Mind-Blown: Orange Drops have Polarity?

[bal704]

Thanks for the tip!

[R.G.]

I think you should add HiFi amp tinkerers. IMO guitar amp builders (usually) tend to be quite grounded in regards to perceiving circuit changes.

Hence my use of the word "often". My impression is that most guitar amp builders are subsets of the species "human"; the perception traps seem to be common to humans from what little psych stuff I've read.

It's not that a human won't do their best to be objective, and sometimes achieve it. It's just that being human means you have certain forts and foibles, and the is-it-better-if-I-changed-it situation is one of the foibles.

Any component change may have three outcomes: it can sound better, it can sound worse, or not do much at all. "Better" can become a very elusive thing to get a handle on.

It's just something to be aware of. If you can measure something by means other than your ears, it's real. If you can only measure something with your ears, it *may be* real.

I've build 3 dumble clones [...] The noise level in the clean channel in those three Dumble clones is so low, that i sometimes wonder if an amp is actually switched on from standby. [...] more importantly the amps sound great. Take a look at a gut shot of any Two Rock amp and you'll that the mark all signal caps as well.

I don't doubt a bit of it. I'm sure the amps are very quiet, and sound good, and that other amp builders are firm believers in the "outer foil" theory too.

As I noted, there are certain situations where the "outer foil" theory can work. But those situations are dependent on the rest of the circuit being just so. I guess, being scrupulously fair, if I can posit situations where it would help, then if you always observe one orientation, you'll always have it right when the situation comes up. Kind of like saying "never waste a drop of water - you may need it." That will certainly come in handy in some situations, so if you always do it, you're OK when the need comes up. And most of the time, it won't matter, so you're not worse off.

Just my two cents.

[martin manning]

Yes you can,

1. make up a short cable with a 1/4 jack Plug on one end and two croc clips on the other end.
2. Plug it into an amp volume turned up a bit and connect the cap between the croc clips, hold the cap body , not touching any metal parts, it will hum.
3 Now flip the cap around on the croc clips...

Adding a DPDT switch is a good idea so you can quickly flip the orientation. If you arrange it properly the switch bat can be made to point to the outer foil end. To RG's point, if you do this test with the caps you are using and it doesn't make any difference, then you know it doesn't make any difference.

[guitarmike2107]

That brings back memories, here Gabi shows how to make a tester, this was all the rage on 18watt.com a few years ago

https://www.youtube.com/watch?v=VP6ZIHXq6Yg

[JD0x0]

Did some orientation today simply using a 1/4'' cable and holding the leads to the cable. (1 lead to Tip/sleeve each)

As long as you touch any metal, it works really great. Really easy to tell. One way has a deep hum that's very apparent, the other way doesn't.

Edit: One thing I'd like to confirm/clear up, though. If I mark the side of the cap that hums less, when connected to the tip of the input jack, that indicats that side is the 'outer foil' correct? Or is it when the lead is connected to the tip, and hums more, that side is the outer foil?

[martin manning]

The outer foil lead is the one connected to the sleeve when the hum is lowest.

[JD0x0]

The outer foil lead is the one connected to the sleeve when the hum is lowest.

Thanks, I figured I had it backwards. So I marked the non-foil side. No big deal for me.

[TUBEDUDE]

Seems to.make sense, but may turn out to be a distinction without a difference. Tests in circuit would hold more validity than.laying the cap on the bench with no ground reference.

[martin manning]

Seems to.make sense, but may turn out to be a distinction without a difference. Tests in circuit would hold more validity than.laying the cap on the bench with no ground reference.

The amp's input ground is the ground reference, and it is in-circuit. Probably in the worst possible place, though.

[bluesfendermanblues]

..........I don't doubt a bit of it. I'm sure the amps are very quiet, and sound good, and that other amp builders are firm believers in the "outer foil" theory too.

As I noted, there are certain situations where the "outer foil" theory can work. But those situations are dependent on the rest of the circuit being just so. I guess, being scrupulously fair, if I can posit situations where it would help, then if you always observe one orientation, you'll always have it right when the situation comes up. Kind of like saying "never waste a drop of water - you may need it." That will certainly come in handy in some situations, so if you always do it, you're OK when the need comes up. And most of the time, it won't matter, so you're not worse off.

