wiring heaters...ugh

[PCollen]

The whole twisted over the top thing is overrated. It looks slick, but it doesn't seem to do dick as far as lowering noise imho.

LMAO...I love a direct, definitive response.

[Andy Le Blanc]

So... whats a good way (diy) to measure the noise?

I see different dress based on the build/mfg or meeting a noise "standard".

Whats the "standard"?

[Colossal]

So... whats a good way (diy) to measure the noise?

I see different dress based on the build/mfg or meeting a noise "standard".

Whats the "standard"?

Hi Andy,

I don't know if there is a standard on the guitar amp side. I would guess that for most it is largely 0 or 1: whether the amp buzzes due to poor heater wiring technique or it is quiet...that's probably "the standard" I would also suppose that any true standard in terms of a means of measurement would come from the hifi industry where every last means of noise input is scrutinized and removed.

We see everything from Ken Fischer's "lazy loop" heater wiring which is copied verbatim in true clones, to Merlin's "over the top" method to the Metro-amp/Marshall "along the side of the socket" method to the SLO buss-wire method. Lots of means to an end, but as long as the end is dead quiet, that passes muster. Not very quantifiable though save for the end result of listening.

[PCollen]

So... whats a good way (diy) to measure the noise?

I see different dress based on the build/mfg or meeting a noise "standard".

Whats the "standard"?

Hi Andy,

I don't know if there is a standard on the guitar amp side. I would guess that for most it is largely 0 or 1: whether the amp buzzes due to poor heater wiring technique or it is quiet...that's probably "the standard" I would also suppose that any true standard in terms of a means of measurement would come from the hifi industry where every last means of noise input is scrutinized and removed.

We see everything from Ken Fischer's "lazy loop" heater wiring which is copied verbatim in true clones, to Merlin's "over the top" method to the Metro-amp/Marshall "along the side of the socket" method to the SLO buss-wire method. Lots of means to an end, but as long as the end is dead quiet, that passes muster. Not very quantifiable though save for the end result of listening.

It's quite common to find the HEURISTIC METHOD being employed to resolve these type of issues.

[amplifiednation]

So I dont have to use 18g stranded wire? That's good because I couldn't get two sets of stands in the socket terminals. Great discussion for my morning coffee !

[Phil_S]

For noval sockets, a pair of #18 stranded is very challenging. Try using solid, feeding both at the same time. Whether you "have to" use #18, that's a debate I'm not getting into. Others know more about this than me.

[surfsup]

Why don't tube manufacturers simply standardize on putting heater pins next to each other. It would GREATLY simplify things...

signal wires away from heater wires

Am I correct in saying the main signal runs are the cathode and grid. The plate runs are not a big worry...?

Also, how much distance is enough to say the wires are "away" from the heaters? 1/4 inch? 1/2 inch? is it a gauge thing?

[David Root]

I twist tightly by hand with the other end in a vise. I use 16 ga teflon/stranded for power tubes and 20 ga ditto for preamp tubes.

I cut the U- shape after winding and only unwind enough to connect to the sockets, I normally use Belton Celanex octal sockets which have two holes in each pin, each hole comfortably takes a carefully tinned 16 ga wire. In the example below I used some NOS Omron Japan black phenolics with the same size holes. (BTW these are only $1.75 ea. from Steve at Apex Jr.)

20 ga seems to fit most noval sockets. I route them all up in the air Dumble style, and I've never had a hum problem.

In the amp below, for some reason I wound the noval sockets opposite twist to the octals, which looks a bit odd but didn't affect performance.

[Alexo]

I twist tightly by hand with the other end in a vise. I use 16 ga teflon/stranded for power tubes and 20 ga ditto for preamp tubes.

I cut the U- shape after winding and only unwind enough to connect to the sockets, I use Belton Celanex octal sockets which have two holes in each pin, each hole comfortably takes a carefully tinned 16 ga wire.

20 ga seems to fit most noval sockets. I route them all up in the air Dumble style, and I've never had a hum problem.

In the amp below, for some reason I wound the noval sockets opposite twist to the octals, which looks a bit odd but didn't affect performance.

Finally someone else who winds them up in the air!

I am a PTP-er and flying heaters is the only way to go for me. 20ga solid core, by hand - never had any luck with the drill method...

[David Root]

I think the solid wire holds the twist better but I worry about metal fatigue failure in this application.

[Structo]

I used to worry about if I was running heavy enough gauge wire on the heaters.

After struggling with 18 gauge I gave up on it and installed 20 gauge.
I suppose I could have used it on the power tubes then stepped down to 20 ga on the preamp tubes.

Looking at the AWG tables you will see that 20 gauge can handle 11 amps.

I calculate my 100 watt ODS amp has 4.5 amps of heater current.
Since it is less than half the capacity of 20 gauge (11 amps) I feel secure that it will not over heat or cause problems, especially since it is mil spec Teflon insulated silver plated stranded wire.

[Phil_S]

Careful about those AWG tables and current capacity. I was fortunate to have some contact with a couple of Licensed Master Electricians at another forum. There is something involved in understanding those ratings that I'm not qualified to explain. Basically, it has to do with whether the wire is in "open air" or "enclosed". I think an amp chassis qualifies as enclosed and those ratings are for open air. This means the current carrying capacity isn't 11A or whatever for the given gauge the way we use it. On the other hand, our wire runs are generally quite short (a few inches -- not the individual segments but the whole string), which works in our favor.

I have used 22, 20, and 18 under different circumstances and without a second thought. Remember, the last bit of wire in the string only has to carry enough current for the last tube, for a 12AX7 that's 0.3A, which isn't very much. For the first tube, the wire has to carry the whole load of all the filaments, depending on the amp, probably 2-4A. This probably requires something larger than #22.

[rp]

I use 16 ga teflon/stranded for power tubes and 20 ga ditto for preamp tubes.

Never occurred to me to do this. Thanks for the duh slap.

After struggling with 18 gauge I gave up on it and installed 20 gauge. I suppose I could have used it on the power tubes then stepped down to 20 ga on the preamp tubes. Looking at the AWG tables you will see that 20 gauge can handle 11 amps.

Been years since I looked inside an old Marshall but I remember pretty thin pvc heater wire - same as the hook up if I recall correctly. They've survived the decades well enough. Like Tom I've been using teflon stranded 20 as I got tired of trying to get 2 18s in a noval and figured the 600V teflon rated wire should be fine.

Drill works great. I make like 8' and have it for a few builds.

But let's get to what really matters: what's everyone's fave color combo

[iknowjohnny]

Too long to read the whole thread, so someone may have already asked, but if there is even a slight bit of truth about the notion that heaters must be twisted, then why does the solid buss ala soldono work? The way i see it, if soldono's aren't noisy then the need for twisting is a wives tale. Tell me why i'm worng? I really don't get it. Do soldonos hum a lot?

[Phil_S]

There are all sorts of styles that work: twisted (air or chassis), zip/lamp cord, buss, lazy loop, no loop at all....

The trick is to understand what causes hum and do it in a way that is hum canceling. IMO, tightly twisted is one of the easier implementations and that's probably why you see so much of it in hand built amps.