heating wire question for you builders

[Darcy Hoover]

I see most builds have the heating wires up above from the tubes, but I've seen a couple tucked away against the chassis, which looks far cleaner IMO. I'm pretty new to building, are there pro/cons to either method?

Found this cool image, hope it's OK to use it....



Here's some advertising for the guy...

http://www.tjadamowicz.com/pMach/more.php?id=41_0_1_0_M

[Darcy Hoover]

Got a Deluxe Reverb build on the go so I'm curious, they'd be under stuff on the back of the chassis (speaker jacks, etc.) if I went this route.

[51Esquire]

Sorry, dupe posting!

[51Esquire]

Twisting the filament wires and getting them out of the way of the actual signal you are amplifying is the best building practice. If hum is encountered, those wires can be rerouted for best performance.

Those screws that mount the tube sockets are a little long, and don't have lockwashers under the nuts which is a bad practice.

[Dacious]

+1 on 51Esq. I prefer to do run heater wires this way myself. Have your signal wires cross the heaters at right angle and physical separation.

I also prefer to rivet the tube sockets in. You don't want anything coming loose over time, creating a maintenance issue and potentially a arcing problem if both screws come loose and let the tube/socket lean over.

[teleamp]

If you are going to lay down the filament wiring on a DR type build make sure that any signal wires that cross them do so at a 90 degree angle.

Don't twist your filament wiring any tighter than what is shown in the pic you posted.

[sjhusting]

Tweed style amps usually do them like in the photo you posted, blackface up above. Whichever works better to keep the heater wire away and perpendicular to signal wires.

Here's a good example of blackface-style wiring

http://www.texasamp.com/66princeton.html

steven

[JohnnyCrash]

Originally Posted by Dacious

+1 on 51Esq. I prefer to do run heater wires this way myself. Have your signal wires cross the heaters at right angle and physical separation.

I also prefer to rivet the tube sockets in. You don't want anything coming loose over time, creating a maintenance issue and potentially a arcing problem if both screws come loose and let the tube/socket lean over.

I'd love to rivet my sockets in. Any particular rivet tools you can recommend?

[Darcy Hoover]

90 degrees to the signal wires, got it! Thanks. I thought they just had to be away from them, but I can see how it would be easier to have the wires against the chassis and 90 degrees in a tweed type build.

Love those Princeton photos, just rebuilt one and that's the route I went with the heating wires, just not nearly so professional looking! Going for gold with the Deluxe Reverb build!

[mr_hankey]

In many cases, running the heater wires will position them closer to signal wires. That is, if the wires from the board reach the sockets from the side, not from above, like in that picture.

[11 Gauge]

Originally Posted by JohnnyCrash

I'd love to rivet my sockets in. Any particular rivet tools you can recommend?

DON'T use the standard B&D blind rivet unit from from HD, et al. Something smaller is in order, and it's a major PITA to get the rivets in once everything's wired up (with a big snapgun). Model number TO-VHR-2 is an example of a good one for an amp chassis, from this online catalog:

http://www.rivetsinstock.com/rivet45.htm

Note: I haven't ordered from that particular company - just trying to provide a visual reference.

Using the right rivet is important, too. Aluminum sure is nice when you need to drill it out. Plain steel will corrode in short order, IME. The ultimate would be stainless rivets, but they'd probably be a super PITA to drill out. I'd typically use plain steel and coat them with a little finish to keep corrosion at bay. While they are probably a little overkill, I like the Q Rivet line.

My favorite method is a little more time consuming, but is a clean, solid method, IMO. I use nice high grade machine bolts and nuts with a split washer, and a dab of Loctite. That way, you don't need to take a drill to the chassis to replace a socket, the bolts look clean, and they'll never come loose. You can get carbon steel, cad coated, whatever floats your boat.

[11 Gauge]

I personally prefer the elevated method - it makes the 90 degree to signal wire a bit of a moot point.

Filament wire is about the only instance when I use solid core wire, since you can twist them nice and neat, and angle them up prior to soldering. Some folks actually use a hand drill to twist them up. I haven't had a problem twisting them by hand.

I also use 2 diff colors for the wire, in the event I want to go to D.C. filaments somewhere down the road. It makes life a lot easier.

The advantage to the chassis hugging method is that the chassis itself acts as a bit of a killing field for A.C. signals. I've seen this in most Marshalls that I've peeked inside.

One other thing that a lot of homebrewers overlook - you don't want to twist the wires and then have a HUGE open loop at the socket - that potentially can create a big A.C. field.

Here's a couple of pics from a Frankenstein build that I did last year. Back then, I was into red and green for my filament wires

[sjhusting]

Last couple of builds I've tried this way of wiring the sockets -

http://www.freewebs.com/valvewizard/heater.html (look down at the bottom)

to avoid those big loops. I haven't decided whether or not I like it, but it sure looks better for those tiny noval sockets

steven

[JohnnyCrash]

Originally Posted by 11 Gauge

My favorite method is a little more time consuming, but is a clean, solid method, IMO. I use nice high grade machine bolts and nuts with a split washer, and a dab of Loctite. That way, you don't need to take a drill to the chassis to replace a socket, the bolts look clean, and they'll never come loose. You can get carbon steel, cad coated, whatever floats your boat.

I've just been using locking washers, but I've got plenty of Loctite so perhaps I'll start using Loctite.

Rivets sound like a pain - plus as you mentioned corrosion and future drill outs... I had to drill out rivets in an old '60s EL84 powered PA. What a pain that was.

[kingofdogs1950]

After reading this thread about heater wires I wondered if the hum in my Allen 5F1+ might be heater related. Easy to check since I've never bought/built a cab. So, flip the chassis over and inspect the heater wires and input leads. Hummm... Everything 'looks' ok but I bent the heater wires over toward the chassis and further away from inputs. Whoa... Background hum is now quite low and does not get louder with volume settings. Still get single coil hum of course. I may re-wire the heater wires to put them even further from the inputs.


Mark


Picture taken before I moved the heater wires. The black shielded inputs look like they are right under the heaters but are actually about 3/4" away. Now the heaters are about 1 1/2" away from the shielded inputs.

[JohnnyCrash]

Originally Posted by kingofdogs1950

After reading this thread about heater wires I wondered if the hum in my Allen 5F1+ might be heater related. Easy to check since I've never bought/built a cab. So, flip the chassis over and inspect the heater wires and input leads. Hummm... Everything 'looks' ok but I bent the heater wires over toward the chassis and further away from inputs. Whoa... Background hum is now quite low and does not get louder with volume settings. Still get single coil hum of course. I may re-wire the heater wires to put them even further from the inputs.


Mark


Picture taken before I moved the heater wires. The black shielded inputs look like they are right under the heaters but are actually about 3/4" away. Now the heaters are about 1 1/2" away from the shielded inputs.

Distance, twists, and putting them against the chassis does help remove noise.

Your build looks pretty clean inside. Nice job!