Author Topic: Power cords for the Blowtorch?  (Read 4123 times)

Gen. Dreedle

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Power cords for the Blowtorch?
« on: May 27, 2010, 09:16:09 AM »
I wonder if the Blowtorch would sound any better, if we stuck one of those nifty TPC-60 cords on it?

I have the cords............who has a Blowtorch? Wonder if JC will let us borrow one of his Blowtorch preamps?

Jocko
"Major Danby, sir."
"Danby. D-A-N-B-Y."
"Take him out and shoot him."
"Sir?"
"I said take him out and shoot him. Can't you hear?"

Gen. Dreedle

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Re: Power cords for the Blowtorch?
« Reply #1 on: May 27, 2010, 09:36:43 AM »
@seagreen:

Speaking of which...............you warned your buddy that I was going to contact him, right? Did he give you any sort of reply?

Jocko
"Major Danby, sir."
"Danby. D-A-N-B-Y."
"Take him out and shoot him."
"Sir?"
"I said take him out and shoot him. Can't you hear?"

seagreen

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Re: Power cords for the Blowtorch?
« Reply #2 on: May 27, 2010, 12:19:47 PM »
He be warned.

If he gives you trouble, remind him of the great wedding gift I gave him.  I don't remember what it was, but I'm sure it was great.
« Last Edit: May 27, 2010, 12:36:53 PM by seagreen »
No double blind testing was used in the making of this post.

Gen. Dreedle

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Re: Power cords for the Blowtorch?
« Reply #3 on: May 28, 2010, 06:52:17 AM »
I'll take you at your word.

Jocko
"Major Danby, sir."
"Danby. D-A-N-B-Y."
"Take him out and shoot him."
"Sir?"
"I said take him out and shoot him. Can't you hear?"

seagreen

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Re: Power cords for the Blowtorch?
« Reply #4 on: May 28, 2010, 11:00:53 AM »
I was thinking about what might make for a good power cable.

As far as power goes, I suppose the ability to pass 60 Hz up through about the 5th or 7th harmonic would be adequate.

But, then there's the rest.

Ideally the cord would be really lossy at RF.  Think of the worst dielectric at RF in the world and put that around the conductors.

Then there is the really nasty business of common mode audio frequency signals that return through the power cable.  Most equipment isn't really great with that part.  I'm not entirely sure what to do there.  Maybe a common mode choke that works at audio frequencies?  You'd have to get rid of any DC component to the incoming AC power so that you don't mess up the choke, but I suppose that isn't really hard.  Perhaps a regular tape wound toroid core could be used for something like this.  No caps to "safety ground" though...

A tank circuit resonant at 60 Hz and connected parallel to the line might be a great thing.
No double blind testing was used in the making of this post.

Gen. Dreedle

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Re: Power cords for the Blowtorch?
« Reply #5 on: May 28, 2010, 11:12:38 AM »
Anyway............back to the TPC.........

The patent isn't written in a easily accessible manner, but, I think the idea is to get the diameter of the "bundle" to be about one skin depth, at 60 Hz. Which is around 0.33" And that is what the mean diameter seems to be.

So, in theory, if you had to pass 20 Hz, you would increase the mean bundle diameter to whatever that works out to be.

I knew a guy, who used to design a lot cables. He would take a plastic fiber, and wrap wire around it. That made one conductor. He always like to call it a "flux gate". Probably a similar idea: get the mean diameter to be one skin depth, at X Hz.

For speaker cables, he would take a bunch of those conductors, and wrap them around another "flux gate". I bet the diameter of those is probably close to what 20 Hz works out to be.

I'll measure one, later today.

Jocko
"Major Danby, sir."
"Danby. D-A-N-B-Y."
"Take him out and shoot him."
"Sir?"
"I said take him out and shoot him. Can't you hear?"

Gen. Dreedle

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Re: Power cords for the Blowtorch?
« Reply #6 on: May 28, 2010, 11:16:09 AM »
The other school of thought, made popular by Dave Magnan, is to make the wire as small as possible. Everything has to ride on the surface. In addition, in his first cable, he found some stuff that had lots of resistance. (Yep, not copper. Some strange alloy.) From what I was told, Dave worked for the evil military-industrial complex, and he found that stuff surplus. Of course, he had to know where to look. That is all I know about that subject.

