and cheap. I have used it in several projects with good results.

Careful to order this exact BELDEN number and not generic RG-174, you want to be sure to get a stranded copper center conductor. There's also versions wirh copper plated steel, and solid copper.

Regards, Max

 

[grindfix]

https://www.redco.com/Mogami-Video-Cable/
http://www.mogamicable.com/category/bulk/video/yc_separate/
http://www.mogamicable.com/category/bulk/video/subminiature_miniature/

and I'm dyslexic. it's 2964/65 (65 is just two 64s in a zip cord type config)

I like the twin version. Great specs and reasonably priced. The only negative there are no color options. I think I can live with that.

 

[WntrMute2]

http://www.aircraftspruce.com/catalog/elpages/coaxialcableconnectors6.php

Some on the DIY forum have suggested this.

 

[Thomas Turk]

Greetings everyone,

I'm building Tube Line/Phono preamp combo and can't seem to settle on what shielded wire to buy for final assembly.
All that effort and you'll still end up with a distorted signal from outdated resistor-based volume control. Intact sell autoformer. Tortuga bringing out a mini LED?