new tubes

[ALBATROS1234]

i got in my set of power tubes today. each one is labeled with a number and a "w". i am sure this is some form of testing on a tube tester but i dont know what the numbers mean.i have heard of testing emission which i think is "kathode " emission. 2 have the same number i assume this means they are a matched pair. i dont know if this is the right place to post but i didnt see a section for general tube questions sorry if it is misplaced. thanks in advance for helping a poor tube newbie (tewbie?)

[shooter]

I liked working on Raytheon amps, the one I fixed used a TWTube

one of the fun parts is spec'in things, like tubes.  if you're doing fixed bias, give each a 1ohm matched R, do the math, swap til you have twins

[kagliostro]

On 6005 (6AQ5) tubes W means military grade tube (6005W)

I don't  know if for 12AQ5 exist a similar designation

Franco

[ALBATROS1234]

Ok so the number is emission and the w could mean military? Ok so it's not just my ignorance. Maybe I can try to contact the seller and see if he has a clue. I thought these guys might be fun to play with being they were so cheap and the tube manual even says they are equal to a 6v6 although they may have a slightly different tone. We shall see.

[kagliostro]

12AQ5 ..... I think that the difference in tone respect 6V6 tubes is present when the 6V6 is feed with a B+ higher than 250V that is the max voltage compatible with 12AQ5 because of the smaller envelope


Franco

[ALBATROS1234]

2one thing I noticed is the plate resistance is different . These say 1970 so if I am correct I may be able to use my universal output tr which has a tap for 2000. You are supposed to try and get close right?

[PRR]

The "W" is hand printed; not a military designation.

The numbers relate to some specific tube tester but only the seller knows which one.

It is remotely possible the box markings were done long ago and the tubes inside are not the ones tested.

I would just use them. A 12AQ5 amp is not a high-strung sensitive thing.

[chockablock]

You can buy exactly the same thing from Svetlana for 2 USD.


"Its maximum plate/screen voltage and dissipation ratings are actually slightly higher than a 6AQ5"

6п1п-ев mil spec, rugged, made in USSR - Leningrad.

[kagliostro]

6P1P is a 9 pin tube 12AQ5 (as 6AQ5) is a 7 pin tube

http://www.mif.pg.gda.pl/homepages/frank/sheets/079/1/12AQ5.pdf

I'll not excess the max voltage stated on datasheet more of 50v

Franco

[chockablock]

Hmmm the only decent 7 pin power output valves were made by GEC.
Loads more gain, a lot less pain.

All that other 7 pin stuff made by Mullard and their ilk reminds me of "chocolate" and "teapots".
Too small, too old, too inefficient.

[ALBATROS1234]

thanks guys i got them 2 bucks a piece the are similar to 6v6 except for max voltage is 275v on paper instead of 350 of 6v6. it is just a 12v heater 6aq5 which is referenced in my rca manual under 6v6. it says refer to type 6aq5 for plate characteristic curves and it says under 6v6 and 6aq5 that they are equivalent in performance. the main differences i can see are the max voltage, pin/socket config and the ones i got are 1/10 the price for nos tubes. hopefully they have a unique character to the tone which is another reason i used oddball tubes. i felt for $10 i now have 5 output tubes to experiment with. thanks for interest.

[DummyLoad]

thanks guys i got them 2 bucks a piece the are similar to 6v6 except for max voltage is 275v on paper instead of 350 of 6v6. it is just a 12v heater 6aq5 which is referenced in my rca manual under 6v6. it says refer to type 6aq5 for plate characteristic curves and it says under 6v6 and 6aq5 that they are equivalent in performance. the main differences i can see are the max voltage, pin/socket config and the ones i got are 1/10 the price for nos tubes. hopefully they have a unique character to the tone which is another reason i used oddball tubes. i felt for $10 i now have 5 output tubes to experiment with. thanks for interest.

fun tubes and they sound really good when matched to the load correctly. bogen pushed them reliably with over 300V to the plates. my favorite spin is the black-plate GE 5-star 6005 variant.


--pete

[ALBATROS1234]

built the basic power supply today i got 285vdc to play with. i am using a 150va control trannie again because they are free. at first i used the 230vac tap and got 325 after 1.41 from the ss bridge. so i went with the 208vac tap and got the 285vdc after filtering. i have 5 tubes so maybe i can try the 325vdc and see if it blows a single tube. if so im only out $2 and still have 2 more pair.

[DummyLoad]

run with 325V  click below: 6005 in P-P driving a 10K a-a load. see attached PDF.


couple of folks here have built it and love it.


--pete