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6Н6П vs 6Н6П-И (gold grid etc claims ? )

So I wonder what is the difference?
In Ebay for example I read all kinds of claims , some add a phrase GOLD GRID , some don't etc etc.
Could you please clarify me , maybe someone here knows what this is all about, did some of them really had golden plated grids and others didn't or all of them had or what ?


thank you.
 
According to Sovtek and other Russian manufacturers 6Н6П-И does not exist in real life, just the 6Н6П.
Gold grids are no advantage.They are almost an ECC99 equivalent but have combined heaters, unlike ECC83.
No. Defference is in some parameters, and as mentioned before, "-И" stands for "pulsed". Here is original datasheet (in russian, inside datasheet is screenshot, and no troubles with encoding):
''Èñòîê2''. Ðàäèîëàìïû - ïî÷òîé. Ïàðàìåòðû è õàðàêòåðèñòèêè 6Í6Ï-È
 

mcl2k6

Member
2013-08-23 10:38 pm
The pulsed version has higher cathode capacity (more powerful heater) therefore I presume it can provide more current peaks. Apart from this, it's of tighter tolerances. I've used them both as drivers in my 6P36S amp, with good results. Gold grids and other marketing stuff like it is mostly snake oil, just to increase price. My 2 cents...
Grab whichever is cheaper. Perhaps consider 6N1P too, I found it to be better in my application as driver.
 
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Gold (and other low resistance metals) are used at RF for plating to assist with the "skin effect" where electrons at high frequencies like to travel in the top layer of the conductor. Not required for audio, but do provide a consistent surface for emission/collection.

As for the difference between the two 6N6P types, I have both here and the only difference I can see is the height of the glass. The -I version is slightly shorter.

Both measure the same on my uTracer:
 

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ericj

Member
2008-12-08 10:24 pm
The pulsed version has higher cathode capacity (more powerful heater) therefore I presume it can provide more current peaks. Apart from this, it's of tighter tolerances. I've used them both as drivers in my 6P36S amp, with good results. Gold grids and other marketing stuff like it is mostly snake oil, just to increase price. My 2 cents...
Grab whichever is cheaper. Perhaps consider 6N1P too, I found it to be better in my application as driver.

The soviets DID have some cost-no-object military parts. But the russians i've talked to don't seem to buy into the gold grid rumor. Even the guys who have preamps made out of huge single-crystal jfets that are known to have more than a gram of gold in each package. And have speaker wires made from the weapons harness of a mig jet, said to be an exotic alloy.
 
rotaspec said:
Gold (and other low resistance metals) are used at RF for plating to assist with the "skin effect" where electrons at high frequencies like to travel in the top layer of the conductor.
Where skin effect is a genuine problem silver plating is used. Gold plating is used where corrosion may be a problem, and for cosmetic purposes - nothing to do with skin effect.

Incidentally, skin effect is not an electron issue but a field issue - it would apply whatever the charged particle is, or even in the hypothetical case of a continuous electrical fluid.
 

gyro

Member
2004-07-26 3:43 pm
Gold grids are nothing to do with marketing or snake oil. Remember that these tubes were never originally intended for audiophile use - they were mostly military, so audiophile snake oil and marketing just don't have any relevance at all.

The reason for plating the control grid with Gold is that it has a high work function and so is much less likely to emit electrons when heated by the closely positioned cathode. Hence the lower grid current that others have mentioned. Carbon coating is another method employed, sometimes on other grids, for the same purpose. It's a straightforward tube engineering design decision based on cathode dissipation, geometry, grid-cathode spacing, grid current requirements and other factors.

Others stating Gold plating for skin-effect reasons need to remember that Gold has a lower conductivity than Copper, so would actually worsen RF performance. Only Silver (higher conductivity than Copper) has any benefit in this context.
 
I had an email exchange with a tube engineer at New Sensor some time ago and he stated that it is just common practice to gold plate control grids on most tubes because it reduces grid current and allows for higher value grid bias resistors to be used, which reduces loading on the driving stage. All good things for audio amps.

He also stated that gold plating may be undesirable in some circumstances, like when the grid is designed to dissipate significant power. If the grid gets too hot, the gold can end up on the cathode which ruins its ability to emit electrons. I later looked at some 841s, which were designed for A2 operation and have the grid visible from outside the envelope and I did notice that they were silver in color. I have dissected several beam tubes/pentodes and I think all of them had control grids that were gold in color. The information seems to hold up, at least in the few cases that I can verify.

So from what I understand, gold grids are not snake oil at all. Just good engineering when used in the right place.
 

mcl2k6

Member
2013-08-23 10:38 pm
Perhaps you've misunderstood me a bit.
I fully understand the reasons why they've introduced gold plating for the grids, but obviously in our audio context it would count close to nothing. Sellers, though, use this as marketing catch, so they can sell more to some naive beginners.
I've seen many such guys, who thought that by buying a bunch of "gold grid" tubes, they've just built the badass amp of them all. Most of these guy haven't got any idea why they've chose those tubes, but it just must be good, because it's gold. Just like with super-duper vintage caps, made from some obscure meteorite alloy from Tunguzka, and other audiophoolies soaked with snake oil. However, until you've got such people, why not take advantage of them?!
BTW, if I'm not mistaken, some say, that the 6N6P-I was renamed 6N30P for some reason. That one sells for at least 5 times the price, because of rumors.
 
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Well, the way I understand the term "snake oil" is as a term for a product with no benefit. I was just trying to make clear that gold plated grid wires have real benefits and even some drawbacks.

I don't agree that it "counts close to nothing" in audio. Gold grids reduce grid current and allow higher value grid bias resistors. A higher value grid bias resistor will reduce the load on the driving stage and will reduce overall distortion. Imagine if you were to build a KT88 fixed-biased amp and the KT88s didn't have gold plated grids. You may have to use a 50k grid bias resistor instead of the 100k resistor called out in the spec. This would make a big difference in the driver design. This is why if you dissect common beam power tubes and power pentodes, you will almost always find a gold-plated grid. I'd venture a guess that you probably couldn't build a KT88 or similar tube to spec without a gold-plated control grid, but that'd be an uneducated guess in my case.

But I certainly agree that gold is frequently assumed to have magic properties and that sellers frequently exploit this misconception to sell product. Gold is like anything, it makes sense to use it where there are real benefits that outweigh the costs.