Anyone routed heaters with plate/screen wiring?

[HotBluePlates]

I'm working up an amp layout, and wondered if anyone has noticed an issue with routing the heater wiring (say for output tubes) alongside plate/screen B+ wiring. The plan for neat wiring would be to bundle these together in the build I'm planning.

Thinking along theoretical lines, I can't see how 6vac would bother several hundred volts of d.c., but I always defer to practical experience.

[sluckey]

Sunn did it. I did several amps back in the '70s with B+ and heater wires laced together. Haven't done it lately, although I would if the layout called for it.

Here's my Sunn Sceptre...

[Willabe]

Isn't the possible noise from the AC heaters caused by the current and not the voltage?


                      Brad     

[sluckey]

Yes. The stronger the current thru a wire, the stronger the electro magnetic field surrounding that wire and the greater the chance of that magnetic field inducing an unwanted voltage into adjacent wires. So keep heater wires away from sensitive signal carrying wires. But B+ wires are at signal ground potential if the filter caps are doing their job.

[Willabe]

But B+ wires are at signal ground potential if the filter caps are doing their job.

Meaning, if the filter caps are not doing their job this is where ESR is increased and now the B+ is lifted above ground potenial?


             Thanks,   Brad       

[jjasilli]

My Stromberg Carlson PA amps have all their internal wiring bundled together per original design -- B+, heater, speaker -- and passing right by the trannies.  There's no noise.

[Willabe]

So keep heater wires away from sensitive signal carrying wires.

Normally grid wires?

 
               Thanks,     Brad   

[stratele52]

Keep heater wires far from grid wire and other wire.

When I build amp I follow how Fender Blackface amp are build , that's the best way IMO

[kagliostro]

May be is due to my scarce experience, but I'll hesitate to route B+ and Heater wiring together

if I must have B+ wires and Heater wires near each other, may be I'll use a (grounded) small iron pipe (or copper pipe, iron however is better) and put the heater wires across it

otherwise I'll use a piece of RG58 shielded cable for B+, connecting the shield at one extremity to ground

but this sure will due to my insecurity and may result in an excess of precaution

---

may be that also B+ signal carry High Frequency noise that can be transmitted to the preamp tubes via the Heater wiring, so a large poly capacitor across the heater supply can help avoid this

with respect

Kagliostro

[stratele52]

otherwise I'll use a piece of RG58 shielded cable for B+, connecting the shield at one extremity to ground

 Kagliostro

Be carefull RG cable are not for high voltage use .

[kagliostro]

RG58 = 15Kv DC

http://datasheet.octopart.com/RG58BU-100M-Pro-datasheet-564768.pdf

Kagliostro

[stratele52]

I'm very surprise , thank's I learn something

[triode]

I'm very surprise , thank's I learn something

Always check the manufacturer spec sheet... Belden claims 300V on the RG58 I use.
But it does claim 1500V on the microwave cable, which is different.

http://www.belden.com/resourcecenter/tools/cablefinder/upload/06-3_15.pdf

[HotBluePlates]

Thanks for the responses. I think I have less hesitation routing the heaters with the B+ wiring now.

As for filter cap ESR, my particular build will be using Solen filter caps, so I have little worry about that issue.

Just in case anyone might get the wrong idea, I'm using Solens because I already have some on hand, and can spec the chassis to be any size I want; I have nothing against using e'lytic caps (I originally planned on using some can caps for this build, then changed my mind to use the Solens). Either way, I mainly use these caps simply because they'll likely never need replacing.