Just my two cents.

Some people like to study, discuss and evaluate theories other people simply grab a soldering iron and keep modding, until it sounds great.

I understand your points of view as a quest for rationality and for a lesser amount of subjective personal perception - and thats fine. However, rationality alone will not produce a Stradivarius. Besides science and rationality, we need that little extra 'something else'.

The great personal ear opener for me was studying, Dumble's building style in regards to lead dress, component and cable choice etc. etc. the impact of small adjustments

Example: In terms of lead dress to making sure the anode and cathode wires from the turrent board to the preamp tube sockets, are run close together for a couple of inches, close to the chassis. At the same time paying close attention to separating the grid wires from the anode/cathode, by floated the grid above the anode and cathode wires via terminal strips. The overtones becomes clearer. Why? because of magnetic field strays and reduction of oscillation. Dumble knows his science, but he's also used his ear to arrive at this practice.

Prior to discovering Dumble's amps and attempting to build clones hereof, I had been building and modding tube amps for 20 years. So I wasn't easily convinced about that stuff I read about in the Dumble section of this forum, but if you dive in, you will discover a lot of small things, that may seem a little far fetched at first, but IME the magic lies in the small details.

That being said, the sound of guitar speakers is by far the most important single component of an amps given sound. Many of us should probably spend more time finding the right speakers for the tone we seek before we start soldering.

With respect - all the best.

[Reeltarded]

if you do this test with the caps you are using and it doesn't make any difference, then you know it doesn't make any difference.

lmfao

[Malcolm Irving]

...
Example: In terms of lead dress to making sure the anode and cathode wires from the turrent board to the preamp tube sockets, are run close together for a couple of inches, close to the chassis. At the same time paying close attention to separating the grid wires from the anode/cathode, by floated the grid above the anode and cathode wires via terminal strips. The overtones becomes clearer. Why? because of magnetic field strays and reduction of oscillation.....

Interesting, but wouldn't it be better to keep the grid wire close to the chassis and float the anode and cathode wires above and close together?
The grid wire is more sensitive to picking up unwanted fields and would be better screened if it was close to the chassis. The anode and cathode wires have relatively low impedance to AC ground already and wouldn't benefit much from being close to the chassis.

On the other hand, maybe the grid wire picking up a field is 'wanted' rather than 'unwanted'. Screening the grid wire would minimise buzz and hum but would also maximize stability. There is a theory that some classic amps get their 'magic' tone by being close to instability.

[R.G.]

Some people like to study, discuss and evaluate theories other people simply grab a soldering iron and keep modding, until it sounds great.

Yes - and simply replacing parts until it sounds great is a valid way to explore what some versions of operations research refer to as the possibility space.

The problem with that is that it takes a long time, and unless you understand why replacing that last part made it sound 14.3% more great, you have real problems figuring out what to do next time. Then there is the issue of what "great" means.

I understand your points of view as a quest for rationality and for a lesser amount of subjective personal perception - and thats fine.

Well, maybe tangentially. It's actually a quest for understanding, not for rationality over subjectivity.

I find that if I understand something, I can either do the same thing again, or do more or less of the same thing next time, as I choose. I find that "great" is a multivariate quantity. "Great" in an amp is composed of a whole lot of things - lead routing, grounding, layout, socket metallurgy, flux composition and whether it's removed or not, humidity of the air, dust concentration and conductivity at the humidity level, shape of the Faraday cage of the chassis enclosing the wiring, tube source, tube internal materials, vacuum level - the list gets long, and we haven't even got to the part where we swap capacitor orientation ( or resistor orientation! ) yet.

Back at that "possibility space" and exploration. Without an understanding of the underlying processes, you're at the mercy of getting trapped in a local minimum - it sounds a little greater having tweaked this and every tweak you do sounds a little less great. Problem is, those little less greats prevent you from going and exploring way over there, where an even greater greatness waits.

