[mab1376]

Pulled out the old MK IV SE and this is still my favorite tube combo.

 

[Cognomen]

Pulled out the old MK IV SE and this is still my favorite tube combo.

 

[Cognomen]

I am wondering about a tube for sale on eBay, 6N6P-T. What does the suffix mean and what could it mean for audio? I've queried the web and saw it could mean it is a Transmission Tube or a Frequency Carrier Tube. I don't know what that means. Could T also mean it's a Thorium tube? It's expensive and it seems the vendor has not sold any.

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313&_nkw=6n6P-T&_sacat=0

 

[barbazz]

According to a Russian audio forum (https://forum.vegalab.ru/showthread.php?t=61505&page=257&p=2357037&viewfull=1#post2357037) the "T" might stand for "Titanium" and the tubes were used in aircraft radio equipment.

But even the author seems to be not completely sure about it: "If so, I got some information for you, I’ll make a reservation as to how objective or reliable it is, I don’t know. 6N6P-T-these lamps were once used on aircraft in radio equipment, a T-titanium anode, possibly in order to reduce weight, but I personally believe, because military acceptance means: the production time is longer, increased resistance to maximum permissible parameters, resistance to radiation is not excluded and the conclusions may be nickel-plated (shiny) to prevent oxidation over time." (Google translation of the post)

 

[mab1376]

According to a Russian audio forum (https://forum.vegalab.ru/showthread.php?t=61505&page=257&p=2357037&viewfull=1#post2357037) the "T" might stand for "Titanium" and the tubes were used in aircraft radio equipment.

But even the author seems to be not completely sure about it: "If so, I got some information for you, I’ll make a reservation as to how objective or reliable it is, I don’t know. 6N6P-T-these lamps were once used on aircraft in radio equipment, a T-titanium anode, possibly in order to reduce weight, but I personally believe, because military acceptance means: the production time is longer, increased resistance to maximum permissible parameters, resistance to radiation is not excluded and the conclusions may be nickel-plated (shiny) to prevent oxidation over time." (Google translation of the post)

Maybe it's the variant designed to be used as logic gates in old computer systems. I know there is a 6n6p designed for this frequent "on/off" type operation, but I don't know the designation.

 

[Cognomen]

Maybe it's the variant designed to be used as logic gates in old computer systems. I know there is a 6n6p designed for this frequent "on/off" type operation, but I don't know the designation.

I have read on www that 6n6p-i is an impulse tube that was used in rocket computers.

 

[Cognomen]

According to a Russian audio forum (https://forum.vegalab.ru/showthread.php?t=61505&page=257&p=2357037&viewfull=1#post2357037) the "T" might stand for "Titanium" and the tubes were used in aircraft radio equipment.

But even the author seems to be not completely sure about it: "If so, I got some information for you, I’ll make a reservation as to how objective or reliable it is, I don’t know. 6N6P-T-these lamps were once used on aircraft in radio equipment, a T-titanium anode, possibly in order to reduce weight, but I personally believe, because military acceptance means: the production time is longer, increased resistance to maximum permissible parameters, resistance to radiation is not excluded and the conclusions may be nickel-plated (shiny) to prevent oxidation over time." (Google translation of the post)

Thank you for finding that and translating it. It's another possibility that does not feel definitive such as the sources I saw thinking it might be a Transmission tube or Frequency Carrier tube. Because some tubes have thorium filaments and T represents thorium on the periodic table of elements, I wondered if it could be a thorium tube. Ti represents Titanium. While both metals begin with a T in Russian, the online translation for transmission that I saw did not but that does not rule out the possibility of a synonym beginning with T.

 

[mordy]

Might be 6n6p-i

You probably mean the 6N6P-IR tube which was made for intermittent operation. If I remember correctly the stated lifespan of this tube was only 500 hours, but I am sure that referred to military conditions. Such tubes (which i have) should last much longer when used in headphone amps.

 

[barbazz]

Thank you for finding that and translating it. It's another possibility that does not feel definitive such as the sources I saw thinking it might be a Transmission tube or Frequency Carrier tube. Because some tubes have thorium filaments and T represents thorium on the periodic table of elements, I wondered if it could be a thorium tube. Ti represents Titanium. While both metals begin with a T in Russian, the online translation for transmission that I saw did not but that does not rule out the possibility of a synonym beginning with T.

