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In the Forum: Audio For Dummies ™
In the Thread: Get, or made up a tube tester, it’s necessary
Post Subject: Ok, let have tube testing fun.Posted by Romy the Cat on: 1/10/2007

Jim, I have sent you the tubes – it might be an interesting journey.

I send you:

1) 6C33C that was working with both cathodes approximately a year. It is not dead year but it is deep into retirement age. Run it at 220V and 200-250mA full-tube, or around 135-150mA if you use a single cathode. It might need bais from minus 65V to minus 110V on grid for the full curent.

2) 6C33C new. It is brand new tube, never works. Market with word “new”. Be advised that since it is “random” 6C33C it might not necessary push more current at the given bias then the use tube. Still, most likely it will need to close the tube more to give the necessary current. I did not measure it.

3) 6E5P, new. This is the Milq’s driver. Take a look what it is. Use it at 180V-200V and ~15-20mA. It will be around -3.4V in grid

4) 6E5P, heavily used, it could be easily spotted as its walls looks like after Hiroshima.

5) A kinky 6E6P-DR (it is shorter and has a gold string inside). It is an equivalent of 6E5P, the same constriction, only with “western” pins layout. This tube was designed to meet military specification and made with expensive materials and to very high QA specs.  I use it in the Super Milq HF channel. The tube that you got is very fresh and might be conceded as “new”. It has “brownish” wall but it is not the use of the tube in the field. All “DR” tubes were pre-burned for 200 hours in the plant and then were retested before they ever left the manufacturing facility. Use the 5E6P-DR in the same way as the 6E5P.

Everything it very straightforward with those tube tubes. If you never dealt with 6C33C then be advised that there is not such a thing as too mach to heat the tube. If you look on-line or talk with people then you might see that the Morons complain that 6C33C has tendency to overheat anode with fixed bias. It is incorrect. The tube in order to care power should be really hot, deep hot. Do not give to her more then 30W before first 15 minutes, more then 45W before 30 minutes. After one hour of heating you might dissipate on it 55-60W and the tube will do perfectly fine. I made Milq to have 2 min delay before I do B+ do not stress the amps with high signal during the first half hour-45 min. Well, the amp sound not good in beginning anyhow…


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