If you're truly doing a random search, you will get out of the local minimum and jump to other random areas in the possibility space, and you at least have a chance to find the greater great. A great deal of that quest for rationality has gone into finding better ways to explore what's possible. Pruning off what's not possible is a biggie - that's what a lot of modern chess-playing programs use as a first step. Then introducing some degree of randomness, but not pure random easter-egging seems to help. This is the approach of genetic search algorithms, which seem to do a GREAT job of finding "great" maxima, given enough iterations. It's that "given enough iterations" that is the problem with genetic algorithms.

However, rationality alone will not produce a Stradivarius

.
Good point. Stradivarius himself didn't always produce a Stradivarius. I bet he'd have paid all he had to truly understand what made his best violins better than the just good ones. And Stradivarius violins, the surviving examples, do vary.

A guy at Texas A&M found one of the variables that prevent modern violin makers from making a Stradivarius-equivalent, and it's something that Stradivarius didn't know. In Stradivarius' time, the wood for all kinds of uses, including violin-making, was cut in the mountains and floated down river to towns at the shore. They rested there in the water until needed to be cut up and sold. The TAMU guy, Joseph Nagyvary, decided that the long flotation might have affected the wood. That seems to have been part of the "magic".
See http://today.tamu.edu/2009/01/22/secret ... -revealed/

Who knew that "cut a big, straight spruce tree, float it down to the harbor and leave it for years before drying it and making violins out of it" was part of the recipe?

Besides science and rationality, we need that little extra 'something else'.

I agree. It does seem that the human psyche has a built-in need for a bit of magic. It's built into our humanness.

But I find it odd that once something has been understood well enough to be produced whenever needed that the greater 'we' then decides there is no longer magic there. Humans seem disappointed upon finding out that something **amazing** is just a logical result of scientific principles. Nobody is much amazed by cell phones any more. But if you had told someone from 50 years ago that nearly everyone on the planet would carry a shirt pocket sized device that let them phone anyone, they would have called you a liar, and if you produced one, a magician.

The best working definition of "magic" is "any technology you do not yet understand".

So yes - I am on a quest, but it's a quest for being able to produce magic any time I want, because I understand it.

The great personal ear opener for me was studying, Dumble's building style in regards to lead dress, component and cable choice etc. etc. the impact of small adjustments

That's very reasonable - tiny adjustments do make big differences sometimes if you happen to be near some "greatness" maximum in the possibility space. Other times, no big thing happens. Knowing *what* to change a tiny amount, that's the secret.

if you dive in, you will discover a lot of small things, that may seem a little far fetched at first, but IME the magic lies in the small details.

I agree - the devil is always in the details - but I really, really want to know which details matter, which ones don't, and which ones matter versus which ones MATTER, and how much. Knowing why they matter is the first step.

That being said, the sound of guitar speakers is by far the most important single component of an amps given sound. Many of us should probably spend more time finding the right speakers for the tone we seek before we start soldering.

And I could not agree more with this.

Also with respect - we're in violent agreement.

[bluesfendermanblues]

Hi R.G.

Even though we might have slightly different views, we are kindred spirits. I'm sure we could have many fruitfull and interesting conversations.

Great link regarding Stradivarious. I was in Cremona, Italy in October and went to the very interesting Violin museum. Great place for a music buff.:

By the way, in the article you linked to, there was a great quote :

"When you use science to prove a point, it often de-mystifies the glory of the legendary masters, and for that reason, there has been some reluctance to get to the truth. To have undeniable scientific proof that supports my work is very satisfying"


The article is very interesting in regards to the finding that stratevarius and other builder used chemical treatment of their wood - maybe in order to prevent worms in the wood - that has an impact on how the violins sound. if the people at Texas A&M could come up with a recipe, I'd be the first to try it out for treament of tweed pine cabs and guitar bodies.

With respect.

[TUBEDUDE]

There is a violin maker in Collingswood NJ that discovered the pores in the Strad's and Guanieri's were open, making the top resonate across a wider spectrum. A lower,broader Q if you will. He soaked wood immediately after harvest to wash out the sap before it could harden. I think he said it took 6 months or more. Then he made some instruments, and they were.so good Itzhak Perlman bought several, and took them on tour, locking the Strad in a safe place. He said they had 95% of the magic in his Stradivari's. This was like 1975. The luthier's day job gave him access to an electron microscope allowing him to make the discovery.