Well, it seems that both of us were completely wrong. Found this article (https://elektrouzel.ru/instrumentat...,91-samopisec-tipa-ds1-dsr1-ds1-t-dsr1-t.html) that finally explains the meaning of the "T". It stands for "Tropical" and it's apllied to tubes that can widstand ambient temperatures from 5 to 55°С and relative humidity up to 95%.

 

[mordy]

Well, it seems that both of us were completely wrong. Found this article (https://elektrouzel.ru/instrumentat...,91-samopisec-tipa-ds1-dsr1-ds1-t-dsr1-t.html) that finally explains the meaning of the "T". It stands for "Tropical" and it's apllied to tubes that can widstand ambient temperatures from 5 to 55°С and relative humidity up to 95%.

Seems to me that most any tube could withstand these conditions... After all, once the tube is turned on, it will heat up to anywhere between 35C to 120C or more, depending on the tube.
Don't know how the relative humidity affects the tube.

 

[Cognomen]

You probably mean the 6N6P-IR tube which was made for intermittent operation. If I remember correctly the stated lifespan of this tube was only 500 hours, but I am sure that referred to military conditions. Such tubes (which i have) should last much longer when used in headphone amps.

6N6P-I and 6N6P-IR are both on ebay. I believe I means impulse and R long durability with military applications rating for the 6N6P-I 500 hours and the 6N6P-IR for 5,000 hours.

 

[barbazz]

Seems to me that most any tube could withstand these conditions... After all, once the tube is turned on, it will heat up to anywhere between 35C to 120C or more, depending on the tube.
Don't know how the relative humidity affects the tube.

Yes, that makes sense. I think those specs are related to the original device described in the page (some sort of temperature/humidity recorder device?). Nevertheless, later in the same page there's a table describing the schematics of a "electronic amplifier" and one of the components is a 6Н6П-Т tube. The column reads "Tropical performance".

Did some more digging about these "tropical" tubes and found an interesting discussion about it. There's a 1963 reference book called "Generator and modulator lamps" by Bondarenko V.I. that describes the "T" tubes as "with increased dielectric strength" (https://forum.datagor.ru/uploads/monthly_10_2011/post-2776-1319195029.jpg). This makes sense as tubes will have to work in conditions of overheating and humidity - up to condensation (and the breakdown voltage of the tubes will drop when overheated).

Take all this with a pinch of salt, as I cannot read Russian, and I'm relying on Google Translator and Lens.

 

[mordy]

Well, it seems that both of us were completely wrong. Found this article (https://elektrouzel.ru/instrumentat...,91-samopisec-tipa-ds1-dsr1-ds1-t-dsr1-t.html) that finally explains the meaning of the "T". It stands for "Tropical" and it's apllied to tubes that can widstand ambient temperatures from 5 to 55°С and relative humidity up to 95%.

I contacted a Russian tube amp designer that I have been in contact with and asked what the T designation means.
Here is his answer:

The letter "T" stands for thermal stability. Such tubes are designed to work in high temperature conditions, for example in deep wells.

 

[dany9107]

Hi guys I bought these power tubes for my Little Dot Mk3. Are they okay? My old tubes were now worn out.

https://www.ebay.it/itm/32241512181...tiLC9dgUGAnB2Y7I+Ztc86WzQ=|tkp:Bk9SR4z3gb_KYQ

 

[mordy]

Hi guys I bought these power tubes for my Little Dot Mk3. Are they okay? My old tubes were now worn out.

https://www.ebay.it/itm/322415121810?hash=item4b11705592:g:kmYAAOSw241YmHXr&amdata=enc:AQAHAAAAoP4531MxBW+OKuNRHaBD8VHNBASjeAxKItWJsAL+VXQeOD1bTyeL4ImH8o1CLfMyQ4wJEQFhe+dc4IF0y5xHN7AcDKOOwsQDxD18yjoZ+Xz8zthH/1LK2O6CZ89CEL9V/ezTyLK6+idIyBx7R5cD5BCmdy7YO8vFJNR8pV5fWiJfiCD0S2UkvLwxy+MS8htiLC9dgUGAnB2Y7I+Ztc86WzQ=|tkp:Bk9SR4z3gb_KYQ

Should be just fine - no problems and perhaps you will like them better than the original ones.