Jocko
"Major Danby, sir."
"Danby. D-A-N-B-Y."
"Take him out and shoot him."
"Sir?"
"I said take him out and shoot him. Can't you hear?"

seagreen

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Re: Power cords for the Blowtorch?
« Reply #7 on: May 28, 2010, 11:40:33 AM »
Patents are supposed to be unintelligible.

From the explanation I got, your analysis is correct.

Here's the thing.  It's hard to imagine that the last couple of feet of wire in the power system are making a big difference in the power availability or transmission.  But for RF and common mode audio signals, that certainly isn't the case.  The RF part is obvious (the late Bob Crump used to say that was the entire point of a specialty cable - getting rid of RF.  That and having good connectors.)  The common mode part is less obvious, but I bet is pretty important. 

Still, there's something odd with all of this.  Not that long ago I tried listening to a battery powered source running into a mains powered headphone amp.  I could hear a big difference when I switched to a TPC-60 cord on the headphone amp from any of the others I had around here.  No common mode connection involved there.  At headphone levels, everything was running class A at maybe two watts or so from the wall, so no power demand considerations.

Beats me.
No double blind testing was used in the making of this post.

Gen. Dreedle

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Re: Power cords for the Blowtorch?
« Reply #8 on: May 28, 2010, 08:19:29 PM »
I had the unfortunate experience of seeing some audio neurotic that had a power cord that was several inches, in diameter. Of course, he had to neck it down on both ends, to make it fit into a usable connector.

I don't get it, either. But both of us have used TPCs, and they do something. No idea what that punter was trying to do. As bad as his set-up was, I doubt he was capable of hearing an improvement. But I am sure he heard one.

Jocko
"Major Danby, sir."
"Danby. D-A-N-B-Y."
"Take him out and shoot him."
"Sir?"
"I said take him out and shoot him. Can't you hear?"

seagreen

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Re: Power cords for the Blowtorch?
« Reply #9 on: May 28, 2010, 08:27:40 PM »
Well, I guess his was bigger after all.
No double blind testing was used in the making of this post.

seagreen

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Re: Power cords for the Blowtorch?
« Reply #10 on: June 10, 2010, 09:19:36 AM »
I've been pondering the power cord question a lot as of late.  As in, "Just what makes for a good power cord?"

1.  You'd think that the ability to pass audio signals really well wouldn't matter.  Hopefully, common mode signals using the power system as the return are minimized by the actual equipment. Perhaps not, though.

2.  Minimize the effect of HF and above junk on the equipment power input.

3.  Passing 60 Hz and maybe up to its 10th harmonic efficiently is a good idea, too.

So, given all of that...

Why are the safety ground wires so f'ing large on many of the highly touted power cords?  You would think that they'd be the minimum size needed for safety requirements in equipment that's not double insulated.  I'd think you'd want minimum coupling between the hot/neutral and the safety ground as well as maximum inductance and resistance for the safety ground.  Wouldn't you?

Why use Teflon insulation or similar plastics?  You'd think that you'd want something that was *really* lossy at RF, wouldn't you?    Like PVC or something.  Carbon loaded PVC might be even better.  Or something like that.  If the power cable somehow could act as a dissipative 50-100 Ohm load (Romex is supposed to be that impedance) up through at least GHz, I'd think that would minimize RF ingress into the power input, and also minimize RF voltage peaks elsewhere in the power system, too.  (That gives me an idea...)

Why silver?  Or even silver plated copper?  The difference in resistivity at 600 Hz is almost nothing between those and copper.  At RF...

Why Litz wire?  You'd think that would be a *really* bad idea.

I am *sure* I'm missing something obvious.  What?

The connector aspect is something different.

No double blind testing was used in the making of this post.

Gen. Dreedle

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Re: Power cords for the Blowtorch?
« Reply #11 on: June 10, 2010, 01:30:05 PM »
Carbon-loaded, with 120 VAC? OK, for interconnects, but power cords?

Alright, OCOS made speaker cables that were carbon-loaded. Sounded pretty good.

Jocko
"Major Danby, sir."
"Danby. D-A-N-B-Y."
"Take him out and shoot him."
"Sir?"
"I said take him out and shoot him. Can't you hear?"

seagreen

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Re: Power cords for the Blowtorch?
« Reply #12 on: June 10, 2010, 02:14:45 PM »
I presumed that there'd be some actual insulation in there, too.

Whatever happened to those OCOS guys?
No double blind testing was used in the making of this post.